Preference and torque asymmetry for elbow joint

Abstract

Extensively unilateral recruitment for daily activities may determine performance asymmetries in favor of the preferred side eliciting functional adaptation. Our study evaluated asymmetries in elbow torque output between preferred and non-preferred limbs. Eighteen subjects performed maximal elbow flexor and extensor isometric contractions at five different elbow joint angles (0º, 30º, 60º, 90º, 120º) and five different angular velocities (60, 120, 180, 240, 300º.s-1) on an isokinetic dynamometer. Higher flexor torque in favor of preferred arm was observed at 90º of flexion (p<0.05), which also corresponded to the highest torque produced (p<0.05). The fact that joint angle influenced torque asymmetries, whereas angular velocity did not, suggest that the observed asymmetry is likely related to preferential recruitment of elbow flexors at a 90º joint angle for daily tasks requiring high levels of force production. Muscle functional adaptation to frequent stimuli at this joint angle in healthy subjects may explain these results.

Bilateral assessment of knee muscle relationships in healthy adults

“…When untrained individuals were evaluated for the torque -angle and torque-velocity relationships of elbow flexor and extensor torque, the only asymmetry reported occurred at the flexor isometric peak torque at the angle where highest peak torque was produced, in favor of the preferred limb (Carpes et al, 2012). The results were discussed considering that even among untrained individuals there is a preferential recruitment of the preferred arm for weight sustaining tasks, and for mostly of cases it happen with elbow flexed at 90º, angle where asymmetry was reported.…”