High-intensity laser therapy for hamstring muscle tightness: rationale and study design for a single-blinded randomized controlled trial

BACKGROUND: Prolonged sitting and a sedentary lifestyle may result in hamstring shortness. A decline in regular physical activity could lead to a decrease in the flexibility of the muscle in a younger adult. Increasing hamstring muscle flexibility could decrease the possibility of injuries and prevent low back pain. The application of high-intensity laser therapy (HILT) has proved to be innumerable benefits for many conditions. However, to date, no published research is available on the effectiveness of this therapy in improving hamstring muscle length in healthy young adults. This article describes the study protocol for investigating the benefits of HILT in treating hamstring muscle tightness among young adults. METHODS: 136 healthy young individuals will be recruited, by purposive sampling method, to participate in a randomized, single-blinded, sham-controlled study. Recruited participants will be randomly divided into two groups, the active HILT group, and the sham HILT group. The treatment duration will be 8-10 minutes per session, on both lower limbs, for alternate days a week, for two weeks. The active knee extension test and sit-toe and touch test are the outcome measures that will be recorded at baseline, end of the 2-week post-intervention period. The p-value ≤0.05 will be considered statistically significant. DISCUSSION: The study findings will provide the data to determine whether HILT would be a future non-pharmacological non-invasive intervention to reduce hamstring muscle tightness among young adults. Trial Registry: Clinical Trials Registry (NCT05077761).