on Nov 25,2014

The issue of specificity

Recently I've been asked a lot about training for sport. Questions like - "should I use any resistance while running, or should I use a weighted club, bat, football, etc to speed up my movement?" Here is a great snippet from James Fisher that takes a look at the research behind skill specificity: relates to an earlier post I quoted from the book "if you like exercise... Chances are you're doing it wrong."

The issue of specificity-

In their position stand [15], the ACSM argued that free weights are preferable to machines for athletes’ strength training because the former can mimic better the movement patterns involved in sporting skills. Surprisingly for such an important claim, the authors provided no research evidence to substantiate it.

There is no evidence that skill development is aided by the performance of resistance exercises that bear some superficial resemblance to skills performed on the sports field. Skill enhancement is highly specific, with little correlation between the performances of different skills, even when they appear very similar. For example, Drowatzky and Zuccato [102] showed that the correlations between performances on dif- ferent (superficially very similar) balance tasks were extremely low and non-significant. They concluded that there is no such thing as a general phenomenon called ‘balance’. Instead, there are many different balancing skills, and because an individual is good at one type of balancing task it does not follow that he or she will be good at a different balancing task.

Not only is the transfer between superficially similar motor tasks quite low, but the performance of tasks in training that are similar (but not identical) to those used in actual performance can lead to negative transfer and a concomitant decrease in performance on the criterion task. For example, Mount [103] ex- amined the effect of learning a dart throwing skill in two different body positions (sitting on a chair and reclining on a table). Not only was performance poorer after switching position compared to remaining in the same position, but performance after practice in the alternate position was poorer than after no practice.

Therefore, the often-made claim that free weights are superior to machines because they improve athletes’ balance, or that Olympic lifting might enhance sport- ing performance due to the forceful extension of the hips, knees and ankles [104] is simply not supported by the motor learning research. The balance involved in free weight exercises is specific to that task and will not aid the athlete unless he or she is a competitive weight lifter, when of course such lifts will need to be practised. Indeed research has shown that the transfer effects of weight training at different loads, velocities and movement patterns are limited [105]. Interestingly, in spite of this, Brewer [104] suggests “when training to enhance sports performance....train the movements, not the muscles”, and attempts to make analogies of move- ment patterns between Olympic lifts and rugby, cricket, judo, tennis and javelin (amongst others).

However, Brewer [104] appears to be offering bad advice as performing exercises that mimic a specificskill with resistance added may interfere with the performance of the relevant skill by altering the ath- lete’s movement pattern. For example, Montoya et al. [106] found that the use of a heavily weighted baseball bat for practice actually reduced the velocity of the swing when using the normally weighted bat. This is hardly surprising as it is impossible to swing a heavily weighted bat as fast as a normal bat, and therefore by slowing the movement down in this manner the athlete is effectively learning to swing the bat more slowly, and will change the mechanics of the swing accordingly. Therefore, movements that mimic the performance of a sports skill with added resistance should be avoided.

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