Stretch Exercises Increase Tolerance to Stretch in Patients With Chronic Musculoskeletal Pain: A Randomized Controlled Trial

Background. Stretch is commonly prescribed as part of physical rehabilitation in pain management programs, yet little is known about its effectiveness. Objective. A randomized controlled trial was conducted to investigate the effects of a 3-week stretch program on muscle extensibility and stretch tolerance in patients with chronic musculoskeletal pain. Design. A within-subject design was used, with one leg of each participant randomly allocated to an experimental (stretch) condition and the other leg randomly allocated to a control (no-stretch) condition. Patients and Setting. Thirty adults with pain of musculoskeletal origin persisting for at least 3 months were recruited from patients enrolled in a multidisciplinary pain management program at a hospital in Sydney, Australia. Intervention. The hamstring muscles of the experimental leg were stretched daily for 1 minute over 3 weeks; the control leg was not stretched. This intervention was embedded within a pain management program and supervised by physical therapists. Measurements. Primary outcomes were muscle extensibility and stretch tolerance, which were reflected by passive hip flexion angles measured with standardized and nonstandardized torques, respectively. Initial measurements were taken before the first stretch on day 1, and final measurements were taken 1 to 2 days after the last stretch. A blinded assessor was used for testing. Results. Stretch did not increase muscle extensibility (mean between-group difference in hip flexion was 1 degrees, 95% confidence interval = -2 degrees to 4 degrees), but it did improve stretch tolerance (mean between-group difference in hip flexion was 8 degrees, 95% confidence interval=5 degrees to 10 degrees). Conclusion. Three weeks of stretch increases tolerance to the discomfort associated with stretch but does not change muscle extensibility in patients with chronic musculoskeletal pain.