Comparing the Effect of Capacitive and Capacitive-Resistive TECAR Therapy on Hamstring Muscle Flexibility in Individuals with Hamstring Shortness: A Randomized Controlled Trial

Background: Flexibility refers to the ability of muscles and joints to move freely through their full range of motion. It is a key component of physical fitness, contributing to good posture, injury prevention, and enhanced overall movement quality. The hamstring muscle is particularly prone to injury due to reduced flexibility. Deep heat modalities are commonly used to improve muscle flexibility. Previous studies suggest that trans-electrical capacitive and resistive (TECAR) therapy offers an effective alternative for producing heat in deep tissues. Objectives: This study aims to compare the effects of capacitive TECAR therapy (CTT) and capacitive-resistive TECAR therapy (CRTT) on hamstring muscle flexibility in individuals with hamstring shortness. Methods: This randomized, double-blinded clinical trial involved 33 individuals with hamstring shortness. Participants were randomly allocated into three groups: The CTT group (11 individuals), the CRTT group (11 individuals), and the sham group (11 individuals). Each participant underwent five intervention sessions on alternate days. The straight leg raising (SLR) and passive knee extension (PKE) tests were used to assess hamstring flexibility before the treatment and after the fifth session. Results: A total of 33 participants (mean age: 24.85 ± 4.82 years; 16 males and 17 females) completed the study. Both the CTT and CRTT groups showed significant improvements in SLR and PKE by the fifth session (P < 0.001). However, no significant differences were observed between the CTT and CRTT groups in terms of their effectiveness (P > 0.999). Conclusions: Both CTT and CRTT were effective in improving hamstring flexibility compared to the sham treatment, demonstrating their clinical utility. The lack of significant differences between the two modalities suggests that either can be selected based on clinical judgment or patient preference. Further research is recommended to evaluate the long-term effects of these therapies.