The hypothetical advantages of muscle stretching performed before sporting activity have recently been questioned due to the fear that this could significantly reduce the development of strength and the production of muscular energy.
Moreover, the different points of view regarding the methodology and the results of the researches, have hindered the reaching of a unanimous consensus by sports professionals. This is because there is no specific and detailed review, as the literature only describes the muscular response to static and acute stretching.
A 2012 review entitled " Effect of acute static stretch on maximal muscle performance: a systematic review ", sought to shed more light by bringing together the results of the most significant experiments.
The authors searched in: MEDLINE, ScienceDirect, SPORTDiscus and Zetoc. The selection criteria included controlled clinical trials (randomized or quasi-randomized) and publications (in scientific journals) that examine the effect of an acute static stretch in maximal muscle performance.
106 articles met the inclusion criteria for the review. However, the design of the study was rather meager, because as much as 30% of the sources did not provide an adequately reliable statistic.
Contrary to what one might believe, this is nothing short of clear evidence that static stretching of less than 30 seconds does NOT produce negative effects on strength, with significant clues that exclude any compromise up to 45 seconds.
A sigmoid dose-response effect between the duration of the stretching, the probability and the magnitude of the significant decreases on the force is shown; the increase in probability referred to elongations greater than or equal to 60 seconds is therefore evident.
This dose-response effect appeared to be independent of the type of performance, the contraction mode and the muscle group.
Studies have examined only changes in eccentric strength after stretching for more than 60 seconds.
In conclusion, in the clinical subjects, healthy and athletes, the negative effects of static stretching on strength are mainly referred to those of long duration (over 60 seconds), which are generally not used during the pre-exercise preparation. On the other hand, lengthening stretches (<60 seconds) can be applied in the pre-exercise routine (without running the risk of compromising maximal muscular performance).
