Postural control during a sit-to-stand task in individuals with mild Parkinson's disease.

Individuals with Parkinson's disease (PD) typically have difficulty rising from a chair. A major contributing factor may be altered anticipatory postural control; this hypothesis has been fueled by reports of altered function of the supplementary motor area in PD, an area linked to the preparation of movements. This study tested the hypothesis that individuals with PD would exhibit altered anticipatory postural control which would include a reduced preparatory hip flexion and decreased forward displacement of the COM prior to lift-off of the buttocks from the chair.

Strategies for avoiding hip impact during sideways falls.

Unlabelled: During a fall, hip fracture risk increases 30-fold if there is direct impact to the hip. We conducted sideways falling experiments and found that subjects were able to avoid hip impact by rotating forward or by rotating backward during descent. These simple safe-landing strategies should be considered in designing hip fracture prevention programs.

Leg muscle strength is reduced in Parkinson's disease and relates to the ability to rise from a chair.

Individuals with Parkinson's disease (PD) have difficulties rising from a chair; however, factors contributing to this inability have never been investigated. We compared lower extremity strength between individuals with PD and healthy controls and quantified the relationships between strength and the ability to rise from a chair. Ten men with mild PD and 10 sex- and age-matched controls performed maximal concentric, isokinetic knee and hip extensor torque on an isokinetic dynamometer to quantify muscle strength.