Research into the effects of high-volume swim training on performance suggests there is no advantage to piling on the kilometres. The legendary US physiologist Dave Costill has undertaken a great deal of research on swim training over the last three decades. In one study his team of scientists followed two groups of swimmers over a 25-week training period. Both groups began with once daily training, but one group moved to twice daily training in weeks 10-15, reverting to once daily for the rest of the study period. At no stage of the 25-week training period did this group show enhanced performance or increased aerobic capacity as a result of their extra training. Basically, it was a waste of time. In another study, Costill tracked the performance of competitive swimmers over a four-year period, comparing a group averaging 10k per day with a group averaging 5km per day in relation to changes in competitive performance time over 100, 200, 500 and 1600 yards. Improvements in swim times were identical for both groups at around 0.8% per year for all events. Again, even though one group did twice as much training, both groups benefited to the same extent in the long term. To quote Costill directly: 'Most competitive swimming events last less than two minutes. How can training for 3-4 hours per day at speeds that are markedly slower than competitive pace prepare the swimmer for the maximal efforts of competition?' Research from France supports Costill's conclusions. A team of scientists analysed the training and performance of competitive 100m and 200m swimmers over a 44-week period. Their findings were as follows:
- Most swimmers completed two training sessions per day;
- Swimmers trained at five specific intensities. These were swim speeds equivalent to 2, 4, 6 and a high 10 mmol/l blood lactate concentration pace and, finally, maximal sprint swimming;
- Over the whole season the swimmers who made the biggest improvements were those who performed more of their training at higher paces. The volume of training had no influence on swim performance.
Feeling comfortable is not the point
The only conclusion to be drawn from this research is that faster and not longer training is the key to swimming success. Nevertheless, the high-volume, low-intensity training model probably remains the most common practice among élite swimmers, with even sprint swimmers focusing on clocking up the kilometres rather than more race pace- specific training. One of reasons for this high-volume bias is that swimmers and coaches believe that swim technique, efficiency through the water and the 'feel' of the stroke are optimised by spending many hours in the pool. I have heard swimmers say they do not feel as comfortable in the water and confident about their technique unless they complete high doses of training. As a non-swimmer I am happy to admit my ignorance and to concede that the technical aspect of swim training is very important. However, the idea that high-volume training equates to superior race technique has no logical basis. If you told a 100m runner that the best way to optimise his sprint technique at maximum speed would be to complete many miles a week at 10k pace, you would be laughed off the track! Track sprinters focus on workouts and technical drills carried out at high intensity and positively avoid low intensity/high volume training in the belief that it inhibits power development. The same must be true of swimming to a large extent; if a swimmer wants to increase stroke efficiency and technique during a competition, surely the best way to do this is to train at target race pace. The more training time is spent at target race pace, the more comfortable it will feel in competition. Dave Costill says: '...large training volume prepares the athlete to tolerate a high volume of training but likely does little to benefit actual performance'. When swimmers talk of 'feeling comfortable' in the water, they may be referring to the sub-maximal speeds they perform in training, not the maximal efforts required in competition. Not only does high-volume training offer no benefit for swim performance, it may have negative effects. Two known consequences of high-volume training are depletion of glycogen muscle stores and fatigue of the fast twitch muscle fibres, both of which will reduce the effectiveness of high-intensity race pace training sessions and severely compromise any competitive performance. Research has also shown that periods of high-volume training reduce the force production in the fast twitch muscle fibres, which are essential for producing the fastest swim speeds. It has been shown that sprint swimmers have quite high proportions of fast twitch muscles – over 60% in the deltoid and quadriceps. High-volume training does nothing for these fibres: indeed it will dampen their force production by reducing the shortening velocity of the muscle contraction. In this way, high volume training can change fast twitch fibres into the slow twitch variety. This probably explains why 'tapering' is so effective at improving performance for swimmers, as the fast twitch fibres are able to recover during the period of low-volume training. It is known that maximal power increases after a tapering period, probably due to the fast twitch fibres reproducing their high-velocity contraction properties. The French researchers mentioned above analysed the effects of tapering on swim performance and found that swimmers who used the most severe tapers – reductions of about half normal training volume – produced the biggest improvements in performance.
This begs the following questions:
- If such dramatic tapers in training are required to optimise performance, why are training volumes so high in the first place?
- Would it not be better for swimmers to develop power in a positive fashion during the training period?
Examination of the demands of sprint swimming events will help to answer these questions.
The metabolic demands of swimming
The shorter the swim event the greater the demand on the anaerobic energy systems. This is particularly true of the 50m, 100m and 200m events, lasting from around 20 to 120 seconds. The longer events, from 800m upwards, demand a larger contribution from the aerobic energy system. Evidence for this comes from blood lactate concentrations following 100m and 200m competition swims, which are a very high 16-20 mmol / L, suggesting that a great deal of energy is derived from the anaerobic breakdown of glycogen, resulting in lactic acid as a by-product. The highly anaerobic nature of sprint swim events would support the argument for more high-intensity and less high-volume training. Some athletes and coaches go wrong by assuming it is best to do training that will reduce blood lactate concentrations. This philosophy is based on the idea that high lactate is bad and will have a negative impact on performance. This leads to training programmes that focus on 'lactate threshold' training to improve the turnover of lactate and enhance the ability of the aerobic systems to produce more of the energy required for the event.
There are two problems with this model of training
- You need to be careful about assuming high lactate levels are a bad thing. Remember that lactic acid is the by-product of anaerobic breakdown of glycogen. Lactic acid splits into the H+ ion and the lactate ion. It is the acidic H+ ion that is the bad guy, interfering with force production in the muscles and reducing the rate of glycolysis, thus slowing the athlete down. The lactate ion simply diffuses through the muscle and into the bloodstream, with no evidence to suggest it has any negative impact on muscle function or energy production. In fact, the lactate ion can be recycled in the energy production cycle and used positively to help produce energy. So a high level of lactate in the blood is not bad in itself: it is simply an indicator that a lot of anaerobic energy production is occurring. The training adaptation you are seeking is not a reduction in lactate production, but rather an increase in the buffering of the H+ ion. Training at high intensities and so generating high levels of lactic acid helps the body get used to the increase in H+ in the muscles and improve its ability to buffer the acid;
- Anaerobic glycolysis involves the fast breakdown of glycogen into energy-giving phosphates, while aerobic glycolysis involves a much slower breakdown. Without the anaerobic energy systems, maximal power and high speeds would be impossible, as the muscles would not get a fast enough supply of energy. If you want high power you have to have high levels of anaerobic energy supply.
For sprint swimming, anaerobic capacity is the good guy and it needs to be developed. If an event places great demands on the anaerobic system, the athlete needs to become more anaerobic! This may seem odd to those of you with traditional beliefs about training, but it is true. By focusing on high-volume aerobic training to reduce lactate levels you are in fact compromising your anaerobic fitness, which is the most important attribute for competitive success in sprint swimming. For sprint swimmers, lactate-threshold training geared to keeping lactate levels low is, I would argue, irrelevant. For swim distances up to and including 200m, the accumulation of high levels of lactate does not matter: indeed it is probably a good thing as it reflects a good anaerobic capacity. For longer events, such as 800m and 1500m, where the aerobic system is much more important, lactate-threshold training would be relevant, as swimmers need to maintain an intensity level for much longer, relying on the aerobic energy system.
The race pace model of training
The implication of all the research mentioned above is that spending more training time at high-intensity levels, at and above race pace, will offer greater benefits than swimming lots of kilometres per day at much slower than race speeds. In the world of running – thanks to the influence of pioneering physiologists and coaches such as Frank Horwill, Veronique Billat, Jack Daniels and our own Owen Anderson – the focus of training is now on 'pace' rather than lactate levels or heart rates. By using pace to monitor the intensity of training, the athlete is switching into a performance mentality, ensuring the training is specific to the competitive event. Middle distance running coach Frank Horwill created a five-pace system of training, which involves performing regular, quality training sessions at two paces higher than race pace, race pace itself and two paces slower than race pace. If you are a 1500m runner, you will complete interval workouts at 400m, 800m, 1500m, 5000m and 10000m race paces. This model of training breeds a philosophy that values high intensity ahead of high volume. The coaches referred to above also recognise that different events call for different kinds of training. The 5k running event – which takes about 12-15 minutes – requires a high proportion of aerobic training and 5k pace-specific workouts, while the 800m event, lasting about two minutes, requires a high proportion of anaerobic training and 800m pace workouts. I would argue that this kind of training model would serve competitive swimmers much better than the traditional high volume approach. There is evidence that the difference between swimmers who reach the Olympics and those who do not is due more to the distance achieved per stroke than to stroke frequency. The way to increase your distance per stroke is to increase the force generated by the active muscles and achieve an optimum position in the water. This is best achieved by high-intensity training, with the aim of developing power in the water at race pace. How can swimmers change their training to enhance power at pace speeds? Again there may be lessons to learn from running. The 100m swim takes about 50 seconds, and so is similar to the 400m track event; the 200m swim takes about 110 seconds and so is analogous to the 800m running race. It may therefore be possible for swimmers to improve their performances by modelling the training of middle distance and long sprint track athletes. For example, an international 800m runner will carry out a preparation period of aerobic capacity training with continuous running at 10k pace and slower, plus interval training at 5k pace. The 200m swimmer's equivalent could be the usual high-volume training programme.
This base training phase will be followed by more specific training, with more 5k and 10k-pace runs and some more interval workouts for the anaerobic system, at 800m and 1500m pace, probably about three times a week. The 200m swimmer's equivalent could be to maintain a fairly high volume but include more above-lactate-threshold pace workouts and race pace or close-to-race pace interval workouts three times a week: for example, 10 x 100m at 400m race pace, with 60 seconds rest. This phase is followed by a very intense pre-competition phase of training, the goal of which is to maximise the athlete's anaerobic capacity. Aerobic training is cut to a minimum maintenance level, and high-intensity anaerobic sessions at 400m, 800m, and 1500m pace performed about 5-6 times a week. For the swimmer, this could involve a morning swim at an easy lactate-threshold pace or below, with very high quality race pace and faster-than-race pace interval workouts in the evening. For example, 8 x 50m at 200m race pace, with 60 seconds rest. The competition phase for runners will simply maintain aerobic and anaerobic fitness with maintenance training and plenty of recovery between races. For the swimmer this could involve some 'aerobic' slow-speed workouts and some race-pace and sprint workouts, probably limiting training to 5-6 times per week.
The best middle distance runners probably perform a maximal sprint workout once a week throughout the year to keep speed up to scratch. Swimmers could also incorporate this into their programmes with, for example, 10 x turn into 20m max sprint with three minutes rest, once a week. I have argued, based on research, analysis of the energy demands of swimming races and the training methods of comparable athletes, that it is best for swimmers to focus on high-intensity rather than high-volume training. More specifically, swimmers would benefit from plenty of race-pace training to develop power and efficiency in the water at the speeds they use to compete.