Influence of lever arm and stabilization on measures of hip abduction and adduction torque obtained by hand-held dynamometry.

Abstract

To examine the reliability of clinical techniques for testing hip abductor and adductor muscle performance. Repeated measures. Academic laboratory. A sample of 21 healthy subjects (12 men, 9 women) between 22 and 31 years of age. Not applicable. Reliability of repeated measures was estimated by calculating intraclass correlation coefficients. Torque production capability was calculated by multiplying force output obtained with a hand-held dynamometer by the length of the resistance lever arm. The reliability of abduction testing was greatest in the long-lever condition. Adduction test reliability was greatest in the long-lever condition with bench stabilization. The maximal hip abduction torque tested in the long-lever position was significantly greater (t(20)=9.21, P<.001) than that in the short-lever position. The maximal hip adduction torque occurred using a long lever for resistance application and a bench to stabilize the nontest leg (F(1,20)=15.64, P=.001). Muscle performance testing of hip abductors and adductors with a hand-held dynamometer can be performed with good to excellent intratester and intertester reliability. Hip abduction testing is best performed with a long lever. Hip adduction is best performed with a long lever and a bench to stabilize the nontest extremity.