Analysis of a modified active knee extension test.

Abstract

When this study was conducted, the authors were pursuing Master of Science degrees in physical therapy, orthopaedic and sports medicine, at the MGH Institute of Health Professions, Boston, MA. Hamstring injuries occur and reoccur at high rates in the athletic population. The purpose of this study was to describe the effect of contralateral hip flexion on pelvic rotation in the sagittal plane and ipsilateral active knee extension during a modified active knee extension test. Twenty-seven normal subjects were tested, yielding 54 sets of data. Active knee extension was performed in five positions of contralateral hip flexion and was videotaped. Measurements of pelvic and knee joint angles were obtained from the film. The results indicated the least amount of pelvic rotation was 5.5 degrees , which occurred at maximum contralateral hip flexion. Analysis of variance revealed a difference between test positions that was statistically significant for pelvic rotation and knee extension (p < .05). Pelvic rotation can be effectively controlled during an active knee extension test by maximally flexing the contralateral hip. The active knee extension test can be used as an accurate assessment tool to evaluate hamstring muscle length. J Orthop Sports Phys Ther 1992;15(3):141-146.