EFFECT OF DEEP HEAT, COLD, ACTIVE EXERCISE, AND STRETCHING ON HAMSTRING FLEXIBILITY

PURPOSE Stretching muscles to improve flexibility is a common intervention during rehabilitation of musculoskeletal injuries. Thermal agents (heat or cold) or warm-up exercises are often used to facilitate the effects of stretching. The purpose of this study was to determine the effects of deep heat, cold and active exercise prior to stretching compared to stretching alone on flexibility of the hamstring muscles. METHODS Twenty seven college-age individuals (14 females, 13 males) with limited hamstring flexibility participated in four testing sessions (passive stretching (PS); thermal ultrasound and passive stretching (TUPS); cold and passive stretching (CPS), and active exercise and passive stretching (EPS) at one-week intervals. The condition order was randomized and hamstring flexibility was determined by measuring knee range of motion during a 90/90 straight leg raise both pre and post treatment. A 2×4×4 (gender × time × condition) ANOVA with repeated measures on condition effects was run for knee angle. RESULTS There were no significant interaction effects for knee angle. Significant differences were found comparing pre and post measures regardless of condition (p = 0.000). No significant differences were noted between conditions (p = 0.944)(mean differences: PS=9.00°, TUPS=10.81°, CPS=7.56°, EPS=9.19°). CONCLUSION The results of this study indicate that each condition provided improvements in flexibility but hamstring stretching alone appears as effective as stretching following other interventions.