By: Dr Richard Godfrey and Greg Whyte
From: Elite Rowing: Maintaining Maximum Condition
Dr Richard Godfrey is a Senior Research Lecturer at Brunel University and has previously spent 12 years working as a chief physiologist for the British Olympic Association
Greg Whyte FACSM is director of science and research at the English Institute of Sport
Life at the top – how are elite rowers tested and monitored?
Elite rowers subject their bodies to incredibly high levels of physiological stress. So what kind of testing and monitoring is needed to maintain maximum condition during rowing training without complete breakdown? Richard Godfrey and Greg Whyte explain.
Olympic rowing events are conducted over a 2,000m course. The event lasts about 320 seconds (s) to 460s, depending upon the number of rowers in the boat and upon competition classification eg heavyweight (now more commonly referred to as ‘open weight’), lightweight, men or women, sculling or rowing. Furthermore, performance, as measured on the water, also depends on external factors, including the environmental conditions ie water temperature, wind speed and direction, and air temperature.
The advent of rowing ergometers has facilitated training by providing a controllable and repeatable tool in the assessment of rowing performance. Performance over 2,000m on a rowing ergometer is dependent upon the functional capacity of both the aerobic and anaerobic energy pathways, with the relative amount of energy derived from anaerobic metabolism being 21-30%(1).
The study of physiological characteristics of rowers has revealed that power at VO2max, VO2 at lactate threshold (LT), maximum power production and power at a blood lactate of 4mmol.L-1 are the most important predictors of 2,000m rowing ergometer performance in elite rowers(2). (The use of power output at 4mmol·L-1 blood lactate level has been used by a number of coaches and is widely agreed to be important predictor of performance.) However, of the measures listed it is generally agreed that power at VO2max is the strongest aerobic correlate of performance (a finding similar to that seen for endurance running).
Of the short-term maximal effort tests, maximum force and power production are the strongest correlates of rowing performance. Elite rowers sustain, on average, 77% of maximum power during a 2,000m time trial(1). Thus, if all other determinants remain the same, the greater the maximum power, the greater the average power and resultant speed.
The results of ‘off-water’ ergometer studies indicate the importance of higher intensity parameters (power at VO2max and maximum power) in rowing performance. Given this fact, it is perhaps surprising to note that most international teams utilise vast volumes of low intensity training for competition preparation(3). It must be remembered however that sub-maximal economy is important in underpinning power at VO2max, and thus the importance of training that is focused on improving economy and sub-maximal parameters should not be ignored. This type of training typically consists of a number of sessions per week dedicated to lactate threshold training, which has the dual advantage of improving submaximal economy, and improving the power output that can be sustained.
Weight and gender differences
There are significant performance differences between male and female and between heavyweight and lightweight rowers. On the ergometer, researchers have shown that male rowers were on average 7.7% faster than their female counterparts(2). Results from World Championships and World Cup single scull events, suggest that this difference is increased to 10.9% on-water (there are subtle relationships between technique and power delivery which make on-water rowing harder than ergometer rowing, but why the difference is greater between ergometer and on-water rowing in women is not known).
The difference between heavyweight and lightweight rowers was 5.5% on-ergometer compared to 4% on-water. While heavyweights are faster than lightweights, research suggests that any increase in body mass should be primarily composed of functional (lean) mass to effect a change in ergometer/boat speed. This is particularly true for lightweight rowers and requires the right combination of diet, rowing-specific ergometer and on-water work, coupled with weight training, which ensures the development of an appropriate functional mass.
In describing the physiological components that are necessary for good rowing performance it must be remembered that anthropometric (ie height, limb length), technical (ie stroke length, stroke rate) and psychological factors are also crucial elements of that performance. Assessing the physiological aspects of performance is important in the profiling of athletes, as this allows the design of better training programmes, which in turn improves adaptation.
The physiological assessment of the rower should aim to test the range of physiological requirements of rowing performance, both aerobic and anaerobic. The following section outlines the range of tests employed by physiologists to assess elite rowers in laboratory and field (on-water or on ergometers in the boathouse or gym) settings.
Laboratory testing for rowers
Rowing is a strength-endurance sport with a large aerobic component. A number of endurance sports have been proposed as the ‘most aerobic’, including cross-country skiing and running. But when scaling is used (that is a mathematical technique to allow individuals of different sizes and weights to be compared) then heavyweight rowers come out on top (4,5).
Heavyweight rowers are large individuals with an average height of 1.93m and average weight of 93kg. Although their body fat values tend to be slightly higher than their lightweight team-mates, they still carry considerable muscle mass.
Elite rowers require the ability to generate moderate to high forces and sustain efforts for six minutes (the average time to complete 2,000m in competition at World Championships or Olympic games). Physiology support in the laboratory is therefore designed to examine the current conditioned state of the individual with respect to body composition, muscle power and force, aerobic power and sustainable percentage of maximal aerobic power.
Body composition testing is particularly important for lightweight rowers because they cannot afford to be carrying excess ‘non-functional’ weight (ie body fat).
As mentioned previously, it is important to measure maximal aerobic power (VO2max) and the percentage of maximal aerobic power that can be sustained. To do this the discontinuous incremental protocol (commonly referred to as a ‘step-test to max’ and shown in figure 1) is the usual test used.
In the lab, testing occurs on a Concept 2 Model C rowing ergometer, the kind of rowing machine found in most health clubs. There is a difference however, as (unlike the standard rowers) the lab ergometer is also fitted with a special force transducer at the handle, so that the force produced by the rower can be directly and very accurately measured.
On this equipment, a test is first carried out to examine strength and power. Before the test begins the rower performs a 10-minute warm-up followed by some light stretching. A specific warm-up is then completed using hard efforts of two, three, and four strokes prior to starting the test. For the test itself, the rower is instructed to carry out seven strokes as hard as possible at a rate of 30 strokes per minute. From this test, work (in joules), mean force (in newtons), mean power (in watts), stroke rate (strokes per minute, spm) and stroke length (in metres) are reported from the last five strokes.
Elite rowers are often asked to perform 2,000m time trials on the ergometer in training, and so will have a recent 2,000m time. If a young rower visits the lab for the first time it can be difficult to know what intensity to start the step test at. However, a means of determining this has been devised.
The time for 2,000m should be converted into a 500m split time. For heavyweight men and women add 15 seconds to this time and you have the split for the third stage of the step-test. For the power output that equates to the time for stage 3, subtract 25 watts to get the power output (and split time) for stage 2 and subtract 50 watts for stage 1. For stage 4 add 25 watts and for stage 5 add 50 watts. For lightweight men and women, also add 15 seconds to the calculated 500m split time to find the split for the third stage. However, it may be more appropriate to use 15-20 watt increments (rather than a 25 watt increment) to calculate subsequent stage workloads(5).
During the step test the rower wears a heart rate monitor and a mouthpiece for collection and analysis of expired air, and every four minutes the rower stops to have an earlobe blood sample taken for blood lactate analysis.
The heart rate associated with LT can be used to determine a number of heart rate zones that can be used for training, and, after a few weeks, improvements in endurance are detected as a rightward shift of the lactate curve.
For the final stage of testing, the individual is asked to cover the furthest distance possible (at a relatively even pace) in four minutes. Traditionally, laboratory-based blood lactate measuring equipment such as Analox, Yellow Springs or Eppendorf lactate analysers have been preferred, as their validity and reliability has been tested and is well known. Although it is possible to use new ‘palm top’ lactate analysers, their validity and reliability continue to be questioned.
The data collected and calculated from the step test includes VO2max, power at VO2max, the percentage of maximum that can be sustained (ie at lactate threshold as a percentage of VO2max), power at LT and power at reference blood lactate vales of 2 and 4mmol.L-1
Field-testing for rowers
Many elite sports routinely enjoy a physiology support programme and hence, coaches and athletes have greater experience of sports science. As a result, coaches in many sports are increasingly demanding that field-based testing replace laboratory-based testing. However, coaches and athletes rarely have the training and experience of professional sports scientists and, while many physiologists are not averse to an increase in the use of field-testing, it is very difficult to justify the elimination of laboratory-based testing altogether.
Laboratory-based testing provides an objective set of data collected under standardised conditions(5). This level of standardisation and objectivity could never be achieved in the field. However, field-based data has greater sports specificity, something which is very difficult, or is impossible, to achieve in a laboratory-based simulation of the sport. Accordingly, GB elite rowers are still lab tested two to three times per year with 4-5 field-based (step-test) sessions. To supplement this, the coach also carries out some performance tests such as, 18km, 30minute, 2km or 250m rows. On some occasions blood samples can be taken (by a physiologist) at the end of such rows, or the 18km row can be broken into 3 x 6km rows with a 30-60 second rest interval for blood samples to be taken.
At field camps overseas, early morning monitoring is routinely carried out prior to daily training. This involves the measurement of urine concentration to monitor hydration status, blood urea, body mass and resting heart rate to examine how the athlete is coping with the physical stress of exposure to a new, often extreme, environment, coupled with normal training. All of these measures are viewed in combination with a psychological inventory and some discussion with the coach and athlete. As a result, the coach decides on whether any modification of training is required for certain individuals as a consequence of this plus on-water and gym-based data.
Originating in Eastern Europe, the use of altitude training camps in rowing has become commonplace. Elite rowers may ascend to altitude for training camps lasting up to 3 weeks on as many as three occasions per year. Altitude results in a lower availability of oxygen to the working muscles, due to lower barometric pressures, and this reduced availability of oxygen results in an increased physiological stress both at rest and during exercise.
The primary purpose of altitude training is to capitalise on the adaptations associated with this increased physiological stress, which is suggested to increase red cell mass and haemoglobin concentration and hence, increase oxygen carrying capacity.
Unfortunately, these adaptations come at a price; altitude has a number of undesirable effects that can affect the health and performance of the rower including; sleep disturbance, dehydration, glycogen depletion, immune suppression and an increased incidence of illness including upper respiratory tract infections and gastrointestinal upsets. Altitude training can even lead to a reduction in performance due to a relative deconditioning associated with an enforced lowering of training intensity(6).
It is for these reasons that monitoring rowers at altitude is crucial to optimise the beneficial effects and reduce the adverse effects of low oxygen availability. Physiological monitoring of the rower at altitude is based upon assessing sleep quality, recovery, hydration and training intensities. Recent advances in the simulation of high altitude environments at sea level by reducing partial oxygen pressure (ie reduced O2 concentration) in chambers, tents and face masks has led to new opportunities in the use of hypoxia (low oxygen) for training and competition(6).
The functional capacities of the aerobic and anaerobic energy systems are important in 2,000m rowing, and performance and power at VO2max, VO2 at lactate threshold, power at a blood lactate of 4mmol.L-1 and maximum power production are the most important predictors of 2,000m rowing ergometer performance in elite rowers. Laboratory-based testing is centred on step and maximum power tests and body composition assessment, while field-testing includes ‘on-water’ tests such as 18km, 30minute, 2km or 250m rows and lactate measurement following set pieces.