EVIDENCE FOR ISOKINETIC KNEE TORQUE ASYMMETRIES IN MALE LONG DISTANCE-TRAINED RUNNERS.

PURPOSE/BACKGROUND: 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.

METHODS: Twenty-three healthy and well-trained male long-distance runners performed open-chain isokinetic trials for assessment of concentric quadriceps and hamstrings contractions at velocities of 60 °·s(-1) and 240 °·s(-1). Data were compared between the lower limbs at different velocities.

RESULTS: 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).

CONCLUSION: 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.

LEVEL OF EVIDENCE: 3.