Effect of pelvic belt on the perception of difficulty and muscle activity during active straight leg raising test in pain-free subjects.

A pelvic belt decreases patient-reported perception of difficulty during the active straight leg raising (ASLR) test in individuals with pelvic girdle pain. However, the influence of a pelvic belt on the perception of difficulty during ASLR was not investigated in pain-free subjects. Therefore, this influence excluding the impact of pain is not clear. This paper aimed to clarify the effect of a pelvic belt on the perception of difficulty and muscle activity during ASLR performance in the subjective heavier side leg in pain-free subjects. Twenty pain-free female subjects participated. ASLR using the subjective heavier side leg was performed under two conditions: without and with a pelvic belt. Muscle activation of the external oblique, internal oblique, rectus abdominis, rectus femoris, and biceps femoris was measured during ASLR using a surface electromyograph. Difference in perceived difficulty in performing ASLR with and without a belt was assessed. In total, 80% of subjects had decreased perception of difficulty using a pelvic belt during ASLR. For ASLR performed with a pelvic belt, muscle activity significantly decreased in the contralateral rectus abdominis, ipsilateral external oblique, and bilateral internal oblique (P<0.05), while it significantly increased in the contralateral biceps femoris (P<0.05). There were no significant differences in muscle activity of the ipsilateral rectus abdominis, contralateral external oblique, and ipsilateral rectus femoris between the two conditions (P>0.05). In conclusion, using a pelvic belt can decrease the perception of difficulty during ASLR, and the pelvic belt may improve impairment of load transfer between the trunk and pelvis.