GRAVITATIONAL MOMENT CORRECTION IN ISOKINETIC DYNAMOMETRY USING ANTHROPOMETRIC DATA

The purpose of this study was to compare different methods of gravity correction in isokinetic dynamometry. The gravitational moment of the left leg-foot segment of 25 males was measured on a Biodex dynamometer at 300 of knee flexion statically, and as the segment was passively f alling from 0 degrees to 90 degrees with a constant velocity of 0.035 rad . s(-1). The tests were performed in a supine and a seated positio n. The gravitational moments were also estimated from anthropometric d ata and directly, using a reaction board method that was considered as the criterion measurement. Furthermore, the isokinetic maximum moment output of the knee flexors and extensors was measured and corrected f or gravity using the above methods at angular velocities of 0.52 rad . s(-1) and 2.62 rad . s(-1) during eccentric, and at 0.52 rad . s(-1), 2.62 rad . s(-1), and 4.71 rad . s(-1) during concentric activations. One-way repeated-measures analysis of variance tests revealed signifi cant differences (P < 0.05) between the gravitational moments obtained on the isokinetic dynamometer and those estimated from anthropometric data or by the reaction board method. The maximum extensor and flexor moments were significantly different, corrected using the gravity cor rection methods on the dynamometer relative to the anthropometric mode l or the reaction board (P < 0.05). These results suggest that the det ermination of gravitational moments based on anthropometric data is mo re accurate than current gravity correction methods. This new proposed method should be implemented in isokinetic dynamometry applications.