Science of Sport: Strength training - When it comes to strength training, athletes need to be treated as a ‘special population’

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Sport scientists, coaches and trainers are becoming increasingly aware of a worryingly wide gap between the findings of strength training studies, as reported in the scientific journals, and what is applicable in the field. More specifically, there is a need for studies that investigate the training responses of competitive athletes directly rather than making inferences based on studies of non-athletes.

Findings from strength training studies have been generalised in order to establish guidelines for the frequency, volume and intensity of strength training likely to produce the greatest gains in trained and untrained subjects respectively^(1,2). However, such ‘dose-response’ relationships have not been identified in competitive athletes until recently.

A study published last year set out to investigate the relevance of the strength training literature to competitive athletes⁽³⁾. The authors conducted a meta-analysis (review of pooled data) of 37 individual studies involving competitive athletes from a range of sports and athletic backgrounds. Their aim was to identify the ‘doses’ of training frequency, volume and intensity that produced the greatest measured strength gains and to generalise the doseresponse relationship from these findings.

Their key finding was that the training parameters found to optimise strength gains in competitive athletes differed markedly from those identified by similar studies on non-athletes. Specifically, the training volume (sets per muscle group), training frequency (days per week for each muscle group) and training intensity (resistance load) found to be most effective in a range of studies were very different for athletes from those applying to non-athletes – even those experienced in strength training.

The researchers concluded, quite naturally, that competitive athletes appear to exhibit different training responses from even recreationally trained non-athletes. Given this divergence, it would seem unwise – unsafe even – to generalise from findings about non-athletes, as has happened in the past.

The performance pressures on competitive athletes are vastly different from those on recreationally trained individuals. So perhaps we shouldn’t be too surprised that their training needs are also different. On this basis, elite performers need to be treated as a special population.

It is increasingly common these days for training guidelines to make distinctions based on individual training status and experience. An extensive analysis of the strength training literature (covering 140 studies in total) identified a continuum of optimal training variables for maximal strength gains, depending on individual training status and experience⁽⁴⁾.

Training intensity

Maximal strength gains are demonstrated in untrained individuals when training at an average intensity of 60% 1RM (Repetition Maximum) and in strength-trained individuals when training at 80% 1RM. Competitive athletes appear to inhabit a territory still further along this continuum; and, in recognition of their specific needs, the American College of Sports Medicine (ACSM) recently updated its guidelines to include training prescriptions specifically for elite lifters⁽²⁾. However, attempts to treat competitive athletes as a special case are bedevilled by a lack of relevant data – particularly on team sports athletes – on which training prescriptions can be based.

There is an inevitable trade-off between obtaining access to these athletes as subjects and imposing the kind of scientific rigour that generates valid results. Counterbalanced study design requires a control group to act as a baseline for comparison with a ‘treatment’ group. But the problem is that the more beneficial a ‘treatment’ is perceived to be, the harder it is to accept no treatment or a placebo in its place.

As the demands and profile of competitive sport continue to increase and the financial stakes continue to rise, there is a proportionately increased emphasis on athletes’ physical preparation, including strength training and conditioning. In this climate, no coach to a professional team would agree to having half the squad perform entirely different training, or even no training at all, to satisfy experimental protocol. Similarly, players would naturally be averse to having their chances for selection – and ultimately winning a contract – jeopardised by receiving inferior physical preparation as a result of being randomly assigned to the ‘wrong’ experimental group.

But in view of the doubts about the applicability of findings from studies on non-athletes and the lack of objective data relating to athletes, there is a critical need to gather information about this group. Until this can be done, strength and conditioning coaches in the majority of team sports will be without a quantitative basis for strength training prescription for their sport.

Given the time constraints imposed by extended playing seasons and the high volumes of concurrent training and team practices common to all professional team sports, the effectiveness of physical preparation is paramount. This data vacuum is therefore a critical issue. In the absence of specific objective data relating to their sport, coaches will continue to use their own observations and training experience as the basis for designing training programmes, and athletes’ physical preparation will continue to be adversely affected as a result.

However, from the data that is available, some suggestions for the kind of training volumes, frequency and intensity relevant to competitive athletes can be derived. A mean training intensity of 85% 1RM has been found to have the greatest effect in competitive athletes in the majority of relevant studies. This equates to 6RM – ie the greatest weight that can be lifted for six repetitions when lifting to failure. It is also in general agreement with the recent finding that loads greater than 80% 1RM were necessary to maintain or improve strength throughout the playing season in American college football players⁽⁵⁾.

This requirement for greater average intensity appears to be a common theme for athletes as a special population. Training studies featuring protocols in which the athlete subject group lifted to failure report greater average strength gains. Accordingly, there is a need for strength training regimes for competitive athletes that stipulate the athlete must lift to failure at the specified load, as training at lesser intensities has been shown to elicit minimal improvements.

Training frequency

In terms of frequency of strength training, recommendations are based on the number of times per week individual muscle groups should be trained. Data from athletes has shown that it is similarly effective to train a particular muscle group on two or three days a week. How many strength training sessions per week this equates to will depend on the design of the workout. It could mean two workouts per week if both workouts involved whole-body sessions. On the other hand, if a ‘split routine’ format is used to work on particular muscle groups independently, it could equate to four or more strength training sessions per week. Given the time constraints imposed by many team sports, the whole-body format is likely to be more time-efficient.

Strength training volume recommendations for competitive athletes are also made for individual muscle groups. A mean number of eight sets per muscle group per week have been found to maximise strength gains in groups of athletes. By contrast, most studies on nonathletes (both strength-trained and untrained) have found four sets per muscle group per week to be effective in evoking maximal strength gains. These observations reinforce the specific needs of athletes as a special population.

As far as training mode is concerned, exercise selection must be addressed on an individual basis, based on a ‘needs analysis’ for the particular sport and the individual athlete. This should include biomechanical analysis of the movements involved in match play and profiles of injury risk for that specific sport, as well as the biomechanical peculiarities and injury record of the athlete.

In conclusion, data from studies on competitive athletes reveal demonstrable differences between their strength training needs and those identified for non-athletes. Some strength training guidelines for competitive athletes have been suggested in this article, based on the limited data available.

Further research, which directly assesses the training responses of competitive athletes, is required in order to firm up and develop these guidelines. This is critical to providing coaches in professional sports with an objective basis for their strength training programmes and thus, ultimately, to optimising performance in these sports.

It is well recognised that randomised controlled scientific studies are the best route to valid results but, where professional athletes are concerned, some compromises on experimental design are likely to be needed.

Paul Gamble

References

1. Medicine and Science in Sports & Exercise 30: 975- 991, 1998
2. Medicine & Science in Sports and Exercise 34(2): 364-380, 2002
3. Journal of Strength & Conditioning Research 18(2): 377-382, 2004
4. Medicine & Science in Sports and Exercise 35: 456-464, 2003
5. Journal of Strength & Conditioning Research 17(1): 109-114, 2003

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