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Why high-intensity training is better
than high-volume training

It is probably fair to say that most swimmers and swim coaches see the number of hours spent in the pool as the main ingredient of swimming success, and distances of 6 to 10 kilometres per day are common in elite swimming circles. Is this the key to success, or is there an alternative approach that can produce even better results? This article aims to stir up the debate by suggesting the traditional high-volume model of training will not optimise performance, especially for 100-metre and 200-metre swimmers.

It is written not from a swimming coach's perspective but in the light of research on swim training, scientific analysis of the demands of competitive swimming, and running training methods that have been shown to optimise performance. Swimmers should read on with open minds and may then choose to apply some of the principles to their training programs.

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 done much 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 to 15, reverting to once daily for the rest of the study period. At no stage of the 25-week training did this group show enhanced performance or increased aerobic capacity due to their extra training? It was a waste of time.

In another study, Costill tracked the performance of competitive swimmers over four years, comparing a group averaging 10 kilometres per day with a group averaging 5 kilometres per day to changes in competitive performance time over 100, 200, 500 and 1600 yards. Again, even though one group did twice as much training, both groups benefited significantly in the long term. Improvements in swim times were identical for both groups at around 0.8% per year for all events.

To quote Costill directly: 'Most competitive swimming events last less than two minutes. How can training for 3 to 4 hours per day at markedly slower speeds 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 100-metre and 200-metre swimmers over 44 weeks. 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 most significant improvements were those who performed more of their training at higher paces. The volume of training did not influence swim performance.

Feeling comfortable is not the point

The only conclusion from this research is that faster and no longer training is the key to swimming success. Nevertheless, the high-volume, low-intensity training model probably remains the most common practice among elite swimmers, with even sprint swimmers focusing on clocking up the kilometres rather than more race pace-specific training.

One of the 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 concede that the technical aspect of swim training is essential. However, the idea that high-volume training equates to superior race technique has no logical basis. If you told a 100-metre runner that the best way to optimise his sprint technique at maximum speed would be to complete many miles a week at 10 kilometres 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, the best way to do this is to train at a target race pace. The more training time is spent at the 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, but it may also 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. IThis way, high-volume training can change fast-twitch fibres into the slow-twitch variety.

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 performance improvements. This probably explains why 'tapering' is so effective at improving performance for swimmers, as the fast-twitch fibres can recover during 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.

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 positively during the training?

Examining the demands of sprint swimming events will help answer these questions.

The metabolic demands of swimming

The highly anaerobic nature of sprint swim events would support the argument for more high-intensity and less high-volume training. The shorter the swim event, the greater the demand for the anaerobic energy systems. This is particularly true of the 50 metres, 100 metres and 200 metres events, lasting from around 20 to 120 seconds. From 800 metres upwards, the longer events demand a larger contribution from the aerobic energy system. Evidence for this comes from blood lactate concentrations following 100 metres and 200 metres competition swims, which are a very high 16 to 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.

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 harm performance. This leads to training programs that focus on 'lactate threshold' training to improve lactate turnover and enhance aerobic systems' ability to produce more energy required for the event.

There are two problems with this model of training:

  1. You must be careful about assuming high lactate levels are harmful. Remember that lactic acid is the by-product of the 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 diffuses through the muscle and into the bloodstream, with no evidence to suggest it negatively impacts muscle function or energy production. The lactate ion can be recycled in the energy production cycle and used positively to help produce energy. Therefore, a high level of lactate in the blood is not wrong in itself: it is merely an indicator that a lot of anaerobic energy production is occurring. TThe training adaptation you seek 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;
  2. If you want high power, you have to have high levels of anaerobic energy supply. 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.

For sprint swimming, anaerobic capacity is a good guy, and it needs to be developed. If an event places high demands on the anaerobic system, the athlete needs to become more anaerobic! This may seem odd to those with traditional training beliefs, but it is true. Focusing on high-volume aerobic training to reduce lactate levels compromises your anaerobic fitness, which is essential 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 200 metres, the accumulation of high lactate levels does not matter: indeed, it is probably a good thing as it reflects an excellent anaerobic capacity. For longer events, such as 800 metres and 1500 metres, where the aerobic system is much more critical, 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

All the research mentioned above implies 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 running, the focus of training is now on 'pace' rather than lactate levels or heart rates. By using pace to monitor training intensity, 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 speeds slower than race pace. This training model breeds a philosophy that values high intensity ahead of high volume. If you are a 1500 metres runner, you will complete interval workouts at 400 metres, 800 metres, 1500 metres, 5000 metres and 10000 metres race paces.

The coaches mentioned above also recognise that different events call for additional training. The 5-kilometre running event - which takes about 12 to 15 minutes - requires a high proportion of aerobic training and 5-kilometres pace-specific workouts. In contrast, the 800 metres event, lasting about two minutes, requires a high balance of anaerobic training and 800 metres pace workouts. I would argue that this 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. Increasing your distance per stroke increases the force generated by the active muscles and reaches an optimum position in the water. It is best achieved by high-intensity training to develop power in the water at a race pace.

How can swimmers change their training to enhance power at pace speeds? Again, there may be lessons to learn from running. The 100 metres swim takes about 50 seconds, which is similar to the 400 metres track event; the 200 metres swim takes about 110 seconds and is analogous to the 800-metre 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 800 metres runner will carry out a preparation period of aerobic capacity training with continuous running at 10 kilometres pace and slower, plus interval training at a 5-kilometre pace. The 200 metres swimmer's equivalent could be the usual high-volume training programme.

This base training phase will be followed by more specific training, with more 5-kilometre and 10-kilometre pace runs and more interval workouts for the anaerobic system, at 800 metres and 1500 metres pace, probably about three times a week. The 200 metres swimmer's equivalent could be to maintain a high volume but include more above lactate threshold pace and race pace or close-to-race pace interval workouts three times a week: 10 x 100 metres at 400 metres race pace, with 60 seconds rest.

This phase is followed by a very intense pre-competition phase of training, which aims to maximise the athlete's anaerobic capacity. Aerobic training is cut to a minimum maintenance level, and high-intensity anaerobic sessions at 400 metres, 800 metres, and 1500 metres pace are performed about 5 to 6 times a week. For the swimmer, this could involve a morning swim at a leisurely lactate threshold pace or below, with a high-quality race pace and faster than race pace interval workouts in the evening. For example, 8 x 50 metres at 200 metres race pace, with 60 seconds rest.

The competition phase for runners will 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 to 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 programs with, for example, 10 x turn into 20 metres max sprint with three minutes rest, once a week.

Based on research, analysis of the energy demands of swimming races and the training methods of comparable athletes, I have argued that swimmers should 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.

First-hand Experience

The following feedback, in January 2016, on this approach to training was provided by Grant Bubb, a USA triathlete.

I am currently 33 (male). I ran cross-country and swam as a high school student. I kept running after high school but stopped swimming, mainly due to too much time/volume in the pool as a kid. After not swimming for 15 years, I started swimming again about a year ago for a triathlon I completed last summer. Rather than putting in the long-hours, high-volume, and swim-by-the-clock techniques that I was familiar with from my youth (similar to what you mentioned in your article), I adapted my run training plan to swimming.

I swam two or three times a week, usually one day as interval training (12 x 100m or 6 x 200m) or short distance (3 x 400m) and the other day as long-distance (1 x 2000m). Over time, I found that my 100m swim (1:20) and 400m run (1:18), 200m swim (2:48), and 800m run (2:42), and 400m swim (5:42) and 1-mile run (5:40) average training times are very similar to each other.

Long story short, after 15 years of not swimming and six months of training, swimming only 2 or 3 times a week, no more than 45 minutes at a time, I finished my first-ever 1.9 km open-water swim in about 32:30 (1:41 per 100m) last August. This is a little slower than I can run an equivalent distance of 7.6 km, but it was both open-water and the first leg of a half-Ironman distance triathlon, so I was going all out.

Due to work requirements, I took four months off swimming (Sep to Dec 2015) and started up again about a month ago. Using the same "training program," I have got my 1500m pool time down to about 22 min. While l know that this time won't get me to the Olympics soon, my limited experience over the past year supports your research and shows that low-volume, high-intensity training can be practical and time-efficient.

Although my years in the pool as a child (age 5 - 17, 5-days a week, year-round) certainly helped me develop my technique and might suggest that a non-swimmer may not experience the same success in my "training program" as I have this past year, I think it's a sound training program for someone who already has the basic technique but does not have 10-hours a week to dedicate solely to swimming.

I followed the typical advice for high-intensity interval training, e.g. a 1:1 work: rest interval. The rest interval usually ended up about half the distance of the work interval, as is the case with my run training. So, if my 200-meter work interval took 2:48, I swam easily for 2:48 before beginning my next work interval.

Article Reference

The information on this page is adapted from Brandon (2002)[1] with the kind permission of Electric Word plc.


  1. BRANDON, R. (2002) Why high-intensity training is a better model than high volume training for swimmers, especially sprinters. Peak Performance, 167, p. 8-11

Page Reference

If you quote information from this page in your work, then the reference for this page is:

  • MACKENZIE, B. (2006) Why high-intensity training is better than high-volume training [WWW] Available from: [Accessed