Abstract

The purpose of this study was to examine the age and sex associated differences in the eccentric/concentric functional ratio for the knee. Isokinetic concentric and eccentric knee extension and flexion was measured at 0.52 rad/s and 3.14 rad/s in 121 subjects. Other than mass there were no significant age-by-sex interaction effects for all variables examined. A significant velocity-by-age group effect was demonstrated for ECCKF/CONKE with higher ratios at 3.14 compared to 0.52 rad/s. Females' CONKF/ECCKE was significantly lower than males at both velocities. Adults demonstrated significantly lower CONKF/ECCKE than the teenagers at 0.52 rad/s and lower than the prepubertal and teenager groups at 3.14 rad/s. However, for ECCKF/CONKE at 3.14 rad/s, prepubertal ratios were significantly lower than teenagers and adults. The results of the current study suggest that functional rather than conventional ratio should be used when examining knee stability. During fast velocity movements, prepubertal children have a lower capacity for generating eccentric compared to concentric torque. The lower CONKF/ECCKE ratio in adults appears to be due to a greater ability to generate large eccentric torques at all slow and fast movement velocities. The lower CONKF/ECCKE ratio in females is a product of lower concentric torque as opposed to high eccentric torque producing capability as previously thought. Verf.-Referat