A randomised controlled trial between hamstring muscle tightness and lumbar lordotic angle

Shortening of the hamstring muscles is a common problem in both symptomatic and asymptomatic individuals. Low back pain and injury caused by postural deficits might be caused by an imbalance of this muscle. The various degrees of hamstring muscle stiffness and its impact on trunk postures are relatively unknown. The goal of this study was to see how different hamstring muscle length (HML) ranges influenced lumbar lordotic angle (LLA). Sixty asymptomatic healthy male and female subjects with a mean age of 40.4±9.2 years and a body mass index of 25.5± 2.2 kg/m2 participated in this study. Subjects were randomly assigned to one of three groups (n=20) with hamstring muscle lengths of 111-120 degrees, 121-130 degrees, or 131-140 degrees, respectively by using a random number generator. The LLA was estimated on a lateral lumbosacral radiograph using the Kinovea application, and hamstring muscle length was measured using the active knee extension test at the university’s rehabilitation centre within a week of subject selection. The Pearson correlation test was used to examine the relationship between LLA and HML, and one-way ANOVA was used to compare the two groups. The correlation coefficients were expressed using 95% confidence intervals. A significant relationship between LLA and HML was observed in 111-120 degrees and 121-130 degrees groups (P<0.05), whereas, the HML >130 degrees group had no influence on LLA (P>0.05). The findings show that hamstring muscle tightness between 111 and 130 degrees has a negative impact on lumbar curvature mechanisms. As a result, hamstring muscle tightness less than 130 degrees should be addressed first in clinical stretching programs for patients. The findings also suggest that instead of focusing on HML, rehabilitation specialists should devote more time to other high-priority interventions, particularly in patients with hamstring muscle lengths greater than 130 degrees.