Stretching

Why do they play such an important role in sports beliefs ?

Stretching has been the subject of debate for several years now, with its application, optimal duration and, most importantly, physiological effects being disputed by many. Overall, the analysis of individual studies showed that there was no evidence for improved recovery with stretching compared to passive recovery (i.e. rest) or other recovery modalities (cryotherapy, active recovery). However, there was also no evidence to the contrary, i.e. that stretching impaired recovery (1). In pre-game, it is nevertheless interesting to use activo-dynamic or ballistic stretching in order not to create micro-lesions before an effort. 

Stretching can play an important role in muscle recovery, but not by using this notion only in post-exercise. Why ? 

One of the important aims of this technique is to increase the range of motion and decrease the resistance to stretching, thus providing the muscles with a freer pattern of movement during sports activities (2). The body will thus be faced with greater flexibility in the face of stress, reducing the risk of micro-lesions responsible for muscle soreness. It has been shown that subjects who stretch after intense exercise show a much greater decrease in performance and, at the same time, an increase in muscle soreness compared to individuals who stretch regularly. According to Nosaka et al, this reduction in muscle stiffness would be beneficial in preventing the onset of muscle damage (3). These studies show that it is far more beneficial to organise regular stretching routines than to stretch only after games or training sessions, and it is this initial flexibility that will improve recovery after an activity, not the stretching itself.  

But physiologically, what happens during stretching ?

Stretching makes the muscle-tendon unit more flexible, allowing greater shortening of the muscle when muscle contractions are initiated at longer muscle lengths. This allows for greater cross-bridge formation and results in a change in the joint angle at which maximum torque occurs (force exerted as a function of muscle length at a specific angle). It also allows for a change in the angle-torque relationship by decreasing torque or force production at short muscle lengths and increasing torque production at long muscle lengths (2). In summary, increased flexibility changes the angle-torque relationship to allow for greater relative force production at longer muscle lengths, allowing the muscle to be used to its fullest potential when loaded (4) (5).

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