Background/Purpose The ability to step up and over an obstacle in the environment is required for safe independent living. This task may become particularly difficult and unsafe as strength and postural stability are compromised during a progressive disease state such as in Parkinson's disease, thus predisposing these individuals to a fall. The purpose of this study was to examine the relationship between knee flexion/extension strength and three key motor characteristics of stepping-up and over obstacle.
Method Eight patients (aged 74.83 ± 8.26) with Parkinson's disease (Modified Hoehn & Yahr Stage between 1 to 3) were assessed on the NeuroCom EquiTest StepUp/Over task with outcomes including: 1. Lift-Up Index- quantifies the maximal lifting force exerted by the leading leg. 2. Movement Time- quantifies the number of seconds to complete the maneuver. 3. Impact Index- quantifies the maximum vertical impact force as the lagging leg lands on the force plate. Additionally participants peak torque values for maximal knee flexion/extension were recorded in Newton-meters at an angular velocity of 90 deg/sec of the dominant limb on an isokinetic dynamometer .
Analysis/Results Results indicated that knee flexion strength correlated with Impact Index (r=.837; p=.009) and knee extension strength correlated with the Lift-Up Index (r=.723; p=.043).
Conclusions These results demonstrate a significant positive relationship between strength and the commonly executed functional task of stepping up and over an obstacle. Due to the high prevalence of falls demonstrated in Parkinson's disease, intervention should, among other goals, aim to increase lower extremity leg strength.
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