Developing a clinical measure of lower limb motor impairment after stroke: Test-retest reliability and concurrent validity of upright pedaling.
Objective and sensitive measurement of motor impairment after stroke in clinical settings is challenging. Clinical measures, e.g the Motricity Index (MI), do not provide i) biological insights into recovery or ii) information about movement performance during functional activities. Motion analysis systems are expensive and often inaccessible in clinical practice. This study will investigate test-retest reliability and concurrent validity of instrumented upright Pedaling (UP) on a exercise bike as a potential objective sensitive clinical measure of motor impairment.
Design: Prospective correlational study. Participants: adults, any time after stroke with lower limb paresis, able to walk scoring 1+ on Functional Ambulatory Category). Sample size: n=30, to provide a precise estimate of the reliability coefficient, with narrow confidence intervals. Instrumentation: Modified upright static bike, portable surface EMG system (Biometrics UK) to measure muscle activity synchronised with a sensor registering crank angle over time. Data recorded on a laptop computer for later processing.
MI lower limb score is recorded. Surface EMG electrodes are placed on prepared skin over right and left quadriceps and hamstrings. Participants will then perform two sessions of UP at their comfortable speed separated by a one-hour rest period. Measures: onset and offset of muscle activity, reciprocity of muscle activity, and smoothness of pedaling.
Analysis: Test-retest reliability of EMG measures and concurrent validity of EMG measures with MI will be determined using Interclass correlation coefficients [95% confidence intervals] together with limits of agreement.
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