In the aim of improving athletic performance or to prevent injury or to enhance an athlete’s abilities, it is common to read that the muscles should be balanced. What this means is never fully explained but is taken for granted that somehow the muscles on both sides of a joint should be equal in strength. As a result, you are advised to do equal training for the muscles on both or all sides of the joint.
This is done in the aim of obtaining or maintaining symmetry which means that you are balanced not only on all sides of a joint but from the left side of the body to the right side as well as from the front to the back of the body. Is this, however, always the wisest thing to do in relation to high-level athletic performance?
From the few studies done on this topic in the past and from observation of many high-level athletes, I have come to the conclusion that it may not be an effective means of improving performance. It appears that most high-level athletes are asymmetrical!
This should not be surprising if you have been looking closely at high-level athletes. You will find that almost all of them have the muscles that are involved in execution of the main skill overdeveloped. For example, tennis players have much larger forearms in the arm that holds the racket, sprinters and throwers have larger thighs than most other athletes, professional golfers have much larger erector spinae muscles on the left side of the body and most throwers have a tendency to be round shouldered because of an overdeveloped chest. In regard to runners, I have yet to see one who had perfectly balanced leg drives in regard to height and direction.
If you try to balance muscular development it will interfere greatly with the athlete’s performance. Keep in mind that this muscular development is not only a consequence of their training but also what the sport demands. To take time out of their training to balance the musculature would interfere with other more productive types of training.
This does not mean that they do not do exercises to develop the muscles on opposing sides of the body or limb. They do many exercises for this purpose but they are typically done in the general preparatory period, not in the competitive or precompetitive periods. These exercises done mainly for the prevention of injury and to allow better development of the main muscles involved in the sport.
According to a former Soviet study, asymmetry appears to be a key to their success. They believe there may be some factor, still unknown, that produces this asymmetry but which also allows them to go above and beyond what other ”well-balanced” athletes are capable of doing. It seems that the asymmetry lends itself to allowing the athlete to perform on a higher level.
The final answer may not be in yet but there is enough evidence to indicate that perhaps we should not be anxious to “balance” everyone’s development. Keep in mind that this does not mean that you ignore development of the antagonistic muscles. You do not. But you do not emphasize them to the same extent as you do with the main muscles involved in the sports skill.
For more information on development of a high-level athlete see Build a Better Athlete.