Reliability of lower extremity isokinetic strength testing in adults with stroke

Objective: To evaluate the reliability of isokinetic strength testing of knee flexion and extension at 60 degrees per second, and ankle plantar flexion and dorsiflexion at 30 degrees per second in adults with stroke. Design: Test-retest using intraclass correlation coefficients (ICC). Setting: Human performance laboratory. Subjects: Ten adults post stroke with a mean age of 64 years (five males) and 10 adults without neurological injury with a mean age of 69 years (three males) who served as controls. Main outcome measures: Peak torque and average torque. Results: The reliability of strength of the less-affected lower extremity was high with values ranging from 0.75 to 0.97. Knee extension, ankle plantar flexion and the peak torque of dorsiflexion were reliable for the affected limb, ranging from 0.80 to 0.90. In contrast, affected knee flexion was not reliable with values of 0.48 and 0.44 for peak torque and average peak torque respectively. Conclusions: Isokinetic knee and ankle strength of the less-affected limb are reliable. Isokinetic strength of the affected lower extremity is also reliable with the noted exception of knee flexion.