Reliability of isometric quadriceps muscle strength testing in young and elderly osteo-arthritic subjects

The purpose of this study was to examine the reliability of apparatus and the variability of subject performance in isometric strength testing of the quadriceps in young subjects and elderly osteo-arthritic subjects. Repeated applications of various loads were applied to a torque transducer within a specially designed chair for assessing isometric quadriceps function. The test-retest reliability of this procedure was high. Coefficients of variation were 0% for all test conditions, and the transducer acted linearly throughout the calibration range. Subject performance of maximum voluntary isometric contractions was measured six times over a 30-minute period and over three days of the same week. The reliability of these procedures was high for all groups. Repeated measures MANOV As revealed no significant learning or training effects over one week (p > 0.05) and no fatiguing effects over a 30-minute period (p > 0.05). These results indicate that this test may be used for successive measures of strength in these subject groups.