Comparison of the Effects of Static Stretching and Strengthening on Electromyographic ‎Activity of Paravertebral Muscles in Patients with Chronic Non-specific LBP with ‎Tightened Hamstring Muscles: A Randomized Controlled Clinical Trial ‎

This randomized clinical trial study was performed to compare the effect of static stretching exercises and strengthening exercises in lengthened position of shortened hamstring muscles on changes in electrical activity (EMG) of the paravertebral muscles in the back of patients with chronic low back pain.

Forty-five patients with chronic low back pain were selected for this clinical trial through sampling available in the outpatient clinic of Kermanshah University of Medical Sciences. In addition to receiving conventional physiotherapy treatment for low back pain, all samples were randomly allocated into 3 groups: stretching exercises (n=15), strengthening exercises in muscle lengthened position (n=15) and the control group without additional intervention (n=15). Therapeutic interventions were performed for 4 weeks, 3 days a week and for a total of 12 sessions. Hamstring muscle length was measured by Norris test (thigh in vertical position and the patient tried to straighten the knee joint) with a goniometer. Electromyography information was recorded from the lumbar muscles of the patients during knee flexion against an elastic band.

Analysis of repeated measures showed that there was a non-significant difference between time, group, and time and group in the EMG activity of the back muscles (langismus and iliocostalis) (p>0.05) and only the time factor had a significant effect on pain and disability.

None of the static stretching exercise and hamstring muscle strengthening exercises in lengthened position did not cause a significant change in the electromyographic activity of the paravertebral muscles of the patients.