Lower limb performance in older female patients with Parkinson's disease.

AIMS This study examined lower limb performance in older sedentary patients with Parkinson's disease (PD). METHODS Fourteen female patients with mild to moderate PD and 12 age-matched controls were included in this study. The force preparation and production of the knee extensor muscles during maximal isometric contraction were measured by dynamometric chair. Two force plates were used to measure the chair rising performance. RESULTS PD patients had longer visual reaction time during performing maximal isometric contraction, and lower maximal isometric force (MF) and rate of force development of the knee extensor muscles compared with controls. However, MF relative to body weight (BW) did not differ significantly in PD patients and controls. A longer chair rising time and lower maximal rate of vertical ground reaction force (VGRF) development while rising from a chair were found in PD patients compared with controls. No significant differences in maximal VGRF, and the sum of maximal VGRF of the right and left legs relative to the BW while rising from a chair were observed between the groups. In PD patients, chair rising time correlated negatively with MF of the knee extensor muscles. PD subjects also showed a positive correlation between the BW-related maximal VGRF while rising from a chair and MF of the knee extensor muscles relative to BW. CONCLUSIONS These data suggest that subjects with PD are more deficient in the regulation of force-time parameters, rather than simply in force production of the knee extensor muscles.