The effect of increased straight leg raise on work production in subjects with tight hamstrings

Abstract

This study examined the effect of a 20% increase in straight leg raise (SLR) on concentric isokinetic measures of work in subjects with tight hamstrings. Subjects were deemed eligible if passive SLR of the dominate limb was < 70° and if subjects had no documented problems with the tested limb. Thirty-two volunteer subjects were randomly assigned to experimental and control groups (n = 16 each) and baseline measures were completed. Experimental group subjects then participated in supervised stretching and a home program with SLR re-assessment prior to each supervised session. Within 24 hours of an experimental subject reaching the 20% targeted increase in SLR range, that subject and a control subject were re-tested. The results showed no significant change in work production despite a 20% increase in SLR. This study suggests that a modest increase in SLR does not adversely affect the strength of tight hamstring muscles. Clinical implications are that an increase in flexibility of a tight muscle may not adversely effect a subject's ability to maximize muscular potential.