The efficacy of manual assessment of muscle strength using a new device.

The purpose of this study was to compare the manual assessment of muscle strength with a small, handheld (by the examiner) force-measuring device developed by the Institute of Sports Medicine and Athletic Trauma (ISMAT). One hundred twenty-eight patients presented with a known lower extremity orthopaedic pathology. All patients were clinically evaluated for hip abductor and hip flexor weakness in standard positions using the "break test" technique. All 128 patients were then evaluated with the ISMAT Manual Muscle Tester, a small, hand-held device which recorded the peak force (kg) required to break a muscle contraction. Three bilateral measures of hip abduction and hip flexion were recorded, averaged, and compared to the subjective clinical evaluation using a chisquare analysis. Bilateral values which were within 5% of each other were not considered significant and therefore not included in the calculations. The average hip abduction and hip flexion scores measured by the ISMAT tester were consistent with the examiner's perception of muscle weakness (P less than 0.001). The results demonstrate consistent detection of muscle weakness by the ISMAT Manual Muscle tester over a broad range of testing conditions.