The effect of dynamic constant external resistance training on the isokinetic torque-velocity curve

The purpose of this investigation was to examine the effects of dynamic constant external resistance (DCER) training on isokinetic peak torque (PT) and constant joint angle (CJA) torque at velocities from zero to 5.03 rad.s-1. Twelve male volunteers (mean age +/- SD = 21.67 +/- 2.61 years) were trained using DCER exercises (leg extension and squat) for eight weeks. The subjects were tested pre-training and post-training for isokinetic leg extension PT as well as CJA torque (0.26 rad below the horizontal plane) at multiple velocities (zero, 0.84, 1.68, 2.51, 3.35, 4.19 and 5.03 rad.s-1) using a Cybex II isokinetic dynamometer. Film analyses indicated that the mean training velocities for leg extension and squat were 1.50 +/- 0.20 rad.s-1 and 1.41 +/- 0.26 rad.s-1, respectively. Univariate two-way repeated measures (within subjects design) ANOVAs [time (pre-training versus posttraining) x velocity] were used to analyze the changes in PT and CJA torque across the training period. There was no interaction but a significant (p < 0.05) main effect for time for the CJA torque measures. The increases in CJA torque ranged from 6.3 to 10.7%. For PT, there was a significant (p < 0.05) time x velocity interaction. Post-hoc comparisons showed that PT increased significantly at all velocities (p < 0.0083) as a result of the training (8.1 to 10.9%). The results of this investigation indicated that DCER training significantly increased isokinetic PT and CJA torque values at velocities up to 3.53 rad.s-1 above the training velocity.