The effects of therapeutic application of heat or cold followed by static stretch on hamstring muscle length.

Hamstring stretching is an important part of treatment programs aimed at decreasing the likelihood of hamstring injury. Few studies have examined the use of superficial thermal modalities in conjunction with hamstring stretching. The purpose of this study was to determine if the application of a superficial heating or cooling modality, followed by static stretch, increased the efficacy of static stretching of the hamstring muscles. This study examined 12 male and 12 female subjects, ages 18-38. All subjects received each of the following treatments: heat followed by static stretch, cold followed by static stretch, and static stretch alone. Each treatment was separated by at least 1 week. Pre- and post-treatment measurements of hamstring length were obtained using the Active-Knee-Extension (AKE) test. The data were analyzed via a 2 x 3 analysis of variance experimental design. Results indicated that there was an increase in hamstring length regardless of stretch treatment used, with F(1,23) = 35.49, p < .001. However, no significant differences were detected among stretch treatments, F < 1.0, nor among interaction effects, F < 1.0. The results of this study suggest that adequate hamstring stretching can occur without the use of a superficial thermal modality.