Correlation Between SLR and Active Knee Extension Tests in LBP Patients with Tightened Hamstring

Background: The length of the hamstring muscle is measured indirectly. This evaluation can be done by doing the passive straight leg raising (SLR) test or performing an active knee extension (AKE) test. It is important to know how much these two tests are correlated to each other. If they are highly correlated, a high SLR degree may conclude a high amount of AKE. Objectives: The aim of this study was to determine the correlation between these two tests among patients with LBP having tightness in their hamstring muscle. Methods: The sample size was calculated to be 50 patients. Participants with chronic low back pain (LBP) and short hamstring were selected. The hamstring muscles length of the participants were assessed using two clinical tests, 1- AKE test, and 2- SLR test. Results: The mean ± SD of the hamstring length of the patients using the SLR method was 72.52 ± 10.32 degrees. Also, the mean ± SD of hamstring muscle length was 157.28 ± 7.70 degrees using the AKE test. There was a positive and significant correlation between Hamstring length score using SLR and Hamstring length in patients with AKE test (P < 0.05, r = 0.30). Conclusions: The results of this study showed that there is a correlation between the results of two types of testing hamstring muscle length including SRL and AKE tests among patients with LBP having tightness in their hamstring muscle.