Isokinetic measures during concentric-eccentric cycles of the knee extensors

The purpose of this study was to examine the peak and average torques produced by the knee extensors during continuous concentric-eccentric cycles at angular velocities of 45, 90, 135, and 180/s. Forty-one healthy females (mean age 26 years) were tested through the range of 80 to 10 flexion on a computerised dynamometer. Peak torques were significantly greater than average torques, and eccentric torques were significantly greater than concentric torques at all angular velocities (p < 0.01). As angular velocity increased, concentric peak and average torques decreased (-26% and -21%, respectively), whereas eccentric torques varied only slightly (3% and 5%, respectively). The extent to which eccentric testing may provide additional information about muscle performance and aid in clinical decisions requires further study.