Intrarater reliability of manual passive movement velocity in the clinicalevaluation of knee extensor muscle tone

Objective: To quantify the relationship between therapist-applied velocity of passive movement during a manual muscle test of muscle tone and the leve l of muscle tone represented by the relaxation index of the pendulum test. Design: Comparison of therapist-applied passive limb movement velocity duri ng a manual muscle test with the same subject's level of muscle tone measur ed by the pendulum test. Three different therapists tested each subject. Th e relation between the velocity scores and pendulum test scores both intrat herapist and intertherapist were assessed statistically by means of analysi s of variance and correlation coefficients. Setting: A university-affiliate tertiary care outpatient and inpatient spin al cord injury rehabilitation center. Participants: Twenty-two volunteer subjects with spinal cord injuries. Main Outcome Measures: Passive knee angular displacement data were collecte d during both manual knee muscle testing and pendulum tests by using an ele ctrogoniometer. Results: The therapists produced significantly different movement velocitie s during the manual muscle tests (p < .05). A significant correlation (p < .001) was found between pendulum rest scores and passive velocities, indica ting that in higher levels of muscle tone, the greater stretch reflex prese nt provided greater resistance against the therapist force and subsequently decreased the velocity of the passive stretching. Conclusions: Measurement of average velocity during passive stretching by i tself can be used to evaluate muscle tone.