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

Joel T. Cramer, Terry J. Housh, Glen O. Johnson, Travis W. Beck, Jared W. Coburn, Joseph P. Weir

DOI: 10.2519/jospt.2007.2389

STUDY DESIGN: Repeated-measures experi­mental design. OBJECTIVE: 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. BACKGROUND: 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. METHODS AND MEASURES: Fifteen men (mean 6 SD age, 23.4 6 2.4 years) performed maximal eccentric isokinetic muscle actions of the dominant and nondominant knee extensor muscles at 60°·s–1 and 180°·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 (°), 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. RESULTS: 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≤.05) that were unrelated to the stretching intervention. CONCLUSION: These results suggest that static stretching does not affect maximal eccentric isokinetic torque or power production, nor does it change muscle activation.  

J Orthop Sports Phys Ther. 2007;37(3):130-139. doi:10.2519/jospt.2007.2389 

KEY WORDS: EMG, muscle activation, muscle stiffness, stretching-induced force deficit

The results of this study suggest that static stretching does not affect maximal eccentric isokinetic torque or power production, nor does it change muscle activation.

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