Reliability of lower extremity strength measures in persons with chronic stroke

Objective: To determine the reliability of isokinetic, concentric strength measures of both the hemiparetic and noninvolved limbs for flexion and extension motions of the hip, knee, and ankle joints in individuals who have had a stroke. Design: Test-retest, repeated-measures intraobserver reliability design. Setting: Tertiary rehabilitation center. Participants: Twenty community-dwelling individuals who have had a stroke, with motor deficits ranging from 3 to 6 on the Chedoke-McMaster Stroke Assessment; volunteer sample. Interventions: Not applicable. Main Outcome Measures: Peak torque and average torque (ie, mean over the range of motion tested) from an ensemble-averaged (3 trials) torque-angle curve during isokinetic concentric extension and flexion movements of the ankle, knee, and hip. Results: Although peak and average. torque were significantly less for the hemiparetic limb compared with the noninvolved limb, the intraclass correlation coefficients (ICCs) between the 2 test sessions were high (.95-.99 for peak torque, .88-.98 for average torque) for both limbs for all 3 joints. However, there was a learning effect, as observed by the slightly greater values attained from the second test session. Conclusions: Peak and average isokinetic, torque can be used to assess reliably lower extremity strength in persons with chronic stroke. Practice sessions may be required before the actual test to reduce the effect of learning.