Abstract
BACKGROUND: Parkinson's disease (PD) is an advancing neurodegenerative disorder characterized by spinal anomalies and muscular weakness, which may restrict daily functional capacities. A gender-focused examination of these effects could provide valuable insights into customized rehabilitation strategies for both sexes. PURPOSE: This study investigates the influence of spinal alignment on lower-limb function during the sit-to-stand (STS) movement in patients with Parkinson's disease compared to healthy individuals. METHODS: A cross-sectional study was conducted with 43 consecutive patients with PD (25 males and 18 females; average age 73.7 ± 7.1 years) and 42 healthy controls (22 males and 20 females; average age 69.8 ± 6.0 years). Assessments included the International Physical Activity Questionnaire (IPAQ), Hoehn and Yahr staging, and measurements of vertical deviations from several spinal landmarks. Lower-limb muscle power during the STS task was evaluated using the Muscle Quality Index (MQI). RESULTS: Both absolute (Watts) and relative (Watts/Kg) muscle power in the lower limbs were notably decreased in the PD group compared to the control group. Within the PD cohort, muscle power showed a negative relationship with age and a positive association with the degree of lumbar lordosis (PL-L3). Importantly, gender-specific analysis revealed that male patients with PD had significantly higher lower-limb muscle power compared to female patients with PD, highlighting the need for gender-tailored therapeutic approaches. CONCLUSIONS: The findings suggest that preserving lumbar lordosis is crucial for maintaining effective lower-limb muscle biomechanics in individuals with Parkinson's disease.