Investigation of the effect of passive therapy and active exercise therapy in athletes suspected of low back pain with Piriformis muscle contracture

Abstract

Problem statement: Recently, a relationship between piriformis syndrome and nonspecific low back pain has been proposed; however, this has only been investigated in terms of the patient's subjective pain and anatomical and structural perspectives. Furthermore, it has been suggested that evaluating changes in the piriformis muscle elastic modulus is a painless and noninvasive method for the measurement of changes in nonspecific low back pain after passive therapy; however, this was only evaluated cross-sectionally and did not clarify the long-term changes caused by continuous passive therapy intervention. Purpose: This study aimed to clarify the effects of continuous passive therapy and active exercise therapy in athletes with nonspecific low back pain accompanied by piriformis muscle contracture. Approach: We included 18 athletes with nonspecific low back pain accompanied by piriformis muscle contracture. Nine participants were placed in a passive therapy group that received only passive therapy once a week, while the other nine were placed in a passive therapy and active exercise therapy group that received daily active exercise therapy and passive therapy. Measurements included the mean (Emean) and maximum elastic modulus (Emax) of the piriformis muscle; the straight-leg test; the flexion, abduction, and external rotation test; and the numerical rating scale. We compared the differences in these values pre- and post-intervention, as well as the values at each week. Results: There was a significant difference between the pre-and post-intervention values in both the groups for each week. In the comparison according to each week, the passive therapy group did not exhibit a significant difference in the measurement items. However, the passive therapy and active exercise therapy group exhibited significant differences in all measurements except the straight-leg test after the third week of the experiment. In this group, a significant difference in the straight-leg test results was only observed after the fourth week. Notably, in the group that received passive therapy alone, the post-intervention values returned to those observed before intervention within a week, in both the functional and subjective assessments. Conclusions: This study revealed that performing daily active exercise therapy in addition to passive therapy for approximately 3 weeks alleviated nonspecific low back pain associated with piriformis contractures.