Factors affecting selected reciprocal muscle group ratios in preadolescents

This study examines the influence of limb velocity and lateral dominance on the relationship between the knee flexors and extensors. Thirty preadolescents, 18 male and 12 female, performed a series of reciprocal knee flexion-extension movements on the Cybex II isokinetic system. The tests were performed at a range of selected velocities and on both dominant and nondominant limbs. The agonist-antagonist ratios considered were the peak torque ratios, the torque ratio produced at specific angles, and the ratio comparing the total work performed by the hamstrings with that of the quadriceps. The results showed that an increased limb velocity produces a significant increase in the peak torque and work ratios (P less than 0.05), limb velocity has no significant effect on the torque ratio produced at 30 degrees and 60 degrees in the preadolescents, and lower limb lateral dominance has no significant effect on the three ratios examined.