Rowing poses something of a unique challenge to the human body at the highest competitive levels, illustrated by the apparent natural selection of individuals most suited to the sport. The demands of top-level performance include enormous local (muscular) and general (cardiovascular) endurance capacities, as well as the ability to produce great muscle tension or force during each stroke. It is perhaps the relatively slow cadence of the activity (about 35 strokes per minute) that distinguishes it from other endurance sports such as cycling (about 110 revs per minute), since a slow rate implies a need for a large tension during each stroke. The training demands of rowing thus include a balance between endurance and strength training.
Over the past century, world championship results have improved by an average of 0.8 seconds per year in a fairly consistent manner. The researcher Secher ('The physiology of rowing', Journal of Sports Sciences, 1983, vol. 1 pp 23-53) has calculated that the oxygen cost of rowing at competitive race speed has therefore increased by approximately 200ml per decade - in 1979 the oxygen cost was calculated at 6.4 l.min-1, which suggests a value of 6.7 l.min-1 at present. However, as in many sports, different factors will have produced an improvement at different times, including technical factors such as boat design and improvements in training methods. It has been estimated that elite rowers expend from 5000-7000kcals of energy per day during heavy training, with obvious implications for diet which must meet this demand from mainly carbohydrate resources. One final competitive arena for rowing that deserves a mention is ergometer rowing which, in recent years, has graduated from purely a training aid into a serious form of competition in its own right.
Tall and heavy
Scientific research into the exact energy (and oxygen) cost of rowing at a particular speed is a complex issue, since each increment in speed does not equal the same increment in energy cost. In fact, an increase in speed at slow speeds costs less energy than an increase in speed at high speeds due to the increased drag of the boat in the water at the higher speeds. Thus the faster rowers need to have considerable strength as well as endurance in order to overcome this resistance. One interesting phenomenon is the fact that the fastest speed of the boat actually occurs during the middle of the seat movement phase when the oars are not in the water. This is due to the movement of the rower's body in the opposite direction to the boat producing an equal force in the opposite direction. This is just one reason why a heavier rower may have an advantage over a lighter one.
To take up this last point, physiological assessments of elite rowers have found them to be both tall and heavy. Heavyweight females average 180cm and 80kg, while heavyweight males average 192cm and 90-95kg. In addition, a particularly long arm length, and especially of the upper arm, has been noted in successful rowers. This latter point clearly suggests a form of natural selection that is obviously unaffected by training and unattainable by those not so gifted. However, the ability of a tall individual to gain lean body mass - which is what appears to be required for success in the heavyweight division - is, of course, under the individual's control through training and diet.
More slow-twitch fibres
The form of muscle tissue that is required for success in rowing is predominantly the slow-twitch fibre type, concentrated particularly round the quadriceps and deltoid muscle groups. These muscles in elite rowers have been found to contain about 75% slow-twitch fibres, compared to about 40% in untrained control subjects - although a relatively higher proportion of fast-twitch fibres has been found in the deltoid muscles of stroke rowers when compared to bow rowers, suggesting an adaptation to many years of training in a specific boat position (Roth et al, 'Force-time characteristics of the rowing stroke and corresponding physiological muscle adaptations', International Journal of Sports Medicine, 1993, Vol. 14 (Suppl. 1) pp S32-S34). In addition to this generally high proportion of slow-twitch fibres, the fibres appeared particularly large, had very high concentrations of capillaries to supply large amounts of blood, and had very high activity levels of the enzymes involved in aerobic metabolism. Even the fast-twitch fibres showed responses and adaptations related to endurance training similar to those listed here. All these factors show a very large training response to endurance activity performed when strength is also necessary, and yet when the movements are generally carried out in a rather slow manner.
Implications for training and development of muscle mass suggest that the best approach would be a gradual increase in body mass over a number of years, brought about as a response to slow-movement, high-tension endurance exercise. Rapid gains in muscle mass in response to exclusive strength training tend to produce increases mainly in the size of the fast-twitch fibres, and this will lead to a reduction in capillary density and aerobic enzyme activity in the muscle, and thus a reduction in endurance performance. Therefore it appears that rowing has a highly specialised physiological demand, which moderate overload through performing rowing exercise itself may be the best primary training mode. Of course, some isolated gymnasium work would be advisable to produce overload, but with the emphasis on simulating the rowing action or its discrete parts at a transferable speed of muscle contraction. Examples of suitable weight-training exercises would be upright rowing, bent-over rowing, dead lifts and high pulls (a continuous action of a dead lift followed by an upright rowing action), with the resistance and repetitions co-ordinated so that local muscular endurance is the factor being stressed. That is to say, don't let the mention of dead lifts automatically produce visions of maximal exertion for three repetitions, as this is not the aim - the correct approach would be relatively high repetitions of at least 30 per set.
Vo2max
In terms of that old favourite of exercise physiologists, VO2max, elite standard rowers have produced among the largest values recorded. When maximal oxygen uptake is expressed relative to body weight, as is the convention for many sports, rowers have reasonably high values of about 65 ml.kg-1.min-1, but when VO2max is expressed in absolute terms (independent of body weight), they have some extraordinary values of over six litres per minute. This is more relevant to rowing because the body mass is obviously supported by the boat. Importantly, when expressed relative to body weight, there is little difference between various standards of rowers, but when expressed in absolute terms, one can distinguish between elite and only average competitive standards. Therefore it appears that the larger the body mass the better, as long as this muscle mass is able to work aerobically, and the cardiorespiratory systems are sufficiently trained to supply the required oxygen. Other specific advantages (from Secher, 1993, cited earlier) of a large muscle mass include: with a boat weight per oarsman in the coxed pair of 41kg, a 90kg rower will have a relative advantage over a 70kg rower of 2% - even in a coxless pair, the advantage remains at 1%; the shorter the distance or time of the race, the better for the heavy rower who will tend to have a larger anaerobic capacity which would then become more important.
Lung function
Within the last five years, increasing scientific attention has been paid to the lung function of rowers. While in most sports, even endurance sports, it is not the performance of the lungs that is the limiting factor to improvements in overall performance, rowers, on the other hand, due to the enormous absolute amounts of oxygen required by their muscles, may be more susceptible than most to limits in performance being caused by inadequate lung function. Maximal ventilation rates of rowers have been observed at up to 240 litres per minute of air transported in and out of the lungs. To put this in perspective, a typical value for an untrained male would be between 100-150 litres per minute during maximal exercise. Whether all rowers could achieve such a high ventilation rate, should their muscles require more than six litres of oxygen per minute, is questionable, and yet it may be advantageous to do so. Recent work by Faulman et al ('A comparison between lung function analysis and a rowing performance test in elite and club standard rowers', Journal of Sports Sciences, 1996, Vol. 14, No. 1, p 81) has added to the growing evidence that elite rowers have superior lung function compared to club rowers.
Two different breathing patterns
A complicating factor in all this is that the respiratory muscles are also used in the actual force production during the rowing stroke, as well as for breathing itself. As a result, the breathing pattern has to be synchronised with the stroke rate, and two breathing patterns have been identified to meet the demands of different rowing speeds. They are: (1) one expiration during the stroke and one inspiration during recovery, and (2) one complete breath during stroke and one during recovery (Steinacker et al, 'Pulmonary mechanics and entrainment of respiration and stroke rate during rowing', International Journal of Sports Medicine, 1993, Vol. 14 (Suppl 1), pp S15-S19).
The research team of Smith et al ('Respiratory responses of elite oarsmen, former oarsmen and highly trained non-rowers during rowing, cycling and running', European Journal of Applied Physiology and Occupational Physiology, 1994, Vol. 69, No. 1, pp 44-49) found that it was only elite oarsmen who could maintain a similar ventilation rate during maximal rowing as during cycling and running, and they suggested that this was possibly the effect of years of training that had slowly overcome the problem of the rowing stroke's interference with breathing patterns.
Unfortunately, it appears that the training responses of the respiratory muscles are relatively smaller and slower to achieve in comparison with typical upper and lower body skeletal muscles, and the key to training them might just be months and years of hard toil. Having said that, even with the limited training effects on maximal ventilation rates, a faster improvement does seem to come in how long a submaximal breathing rate can be maintained, and this is obviously promising. Specific training regimes to improve lung function have yet to be recommended, but if the evidence suggesting that lung function is a limit to performance continues to grow, this may be only a matter of time.
The race itself
Finally, it would be logical, given the above discussion, to consider how a rower might tackle a 2000m race. Analysis of competitions has shown a consistent pattern of pacing during a race, including an initial spurt over the first 40 seconds or so with a cadence of 40-50 strokes per minute, after which the cadence reduces to 34-38 strokes per minute until a 'kick' during the last minute of the race. In this way, the second, third and fourth 500m sections are approximately 8, 10 and 5% longer in duration than the first 500m of the race. Although a race pattern like this will incur a significant oxygen debt and lactate build-up for the owner, this can be tolerated since the race, hopefully, is over within seven or eight minutes.
The production of lactic acid, of course, signifies that anaerobic energy production has taken place, and this is estimated to form about 20-25% of the total energy production. However, aerobic metabolism still predominates, and in fact the initial spurt can increase oxygen uptake over the whole race by as much as 7%. This may be produced through a quicker rise in heart rate, muscle blood flow and ventilation rate, than in an even-paced race. Ventilation rate, therefore, appears to be maximised by the current practices of elite rowers, at least during a single race. It appears as if rowers' practical experience of racing has already indicated the optimum approach to a race, although the jury is still out on possible training advances concerning ventilation.
Alun Williams