Reliability of knee flexor peak torque measurements from a standardized test protocol on a Kin/Com dynamometer

The test-retest reliability of a specific test protocol for the measurement of peak torque of the knee flexors using a Kin/Com dynamometer was evaluated. The maximum voluntary torque generated by the left knee flexors during constant velocity resisted-muscle shortening (RMS) and muscle lengthening (RML) was measured in a sitting position in 11 healthy women with no history of knee pathology. Each subject performed two tests at each of two velocities (30 degrees/sec and 180 degrees/sec) in a single session. All subjects repeated these four tests one week later. A test consisted of four complete RMS/RML cycles through a range of 65 degrees. The peak torque generated from each test was used to measure test-retest reliability. All data were gravity compensated. Intraclass correlation coefficients (ICCs) were calculated from ANOVA tests for RML and RMS at both velocities. The within sessions ICCs ranged from .94 to .98 for 30 degrees/sec and from .92 to .97 at 180 degrees/sec. The ICCs between sessions were generally lower and ranged from .79 to .90 for 30 degrees/sec, and from .75 to .88 for 180 degrees/sec. It is concluded that using these test protocols, peak torques for both RMS and RML can be measured with a high degree of reliability at two commonly used velocities.