Eccentric and Concentric Torque-Velocity Characteristics, Torque Output Comparisons, and Gravity Effect Torque Corrections for the Quadriceps and Hamstring Muscles in Females

Abstract

The purpose of this study was to assess and compare eccentric (ECC) and concentric (CONC) torque output of the quadriceps and hamstring muscles and to analyze the effect of gravity effect torque (GET) correction on the calculation of the hamstring/quadriceps peak torque quotient (H/Q quotient). Twenty female subjects performed maximal voluntary CONC and ECC contractions of the quadriceps and hamstring muscles at five isokinetic lever arm velocities from 60°/s to 360°/s. Peak torque was measured and corrected for GET. Mean ECC torque did not significantly change with increasing ECC velocity for either the quadriceps or hamstring muscles (P>0.05). Mean CONC torques were significantly lower than the corresponding ECC torques (P < 0.05) and decreased with increasing CONC velocity. At each test velocity, the CONC H/Q quotient was significantly lower than the corresponding ECC H/Q quotient (P < 0.05). Mean H/Q quotients did not significantly change with increasing velocity for either the CONC or ECC tests (means: 0.46 and 0.57; (P > 0.05). Mean H/Q quotients not corrected for GET significantly increased with increasing velocity for the CONC (0.61 to 0.78; (P < 0.05), but not ECC tests (0.66 to 0.71; (P > 0.05). The results indicate that the ECC torque-velocity curve is essentially level for both quadriceps and hamstring muscles. The present findings point strongly toward the necessity of correcting for GET when calculating both CONC and ECC H/Q quotients. The use of a single test velocity appears statistically defensible when assessing the strength relationship of the knee musculature, but both CONC and ECC torque output should be measured to obtain a complete strength profile.