The efficacy of dynamic contract-relax stretching on delayed-onset muscle soreness among healthy individuals: A randomized clinical trial

Objective: To evaluate the efficacy of dynamic contract-relax stretching on delayed-onset muscle soreness (DOMS) in the calf muscle of healthy individuals. Design: Randomized clinical trial. Setting: Research laboratory. Participants: Three groups of 16 healthy participants (n 5 48) were recruited by convenience sampling. Interventions: Three sets of resisted bilateral heelraising exercises until exhaustion were conducted to initiate DOMS. Participants were randomly allocated into control group without any interventions, dynamic contract-relax stretching (DS), or static stretching (SS) groups. Dynamic contract-relax stretching and SS groups performed DS and SS, respectively, on the dominant leg twice a day for 5 consecutive days (before time points of outcome measurements at 24, 48, 72, 96, and 120 hours postexercise, respectively). Main Outcome Measures: Muscle soreness, lower leg girth, pressure pain threshold (PPT), range of motion (ROM), and muscle strength were measured before exercise, immediately after, and at 24, 48, 72, 96, and 120 hours postexercise. Results: There was a significant effect of time in all outcome measures including muscle soreness, lower leg girth, PPT, ROM, and muscle strength; however, there were no significant group differences or group by time interactions. Conclusions: The effect of DS on relieving DOMS in the calf muscle is insignificant in this study. Further evidence is needed to prove the efficacy of DS on DOMS. Clinical Relevance: Stretching is commonly recommended before and after exercise; however, this study showed no significant impact of DS or SS in treating DOMS.