Do practical durations of stretching alter muscle strength? A dose-response study

Eric D. Ryan, Travis W. Beck, Trent J. Herda, Holly R. Hull, Michael J. Hartman, Jeffery R. Stout, Joel T. Cramer

Research output: Contribution to journalArticlepeer-review

125 Scopus citations


Purpose: To examine the time course (immediate, 10, 20, and 30 min) for the acute effects of 2, 4, and 8 min of passive stretching (PS) on isometric peak torque (PT), percent voluntary activation (%VA), EMG amplitude, peak twitch torque (PTT), rate of twitch torque development (RTD), and range of motion (ROM) of the plantarflexors. Methods: Thirteen volunteers (mean ± SD age, 22 ± 3 yr) participated in four randomly ordered experimental trials: control (CON) with no stretching, 2 min (PS 2), 4 min (PS 4), and 8 min (PS 8) of PS. Testing was conducted before (pre), immediately after (post), and at 10, 20, and 30 min poststretching. The PS trials involved varied repetitions of 30-s passive stretches, whereas the CON trial included 15 min of resting. PT, %VA, EMG amplitude, PTT, and RTD were assessed during the twitch interpolation technique, whereas ROM was quantified as the maximum tolerable angle of passive dorsiflexion. Results: PT decreased (P ≤ 0.05) immediately after all conditions [CON (4%), PS 2 (2%), PS 4 (4%), and PS 8 (6%)] but returned to baseline at 10, 20, and 30 min poststretching. %VA and EMG amplitude were unaltered (P > 0.05) after all conditions. PTT and RTD decreased (P ≤ 0.05) immediately after the PS 4 (7%) and the PS 8 (6%) conditions only; however, these changes were not sufficient to alter voluntary force production. There were also increases (P ≤ 0.05) in ROM after the PS 2 (8%), the PS 4 (14%), and the PS 8 (13%) conditions that returned to baseline after 10 min. Conclusion: Practical durations of stretching (2, 4, or 8 min) of the plantarflexors did not decrease isometric PT compared with the CON but caused temporary improvements in the ROM, thereby questioning the overall detrimental influence of PS on performance.

Original languageEnglish (US)
Pages (from-to)1529-1537
Number of pages9
JournalMedicine and science in sports and exercise
Issue number8
StatePublished - 2008
Externally publishedYes


  • EMG
  • Muscle activation
  • Range of motion
  • Stretching-induced force deficit

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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