Effect of Thermotherapies Associated with Hamstring Stretching in Peak Torque: Randomized Clinical Trial

Background: Stretching is an effective strategy used mainly to reduce muscle stiffness, and increase both flexibility and Range of Motion. Aim: To compare the effects of different thermotherapy modalities associated with static stretching on peak torque (PT) of knee flexor muscles. Methods: This study compared a sample of 34 healthy men, aged between 20 and 30 years, with active knee range of motion (ROM) ≤160 degrees. They were subjected to three sessions of static stretching of the hamstrings, either with or without a thermotherapy modality. The order of interventions was randomized for one of the groups: isolated stretching (IS), stretching with heat (SH), and stretching with cold (SC). The concentric and eccentric PTs were assessed pre and post-intervention. Results: In the comparison of PT among different measures, there was a significant decrease in eccentric and concentric PT of knee flexor muscles in IS, in eccentric PT of knee flexor muscles in SH, and in eccentric and concentric PT of knee flexors in SC groups. Conclusion: Regardless of the use of thermotherapy, one single session of static stretching resulted in decreased PT of knee flexor muscles. This is probably due to the effects of stretching, such as the immediate change of the elastic component of the muscle-tendon unit, which leads to a deficit in acute force production.