Evidence for Isokinetic Knee Torque Asymmetries in Male Long Distance Trained Runners.

Authors: Dellagrana RA, Diefenthaeler F, Carpes FP, Hernandez SG, de Campos W

Strength asymmetries are related to knee injuries and such injuries are frequently observed among runners. The purpose of this study was to examine whether long-distance runners have symmetric performance during knee isokinetic testing at two angular velocities.  Twenty-three healthy and well-trained male long-distance runners performed open-chain isokinetic assessment of concentric the quadriceps and hamstrings at velocities of 60°·s-1 and 240°·s-1. Data were compared between the lower limbs at different velocities.   Peak torque and total work were similar between the limbs. Asymmetry was observed for knee flexor power at 240°·s-1 (237 ± 45 W and 205 ± 53 W, in the preferred and non-preferred limb, respectively). Asymmetry indexes for flexor power were different between the velocities tested (13.1% and 2.21% for 240°·s-1 and 60°·s-1, respectively).  A limb asymmetry was observed among runners for knee flexor power, mainly at higher angular velocities (240°·s-1). In addition, H/Q ratios were observed to be contraction velocity dependent. 

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