Immediate effects of lumbar fascia stretching on hamstring flexibility: A randomized clinical trial

BACKGROUND: The hamstring muscles have a great tendency to decrease their extensibility, a phenomenon that presents a distinct clinical entity called short hamstring syndrome (SHS), in addition to problems with adjacent structures. OBJECTIVE: The objective of this study was to evaluate the immediate effect of lumbar fascia stretching on the flexibility of the hamstring musculature. METHODS: A randomized controlled trial was carried out. Forty-one women between 18 and 39 years old were divided into two groups: the experimental group received a technique of fascial stretching in the lumbar area while the control group participated in a magnetotherapy machine that was turned off. Hamstring flexibility in both lower limbs was measured by the straight leg raising test (SLR) and the passive knee extension test (PKE). RESULTS: The results showed statistically significant improvements (p < 0.05) in the SLR and the PKE for both groups. There was a large effect size (Cohen's d) for both tests. There was a statistically significant correlation between the International Physical Activity Questionnaire (IPAQ) and the SLR. CONCLUSION: The inclusion of lumbar fascia stretching might be an effective part of a treatment protocol to increase the flexibility of the hamstring muscle observing an immediate result in healthy participants.