An Acute Bout of Static Stretching Does Not Affect Maximal Eccentric Isokinetic Peak Torque, the Joint Angle at Peak Torque, Mean Power, Electromyography, or Mechanomyography

Abstract

Repeated-measures experimental design. To examine the acute effects of static stretching on peak torque, the joint angle at peak torque, mean power output, and electromyographic and mechanomyographic amplitudes and mean power frequency of the vastus lateralis and rectus femoris muscles during maximal eccentric isokinetic muscle actions. A bout of static stretching may impair muscle strength during isometric and concentric muscle actions, but it is unclear how static stretching may affect eccentric force production. Fifteen men (mean +/- SD age, 23.4 +/- 2.4 years) performed maximal eccentric isokinetic muscle actions of the dominant and nondominant knee extensor muscles at 60 degrees x s(-1) and 180 degrees x s(-1) on an isokinetic dynamometer, while electromyographic and mechanomyographic amplitudes (root-mean-square) and mean power frequency were calculated for the vastus lateralis and rectus femoris muscles. Peak torque (Nm), the joint angle at peak torque (degrees), and mean power output (W) values were recorded by the dynamometer. Subsequently, the dominant lower extremity knee extensors underwent static stretching exercises, then the assessments were repeated. There were no stretching-related changes in peak torque, the joint angle at peak torque, mean power output, electromyographic or mechanomyographic amplitude, or mean power frequency (P > .05). However, there were expected velocity-related, limb-related, and muscle-related differences (P < or = .05) that were unrelated to the stretching intervention. These results suggest that static stretching does not affect maximal eccentric isokinetic torque or power production, nor does it change muscle activation.