The effects of unilateral velocity-specific concentric strength training

There is conflicting evidence regarding the efficacy of various resistance training programs for increasing strength in trained and contralateral limbs. The purposes of this investigation were to examine the effects of unilateral velocity-specific concentric isokinetric training of the extensor and flexor muscles of the elbow and knee on: 1) the carry-over effect in strength increases to velocities other than the training velocity in the trained limbs and 2) the cross-training effect at various velocities in the contralateral limbs. Twelve adult men (X̄ age ± SD = 24 ± 6 years) volunteered to train their nondominant extremities three times per week (six sets of 10 maximal repetitions) for 2 weeks at 120°/sec using a Cybex II isoxinetic dynamometer. The subjects were tested for increases in peak torque at 60, 120, 180, 240, and 300°/sec. The training resulted in significant (p < 0.05) increases in peak torque on the trained side of the body for elbow extension and flexion as well as knee extension and flexion at all velocities tested. These findings indicated that the velocity-specific training resulted in increases in peak torque at velocities that were both greater and less than the training velocity. In addition, there was a cross-training effect, with significant (p < 0.05) increases in peak torque on the contralateral side of the body for elbow extension (all velocities except 300°/sec) as well as knee extension and flexion (all velocities). These results indicate that unilateral velocity-specific concentric isokinetric training is adequate stimulus for eliciting strength gains at a wide range of velocities in both the trained and contralateral limbs. These findings suggest that velocity-spectrum training is not required for strength increases at a variety of velocities and that velocity-specific training of a noninjured limb may be useful in the rehabilitation of an injured contralateral limb.