The Effectiveness of Passive Knee Extension Exercise in the Sitting Position on Stretching of the Hamstring Muscles of Patients with Lower Back Pain

[Purpose] The purpose of this study was to determine the effect of a knee extension exercise in the sitting position (KES) on stretching of the hamstring muscles of patients who suffered from lower back pain. For this study, we compared the effect of the passive straight leg raise (SLR), an exercise already proven effective, with that of passive KES. [Subjects] Thirty-one subjects (18 males and 13 females) were randomly divided into two groups: one group received the passive KES exercise method, and the other group the passive straight leg raise exercise method. [Method] Forward bending, active SLR and active knee joint extension were measured before and after the two passive exercises. [Results] Forward bending, active SLR, and active knee joint extension improved in both groups. However, the KES exercise group showed greater improvement in forward bending than the SLR exercise group. Although both passive KES exercise and passive SLR exercise were effective at stretching the hamstring, passive KES exercise, which allows for stability of the lumbar spine, was more effective when motion required lumbopelvic rhythm. [Conclusion] On the basis of these results, we conclude that passive KES exercise is a more effective treatment for forward bending of patients with lower back pain.