Effects of unilateral concentric-only dynamic constant external resistance training.

Abstract

The purposes of this investigation were to examine the effects of unilateral concentric-only leg extension dynamic constant external resistance (DCER) training on: (a) concentric DCER strength in the trained and contralateral (untrained) legs, (b) concentric isokinetic peak torque-velocity curves in the trained and contralateral legs, and (c) retention of concentric DCER strength and concentric isokinetic peak torque in the trained and contralateral legs following detraining. Sixteen adult male (mean age +/- SD = 24.0 +/- 4.0 yr) volunteers comprised training (TR, n = 8) and control (CTL, n = 8) groups. The TR group trained the nondominant limb with concentric-only leg extension DCER exercise (3-5 sets of 6 repetitions at 80% of one-repetition maximum load) for eight weeks followed by eight additional weeks of detraining. The CTL group did not train. All subjects were tested pretraining, posttraining and detraining for unilateral concentric-only leg extension DCER strength as well as concentric isokinetic peak torque at 1.05, 2.09, 3.14, 4.19, and 5.24 rad.s-1 in both legs. Mixed factorial ANOVAs, follow-up, and post-hoc analyses indicated that the training resulted in increased DCER strength in both the trained (42%) and contralateral (15%) legs as well as isokinetic peak torque in the trained leg (7-19%) at velocities ranging from 1.05 to 5.24 rad.s-1. There was no cross-training effect, however, for isokinetic peak torque. Furthermore, the training-induced increases in DCER strength and isokinetic peak torque were retained across eight weeks of detraining.