Cannavan, D., Coleman, D. R., & Blazevich, A. J. (2009). Acute effects of static stretching on plantar-flexor moment and tendon stiffness. ACSM 56th Annual Meeting, Seattle, Washington. Presentation Number 783.

"Static stretching prior to exercise and/or athletic performance has been found to impair muscular performance. Several investigators have implicated alterations in tendon stiffness, and subsequent alterations of force-length properties, to be a major contributor to this force loss. However, there is limited data examining this issue." This study examined the effects of an acute, moderate duration bout of static stretching on peak active and passive ankle joint moment, neuromuscular activity (EMG), and gastrocnemius tendon stiffness. The study also explored gender-dependent differences in peak moment and tendon stiffness. Recreationally active men and women (N = 30) completed both a general and task-specific warm-up. Passive joint moment, maximal voluntary isometric moment (i.e., MVC corrected for co-activation), and peak EMG amplitude were measured before and after four 45-second stretches taken to the S's tolerable limit. Changes were compared to those recorded in a time-matched control period of no stretching.

Despite a significant stress-relaxation response during the stretching, there were no significant deviations in maximal voluntary isometric moment, peak EMG amplitude in agonist and antagonist muscles, passive moment, or gastrocnemius tendon stiffness after the acute stretching. The response to stretching was similar in both men and women.

Implication. An acute bout of static stretching consisting of four 45-second stretches does not impair the plantar-flexors' ability to generate force or affect gastrocnemius' tendon stiffness in either men or women.

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