The Time Course of Musculotendinous Stiffness Responses Following Different Durations of Passive Stretching

Eric D. Ryan, Travis W. Beck, Trent J. Herda, Holly R. Hull, Michael J. Hartman, Pablo B. Costa, Jason M. DeFreitas, Jeffery R. Stout, Joel T. Cramer

DOI: 10.2519/jospt.2008.2843

STUDY DESIGN: Repeated-measures experimental design. OBJECTIVE: To examine the acute effects of different durations of passive stretching on the time course of musculotendinous stiffness (MTS) responses in the plantar flexor muscles. BACKGROUND: Stretching is often implemented prior to exercise or athletic competition with the intent to reduce the risk of injury via decreases in MTS. METHODS AND MEASURES: Twelve subjects (mean age ± SD = 24 ± 3 yrs; stature = 169 ± 12 cm; mass = 71 ± 17 kg) participated in 4 randomly-ordered experimental trials: control with no stretching, 2 min (2_min), 4 min (4_min), and 8 min (8_min) of passive stretching. The passive stretching trials involved progressive repetitions of 30 s passive stretches, while the control trial involved 15 min of resting.  MTS assessments were conducted before (pre), immediately after (post), and at 10, 20, and 30 min post-stretching on a Biodex System 3 isokinetic dynamometer. RESULTS: MTS decreased (P<.05) immediately after all stretching conditions (2_min, 4_min, and 8_min). However, MTS for the 2_min condition returned to baseline within 10 min, whereas MTS after the 4_min and 8_min passive stretching conditions returned to baseline within 20 min. CONCLUSIONS: Practical durations of passive stretching resulted in significant decreases in MTS, however, these changes return to baseline levels within 10-20 min.

J Orthop Sports Phys Ther., Epub 11 July 2008. doi:10.2519/jospt.2008.2843  

KEY WORDS: compliance, passive, stiffness, strain injury, stretch

The authors examine the acute effects of different durations of passive stretching on the time course of musculotendinous stiffness (MTS) responses in the plantar flexor muscles.

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