Entries in Recovery (7)

Monday
Feb202012

Sleep and it's Importance in Rowing

From: usrowingjrs.org

By: Steve Hargis


Take a look at the US Junior Rowing page. It is an excellent resource for those who are looking at being competitive junior rowers or coaches.

The article below is an important oversite by many athletes and coaches who tend to take this for granted. This can be a cause of Unexplained Under Performance Syndrome or over-reaching.

Why is sleep important?

Several studies have shown that individuals who engage in regular bouts of physical activity have an increased need for total sleep time and for slow-wave (Stage 3 & 4) sleep.  Repair and growth are maximized during these stages since non-growth-related metabolic activity is reduced while the pituitary releases growth hormones.

What happens if you don’t get enough sleep?

Individuals deprived of 30 hours of sleep show an 11% reduction in cardiovascular function, and those deprived of 50 hours of sleep show a 20% reduction.  Unfortunately, sleep deprivation is likely cumulative, so if an athlete needing 8 hours of sleep per night gets only 6 hours, she will see a significant degradation in performance after only 15 days.  Sleep deprivation also results in a 20% reduction in the detection/reaction response, and an even greater reduction in cognitive tasks involving learning, memory, logical reasoning and decision-making.  Finally, sleep deprivation has been associated with increased levels of depression, stress, anxiety, worry and frustration.

How much sleep do you need?

To determine how much sleep an athlete needs, ideally she would spend a week or two going to bed at a consistent time, waking up naturally without the use of an alarm, and recording how long she slept each night until she reaches a consistent number of hours.  Since this test is difficult to complete in practice (especially while in college!), answering “yes” to two or more questions on the following sleep quiz indicates a need for more sleep than you are currently getting:

• Do you frequently fall asleep if given a sleep opportunity (eg. in class, in movies, other quiet, dark environments)
• Do you usually need an alarm clock to wake you?
• Do you tend to “catch up” on sleep on the weekends?
• Once awake do you feel tired most mornings?
• Do you frequently take naps during the day?

How can you increase the quality of your sleep?

Keeping a regular sleep schedule is the most important means of improving sleep quality.  Inconsistent sleep patterns cause disruptions to one’s internal clock, and increases the amount of time it takes to fall asleep.  Once a regular bedtime has been established, adjustments to earlier or later should be limited to 30 minutes per night.  Similarly, athletes should wake up within an hour of their normal wake-up time, even on weekends.

Creating a high-quality sleep environment that is quiet, dark, cool and comfortable is also important.  Student athletes might establish a quiet policy in their suite after a certain hour, post a “Do Not Disturb Sign” on their door, or use ear plugs or a fan to mask noise.  Turning electronic devices such as clocks and computers away from the bed, using window blinds, and stuffing towels under the door to block hallway light may help create a darker environment.  Opening a window or using a fan can help to cool a room, while additional blankets can help if a room is too cold. 

Recommended

 

 
Tuesday
Dec062011

Exercise Science and Coaching: Correcting Common Misunderstandings About Endurance Exercise

By: Andrew N. Bosch, PhD
UCT/ MRC Research Unit for Exercise Science and Sports Medicine.
Department of Human Biology, University of Cape Town and Sports Science Institute of South Africa
From: International Journal of Sports Science & Coaching Volume 1 • Number 1 • 2006


Many coaches who work with endurance athletes still believe in old concepts that can no longer be considered correct. Prime amongst these are the understanding, or misunderstanding, of the concepts of maximal oxygen uptake (VO2 max), lactate threshold, training heart rate, and dehydration and fluid requirements during prolonged exercise.

Knowing the VO2 max of an athlete is not particularly useful to the coach, and the exact VO2 max value of any particular athlete can vary considerably as fitness changes. Race performance is a more useful measure on which to base training schedules.

Lactic acid production, far from being an undesirable event, is of great importance and is actually beneficial to the athlete. The lactate concentration during exercise, and the lactate turnpoint, are both widely measured. The nature of the information that these measures can provide about training and training status, however, is still based on information from the 1980s, although more current information is available and many of the original concepts have been modified.

Heart rate is often used to prescribe training intensity, but it is important to understand the limitations inherent in its use. If used correctly, it is a useful tool for the coach.
Similarly, many athletes and coaches still believe that it is necessary to maintain a high fluid intake to avoid dehydration and prevent associated collapse. These beliefs are incorrect, but modern exercise science has been able to advance the knowledge in this area and provide more accurate information.
Exercise science continues to progress and can offer much to the coach willing to accept new and changing ideas.

Key words: Anaerobic threshold; Endurance training; hydration; lactic acid; maximal oxygen uptake; training heart rate

Introduction

Sports science knowledge has progressed tremendously in the last 20 years in terms of the understanding of many of the underlying concepts in exercise physiology and human performance. Many coaches, however, have failed to take cognisance of the new information and still believe in old and out-dated concepts, many of which frankly are wrong. And it is this incorrect understanding that is then applied to the coaching of athletes. In the following article, some of these misconceptions related to endurance performance are highlighted, specifically those around maximal oxygen uptake (VO2 max), lactate threshold, training heart rate, dehydration, and fluid requirements during prolonged exercise. Although runners are most often referred to in the discussion that follows, the principles are applicable to all genre of endurance athlete.

VO2 Max

Every so often a request is received from the coach of a runner or cyclist wanting to know ifit would be possible to measure the VO2 max of one of their athletes. I explain that it is, indeed, possible, but then go on to ask why they want to have the VO2 max of the athlete measured? There is usually one of two replies. Firstly, I am told, by knowing his or her VO2 max the runner will know the esoteric time that he or she is ultimately capable of running for some particular race distance, and therefore their ultimate potential as a runner. Secondly, once their VO2 max is known it will be possible to prescribe the ultimate personalised training schedule. Unfortunately, knowing the VO2 max of a runner does not answer either question.

It is widely believed by those involved in endurance sports that the VO2 max is genetically determined and never changes, and that an individual is born with either a high or low VO2 max. Generally, someone with a high VO2 max value is considered to have a cardiovascular system capable of delivering large amounts of oxygen to the working muscle and is able to exercise at a maximum aerobic work output that is determined by the exercise intensity that can be sustained by this supply of oxygen [1]. In this paradigm it does not appear to matter whether a runner or cyclist is unfit or superbly fit, the VO2 max value obtained in a test is theoretically the same. However, it is intuitively obvious that when fit, the athlete can run much faster on the treadmill than when unfit. Thus, since VO2 max is genetically determined and does not change, VO2 max would be reached at a relatively slow running speed when a runner is unfit compared to when very fit, when a much higher speed or workload can be reached. This means that in a totally unfit world class runner we would measure a high VO2 max (for example, 75 ml/kg/min or higher, a reasonable VO2 max value for an elite runner) at a speed of maybe 17 km/hr in a testing protocol in which the treadmill remains flat during the test. When very fit the same athlete will reach the same VO2 max, but now the speed reached on the treadmill will be around 24 km/hr (a reasonable speed for an elite athlete in such a test). The problem is that such a high VO2 max is never measured at a speed of just 17 km/hr, or thereabout. This would be almost impossibly inefficient [2]. The theory of a genetically set and unchanging VO2 max, regardless of work output therefore begins to appear a little shaky.

This concept of VO2 max evolved originally from misinterpretation of the data of early experimental work [1; 3-5]. It was believed that as an athlete ran faster and faster during a treadmill test, an increasing volume of oxygen was needed by the muscles, a process which continued until the supply of oxygen became limiting, or the ability of the muscle to utilise oxygen was exceeded. At this point there would be no further increase in oxygen uptake, despite further increases in running speed [1]. The plateau in oxygen utilisation was regarded as the VO2 max of the runner. If high, then the athlete had great genetic potential. This has been termed the cardiovascular/ anaerobic model by Noakes [1] and needs revision, although others adhere to the concept [6]. However, 30% of all runners and cyclists tested in exercise laboratories never show a plateau in their oxygen uptake [4; 7]. Instead, the oxygen uptake is still increasing when the athlete cannot continue the test. The conventional view of VO2 max now appears to be even more suspect.

Consider a different possibility. The muscles of a runner require a certain amount of oxygen to sustain contraction at a given speed. When the speed is increased, the muscles have to work harder and there is therefore a corresponding increase in the volume of oxygen needed to run at the higher speed. As the runner runs faster and faster, it follows that there is a concomitant increase in the oxygen required, until ultimately something other than oxygen supply to the muscle prevents the muscle from being able to work harder and to sustain a further increase in running speed.

The brain may be the ultimate subconscious controller, by sensing a pending limitation in the maximum capacity of the coronary blood flow to supply oxygen to the heart as exercise intensity increases, and then preventing a further increase in muscle contractility to prevent damage to the heart during maximal exercise [1].

The volume of oxygen being used by the muscle when maximum running speed has been reached is termed the VO2 max. With this theory, the increase in oxygen requirement merely tracks the increase in running speed, until a peak running speed and therefore peak oxygen requirement (VO2 max) is attained. It is easy to see why the VO2 max value will change (which it does) as a runner gets fitter and becomes capable of running faster. Within this framework, the genetically determined limit of VO2 max is actually determined by the highest running speed that the contractility of the muscles can sustain [8] before the brain limits performance to protect the heart, as described above [1]. Of practical importance, is that the exercise scientist and coach cannot use the VO2 max test as a predictor of future performance in someone who still has the capacity to improve their running by utilising a scientifically designed training programme. A great training-induced increase in running speed will result in a substantial change in VO2 max. Only when widely disparate groups of athletes are tested can a VO2 max value be used to distinguish between athletes (i.e. very fast and very slow [2; 9; 10]). In a group of athletes with similar ability, the VO2 max value cannot distinguish between the faster and slower runners i.e. their race performance. Neither is the knowledge of a VO2 max value going to assist in the construction of a training programme, other than by indirectly giving an indication of the time in which a race may currently be completed, by the use of various tables that are available [11]. Indeed, current race performance provides the most useful information for the coach on which to base training prescription [11].

There are, however, some potential uses of a VO2 max test for a coach. When constructing a training programme for someone who has not run any races and who therefore has no race times from which to determine current ability, a VO2 max test will help by giving an indication of the current capability of the athlete on which to base training schedules. If done at regular intervals, the test can provide information about the efficacy of a training programme [11] as laboratory conditions are very reproducible with regard to temperature and absence of wind. However, the peak speed attained in the test is probably the best indicator of current ability [1; 12-14] and not the actual VO2 max value. Race times remain the most useful measure on which to prescribe running speed in training schedules [11].

Lactic Acid

Most athletes and coaches still believe that lactic acid is released during hard or unaccustomed exercise and that this is what limits performance, as well as being the cause of stiffness. Neither is correct. Furthermore, the terminology “lactic acid,” is not correct.

Lactic acid does not exist as such in the body - it exists as lactate at physiological pH [15], and it is this that is actually measured in the blood when “lactic acid” concentration is measured, as is done when a “lactate threshold” is determined in an athlete. This distinction is important not only for the sake of correctness, but more importantly, because lactate and lactic acid would have different physiological effects.

The first misconception is that lactic acid is the cause of the stiffness felt after an event such as a marathon. Stiffness is due to damage to the muscle [1], and not an accumulation of lactic acid crystals in the muscle [1; 16], as is commonly believed.

The second misconception is that lactate is responsible for acidifying the blood, thereby causing fatigue. To the contrary, the production of lactate is actually important for two reasons. Firstly, when lactate is produced from pyruvate in the muscle, a hydrogen ion is “consumed” in the process [15]. Consequently the production of lactate actually reduces the acidity in the muscle cells and is thus a beneficial process. Secondly, lactate is an important fuel that is used by the muscles during prolonged exercise [17; 18]. It can be produced in one muscle cell and utilized as a fuel in another, or it can be released from the muscle and converted in the liver to glucose, which is then used as an energy source. So rather than cause fatigue, lactate production actually helps to delay fatigue [19].

Anaerobic Threshold

Closely allied to the thinking that lactate production is bad for performance, is the concept of measuring the blood lactate concentration to determine the so-called “anaerobic threshold” or “lactate threshold.”. The origin of this belief can probably be traced to the early studies of Fletcher and Hopkins [20]. Thus we see photographs of athletes at the track or at the side of the pool having a blood sample taken, with an accompanying caption indicating that the workout is being monitored by measuring “lactic acid.” The supposed rationale is that as speed is increased, a point is reached at which there is insufficient oxygen available to the muscle and energy sources that do not require oxygen (oxygen independent pathways, previously termed the anaerobic energy system) then contribute to the energy that is needed. This supposedly results in a disproportionate increase in the blood lactate concentration, a point identified as the “anaerobic” or “oxygen deficient” threshold. This is also known as the lactate threshold or lactate turnpoint.

There are two problems with this concept. First of all, the muscle never becomes anaerobic; there are other reasons for the increase that is measured in blood lactate concentration [21]. Secondly, the so-called disproportionate increase causing a turnpoint is not correct, in that the increase is actually exponential [22-24]. This is seen when many samples are taken, as in the exercise laboratory, where a blood sample can be drawn every 30 seconds as an athlete runs faster and faster.

Although a graph showing a “breakpoint” in lactate concentration as speed increases cannot be drawn as the breakpoint does not exist, a graph can nevertheless be drawn depicting the curvilinear increase in blood lactate concentration as running speed or exercise intensity increases. This curve changes in shape (shifts to the right) as fitness level changes. Particularly, the fitter a runner gets, the more the curve shifts to the right on the graph, meaning that at any given lactate concentration the running speed or work output is higher than before. A shift in the lactate curve to a higher workload or percentage VO2 max occurs due to a reduced rate of lactate production by the muscles and an increased ability of the body to clear the lactate produced [25; 26]. Often, the running speed at a lactate concentration of 4mmol/l is used as a standard for comparison. It is sometimes suggested that this can be used as a guide for training speed (i.e. a runner could do some runs each week at the speed corresponding to the 4mmol/l lactate concentration, some runs above this speed, and recovery runs at a lower speed). Of course, as fitness changes and the curve shifts, these speeds will change, and so a new curve will have to be determined. In concept this works well, but the problem is that neither exercise scientists nor coaches know how much running should be done below, at, and above the 4mmol/l concentration. The 4 mmol/l concentration referred to is a somewhat arbitrarily chosen concentration. It could just as well have been 3.5 mmol/l or 4.5 mmol/l, which would result in different training speeds for the athlete utilizing this system. Indeed, Borch et al [27] suggest 3 mmol/l as the lactate concentration representing an average steady state value. Measuring the maximal steady state lactate concentration may be useful, but requires 4-5 laboratory visits. Thus the real value in determining a ‘lactate curve’ is to monitor how it shifts with training. The desirable shift is one in which a faster running speed is achieved at the same lactate concentration. This regular testing can be done in the laboratory, with the athlete running on a treadmill or on a track, in which running speed can be carefully controlled, such as by means of pace lights.

Training Heart Rate

In recent years the concept of using heart rate while training as an indicator of the correct training intensity, has gained in popularity. Specifically, various heart rate “training zones” have been suggested, and ways to calculate these proposed. This approach has been described in many articles written for coaches and runners [27-29] and does have potential for being a precise way to regulate running intensity in training, particularly for novice runners. However, at present there are no scientific data to support an ideal specific heart rate for different types of training, and much of what is written is based on anecdotal experiences. There is no doubt that future studies will refine this area, making the prescription of training heart rate a more exact science.

Probably the greatest value in heart rate in training is for the coach to use it as a way of ensuring that an athlete does not train too hard on those days when nothing more than an easy training session is prescribed. The use of heart rate for more absolute prescription has the risk of the athlete training at the wrong intensity as a result of the large daily variability in heart rate due to influence of diurnal variation, temperature differences, sleep patterns, and stress [30]. All these can result in the prescribed training heart rate being either too high or too low on a given day. Thus the athlete may train too easily on one day, but on another day when more recovery is needed from a prior hard training session, the training intensity may be too high. The coach is probably better able to assess the most suitable intensity for the athlete. Nevertheless, training intensity based on heart rate may have some value [28].

The use of heart rate as a monitoring tool during training, as opposed to being used to dictate training intensity is a useful aid that coaches can use to assess the training response of an athlete. A progressive decline (over weeks) in heart rate for a given training session would indicate appropriate adaptive response by the athlete; a progressive increase in normal training heart rate would indicate a failure in the adaptive process and that the training load should be adjusted. Similarly, an abnormally high heart rate for a given training session may indicate approaching illness or failure to adapt to the training load and impending overtraining. The athlete would then be well-advised to train only lightly, or to rest [30].

Post-Run Stiffness

In the section on lactic acid, it was stated that the stiffness and muscle pain felt after a marathon or hard workout is not caused by lactic acid. While this was believed to be the case some decades ago, it is now known that lactic acid is not the cause of muscle stiffness, but is the result of damage to the muscle cells, connective tissue and contractile proteins [31-33].

Although the precise cause of delayed onset muscle soreness remains unknown, all runners and coaches are aware that the degree of pain depends on the intensity, duration and type of workout. For example, there is more muscle pain after a long or hard downhill run than after running over flat terrain (i.e. if eccentric muscle actions are emphasised [34]). In fact, it is this phenomenon that begins to exclude a build-up of lactic acid as a cause of the pain. In downhill running, the concentration of lactate in the blood and muscle will be low compared to running at the same speed on the flat. Thus, the most painful post-race stiffness can occur when the lactate concentration is lowest.

If a blood sample is taken from a runner the day after a marathon, especially an ultra- marathon, the concentration of an enzyme, creatine kinase, will be high [35-37]. This is an indication that muscle damage has occurred, as this particular enzyme “leaks” from damaged muscle. The “damage” referred to is minute tears or ruptures of the muscle fibres [38; 39]. This trauma to the muscle can be visualised if a sample of the muscle is examined microscopically. However, it is not just the muscle that is damaged. By measuring the amino acid hydroxyproline, it is possible to show that the connective tissue in and around the muscles is also disrupted [40]. What this shows is that stiffness results from muscle damage and breakdown of connective tissue.

Running fast or running downhill places greater strain on the muscle fibres and connective tissue compared with running on the flat. Downhill running is particularly damaging because of the greater eccentric muscle actions that occur. It is this simultaneous contracting of the muscle while being forced biomechanically to lengthen that is most damaging to muscle fibres.

What does this mean for the runner and coach? From a training and racing point of view, after the muscles have recovered from the damage that caused the stiffness and the adaptive process is complete, the muscle is more resistant to damage from subsequent exercise for up to six weeks [41]. From a coaching point of view, hard training sessions should be withheld when there is muscle pain, as further damage could result. It would be better to allow the appropriate physiological adaptations to take place before resuming hard training sessions. Weight training to increase the strength of the muscle [1] may be beneficial. It has been suggested that vitamin E may help to reduce muscle soreness, but there is little evidence to support this idea [42]. Vitamin E is thought to act as an antioxidant that may blunt the damaging action of free radicals, which attack the cell membrane of the muscle fibre.

It has also been suggested that stretching the painful muscle or muscles may be beneficial, but this has not consistently been shown to alleviate delayed onset muscle soreness. Neither is there any evidence that massage or ultrasound speed up recovery [43]. Similarly, an easy “loosening up” run “to flush out the lactic acid” is unlikely to speed up recovery, although it is also unlikely to result in further damage.

The real cause of muscle stiffness after a hard run is clearly not due to lactic acid in the muscle. Coaches will be in a better position to manage the return to normal training of their athletes after training or racing that has induced muscle soreness, if they understand the effects of type, intensity, and volume of training on muscle stiffness after exercise.

Dehydration, Heat Exhaustion and Heat Stroke

Historically, the understanding has been that runners collapse (most often at the end of races) due to dehydration. This is popularly thought to be more likely when the environmental temperature is high and dehydration more severe. “Heat exhaustion” has been incorrectly thought to be associated with dehydration, yet there is no evidence to support this [1]. “Heat stroke” is an entirely different condition, associated with an increase in body temperature.

There are a number of critical errors in the traditional thinking on the issue of dehydration. Firstly, and possibly most importantly, rectal temperatures are not abnormally elevated in collapsed runners suffering from “dehydration” [44; 45]. Secondly, there is no published evidence that runners with dehydration/ heat exhaustion will develop heat stroke if left untreated [46; 47]. And thirdly, the question must be asked why these runners nearly always collapse at the finish of the race and not during the race. Thus we must look for another explanation as to why the runners collapse.

The explanation is found in a condition called postural hypotension [44; 47-50]. While running, the high heart rate and rhythmic contraction of the leg muscles maintain blood pressure and aids in the return of blood from the legs. When running ceases, the pump action of the leg muscles stops and the heart rate drops rapidly. This results in pooling of the blood in the veins of the lower limb, which in turn causes blood pressure to decrease. It is the lowered blood pressure that results in collapse. Secondly, there is an increase in peripheral blood flow to regulate body temperature. This is more pronounced in hot conditions, and results in a reduction in the pressure of blood filling the heart [51]. Treatment is therefore very simple: If the runner lies down with the legs elevated, the return of blood from the legs is aided, blood pressure is restored and after a short while the runner will have recovered. Cooling the legs may be beneficial. As a preventive measure, it is a good idea to continue to walk after the finish line has been crossed. A second possibility is to lie down as soon as possible and elevate the legs slightly, with cooling of the legs as an additional option.

Heat exhaustion as a result of dehydration does not, therefore, exist and is not a condition that coaches need to be concerned about. This contrasts with heat stroke, in which the body temperature becomes very high (rectal temperature above 41°C) and is a potentially dangerous condition. Even after the athlete has stopped, either voluntarily or because of collapse, the temperature remains elevated because of physiological and biochemical abnormalities in the muscles. Thus the athlete must be cooled as quickly as possible, using methods such as fans, to bring the body temperature down to below 38 degrees Celsius.
Heat stroke develops as a result of a combination of a number of factors. Particularly, a high environmental temperature (>28°C) is more likely to result in the problem than when conditions are cooler. If the humidity is also high, there is an additional heat load on the runner because the sweating mechanism of the body is rendered ineffective. Sweat running off the body, as it does when the humidity is high, does not result in cooling. To cool the surface temperature of the skin, the sweat must evaporate. In addition, and also very importantly, the metabolic heat produced by the runner must be high. Thus, it is the faster athletes who are at risk, who are exercising at a high intensity. It is also, therefore, in races shorter than the marathon in which there is a high likelihood of heat stroke because of the much higher running intensity in shorter races such as cross country (on a hot day) or a 10 km race [46; 47; 52]. Thirdly, it appears that some runners are more susceptible to the development of heat stroke than others [53].

Contrary to popular belief, dehydration is not a major cause of the development of heat stroke. Although adequate fluid replacement during racing in the heat may reduce the risk of heat injury, it is not the only factor and may not even be the most important factor [46; 47; 54; 55]. Arunner can develop heat stroke without being dehydrated. Conversely, a runner can be dehydrated, but not develop heat stroke. If the recommended guidelines for fluid ingestion are followed (~600 ml/ hour), it is very unlikely that fluid deficit will play a role in the development of heat stroke.

Fluid Intake During Exercise

During events such as marathon running, one often reads recommendations suggesting that more than 1L of fluid should be ingested every hour. Ingestion of such a high volume is unnecessary, however, and probably impossible for faster runners to adhere to.

The rate at which fluid ingested during exercise empties from the stomach before being absorbed in the small intestine is influenced by a number of factors. These include the temperature of the fluid, the volume of fluid ingested, and the concentration of any carbohydrate such as glucose, fructose, sucrose or glucose polymer in the water. Thus it is important that athletes follow the correct regimen to ensure optimal fluid and carbohydrate replacement. This consists of ingesting 500-600 ml per hour of a fluid containing 7-10% carbohydrate [56]. This serves two purposes. It supplies a source of carbohydrate to maintain blood glucose concentration, as well as all the fluid replacement that is necessary during prolonged exercise, except possibly under extreme environmental conditions.

Ingestion of too much water during prolonged exercise is not only unnecessary, but can be harmful. In some susceptible people, ingesting large volumes of water can result in a condition called “water intoxication” or hyponatraemia. This occurs when the body’s normal sodium concentration becomes significantly diluted, because the amount of water or sports drink ingested is far in excess of what is needed during exercise to maintain hydration [46; 54; 57; 58]. As with heat stroke, in extreme cases this condition can be life threatening, in this case due to cerebral oedema.

Conclusions

VO2 max testing can be of some limited use to a coach when constructing a training programme for someone who has not run any races. If done regularly, the test can provide information about the efficacy of a training programme. However, the peak speed attained in the test is probably the best indicator of current ability, but race times are the most useful measure on which to prescribe running speed in training schedules.

Rather than cause fatigue, the process of lactate production helps to delay fatigue. In addition, it is important as a fuel substrate. The real value in determining a ‘lactate curve’ is to monitor how it shifts with training, the desirable shift being one in which a faster running speed is achieved at the same lactate concentration.

Heart rate during training is a useful monitoring tool, but should not be used to dictate training intensity. Rather, training heart rate information, together with knowledge of current race speeds and training-induced fatigue, should be used by the coach to determine training intensity. Ultimately, the influence of various parameters that effect heart rate response will be well researched and the coach will then be able to prescribe a specific heart rate for different types of training.

Muscle stiffness after a hard run is not due to lactic acid in the muscle. Return to normal training should be prescribed based on the knowledge that soreness is due to muscle damage.

Dehydration is not a major cause of the development of heat stroke. Heat stroke can occur without dehydration, and conversely, dehydration can occur without heat stroke. If the recommended guidelines for fluid ingestion are followed, it is very unlikely that fluid deficit will play a role in the development of heat stroke.

Ingestion of too much water during prolonged exercise is not only unnecessary, but can be harmful. In some susceptible people, ingesting large volumes of water can result in a condition called “water intoxication” or hyponatraemia.

Despite the exponential increase in knowledge in exercise physiology in the last two decades, the process of exercise physiologists and coaches changing old ideas and concepts and accepting new ones has been slow. Both should examine the new information available and use it to proceed with the next series of research studies and coaching concepts, respectively.

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25. MacRae, H.S., Dennis, S.C., Bosch, A.N. and Noakes, T.D., Effects of Training on Lactate Production and Removal During Progressive Exercise in Humans, Journal of Applied Physiology, 1992, 72,1649-1656.
26. Bergman, B.C., Wolfel, E.E., Butterfield, G.E., Lopaschuk, G.D., Casazza G.A., Horning, M.A. and Brooks, G.A., Active Muscle and Whole Body Lactate Kinetics After Endurance Training in Men, Journal of Applied Physiology, 1999, 87, 1684-1696.
27. Pfitzinger, P., Training with Heart Rate, Running Times, 1994, 64-67.
28. Edwards, S., Smart Heart. High Performance Heart Zone Training, Heart Zones Company, Sacremento, California, 1997.
29. Gallagher, J., Using Your Body’s Tachometer, Marathon & Beyond, 1997, 1, 45-56.
30. Lambert, M.I., Mbambo, Z.H. and St Clair Gibson, A., Heart Rate During Training and Competition for Long-Distance Running, Journal of Sports Sciences, 1998, 16, S85-S90.
31. Clarkson, P.M. and Sayers, S.P., Etiology of Exercise-Induced Muscle Damage, Canadian Journal of Applied Physiology, 1999, 24, 234-248.
32. Morgan, D.L. and Allen, D.G., Early Events in Stretch-Induced Muscle Damage, Journal of Applied Physiology, 1999, 87, 2007-2015.
33. Jones, D.A., Newham, D.J. and Clarkson, P.M., Skeletal Muscle Stiffness and Pain Following Eccentric Exercise of the Elbow Flexors, Pain, 1987, 30, 233-242.
34. Clarkson, P.M., Nosaka, K. and Braun, B., Muscle Function After Exercise-Induced Muscle Damage and Rapid Adaptation, Medicine and Science in Sports and Exercise, 1992, 24, 512-520.
35. Noakes, T.D., Challenging Beliefs: Ex Africa Semper Aliquid Novi, Medicine and Science in Sports and Exercise, 1997, 29, 571-590.
36. Noakes, T.D, Kotzenberg, G., McArthur, P.S. and Dykman, J., Elevated Serum Creatine Kinase MB and Creatine Kinase BB-Isoenzyme Fractions After Ultra-Marathon Running, European Journal of Applied Physiology and Occupational Physiology, 1983, 52, 75-79.
37. Strachan, A.F., Noakes, T.D., Kotzenberg, G., Nel, A.E. and de Beer, F.C., C-Reactive Protein Concentrations During Long Distance Running, British Medical Journal: Clinical Research Edition, 1984, 289, 1249-1251.
38. Friden, J., Seger, J., Sjostrom, M. and Ekblom, B., Adaptive Response in Human Skeletal Muscle Subjected to Prolonged Eccentric Training, International Journal of Sports Medicine, 1983, 4, 177-183.
39. Friden, J., Muscle Soreness After Exercise: Implications of Morphological Changes, International Journal of Sports Medicine, 1984, 5, 57-66.
40. Friden, J., Sjostrom, M. and Ekblom, B., Myofibrillar Damage Following Intense Eccentric Exercise in Man, International Journal of Sports Medicine, 1983, 4, 170-176.
41. Byrnes, W.C., Clarkson, P.M., White, J.S., Hsieh,S.S., Frykman, P.N. and Maughan, R.J., Delayed Onset Muscle Soreness Following Repeated Bouts of Downhill Running, Journal of Applied Physiology, 1985, 59, 710-715.
42. Jackson, M.J., Muscle Damage During Exercise: Possible Role of Free Radicals and Protective Effect of Vitamin E. Proceedings of the Nutrition Society, 1987, 46, 77-80.
43. Tiidus, P.M., Massage and Ultrasound as Therapeutic Modalities in Exercise-Induced Muscle Damage, Canadian Journal of Applied Physiology, 1999, 24, 267-278.
44. Holtzhausen, L.M., Noakes, T.D., Kroning, B., de Klerk, M., Roberts, M. and Emsley, R., Clinical and Biochemical Characteristics of Collapsed Ultra-Marathon Runners, Medicine and Science in Sports and Exercise, 1994, 26, 1095-1101.
45. Roberts, W.O., A 12-yr Profile of Medical Injury and Illness for the Twin Cities Marathon, Medicine and Science in Sports and Exercise, 2000, 32, 1549-1555.
46. Noakes, T.D., Fluid Replacement During Exercise, Exercise and Sport Sciences Reviews, 1993, 21, 297-330.
47. Noakes, T.D., Dehydration During Exercise: What are the Real Dangers? Clinical Journal of Sport Medicine, 1995, 5, 123-128.
48. Holtzhausen, L.M. and Noakes, T.D., The Prevalence and Significance of Post-Exercise (Postural) Hypotension in Ultramarathon Runners, Medicine and Science in Sports and Exercise, 1995, 27, 1595-1601.
49. Holtzhausen, L.M. and Noakes, T.D., Collapsed Ultraendurance Athlete: Proposed Mechanisms and an Approach to Management, Clinical Journal of Sport Medicine, 1997, 7, 292-301.
50. Sandell, R.C., Pascoe, M.D. and Noakes, T.D., Factors Associated with Collapse During and After Ultramarathon Footraces: A Preliminary Study, The Physician and Sportsmedicine, 1988, 16, 86-94.
51. Gonzalez-Alonso, J., Teller, C., Andersen, S.L., Jensen, F.B., Hyldig, T. and Nielsen B., Influence of Body Temperature on the Development of Fatigue During Prolonged Exercise in the Heat, Journal of Applied Physiology, 1999, 86, 1032-1039.
52. Noakes, T.D., Myburgh, K.H., du Plessis, J., Lang, L., Lambert, M., van der Riet, C. and Schall, R., Metabolic Rate, Not Percent Dehydration, Predicts Rectal Temperature in Marathon Runners, Medicine and Science in Sports and Exercise, 1991, 23, 443-449.
53. Jardon, O.M., Physiologic Stress, Heat Stroke, Malignant Hyperthermia—A Perspective, Military Medicine, 1982, 147, 8-14.
54. Noakes, T.D., Adams, B.A., Myburgh, K.H., Greeff, C., Lotz, T., and Nathan, M., The Danger of an Inadequate Water Intake During Prolonged Exercise, A Novel Concept Re-visited, European Journal of Applied Physiology and Occupational Physiology, 1988, 57, 210-219.
55. Noakes, T.D., Hyperthermia, Hypothermia and Problems of Hydration in the Endurance performer, in: Shephard, R.J., ed., Endurance in Sport, Blackwell Publishers, London, 2000, 591-613.
56. Bosch, A.N., Dennis, S.C. and Noakes, T.D., Influence of Carbohydrate Ingestion on Fuel Substrate Turnover and Oxidation During Prolonged Exercise, Journal of Applied Physiology, 1994, 76, 2364-2372.
57. Shephard, R. J. and Kavanagh, T. J., Biochemical Changes with Marathon Running, Observations on Post- Coronary Patients, Proceedings of the 2nd International Symposium on Biochemistry of Exercise, Metabolic Adaptation to Prolonged Physical Exercise, Magglingen, Switzerland, 1973, 245-252.
58. Shephard, R.J. and Kavanagh, T., Fluid and Mineral Needs of Middle-Aged and Postcoronary Distance Runners, The Physician and Sportsmedicine, 1978, 6, 90-102.


Sunday
Oct232011

Recovery nutrition?

Written by the AIS Sports Nutrition, last updated July 2009. © Australian Sports Commission

Website link: Australian Rowing


What are the priorities for recovery nutrition?

Recovery is a challenge for athletes who are undertaking two or more sessions each day, training for prolonged periods, or competing in a program that involves multiple events. Between each work-out, the body needs to adapt to the physiological stress. In the training situation, with correct planning of the workload and the recovery time, adaptation allows the body to become fitter, stronger and faster. In the competition scenario, however, there may be less control over the work-to-recovery ratio. A simpler but more realistic goal may be to start all events in the best shape possible.

Recovery encompasses a complex range of processes that include;
 • refueling the muscle and liver glycogen (carbohydrate) stores
 • replacing the fluid and electrolytes lost in sweat
 • manufacturing new muscle protein, red blood cells and other cellular components as part of the repair and adaptation process
 • allowing the immune system to handle the damage and challenges caused by the exercise bout

The emphasis an athlete needs to place on each of these broad goals will vary according to the demands of the exercise session.  Key questions that need to be answered include - How much fuel was utilised?  What was the extent of muscle damage and sweat losses incurred?  Was a stimulus presented to increase muscle protein?

A proactive recovery means providing the body with all the nutrients it needs, in a speedy and practical manner, to optimise the desired processes following each session.  State-of-the-art guidelines for each of the following issues are presented below.

Refueling

Muscle glycogen is the main fuel used by the body during moderate and high intensity exercise. Inability to adequately replace glycogen stores used up during a workout will compromise performance in subsequent sessions.

The major dietary factor in postexercise refueling is the amount of carbohydrate consumed. Depending on the fuel cost of the training schedule or the need to fuel up to race, a serious athlete may need to consume between 7-12 g of carbohydrate per kg body weight each day (350-840 g per day for a 70kg athlete) to ensure adequate glycogen stores. As an overemphasis on other nutrients, such as protein and fat, can easily replace carbohydrate foods within the athlete’s energy requirements, careful planning of meals and snacks throughout the day is needed achieve the required level of intake (for more information on carbohydrate requirements for athletes, refer to the “Carbohydrate”  Fact Sheet). 

In the immediate post exercise period, athletes are encouraged to consume a carbohydrate rich snack or meal that provides 1-1.2 g of carbohydrate per kg body weight within the first hour of finishing, as this is when rates of glycogen synthesis are greatest. This is especially important if the time between prolonged training sessions is less than 8 hrs. The type and form (meal or snack) of carbohydrate that is suitable will depend on a number of factors, including the athletes overall daily carbohydrate and energy requirements, gastric tolerance, access and availability of suitable food options and the length of time before the next training session. Table 1 gives examples snacks providing at least 50g of carbohydrate.

Rehydration

The majority of athletes will finish training or competition sessions with some level of fluid deficit.  Research suggests that many athletes fail to adequately drink sufficient volumes of fluid to restore fluid balance. As a fluid deficit incurred during one session has the potential to negatively impact on performance during subsequent training sessions, athletes need to incorporate strategies to restore fluid balance, especially in situations where there is a limited amount of time before their next training session.

Athletes should aim to consume 125-150% of their estimated fluid losses in the 4-6 hours after exercise (Refer to the “How much do athletes sweat?” Fact Sheet for advice on how to monitor fluid losses during exercise). The recommendation to consume a volume of fluid greater than that lost in sweat takes into account the continued loss of fluid from the body through sweating and obligatory urine losses.

Fluid replacement alone will not guarantee re-hydration after exercise. Unless there is simultaneous replacement of electrolytes lost in sweat, especially sodium, consumption of a large volume of fluid may simply result in large urine losses. The addition of sodium, either in the drink or the food consumed with the fluid, will reduce urine losses and thereby enhance fluid balance in the post exercise period.  Further, sodium will also preserve thirst, enhancing voluntary intake. As the amount of sodium considered optimal for re-hydration (50-80 mmol/L) is in excess of that found in most commercially available sports drinks, athletes may be best advised to consume fluids after exercise with everyday foods containing sodium.

In considering the type of fluids needed to achieve their re-hydration goals, athletes should also consider the length of time before their next session, the degree of the fluid deficit incurred, taste preferences, daily energy budget, as well as their other recovery goals. With the latter, athletes can simultaneously meet their refueling, repair and contribute to their re-hydration goals by consuming fluids that also provide a source of carbohydrate and protein e.g. flavoured milk, liquid meal supplement.

Muscle Repair and Building

Prolonged and high-intensity exercise causes a substantial breakdown of muscle protein. During the recovery phase there is a reduction in catabolic (breakdown) processes and a gradual increase in anabolic (building) processes, which continues for at least 24 hours after exercise. Recent research has shown that early intake after exercise (within the first hour) of essential amino acids from good quality protein foods helps to promote the increase in protein rebuilding. Consuming food sources of protein in meals and snacks after this “window of opportunity” will further promote protein synthesis, though rate at which it occurs is less.

Though research is continuing into the optimal type (e.g. casein Vs whey), timing and amount of protein needed to maximise the desired adaptation from the training stimulus, most agree that both resistance and endurance athletes will benefit from consuming 15-25g of high quality protein in the first hour after exercise. Adding a source of carbohydrate to this post exercise snack will further enhance the training adaptation by reducing the degree of muscle protein breakdown.  Table 2 provides a list of carbohydrate rich snacks that also provide at least 10g of protein, while Table 3 lists a number of everyday foods that provide ~10g of protein.

Immune System

In general, the immune system is suppressed by intensive training, with many parameters being reduced or disturbed during the hours following a work-out.  This may place athletes at risk of succumbing to an infectious illness during this time. Many nutrients or dietary factors have been proposed as an aid to the immune system - for example, vitamins C and E, glutamine, zinc and most recently probiotics - but none of these have proved to provide universal protection.  The most recent evidence points to carbohydrate as one of the most promising nutritional immune protectors.  Ensuring adequate carbohydrate stores before exercise and consuming carbohydrate during and/or after a prolonged or high-intensity work-out has been shown to reduce the disturbance to immune system markers.  The carbohydrate reduces the stress hormone response to exercise, thus minimising its effect on the immune system, as well as also supplying glucose to fuel the activity of many of the immune system white cells.

How does recovery eating fit into the big picture of nutrition goals?

To optimise recovery from a training session, meals (which generally supply all the nutrients needed for recovery) must either be timetabled so that they can be eaten straight after the work-out, or special recovery snacks must be slotted in to cover nutrient needs until the next meal can be eaten.

For athletes who have high-energy needs, these snacks make a useful contribution towards their daily kilojoule requirement.  When there is a large energy budget to play with, it may not matter too much if the snacks only look after the key recovery nutrients - for example carbohydrate e.g. sports drink.  On the other hand, for those athletes with a low energy budget, recovery snacks will also need to contribute towards meeting daily requirement for vitamins, minerals and other nutrients.  Snacks that can supply special needs for calcium, iron or other nutrients may double up as suitable recovery snacks. e.g. yoghurt

Real food Vs supplements

Many athletes fall into the trap of becoming reliant on sports food supplements, believing this to be the only and/or best way to meet their recovery goals. This often results in athletes “doubling up” with their recovery, consuming a sports food supplement that meets certain recovery goals e.g. liquid meal supplement, then following this up soon afterwards with a meal that would help them meet the same recovery goal e.g. bowl of cereal with fresh fruit.  Unless constrained by poor availability or lack of time, athletes are best advised to favour real food/fluid options that allow them to meet recovery and other dietary goals simultaneously. This is especially important for athletes on a low energy budget.

What are some other the practical considerations for recovery eating?

Some athletes finish sessions with a good appetite, so most foods are appealing to eat. On the other hand, a fatigued athlete may only feel like eating something that is compact and easy to chew. When snacks need to be kept or eaten at the training venue itself, foods and drinks that require minimal storage and preparation are useful. At other times, valuable features of recovery foods include being portable and able to travel interstate or overseas. Situations and challenges in sport change from day to day, and between athletes - so recovery snacks need to be carefully chosen to meet these needs.

Table 1- Carbohydrate-rich recovery snacks (50g CHO portions)
 • 700-800ml sports drink
 • 2 sports gels
 • 500ml fruit juice or soft drink
 • 300ml carbohydrate loader drink
 • 2 slices toast/bread with jam or honey or banana topping
 • 2 cereal bars
 • 1 cup thick vegetable soup + large bread roll
 • 115g (1 large or 2 small) cake style muffins, fruit buns or scones
 • 300g (large) baked potato with salsa filling
 • 100g pancakes (2 stack) + 30g syrup

Table 2- Nutritious carbohydrate-protein recovery snacks (contain 50g CHO + valuable source of protein and micronutrients)
 • 250-300ml liquid meal supplement
 • 300g creamed rice
 • 250-300ml milk shake or fruit smoothie
 • 600ml low fat flavoured milk
 • 1-2 sports bars (check labels for carbohydrate and protein content)
 • 1 large bowl (2 cups) breakfast cereal with milk
 • 1 large or 2 small cereal bars + 200g carton fruit-flavoured yoghurt
 • 220g baked beans on 2 slices of toast
 • 1 bread roll with cheese/meat filling + large banana
 • 300g (bowl) fruit salad with 200g fruit-flavoured yoghurt
 • 2 crumpets with thick spread peanut butter + 250ml glass of milk
 • 300g (large) baked potato + cottage cheese filling + glass of milk

Table 3 - Foods providing approximately 10g of protein.

Animal foods
 • 40g of cooked lean beef/pork/lamb
 • 40g skinless cooked chicken
 • 50g of canned tuna/salmon or cooked fish
 • 300 ml of milk/glass of Milo
 • 200g tub of yoghurt
 • 300ml flavoured milk
 • 1.5 slices (30g) of cheese
 • 2 eggs

Plant based foods
 • 120g of tofu
 • 4 slices of bread
 • 200g of baked beans
 • 60g of nuts
 • 2 cups of pasta/3 cups of rice
 • .75 cup cooked lentils/kidney beans

 


Thursday
Oct062011

Heart Rate Variability (HRV), Recovery Index (RI) and Heart Rate Variability Index (HRVI)

By: Eddie Fletcher, Fletcher Sport Science Ltd 2007
A briefing note written by Sports Physiologist and Coach Eddie Fletcher
Accurate tools for assessing Psychological Stress, Physiological Workload and Recovery in Athletes


General Introduction

There are a number of factors which influence training and race performance, ranging from daily living (work and family), diet and hydration, cold, heat and humidity through to the lack of adequate rest and recovery. It is important to understand how stressful a normal training day is and to know the extent of overnight recovery.

The human heart is a wonderful barometer of the overall psychological stress and physical workload experienced by the body. The heart is a muscle, it gets tired and like any other muscle requires time to recover if optimum training and race performance is to be maintained.

The heart responds automatically and immediately to any increase or decrease in stress level. This heart rate response can be used to manage and mitigate the risk of over training, under recovery, illness or injury, to the body.

By monitoring the influence of psychological stress and physiological workload it is possible to use an analysis of heart rate to monitor overnight recovery and to moderate the duration and intensity of training to match the extent of recovery.

The consequences of getting it wrong should not be under estimated. Unless ‘listening to your heart’’ is normal practice deterioration in performance can occur almost unseen.

What are the benefits of measuring daily stress?

• Maximize recovery between training sessions
• Know how travelling, jetlag, high altitude and other stressors influence stress and recovery
• Learn how different daily routines enable and limit recovery
• Measure recovery between training sessions when training in high altitude
• Assess how travelling and jetlag influences recovery after a competition
• Check for social and psychological stressors that influence recovery
• Check athlete's daily routines for arrangements that could be done better to minimize stress during the day
• Interpret results together with athlete to detect stressors that influence recovery and to plan things that could be done differently in the future
• Repeat the daily stress recordings and observe how changes in daily routines influence stress and recovery

What are the benefits of measuring recovery?

• Detect early signs of overtraining or illness
• Optimize training load by finding the balance between training load and recovery
• Evidence based support for critical coaching decisions
• Record individual reference values e.g. during off-season when the body is recovered
• Check the recovery status during hard training periods
• Check recovery status when subjective feelings and fitness level indicates poor recovery
• Make sure that the body is recovered sufficiently before a new hard training period

How does it work?

Tracking daily stress and overnight recovery needs only one physiological signal – beat-by-beat heart rate data (the R-R interval). This measurement may be carried out during normal daily routines, whilst training and whilst sleeping. Although the data collection procedure is simple, the analysis methodology produces accurate recovery information.

Under resting conditions, healthy athletes show a periodic variation in the R-R interval. This rhythmic fluctuation is caused by breathing. Heart rate increases whilst breathing in and decreases when breathing out.

By accurately measuring the time interval between heartbeats (known as Heart Rate Variability HRV) it is possible to use the detected variation in time to measure the psychological and physiological stress and fatigue on the body. Generally speaking the more relaxed and free from fatigue the body is, the more variable the time between heartbeats. Increased Heart Rate Variability is linked to good health; decreased Heart Rate Variability is linked to stress or fatigue.

Heart Rate Variability also distributes as a function of Frequency.

Because of the characteristics of the increase (high frequency HF) and decrease (very low and low frequency LF) of the heart beat, changes in this frequency distribution can be used to monitor overall daily stress and overnight recovery.

Recovery is strongly associated with high frequency reactions and stress with low frequency reactions. These values are highly individual and the most sensitive markers for monitoring stress and recovery status. By looking at the difference from athlete specific baseline values the status of stress and recovery can be monitored and a

Recovery Index or Heart Rate Variability Index created.

The  intensity  of  stress/recovery  is  calculated  from  the  HF,  LF,  Respiration rate and HR.

How easy is it to collect the data?

Very easy, simply wear a Suunto t6 or Suunto Memory Belt during training sessions and overnight. The log is downloaded into Suunto Training manager software and Firstbeat SPORTS or Firstbeat PRO for detailed analysis.

What is a Recovery Index?

The Recovery Index is the relationship between the total duration of the Stress (low frequency) and Recovery (high frequency) reactions during an overnight measurement. The index is generally calculated from the first 4 hours of sleeping time as this time period is the most sensitive time for detecting recovery status. Average values provide information for both stress and recovery reactions during the selected time period indicating the relative strength of the reactions.

The intensity of the Stress/Recovery is calculated from the high and low Heart Rate Frequency mix, Respiration Rate and Heart Rate. The Recovery Index is represented by two numbers i.e. 60/100. The left number represents Stress reactions with the right number representing Recovery reactions.

Athletes need to measure their own individual baseline values at rest and compare subsequent values against the baseline figures.

What is a Heart Rate Variability Index?

Another useful tool for detecting recovery is the Heart Rate Variability Index

This is a single number and reflects the slowing down of the heart. The index can be used to detect recovery from an overnight recording. A high index figure represents increased recovery and a low value poor recovery.

During the day the value should be at least 15 but normally over 25. During the night the value should be at least 50 % higher (20-30) although athletes can have a value of several hundred (athlete above is 100 +). These limits are just guidelines; medication, heritage and training status also influence HRV level. Research indicates that these limits may be associated with burn-out.

As with the Recovery Index an individual baseline Heart Rate Variability Index value would need to be established for comparison purposes.

Example

The ratio for this athlete is 42/100 and represents full recovery. For this athlete normal 100% recovery is 40-110



During a period of high stress for a different athlete a ratio of 117/74 represents under recovery. For this athlete normal 100% recovery range is 60-100

Tracking the Recovery Index

There are some endurance athletes whose heart rate level is so low during the night that despite the changes in HF and LF levels the night recording appears to show mainly recovery reactions.

The overall index may indicate 100% recovery when the underlying values show under recovery. It is important to get a reference level by measuring athlete specific baseline values in a rested state and comparing future results to the baseline figures.

In the example below note 100% recovery during the period 6/11/2007 to 18/11/2007.

Baseline resting values for this athlete 50 (stress)/115 (recovery)

By looking at the individual figures for stress and recovery the true extent of stress or recovery can be determined and compared against baseline level.

The intensity of the stress reactions

The intensity of the recovery reactions.

Normally when recovery increases, stress level decreases and vice versa. It will be noted that although the overall index shows 100% recovery for the 16/11/2007 the Recovery Index is approximately 85/100 which when compared against baseline 50/115.

Am I fully recovered?

More precise answers are obtainable with a long measurement history.

In this example the days when the athlete is recovered are marked on both the Stress and Recovery follow-up charts.

Stress reactions:

Recovery reactions:

Am I tired but training can continue? Am I tired and must rest.

These are the too hardest questions to answer and this is where the experience of the athlete and coach in using the Recovery Index is important. When the goal is to train hard and upset the body’s homeostasis the stress level should increase and recovery decrease.

In the charts above the hard training period was 18/10/07 – 25/10/07 (8 days). Based on the rate of recovery (recovery occurred within two days - see Recovery index 27.10.07) the overreaching period was successful.

The chart below is another athlete training at high altitude 12/10-07 – 27/10/07. The last measurement was 25/10/07. The recovery level was below baseline value all the time and the athlete reported subjective feelings of “big fatigue”. This 15 days hard training period without any easy days may have been too long. Time to reach baseline values after the training period took 10 days (recovery occurred 07/11/07).

When will I know I can train again?

After ending the last hard training period, the recovery level should be measured daily to see when the baseline values are reached again. In the example above, the new training period could be started on 07/11/07 or later.

Conclusion

Measuring recovery is a vital component of any training programme if an athlete is to maintain optimum training and race performance. ‘Listening to your heart’ must become normal practice to avoid deterioration in performance, illness or injury.

More information

Coaches and Athletes are referred to the following articles by Eddie Fletcher for more detailed information

Peak Performance Issues:

• 237 Heart rate variability – what is it and how can it be used to enhance athletic performance
• 246 Using HRV to optimize rest and recovery
• 253 Duration-intensity-recovery: a new training concept

Also see www.fletchersportscience.co.uk for further reference articles.

Eddie Fletcher can be contacted by email eddie@fletchersportscience.co.uk

Note: Some sections of this briefing guide are based upon copyrighted materials owned by Firstbeat Technologies Ltd. They are reproduced with the permission.


Thursday
Aug112011

Monitoring of Stress in Trained Male Rowers

By: Jaak Jurimae, Priit Purge, Jarek Maestu, Terje Soot, Toivo Jurimae.
From: Journal of Human Kinetics Volume 7, 2002
Site Link: International Association of Sports Kinetics
Article Link: Monitoring of Stress in Trained Male Rowers


The effect of rapidly increased training volume on performance and recovery stress state over a six-day training camp was investigated in trained male rowers (n=17). The training regimen consisted mainly of low-intensity on-water rowing and resistance training, in total 19.6±3.8 h, corresponding to an approximately 100% increase in training load. 2000 meter rowing ergometer (Concept II, Morrisville, USA) performance time increased from 396.9±10.8 to 406.2±11.9 s (p<0.05) as a result of this training period. The Recovery-Stress-Questionnaire for Athletes revealed an increase in somatic components of stress (Fatigue, Somatic Complaints, Fitness/Injury) and a decrease in recovery factors (Success, Social Relaxation, Sleep Quality, Fitness/Being in Shape, Self-Efficacy). Relationships were observed between increased training volume, and Fatigue (r=0.49), Somatic Complaints (r=0.50) and Sleep Quality (r=-0.58) at the end of the training camp. In summary, rowing performance decrement indicated a state of short-term overreaching at the end of a six-day high load training period.

Overreaching was further diagnosed by changes in specific stress and recovery scales of the RESTQ-Sport for athletes. The RESTQ-Sport for athletes could be used to monitor heavy training stress in trained rowers.

Key Words: rowing, performance, overreaching, recovery-stress questionnaire

Introduction

It has been demonstrated that there is a dose-response relationship between training stress and performance (Steinacker et al. 1998). Furthermore, it is evident that underestimation or overestimation of trainability and recovery will lead to inappropriate training response or overtraining of the athlete. Optimal performance is only achieved when athletes optimally balance training stress with adequate recovery (Steinacker et al. 1999, 2000). However, the impact of recovery has received comparatively little attention (Kellmann & Günther 2000).

The existence of dose-response relationship has also been demonstrated between training volume and mood disturbances (Raglin 1993). Increases in training volume correspond to elevations in mood disturbances (Morgan et al. 1987). Mood improvements occur when training volume is decreased (Morgan et al. 1987; Raglin 1993). Psychometric monitoring of endurance athletes has mostly focused on the relationship between overtraining and mood (Raglin 1993). However, one approach to monitor training is the measurement of the athletes view of stress and recovery at the same time and to examine the balance/imbalance between these two aspects as restricting the analysis to the stress dimension alone could not be sufficient for elite athletes (Kellmann & Günther 2000; Steinacker et al. 1999). The recovery-stress state indicates the extent to which someone is physically and/or mentally stressed as well as whether or not the person is capable of using individual strategies for recovery and which strategies are used (Kellmann & Günther 2000). Recovery and stress should be treated using a multilevel approach, dealing with psychological, emotional, cognitive behavioral/performance and social aspects of the problem, considering these aspects both separately and together (Kellmann & Günther 2000).

The purpose of the present study was to monitor the relationship between rapidly increased training volume, rowing performance and the recovery-stress state perceived by the Estonian male rowers.

Material and Methods

Seventeen national level male rowers volunteered to participate in the study (18.6±2.0 yrs; 186.9±5.7 cm; 82.4±6.9 kg). The subjects had trained regularly for the last 4.7±2.2 years. The training period constituted their first training camp on water after the winter training period. The rowers were fully familiarized with the procedures before providing their written informed consent to participate in the experiment as approved by the Medical Ethics Committee of the University of Tartu.

The training during the six-day training period amounted to 19.6±3.8 h, which was equivalent to an average increase in training load by approximately 100% compared with their average weekly training during the preceding four weeks. In total, 12 training sessions were completed during the heavy training period compared to six training sessions during previous four weeks. The training load included 85% of low-intensity endurance training (rowing or running), 5% high-intensity anaerobic training (rowing) and 10% resistance training. Rowing performance and recovery-stress state of rowers were assessed before (Test 1) and after (Test 2) the six-day training period. Maximal 2000 metre rowing ergometer test was performed on a wind resistance braked rowing ergometer (Concept II, Morrisville, USA). The Recovery-Stress-Questionnaire for Athletes (RESTQ-Sport) (Kellmann & Kallus 2000) was used to measure the level of current stress of rowers taking recovery-associated activities into consideration (Kellmann & Günther 2000) before and after the heavy training period. The RESTQ-Sport is constructed in a modular way including 12 scales of the general Recovery-Stress-Questionnaire and additional seven sportspecific scales (Kellmann & Günther 2000, Kellmann & Kallus 2000). The RESTQ-Sport consists of 77 items (19 scales with four items each plus one warm-up item) and the 24 hour test-retest reliability has been reported to be above r=0.79 (Kellmann & Kallus 2000). Therefore, it is assumed that inter-individual differences in the recovery-stress state can be well reproduced and the results of the RESTQ-Sport are stable regarding short-term functionary fluctuations and short-term changes of state (Kellmann & Kallus 2000). The 24-hour test-retest reliability of the Estonian version of RESTQ-Sport was also relatively high (r>0.74; n=17). The inter-correlation of the scales indicates that stress and recovery can be seen as two partly independent factors, which allows to analyze the data on the basis of single scales as well as on the factors of stress and recovery (Kellmann & Günther 2000). The first seven scales cover different aspects of subjective strain (General Stress, Emotional Stress, Social Stress, Conflicts/Pressure, Fatigue, Lack of Energy, and Somatic Complaints) as well as the resulting consequences. Success is the only resulting recovery-oriented scale, which is concerned with performance in general but not in a sportspecific context. Social Relaxation, Somatic Relaxation, General Well-Being, and Sleep are the basic scales of the recovery area. Sport-specific details of stress (Injury, Emotional Exhaustion, and Disturbed Breaks) and recovery (Being in Shape, Personal Accomplishment, Self-Regulation, and Self-Efficacy) are examined in scales 13 to 19 (Kellmann & Günther 2000, Kellmann & Kallus 2000). A Likert-type scale is used with values ranging from 0 (never) to 6 (always) indicating how often the respondent participated in various activities during the preceding three days/nights. The mean of each scale can range from 0 to 6, with high scores in the stress-associated activity scales reflecting intense subjective strain, whereas high scores in the recovery-oriented scales mirror plenty recovery activities (Kellmann & Günther 2000, Kellmann & Kallus 2000).

Mean values and standard deviations (SD) were determined. Paired t-tests (two-tailed) were used comparing results from Test 1 to Test 2. Pearson correlation coefficients were calculated between dependent variables and changes in dependent variables during the heavy training period. For all tests, the level of significance was set at 0.05.

Results

2000 metre rowing performance time was significantly increased after the heavy training period (396.9±10.8 vs. 406.2±11.9 s; p<0.05). The recovery-stress state of rowers changed significantly during the heavy training period (Fig. 1). An increase (p<0.05) in Fatigue, Somatic Complaints, and Fitness/Injury from stress-related scales, and a decrease (p<0.05) in Success, Social Relaxation, Sleep Quality, Fitness/Being in Shape and Self-Efficacy from recovery-associated activities were observed (Table 1). Increased training volume (19.6±3.8 h) of rowers was significantly related to the 2000 metre performance time measured in Test 2 (r=0.59). Significant relationships were observed between increased training volume, and Fatigue (r=0.49), Somatic Complaints (r=0.50) and Sleep Quality (r=-0.58) scales of the recovery-stress questionnaire at the end of heavy training period.

Table 1. Significant changes in the scales of RESTQ-Sport for athletes after the training period compared to the results obtained before the training period.

RESTQ-Sport Scales O N Example Question P-value
Fatigue S 4 I was overtired 0.008
Somatic Complaints S 4 I felt physically exhausted 0.004
Success R 4 I was successful in what I did 0.031
Social Relaxation R 4 I had a good time with my friends 0.026
Sleep Quality R 4 I fell asleep satisfied and relaxed 0.03
Fitness/Injury S 4 Parts of my body were aching 0.014
Fitness/Being in Shape R 4 I was in good condition physically 0.047
Self-Efficacy R 4 I was convinced that I had trained well 0.049

O, scale orientation; N, number of questions in each scale; S, stress, R, recovery.

Discussion

The present study investigated whether psychometric parameters could be used to assess short-term overreaching in competitive rowers. The regimen of extremely heavy training period followed by a period of sufficient rest is widely practiced in different endurance events (Jeukendrup et al. 1992, Steinacker et al. 1998). Furthermore, overreaching has been reported to be an integral part of a successful training program (Steinacker et al. 1998, 1999, 2000). Success in rowing is characterized by the amount of time spent on water as low-intensity endurance training (Jürimäe et al. 2001, Steinacker et al. 1998). The increased training volume of 19.6±3.8 h per week performed by our subjects has been reported to be typical in high load training phases for well trained rowers (Steinacker et al. 1998).

The RESTQ-Sport for athletes has been used to assess the subjective stress and recovery during training cycles for major competitions in German rowers (Kellmann & Günther 2000, Steinacker et al. 2000). The Estonian version of the RESTQ-Sport also allowed the psychometric assessment of competitive rowers during rapidly increased training volume in preparation camp when the focus was only on low intensity rowing. The results of this study suggest that a dose-response relationship exists between training volume and the subjective assessment of somatic components of stress and recovery. High duration was indicated by the elevated levels of stress and simultaneous lowered levels of recovery in trained rowers (Fig. 1). This is in line with other investigations (Kellmann & Günther 2000, Morgan et al. 1987), which have found that increases in training volume correspond to increases in mood disturbances and mood improvements occur when training volume is reduced. The results of the current study demonstrated that the RESTQ-Sport for athletes objectively reflected the state of rowers during the short-term overreaching period.

The psychometric scales of stress such as Fatigue and Somatic Complaints were significantly increased after the heavy training period and related to the increased training volume (r>0.49), suggesting a dose-response relationship between training volume and mood disturbance during basic low-intensity endurance training period. Similarly to the results of our study, the values of the Fatigue and Somatic Complaints scales have been reported to increase relatively early in parallel with increased training volume, while the scores of General Stress are quite stable and low for a relatively long period (Steinacker et al. 1999).

The lowered levels of Success, Social Relaxation, Sleep Quality, Fitness/Being in Shape and Self Efficacy from recovery-associated scales demonstrated that emotional, physical and social aspects of recovery were not adequate during this training camp when training volume was rapidly increased.

For example, a significant decrease in Social Relaxation scale demonstrated a drop in social activities during the heavy training period. However, it should always be considered that recovery is a process to reestablish psychological and physical resources (Kellmann & Günther 2000). Athletes should be aware of the importance of active recovery in the training process. This is even more crucial during preparation camps in rowers, when the focus is mostly on low-intensity, high volume training (Kellmann & Günther 2000). Adequate recovery during phases of heavy training allows for the adaptation of the athlete to stress and prevent from overtraining (Raglin 1993). The results of this study demonstrate that the RESTQ-Sport for athletes reflects the extent of different aspects of recovery in addition to stress during the monotonous heavy training of the preparatory period in highly trained rowers.

Conclusions

The monitoring of training adaptation and the adaptation state of an athlete appears to be a very complex task. The results of this study demonstrated performance incompetence by the end of a six-day overreaching training period and were interpreted to reflect a state of short-term overreaching. Overreaching was further diagnosed by changes in specific stress and recovery scales of the RESTQ-Sport for athletes.

REFERENCES

JEUKENDRUP A.E., HESSELINK M.K.C., SNYDER A.C., KEIZER H.A.
1992. Physiological changes in male competitive cyclists after two weeks of intensified training. Int. J. Sports Med. 13: 534-541.

JÜRIMÄE J., JÜRIMÄE T., PURGE P. 2001. Plasma testosterone and cortisol responses to prolonged sculling in male competitive rowers. J. Sports Sci. 19: 893-898.

KELLMANN M., GÜNTHER K.D. 2000. Changes in stress and recovery in elite rowers during preparation for the Olympic Games. Med. Sci. Sports Exerc. 32: 676-683.

KELLMANN M., KALLUS K.W. 2000. Der Erholungs-Belastungs-Fragebogen für Sportler [The Recovery-Stress-Questionnaire for Athletes]. Frankfurt: Swets and Zeitlinger, pp. 48.

MORGAN W.P., BROWN D.R., RAGLIN J.S., O’CONNER P.J., ELLICKSON K.A.1987. Psychological monitoring of overtraining and staleness. Br. J. Sports Med. 21: 107-114.

RAGLIN J.S. 1993. Overtraining and staleness: psychometric monitoring of endurance athletes. In: Handbook of Research on Sport Psychology, R.B. Singer, M. Murphey, and L.K. Tennant (Eds.). New York: Macmillan, pp. 840-850.

STEINACKER J.M., KELLMANN M., BÖHM B.O., LIU Y., OPITZ-GRESS A., KALLUS K.W., LEHMANN M., ALTENBURG D., LORMES W. 1999. Clinical findings and parameters of stress and regeneration in rowers before world championships. In: Overload, Performance Incompedence, and Regeneration in Sport. M. Lehmann, C. Foster, U. Gastmann, H.A. Keizer, and J.M. Steinacker (Eds). New York: Kluwer Academic/Plenum Publishers, pp. 71-80.

STEINACKER J.M., LORMES W., KELLMANN M., LIU Y., REISNECKER A., OPITZ-GRESS A., BALLER B., GÜNTHER K., PETERSEN K.G., KALLUS K.W., LEHMANN M., ALTENBURG D. 2000. Training of junior rowers before world championships. Effects on performance, mood state and selected hormonal and metabolic responses. J. Sports Med. Phys. Fitness. 40: 327-335.

STEINACKER J.M., LORMES W., LEHMANN M., ALTENBURG D. 1998. Training of rowers before world championship. Med. Sci. Sports Exerc. 30: 1158-1163.

Friday
Jul222011

Recovery in Training: The Essential Ingredient

By: Jonathan N. Mike, M.S. and Len Kravitz, Ph.D.
From: International SportMed Journal, 2000, Volume 1, Issue 3


Introduction

Recovery from exercise training is an integral component of the overall training program and is essential for optimal performance and improvement. If rate of recovery is improved, higher training volumes and intensities are possible without the detrimental effects of overtraining (Bishop et al., 2007). While recovery from exercise is significant, personal trainers and coaches use different approaches for the recovery process for clients and athletes. Understanding the physiological concept of recovery is essential for designing optimal training programs. As well, individual variability exists within the recovery process due to training status (trained vs. untrained), factors of fatigue, and a person's ability to deal with physical, emotional, and psychological stressors (Jeffreys, 2005). This article will provide evidence-based research and practical applications on recovery for personal trainers and fitness professionals

What is Recovery?

Bishop et al. (2007) define recovery as the ability to meet or exceed performance in a particular activity. Jeffreys (2005) continues that factors of recovery include 1) normalization of physiological functions (e.g., blood pressure, cardiac cycle), 2) return to homeostasis (resting cell environment), 3) restoration of energy stores (blood glucose and muscle glycogen), and 4) replenishment of cellular energy enzymes (i.e., phosphofructokinase a key enzyme in carbohydrate metabolism). In addition, the recovery is very dependent on specific types of training (see question #1 in the Pertinent Recovery Questions for the Personal Trainer section). Recovery may include an active component (such as a post-workout walk) and/or a passive component (such as a post-workout hydrotherary treatment).

Physiology of Recovery

Muscle recovery occurs during and primarily after exercise and is characterized by continued removal of metabolic end products (e.g., lactate and hydrogen ions). During exercise, recovery is needed to reestablish intramuscular blood flow for oxygen delivery, which promotes replenishment of phosphocreatine stores (used to resynthesize ATP), restoration of intramuscular pH (acid/base balance), and regaining of muscle membrane potential (balance between sodium and potassium exchanges inside and outside of cell) (Weiss, 1991). During post-exercise recovery, there is also an increase in 'excess post-exercise oxygen consumption' (or EPOC). Other physiological functions of recovery during this phase include the return of ventilation, blood circulation and body temperature to pre-exercise levels (Borsheim and Bahr, 2003).

Types of Recovery

The most rapid form of recovery, termed “immediate recovery” occurs during exercise itself. Bishop and colleagues (2007) give an example of a race walker with 1 leg in immediate recovery during each stride. With this phase of recovery, energy regeneration occurs with the lower extremities between strides. As each leg recovers more quickly, the walker will be able to complete the striding task more efficiently.

“Short term recovery” involves recovery between sets of a given exercise or between interval work bouts. Short-term recovery is the most common form of recovery in training (Seiler, 2005). Lastly, the term “training recovery” is used to describe the recovery between workout sessions or athletic competitions (Bishop et al., 2007). If consecutive workouts occur (such as within the same day) without appropriate recovery time, the individual may be improperly prepared for the next training session.

Connection to Fatigue

Fatigue is usually perceived as any reduction in physical or mental performance. However, when discussing various aspects of training, fatigue can be described as failure to maintain the expected force, or the inability to maintain a given exercise intensity or power output level (Meeesen 2006). Bigland (1984) expands that fatigue is any exercise-induced reduction in force or power regardless of whether or not the task can be sustained.

There are two types of fatigue: peripheral and central. Peripheral fatigue during exercise is often described as impairment within the active muscle. The muscle contractile proteins are not responding to their neural stimulation. Depletion of muscle glycogen (for fuel) is thought to be an important factor in peripheral fatigue, especially during prolonged exercise (Jentjens, 2003).
Central fatigue is concerned with the descending motor pathways from the brain and spinal cord. Bishop and colleagues (2008) explain that brain messages may signal reductions or complete cessation of exercise performance. A central fatigue hypothesis suggests that the brain is acting as a protective mechanism to prevent excessive damage to the muscles.

Other Associative Factors of Recovery
Gleeson (2002) elucidates the following related factors involved in the ability of a person to recover.
1) Muscle soreness and weakness
2) Poor exercise performance
3) Decrease in appetite
4) Increased infection
5) Quality and quantity of sleep
6) Gastrointestinal abnormalities
Personal trainers should be aware that these conditions may have an adverse influence on client recovery from exercise.

Pertinent Recovery Questions for the Personal Trainer

1) How Much Rest between Sets? Willardson (2008) describes rest between sets as a multifactorial phenomenon that is affected by several factors (see Figure 1).
However, summarizing previous research, he purposes some specific rest periods (between multiple set training) for the following training protocols.
Muscular endurance training: 30 to 90 seconds
Hypertrophy training: 1 to 2 minutes
Power training: 3 minutes
Muscular strength (for clients less adapted to strength training): 4 to 5 minutes
Muscular strength (for clients well-adapted to strength training): 3 minutes

2) How much rest between sessions? The greater the stress of the workout, the greater the overall muscle recruitment, and the greater the potential for muscle damage and soreness, therefore the need for longer recovery time. Muscle recovery between resistance training sessions for most individuals is also influenced by other types of training performed, such as cardiovascular training, interval sprints and sports conditioning sessions. Rhea (2003) concluded that for untrained individuals and trained individuals a frequency of 3 and 2 days, respectively, per week per muscle group is optimal, which translates to 1-2 days rest between sessions. However, this will vary depending on total volume of resistance training, individual training status, and overall goals (e.g., training for hypertrophy, strength, endurance, etc.).

3) Is there a gender difference in recovery? A gender difference has been shown in fatigue, a factor influencing recovery. Numerous studies have shown fit women have a greater resistance to fatigue than their male counterparts; therefore, fit women are able to sustain continuous and intermittent muscle contractions at low to moderate intensities longer than physically active men (Critchfield and Kravitz, 2008).

4) Do different muscle groups need more rest? Ground based movements such as the deadlift, squat, and overhead press require more rest than smaller muscle groups such biceps, triceps, and forearm flexors. This is due to the increase in motor unit recruitment and larger muscle mass involved with these multi-joint exercises.

5) Can certain supplements aid in the recovery of training? Many supplements have been used to assist in recovery of training. Bloomer (2007) provides evidence on certain antioxidants such as Vitamin C and Vitamin E and their purported affect on attenuating muscle damage, thus enhancing the recovery of training. However, he confirms that these supplements do not eliminate muscle trauma from exercise, only minimize some of the signs and symptoms (e.g., delayed onset damage, inflammation).

6) Does massage therapy affect the recovery process? Weerapong (2005) reported that some studies have shown that massage did in fact reduce delayed onset muscle soreness, while other studies have not realized this effect. However, it should be pointed out that the psychological benefits of massage toward recovery are often quite meaningful to the exercisers.

Bottom Line Message to Trainers

For client's to achieve optimal exercise performance, the personal trainer and fitness professional needs to be proactive in planning recovery into the training program. Although there is no consensus on a central strategy for recovery, monitoring and observing a client's exercise performance will always be most insightful in adjusting and planning for this essential ingredient of training. In addition, educating clients about the importance of recovery (such as proper sleep) may empower them to complete suitable interventions to enhance the process.

Biographies

Jonathan N. Mike, MS, CSCS, NSCA-CPT, is a doctoral student in the exercise science program in the department of health, exercise, and sports sciences at the University of New Mexico (Albuquerque). He earned his undergraduate and graduate degrees in exercise science at Western Kentucky University (Bowling Green) and has research interests in strength and power performance, exercise and energy metabolism, exercise biochemistry, exercise endocrinology, and neuromuscular physiology.

Len Kravitz, PhD, is the program coordinator of exercise science and a researcher at the University of New Mexico, Albuquerque, where he won the Outstanding Teacher of the Year award. Len was honored with the 2006 Can-Fit-Pro Specialty Presenter of the Year award and chosen as the ACE 2006 Fitness Educator of the Year. He was recently presented with the 2008 Can-Fit-Pro Lifetime Achievement Award.


References:
Bigland-Ritchie B, & Woods J.J. (1984). Changes in muscle contractile
properties and neural control during human muscular fatigue. Muscle and Nerve. 7(9): 691-699.

Bishop, P.A, Jones E., & Woods A.K. (2008). Recovery from training: a brief review.
Journal of Strength and Conditioning Research., 22(3):1015-1024.

Bloomer, RJ. (2007). The role of nutritional supplements in the prevention and treatment of resistance exercise-induced skeletal muscle injury. Sports Medicine. 37(6):519-32.

Borsheim, E & Bahr, R. (2003).Effect of exercise intensity, duration and mode on post-exercise oxygen consumption. Sports Medicine. 33(14):1037-1060.

Critchfield, B. & Kravitz, L. (2008). Fatigue resistance: An intriguing difference in gender. IDEA Fitness Journal 5(6), 19-21.

Gleeson, M (2002). Biochemical and Immunological Markers of Overtraining. Journal of Sports Science and Medicine. 1: 31-41.

Hicks, A.L, Kent-Braun, J., & Ditor, D.S. (2001). Sex differences in human skeletal muscle fatigue. Exercise and Sports Sciences Reviews, 29(3), 109-12.

Jeffreys, I. (2005). A multidimensional approach to enhancing recovery. Strength and Conditioning Journal. 27(5): 78-85.

Jentjens, R, & Jeukendrup, A. (2003).Determinants of post-exercise glycogen synthesis during short-term recovery. Sports Medicine. 33(2):117-144.

Meeusen, R, Watson, P., Hasegawa, H, Roelands, B, & Piacentini, M.F. (2006). Central fatigue: the serotonin hypothesis and beyond. Sports Med. 36(10):881-909.

Rhea, M.R., Alvar, B.A., Burkett, L.N., & Ball S.D. (2003). A meta-analysis to determine the dose response for strength development. Medicine and Science in Sports and Exercise, 35(3):456-464.

Seiler, S. & Hetlelid, K.J. (2005). The impact of rest duration on work intensity and RPE during interval training. Medicine and Science in Sports and Exercise, 37(9):1601-1607.

Weerapong, P., Hume, P.A., & Kolt G.S.N. (2005). The mechanisms of massage and effects on performance, muscle recovery and injury prevention. Sports Medicine, 35(3):235-56.

Weiss, LW. (1991). The obtuse nature of muscular strength: The contribution of rest to its development and expression. Journal of Applied Sports Science Research. 5: 219-227.

Willardson, J.M. (2008). A brief review: How much rest between sets. Strength and Conditioning Journal, 30(3): 44-50.


Tuesday
Jul192011

Recovery from training: A Brief Overview

By: Pillip A. Bishop, Eric Jones, and A. Krista Woods
From: Journal of Strength and Conditioning Vol 22 Number 3 May 2008
Kinesiology Department, Human Performance Laboratory, University of Alabama, Tuscaloosa, Alabama
Site Link: Australian Muscle

ABSTRACT

Athletes spend a much greater proportion of their time recovering than they do in training. Yet, much attention has been given to training with very little investigation of recovery. The purpose of this review is to stimulate further research into this vital area of training. Recovery can be categorized in three terms: i) immediate recovery between exertions; ii) short-term recovery between repeats (e.g., between resistance sets or interval bouts); and iii) training recovery between workouts. The focus of this review is training recovery. Full training recovery is essential to optimal performance and improvement. This review includes an examination of extant research on recovery and a very brief review of some potential modalities and techniques for hastening recovery and the time course of recovery and responses to some treatments. Measures of recovery and practical considerations are discussed briefly. Much research is needed in this area, but there are obstacles to high quality research. Attention must be given to key issues in research on recovery, especially the individual response to recovery treatments.

 

INTRODUCTION

Training in its simplest form represents acute challenges to the body intended to optimize chronic improvements in physiological capabilities. Research has advanced our knowledge of physiological, biomechanical, and the psychological aspects of physical training and performance. The majority of research has focused on training, although most exercise induced adaptations take place during recovery. Recovery is one of the least understood and most under researched constituents of the exercise-adaptation cycle. Even the most dedicated athlete spends much more time in recovery than in active training. We define recovery, from a practical perspective, to mean the ability to meet or exceed performance in a particular activity. For example, if a person has done a challenging distance running workout, then that person’s ability to run a personal best 10-km will be reduced for some period of time. Eventually that runner will be recovered, but certainly for the first 3–4 hours after a workout, no runner expects to perform at their best. This concept of recovery has been used by others (14,24,32).

In general, most coaches and athletes have assumed that increased training was the ultimate prescription for improvement. Endurance sports like swimming and running have, in some cases, carried this to an extreme. It is well accepted that over-load is necessary for improvement, whereas overtraining results in a breakdown at some level, thus impairing, rather than improving, performance. Overtraining is usually thought of strictly in terms of training, yet overtraining might also be expressed as under recovering. If the recovery rate can be improved, greater training volumes would be possible without incurring the negative sequelae of overtraining. Improved recovery may result in establishment of a performance plateau at a higher level.

 

QUESTIONS ON RECOVERY

There are many open questions regarding recovery. Is short term recovery, say, between sets, greatly different from recovery between successive workouts? How do the effects of training impact training recovery? Can recovery between sets, or days, be optimized for better training? How much individual variability is there among athletes in recovery? How does periodization impact recovery? Clearly varying the fatigue in the workout will change the recovery needs. What are the cellular and system (e.g., neural) aspects of recovery?

Both recovery on the cellular level and recovery on the system level have to be complete for muscle cells to function in an integrated way. Likewise, different training stresses likely require different durations and possibly modalities for recovery. It seems reasonable to suppose that weight training requires a different type of recovery than distance running. What are the central and peripheral aspects of recovery? How does active exercise compared to passive rest influence recovery? What are some practical means for quantifying recovery? What modalities or techniques are useful in recovery? In fact, there are so many possible avenues of research that this review was limited to a few representative articles in each of the major aspects of recovery.

The purpose of this brief review is to examine the research knowledge regarding training recovery and potential means for improving recovery. This review will restrict itself to human studies only. Likewise, it would be overwhelming to try to review each possible aspect of recovery in any detail. Short sections are provided with a cursory review of several potential aspects of recovery only for the purpose of stimulating further thought and research on those topics. The hope is that this review will spur innovative research on the many aspects of recovery, specifically, of recovery between training bouts.

 

WHAT IS RECOVERY?

Immediate Recovery


A cursory review of the literature will find that the term ‘‘recovery’’ is used in 3 major ways. For purposes of this review, we are proposing 3 terms to encompass the broader field of recovery. The most immediate form of recovery we term, ‘‘immediate recovery.’’ Immediate recovery is the recovery which occurs between rapid, time-proximal finite efforts. For example, a race walker has one leg in immediate recovery between each stride. During the immediate recovery phase, the leg muscles must regenerate ATP and remove by products of bioenergetics. The more rapidly that each leg recovers, the faster the walker can complete a given race distance. If we make the race walker stride faster (while maintaining stride length), thereby reducing immediate recovery time, we find that the tolerable exercise duration (and distance covered) is reduced. This is commonly observed in that the higher the exercise intensity, the shorter the tolerable duration. At least one study has used the term ‘‘recovery’’ in this manner (25).

Short-Term Recovery

The next type of recovery, and perhaps the most common use of this term in exercise science, is what we are calling ‘‘short term recovery.’’ Short-term recovery is the recovery between interval sprints or between weight training sets, for example. The duration of this recovery has been evaluated and various ratios of work-to-rest have been suggested. Several papers have used this meaning for the term recovery (8,10,33). Short-term recovery of power from multi-bout sprint cycling perhaps parallels resynthesis of creatine phosphate (CP). Creatine supplementation has been reported to work only for recovery intervals of less than 6 minutes (33). This example demonstrates the importance of recovery duration. For longer recovery durations, the presence of increased creatine appears to convey no advantage.  

Training Recovery

The third type of recovery, and the one of interest in the present review, is what we are calling ‘‘training recovery.’’ Training recovery is the recovery between successive work-outs or competitions. For swimmers, runners, weight trainers, football players, and others who sometimes do two-a-day workouts, the interval between training sessions is their recovery. Similarly, for some competitive sports with heats and finals the same day, training recovery would also include the recovery between successive same-day competitions. For most athletes who do one work-out a day, recovery is the period between the end of one work-out and the start of the next.An excellent illustration of training recovery has been published by Gomez et al. (15), regarding recovery from a 10-kilometer all out run. Although all 3 of these types of recovery may be related in some way, our major interest lies in training recovery. Our belief is that training recovery holds promise for improving athletic performance. Figure 1 is a hypothetical llustration of training recovery in a nonelite athlete, perhaps a typical recreational exerciser. As can be seen, this person trains at a fairly low level and then recovers fully several hours before the following work-out.

In Figure 2, we see a hypothetical rendering of what may happen in an elite athlete. In this case recovery is barely complete between workouts due to high volume or intensity. In other words, a complete 24-hour period is totally consumed by either working out or recovering. In our view, this may well be a plausible explanation for the plateau in performance, which is common among elite athletes.

Figure 3 illustrates what may happen hypothetically when the athlete over-trains. In this case, recovery between workouts is definitely incomplete, and successive workouts are begun with a less than optimal physiological (and perhaps psychological) condition. If the athlete has control of her/his own work-out, she/he may very well, consciously or unconsciously, reduce the stress of a following work-out to allow her/his body the opportunity to more fully recover. If an under recovered athlete continues to try to complete workouts, over some period of time a breakdown occurs due to over-training. Therefore, the occurrence of overtraining is the simultaneous product of both the recovery and the work-out.


The ultimate answer to overtraining lies in either reducing the workload during training, or perhaps, in improving the quality of recovery. Finally, Figure 4 is a hypothetical illustration of some effective methods for speeding the rate of recovery.

In this situation, the athlete recovers more rapidly from a rigorous workout and therefore has the capacity to perform better. This results in the reestablishment of another performance plateau, but at a higher performance level. n summary, the chief difference between immediate, shortterm, and training recovery lies in the duration of the recovery. In each situation, recovery may be partial or complete. In addition, in each case, speeding recovery could be expected to improve total work capacity and consequently future performance. As you may have noted, there is an abundant use of the word ‘‘hypothetical’’ in this introduction of recovery. For us, this is what makes this area so interesting. There has been so little research in this area that much of what is known is extrapolated from studies originally targeted at another research question. In the remainder of this review, we will examine the extant research with the goal of identifying potential research lines for expanding our actual, as opposed to hypothetical, knowledge of training recovery.

FATIGUE AND TRAINING RECOVERY

Muscular Damage and Fatigue in Training Recovery

Extreme fatigue as either, or both, a central and peripheral phenomenon, and the muscle tissue damage often associated with a very hard work-out are at the opposite end of the physiological spectrum from full recovery. A good understanding of fatigue is essential to understanding and facilitating recovery. That is, recovery is intended to undo the fatigue/damage incurred in training. An understanding of acute and chronic exercise-induced physiological adaptations, mechanical, and biochemical changes contributing to fatigue may help in designing optimal recovery modalities. One of the reasons recovery has not been well investigated is the absence of a clear understanding of fatigue (1,19). So, knowledge of fatigue helps to investigate recovery, and knowledge gained in the study of effective recovery may provide insights into the causes of fatigue. The same could be said about muscle damage. Understanding muscle tissue damage and the repair process is essential to mastering full training recovery. Therefore, this review will begin with a brief examination of the several theories explaining fatigue and exerciseinduced adaptations and then will examine recovery and aids to muscular recovery.

Although there is little definitive information on fatigue, it has been hypothesized to have one, or both, of 2 main origins. In the central fatigue hypothesis, the muscles are believed capable of greater output but the central nervous system blocks continued extraordinary effort, perhaps as protection from injury (38). In peripheral fatigue, the muscle’s homeostasis has been perturbed, either metabolically through tissue damage, or some other way, to the point that the muscle is biochemically or mechanically incapable of responding as effectively as it does when rested (21). Abbiss and Laursen (1) have recently published a good general review of both peripheral and central fatigue as it applies to cycling. It seems that their analysis of fatigue could be broadly applied to any sort of endurance training or competition. Clearly, a review of fatigue is beyond the scope of this paper, but suffice it to say that full training recovery is attempting to overcome all the effects of fatigue, whatever they may be.

Training Recovery from Muscle Tissue Damage

Shlomit et al. (35) studied responses of 31 Israeli defense force troops after 50- and 80-km marches whilst carrying a 35-kg load. Of these, 29 completed 50-km and 16 completed 80-km marches. A summary of the results of this study are shown in Table 1.

Uric acid and protein carbonyl are considered to be plasma antioxidant markers, yet they changed in different directions in response to this exercise stress, and several others, including oxidative stress ascorbic acid, did not change. Most importantly, these investigators suggest that muscle damage was secondary to the chemical levels not primary to them. That is, elevated respiratory rates induced net increases in reactive oxidative species concentrations, which in turn damages muscle cells. They also suggest that the exercise-associated changes in these markers are the best indicator of the ability of humans to withstand physical activity. In our application to training recovery then, hypothetically, an athlete’s plasma concentration of these key markers following a workout would tell us how much recovery would be needed for a successive work-out. Or perhaps, more imaginatively, some of these markers could be used to: i) indicate readiness for the next training session; or ii) quantify the individual severity of the previous training session.

The Central Fatigue Hypothesis

The central fatigue hypothesis suggests that the brain acts as a protective mechanism to prevent excessive damage to the muscles. Central fatigue, if it is the chief mechanism in training recovery, may be more problematic than peripheral fatigue. In central fatigue, unspecified signals may change brain chemistry such to stop or decrease exercise or work. Manipulating both these signals from the periphery and then the central factors in an attempt to speed training recovery doubles the challenge of achieving training recovery. Davis et al. (9) promote the idea that central fatigue is driven by serotonin (5-hydroxytryptamine). They hypothesize that carbohydrate or branch chain amino acid ingestion may mitigate 5-hydroxytryptamine increases thereby reducing fatigue. However, they conclude that there is little research support for this hypothesis.

Noakes (29) in a review argues that a central neural governor controls cardiac output by limiting the volume of skeletal muscle that can be activated during maximal exercise while the muscles are hypoxic. His conclusions are based on electromyography of mucular activity as well as cardiovascular function during maximal muscular exercise at varying conditions of hypoxia, normoxia, and hyperoxia. St. Clair-Gibson et al. (37) make an interesting argument against peripheral disturbance as the sole cause of fatigue.

They suggest that if depletion of energy stores were a prime cause of fatigue, and absolute, then cell death and rigor mortis should occur. Likewise, if peripheral metabolite accumulation were a principle cause of fatigue, then that would eliminate any possibility of any increase in exercise intensity late in exercise, such as that shown by Kay et al. (19). Following this line of thinking they suggest that the central governor mechanism is responsible for preventing such extreme and negative sequelae. In contrast, Enoka states (11) that different types of exercise produce different central factors as well as different muscle cell responses. Also, it might be argued that a peripheral safety mechanism would offer the advantages of both specificity and proximity. Abbiss and Laursen (1) make the very reasonable suggestion, based on foundational work by Lambert, Noakes, and others, that peripheral feedback from the muscles is integrated in a nonlinear fashion with other centrally located senses (e.g., internal clock, memory of past exercise experience, motivation) to produce a central governor to protect the body from injury (19). This seems to agree with Boerio et al. (3), who investigated central and peripheral fatigue in 10 healthy active males. Maximal torque of the plantar flexors significantly decreased by almost 10% following 13 minutes of electrostimulation, and central activation was also reduced as interpreted from twitch interpolation. They interpreted their data to suggest that both central and peripheral fatigue were evoked by a single bout of electrostimulation.

Peripheral Fatigue Hypotheses

Over the years, the concept of fatigue has been explained in many ways according to the understanding of the phenomenon at that time. One of the earliest hypotheses regarding peripheral fatigue was that metabolic products accumulated and interfered with muscle cell function. In 1929, it was noticed that there was a correlation between the appearance of fatigue and accumulation of lactic acid. Since lactic acid accumulation was often associated with a decline in muscle function, it was assumed that the two were related and that lactic acid was possibly causative of fatigue. In 1978, Fabiato and Fabiato (13) supported the idea further by suggesting that acidosis might reduce force production of the contractile proteins. It is clear that metabolic products can directly and indirectly contribute to fatigue in many situations. In addition to metabolic product accumulation, another obvious explanation for fatigue has been exhaustion of muscle glucose supplies. The evidence that glucose deficiency is essential in some types of fatigue is well-supported in the literature. For example, glycogen depletion is accepted to explain fatigue mainly in special situations such as highvolume muscle training. Glycogen synthesis, after depletion during exercise, occurs in 2 major stages (17). The initial stage is a short, 30–60-minute insulin-independent glycogen synthesis phase, in which glucose transporter proteins’ (e.g., GLUT-4) relocation to the muscle cell membrane increases permeability of the membrane to glucose, and thereby enhances muscle induction of glycogen. This rapid phase is followed by a slow phase in which muscle glycogen is captured by muscle cells in the presence of insulin. Ultimate recovery of low muscle glycogen concentration is affected by many factors including insulin concentration and sensitivity, timing, and availability. Immediate intake of carbohydrate rich foods (1.0–1.85g_kg21_h21) after exercise, and, for up to 5 hours, protein and amino acid supplements (for glycogen and muscle tissue synthesis), and muscle contraction seem to be the major factors enhancing glycogen synthesis (17).

These observations suggest that in situations in which glycogen depletion is implicated in fatigue, restoration of glycogen stores is essential to full recovery. Hence, administration of glucose food sources and glucose in combination with amino acids seems a logical strategy for enhancing recovery, which we will discuss later.

Neural Fatigue

Gandevia (14) supports the notion of a central neural fatigue. Gandevia suggests that during sustained muscle contraction, the discharge of motor neurons declines below the level necessary to produce maximal force. Most importantly, Gandevia reports that the brain’s motor cortex shows evidence of reduced output during fatigue (14).

Kay et al. (19) studied fatigue in a group of 11 physically active men and women who performed 60 minutes of selfpaced cycling in a warm and humid environment. After each 10 minutes of exercise, subjects performed 1-minute all out sprints. Power output fell to 87% and integrated electromyography output fell to 77% by sprint number 5, but increased to 94% and 90%, respectively, for the last sprint. This ability to produce almost the full power output on the last sprint was attributed to possible changes in neuromuscular recruitment, central or peripheral control, or the nature of the integrated electromyography. In this study, they also mention the potential contribution of heat storage to fatigue, since fatigue seems to be exacerbated in hot conditions. As Kay et al. (19) point out, neural processes are temperature sensitive, and muscle metabolic properties may also be influenced. In our lab we have observed this ‘‘early fatigue’’ phenomenon for exercise in the heat. However, when the heat storage resolves, the fatigue remains. Though it is apparent that exercise in high temperatures contributes to fatigue, it is unclear what role temperature might play in recovery. We will review some cryotherapy studies later in the paper. Taper as Mitigation of Fatigue in

Training Recovery

Tapering, defined as the insertion of reduced work combined with increased recovery, represents a form of training recovery that is common to swimming and distance running. The idea that tapering is effective in improving performance argues for the value of adequate training recovery. The premise of tapering is that with additional rest, performance can improve. The key objective in taper is to allow for an optimal level of recovery while avoiding detraining. In one review paper, Mujika and Padilla (26) suggest that taper is best accomplished by reducing the training volume whilst maintaining the intensity, often referred to as the quality of training. They suggest that performance can improve between 0.5% and 6.0% due to the improved status of the cardiorespiratory, metabolic, hematological, hormonal, neuromuscular, and psychological systems. They show a broad time for effective taper, suggesting that between 4 and 28 days is optimal. They also conclude that a ‘‘fast exponential’’ taper is optimal, wherein a rapid reduction in volume occurs over 4 days, as opposed to a more gradual reduction in volume. At least some swim coaches see tapering not as an improvement in ‘‘permanent’’ performance (i.e., ability to perform the task), but rather that taper only improves immediate performance as compared to a nontapered immediate performance (i.e., for a particular single event or bout).

One might ask, if an elite performer can improve by as much as 6% by tapering, why not taper very often? The reason this is not typically done is that both athletes and coaches fear that athletes lose substantial training during tapering, and thus, tapering too often will hinder overall performance. Obviously this would be difficult to study, and we know of no systematic investigations of repeated taper. Nevertheless, taper presents a common sport paradigm wherein increased recovery improves performance. If some means can be determined to improve recovery between training bouts, then the quality of training should be improved and improved performance should result (see Figure 4).

Time Course of Training Recovery

Recovery of muscle function is chiefly a matter of reversing the major cause of fatigue or damage. Since the causes of fatigue may be many and varied, depending on the nature of the exercise, there are numerous approaches to restoring homeostasis in the muscle cell. The following sections review the time course of recovery from different exercise exposures. Sayers and Clarkson (32) studied recovery over hours and days in 98 males and 94 females. Fatigue was induced by 50 maximal voluntary eccentric contractions. Maximal voluntary contraction (MVC) ability was not fully recovered (restored to baseline levels) at 132 hours after exercise. In one group, MVC was not recovered for at least 33 days, and in one subject, MVC had not recovered when last tested after 89 days of recovery. This study is also noteworthy because it used the ability to achieve the same performance matching as a marker for recovery. Also, it provides a good example of training recovery. The use of extensive eccentric exercise, however, may not be realistic. Unfortunately, in a study with good sample size, there was no mention of training status. Gomez et al. (15) studied recovery after a 10-km foot race of 10 experienced distance runners using peak torque, and the total work performed over the last 17 repetitions of a 50- repetition knee flexion protocol. Immediately postrace, 30__sec21 torque, average power, and 17-rep outputs were significantly reduced. They found that only vertical jump ability and the total work for the last 17 reps of the 50-rep test were not recovered after 48 hours, although the other measures had recovered. McLester et al. (24) conducted a series of studies in our laboratory to determine training recovery after bouts of resistance training. In trained males we established a 10-rep maximum (10-RM). Subjects performed 3 sets of 10 repetitions of 8 exercises, all to momentary muscular failure.

Then in counterbalanced order, we had them try to replicate the same workout after 24, 48, 72, or 96 hours of recovery. As expected, the variability among participants was substantial. None of these participants was able to reproduce their 10- RM at 24 hours. This suggests that they were not fully recovered. After 48 hours of recovery, 40% of our subjects were recovered. After 72 hours of recovery, and after 96 hours of recovery, 80% were recovered. When the sets were increased to 7 sets of each to failure, recovery was delayed as would be expected. When older (50 to 65 years of age) trained men repeated the 3-set protocol, recovery was delayed, compared to younger exercisers. For example, in 70% of the cases, participants were unable to replicate their baseline performance even after 96 hours, suggesting recovery was not complete.

Jones et al. (18) replicated the McLester study and examined training recovery reliability. In that study, 10 collegeaged resistance trained males performed 3 sets to volitional failure using a 10RM load for 6 exercises. Recovery was evaluated by the number of repetitions performed following recovery periods of 48, 72, 96, and 120 hours in counterbalanced order. When all 6 exercises were pooled, 80% of participants returned to baseline strength levels after the same recovery duration. However, individual muscle group reliability varied from 20% to 70%. Instability in a participant’s performance was at least partly due to rest, nutrition, prior activity, and other factors. When considering summed repetitions for 6 exercises in our first study (24), we found it took 72 hours for 80% of the participants to return to baseline, but in this study we found that by 48 hours 70% of participants had returned to baseline performance. The groups were different and the 6 exercises examined were also slightly different, but the disagreement between studies is difficult to explain other than that a large number of factors influence recovery. It appears that acute recovery also varies within a given person from one training session to another. In a third study in our lab, Church et al. (unpublished) found that 48 hours was sufficient for most lifters to recover.

METHODS FOR POTENTIALLY ENHANCING RECOVERY

Active versus Passive

There have been a few recent studies published on training recovery. Active and passive recovery have been investigated in both short-term and training recovery. In a training recovery study, Bosak et al. (5) compared the effects of active and passive recovery in n = 12 trained runners after a 5-km run. In a prior study on training recovery, Bosak et al. (4) had demonstrated that our sample of recreational runners were unable to fully recover in 24 hours, but were recovered by 72 hours. Consequently we compared active training recovery to passive recovery at 72 hours (5).We found that active and passive recovery yielded similar performances, incidentally providing some evidence of test-retest reliability of this paradigm. But, we noted that variability did occur among the participants and some runners did benefit more from a particular recovery scheme. It seems unwise to suggest, based on one study, that active recovery, on average, confers no benefits. Even if that is true for 5k running, as Enoka has pointed out (11), it may not be true for other forms of training.

Diet, Ergogenics, and Training Recovery

One interesting explanation of muscle damage consequent to training is that reactive oxygen species are the primary cause of muscle cell damage, rather than mechanical trauma. Regardless of whether this hypothesis is true, many investigators are concerned with the impact of free radicals on human physiology. This leads to interest in the role of potential antioxidants onmuscle status and in our case, training recovery.

Poor diets may cause dietary deficiencies which could contribute to early fatigue in some athletes. Researchers have also found that endurance athletes suffer more iron deficiency than control (27). Iron is lost in sweat, feces, and urine in endurance athletes at a rate of 1.75 mg_d21 and 2.3 mg_d21 (1 mg_d21 and 1.4 mg_d21 in population reference values) in males and females, respectively (40). The benefits of normal levels of iron are extensive, but the one that most directly related to exercise performance is that iron is a key component of the oxygen-carrying protein, hemoglobin. Oxygen transport capacity of blood is a major determining factor of maximal oxygen uptake (V_ o2max). Although iron supplementation is beneficial for anemic athletes, it is still debatable whether or not supplements can benefit nonanemic athletes (28). Clearly adding iron to the diets of athletes in the presence of the associated colinked nutrients is relatively inexpensive.

Creatine has been studied as an aid to recovery. Branch (7) found it to be effective for short duration (,30 seconds) recovery, but not for swimming or running events lasting over 3 minutes. This is in contrast to the review by Misic and Kelley (25), who found that it was not effective in enhancing repeated anaerobic performance. Other ergogenics such as ginseng have not proven consistently helpful either (10). This is important because some ergogenics claim their mode of action is in speeding recovery.

Rehydration and Training Recovery

As Maughan and Shirreffs say so well, restoration of body fluids following an intense competition or training bout is a key part of the total training recovery process (23). As many researchers have demonstrated, restoration of fluids necessitates restoration of electrolytes. For this reason, most rehydration experts recommend inclusion of sodium in concentrations of 50 mmol_L21 or greater, along with some potassium in rehydration beverages. Carbohydrates should be included in rehydration beverages to improve palatability and to aid in the immediate restoration of muscle glycogen stores. It is also generally accepted that the volume of fluid replaced must exceed that amount lost during exercise, because the body is not 100% efficient in retaining that fluid. It is generally accepted that inclusion of appropriate concentrations of carbohydrates and reasonably large volumes of fluid will speed gastric emptying.

Massage Therapy

Massage has gained popularity among athletes as a training recovery modality. This may be in part because it feels good, is not prohibited by any sport governing body, and has no known side effects. Despite these advantages there is little to suggest it is effective in speeding training recovery. Martin et al. (22) studied 10 trained cyclists with 20minutes of recovery. Elevated blood lactate was induced by 3 Wingate tests with a 2-minute rest between bouts. Massage had no impact compared to passive rest; however, active recovery sped lactic acid clearance down to 41% of that immediately after exercise compared to about 62% of the post exercise lactate for passive rest or massage (i.e., active recovery lowered lactic acid by a third more over 20 minutes). This approach raises the question of the role of lactate clearance in training recovery. Whereas lactate clearance may be useful in short-term or immediate recovery, it probably is not a useful marker for training recovery. Robertson et al. (31) used a Wingate performance test to measure recovery along with lactic acid clearance in assorted athletes (n = 9). After six 30-secondWingates with 30-second recovery, participants received either 20 minutes of massage or control (passive rest). There was no effect on lactate clearance or on performance except that the fatigue index (FI) was better for massage at 30% versus 34%. However, in this study, fatigue index was calculated as a percent change of first 5 seconds and last 5 seconds. Fatigue index can be an uncertain marker because it is somewhat dependent upon pacing, even in such a short test. Likewise, how the resistance is applied can influence the first 5-second average. Ice massage is a common medical therapy technique for soft tissue injuries. Howatson and Van Someren (16) subjected 9 recreationally trained males to 3 sets of 10 single-arm biceps curls with a 7-second eccentric phase to induce soreness. Ice massage or sham ultrasound was given immediately and at 24, 48, and 72 hours. Plasma CK, 1-RM, and DOMS were checked at pre- and immediately post-, and at 24, 48, and 72 hours after exercise in a random crossover design. Only creatine kinase (CK) at 72 hours was reduced in the ice massage treatment, from 800 6 680 u_L21 to 197 6 56 u_L21. This study suggests that under these conditions ice massage does not appear to be an effective training recovery method, but specificity of recovery may again be a necessary caveat. Weerapong et al. (41) have recently published a comprehensive review of massage, including a section on massage and recovery. Despite a few studies suggesting there could be a positive effect of massage, there appear to be no welldesigned studies that have shown a strong effect of massage on recovery. Weerapong et al. (41) did report that some studies have shown that massage effectively reduced delayed onset muscle soreness, while others have not seen any effect. One good point made in the review is that the potential psychological benefit of massage on recovery should not be discounted.

Analgesics in Training Recovery

Anti-inflammatory analgesics have been used by coaches and athletes to relieve pain and inflammation consequent to hard training. The hypothesis seems to be that the anti-inflammatory effects would minimize edema, and the analgesic effects would allow more motion and quicker return to training, in both cases due to their differing impacts on prostaglandins (30). Semark et al. (34) tested the impact of prophylactic application of flurbiprofen in 25 rugby and field hockey athletes in a single-blind placebo-controlled experiment. DOMS was induced by 7310 drop jumps. Thigh girth, lactic acid levels after 30-m spring test, CK, muscle soreness, and sprint performances were measured pre- and 12, 24, 48, and 72hours postexercise. The analgesic did not induce any significant differences in performance or any other variable and appeared to have no impact on inflammatory processes. Lanier (20) in a review of nonsteroidal anti-inflammatory drugs (NSAIDs) concluded that NSAIDs were useful in speeding training recovery of muscle function but noted that prophylactic use of NSAIDS may be more effective than therapeutic uses.

Some investigators have reported reduced muscle soreness (20) and creatine kinase activity (30) through the use of non-steroidal anti-inflammatory drugs or analgesics. However, Trappet et al. (39) suggested that ibuprofen and acetaminophen in over-the-counter doses suppressed posteccentric- exercise protein synthesis. An increase, rather than a reduction, in protein synthesis would seem to be more useful in training recovery.

Cryotherapy and Training Recovery

Eston and Peters (12) studied cold water immersion as a recovery therapy in 15 females in a between-group design. DOMS was induced by 835 contractions at 0.58 radians_ sec21 of the elbow flexors. The cryotherapy treatment group immersed their exercise arm in 15_C water for 15 minutes immediately after exercise and 6 more times spaced 12 hours apart. Relaxed elbow angle, and CK activity were lower for the cryotherapy group on days 2 and 3 postexercise, but muscle tenderness, edema, and isometric strength were not different up to 3 days following the exercise.

From our lab, Bosak et al. (6) compared 5km racing performance after 24 hours of training recovery with and without cold water immersion in 12 well-trained runners. Repeated-measure treatments were counterbalanced and separated by 6–7 days of normal training. Run times for the cold water immersion were not significantly different (p = 0.09) from baseline, but the control run times were significantly (p = 0.03) slower than baseline, though these differences were not large. The ratings of perceived exertion at the end of the run were lower for cold water immersion than for control. Seven individuals responded negatively to cold water immersion running and 9 individuals responded negatively to control, running slower than baseline. Three individuals responded positively to cold water immersion and 3 to the control by running faster during second day performance. Cold treatment does seem to have some effect on some aspects of recovery, though its effects on performance varies among individuals.

Combined Treatments

Many techniques and treatments have been tested in all 3 types of recovery in athletes. Research performed in our laboratory (2) assessed the impact on training recovery of concurrent use of ibuprofen, a protein supplement, vitamins C and E, and cryotherapy in 22 competitively trained athletes using a counterbalanced crossover repeated measure design to examine the treatment effect on performance, CK, muscle soreness, and ratings of perceived exertion (RPE). A noneccentric exercise protocol consisting of three 30-second Wingate tests were performed in AM and PM sessions to mimic two-a-day exercise sessions or heats and finals. The treatment improved recovery of mean power and mean power per unit body weight without significantly impacting the other variables: CK, RPE, and muscle soreness (2).

A second study investigated the gender differences in response to these same simultaneous recovery procedures in 11 male and 11 female participants. The antioxidant effects of estrogen and the lower resting levels of CK in females suggested a potential gender difference in response. Using the same design as in the previous study, similar responses of both genders in performance and pain were found. In the treatment condition RPE increased in females but this may have been attributed to a trend towards a slight increase in females’ performance under this condition. The difference in the change in CK levels between genders approached significance (p = 0.059).

MARKERS FOR TRAINING RECOVERY

In our studies of recovery we have strongly favoured performance measures. The obvious advantage of performance as a marker for recovery is that it is the most important variable. The disadvantage of performance is that a ‘‘blunt force’’ approach does not indicate the underlying physiology. Second, repeated maximal performance efforts may not be practical for competitive athletes during the competitive season. Gomez et al. (15) used performance measures not of the same type as the fatiguing exercise. Fatigue was induced by a 10-km run and recovery was assessed through leg peak torques, average power output, and work performed at the end of a 50-rep leg flexion protocol.

An alternative to performance markers of recovery are biochemical or muscle-status markers. Many projects, including those from our lab, have used CK as a marker for muscle damage. Reduced muscle damage suggests less training strain and faster recovery. An issue with CK is that it is difficult to measure, and the measure seems unstable.

Many athletes have elevated CK levels consequent to normal training. Interrupting training long enough to normalize CK would be even more disruptive, in many cases, than performance testing. Other markers to identify muscle damage include myoglobin, calpain, myosin heavy chain and Soricher et al. (36) recommend skeletal troponin I. Lanier (20) suggested that strength recovery was one of the best markers of recovery from muscle injury. She also reports that there are gender and age differences, as well as considerable individual variability in CK response to the same exercise bouts, reducing the utility of CK as a marker for muscle injury, and thus recovery status. Magnetic resonance imagery is also suggested as a means for quantifying muscle injury. Of course these observations are useful only if one is open to including muscle injury as a common occurrence in training. Many of these measurements are not practical for some laboratory investigations and are unlikely to be useful in the near future for repeated field measures in athletes.

ISSUES IN STUDIES OF RECOVERY

Future studies of recovery must utilize trained participants. The issue of recovery may be of interest in untrained participants; however, most untrained individuals are probably limited by immediate factors unrelated to training recovery. Trained participants are different physiologically and psychologically from untrained participants, and thus, results are often not transferable between groups. The fatiguing protocol for studies of training recovery should be specific to the sport in question. Previous protocols intended to induce muscle damage have been chiefly eccentric exercise. Although some athletic endeavors have large eccentric components, many do not. Care must be used in applying the results of eccentric protocols to training recovery studies.

There seems to be some evidence supporting a central governing theory of fatigue. This raises questions concerning training recovery. If therapy is applied to the central governor (as suggested by Davis et al. (9), for example), will that impact recovery? That is, will the central governor overcome any extant disturbance of homeostasis in the muscles themselves, or will it be impossible to reset the central governor before the muscle cells are fully cleaned and fueled? Also, what role would motor neural fatigue play in this paradigm? Fatigue is certainly a major part of training. Coaches may well choose to deliberately reduce recovery in an effort to induce a supercompensation response in their athletes. However, effective super-compensation depends on recovery from a long hard period of training. But, this can only occur when training recovery is adequate.

Enoka’s review(11) supports the notion of specific recovery for specific training. In his review, he supports the central fatigue hypothesis and highlights that variations in intensity, duration and muscle type impacts the role of the various factors responsible for fatigue. Since we all acknowledge the specificity of training, does it not also seem rational to suspect a specificity of recovery? If we take this view, this means that all recovery research must be interpreted in light of the exact nature of the fatigue-inducing training from which we are trying to recover. Clearly, specificity of recovery would make our research challenge much more complex. One of the key issues in training recovery is the identification of key markers of recovery. Performance capability is an ecologically valid measure of recovery but not always practical. Other markers are useful indicators of the mechanisms of recovery, but are often impractical and improvement in these other markers seems much less useful if performance is not improved.

Because we have so little foundational research in this area, we recommend testing combined treatments in training recovery studies. The chief advantage to testing combined treatments is the economy. Historically, few treatments have been shown to aid recovery. Testing these one by one is very laborious. In contrast, the chief disadvantage to this approach is that one treatment could cancel another one which alone may be efficacious. It would seem that the probability of that would be quite low.

PRACTICAL APPLICATIONS

Recovery from training is one of the most important aspects of improving athletic performance. Effective training recovery strategies have not been fully elucidated, and may prove to be specific to the individual athlete and to the point in the competitive season. Coaches may be wise to experiment with different techniques for their athletes, noting which are most effective with which athletes. Likewise, research investigators are encouraged to note and provide individual as well as group mean responses to training recovery strategies.

ACKNOWLEDGMENTS

There was no grant support for this work. There is no conflict of interest.
We thank Dr. Ali Al Nawaiseh for his contributions to some of the key points of this manuscript.
The results of the present study do not constitute endorsement of any product by the authors or the NSCA.

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