2026 Theses Doctoral

Relationship of Trunk Range of Motion, Trunk Mobility, and Functional Outcomes in People with Parkinson’s Disease

Romero-Maysonet, Lilliana

Background.
Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor impairments that negatively affect functional mobility and physical activity (PA). Reduced trunk active range of motion (AROM) (e.g., maximum voluntary movement), measured through flexion, extension, lateral flexion, and rotation, and impaired trunk mobility (e.g., natural movement of the trunk during functional tasks) are common in people with Parkinson’s disease (PwP), contributing to gait disturbances, difficulty with transitional movements, increased fall risk, and reduced participation in daily activities. Although trunk impairments are present even in early stages of PD, their relative contribution to functional outcomes and PA remains incompletely understood. Purpose. This study evaluated differences in trunk AROM, trunk mobility, and functional outcomes between PwP and age-matched peers (AMPs) and examined the relationship and contribution of trunk AROM and trunk mobility to functional outcomes and PA in PwP.

Methods.
Twenty PwP with mild disease severity (Hoehn and Yahr stages I-II) and 20 AMPs participated. Trunk AROM (flexion, extension, rotation, and lateral flexion) was measured using goniometry. Trunk mobility during walking and transitional tasks was quantified using wearable sensors. Functional outcomes included duration for floor sitting-rising (FSR) test, Timed Up and Go (TUG), and TUG subcomponents such as sit-to-stand and turning performance. PA was assessed using wrist-worn accelerometry. Between-group differences were examined using independent-samples t-tests for normally distributed variables and the Mann-Whitney U test for non-normally distributed variables. Associations between trunk AROM, trunk mobility, functional outcomes and PA were analyzed using Pearson correlation or Spearman rank correlation, as appropriate. Hierarchical multiple linear regression analyses controlling for disease stage were conducted to determine the contribution of trunk AROM and trunk mobility to functional outcomes.

Results.
Compared to AMPs, PwP demonstrated reduced total trunk AROM (318.9° vs. 366.5°, p = .003), reduced trunk mobility (16.9° vs. 22.4°, p < .001), slower TUG performance (10.9 s vs. 8.8 s, p = .002), and longer FSR durations (median 10.6 s vs. 7.4 s, p < .001). In PwP, trunk mobility showed moderate associations with TUG performance (r = -.466, p < .05), FSR duration (r = -.483, p < .05), and moderate-to-vigorous physical activity (r = .484, p < .05), but trunk mobility was not associated with quadriceps strength or daily steps, whereas trunk AROM showed weaker relationships with functional outcomes and PA than trunk mobility. Quadriceps strength showed a moderate-to-strong correlation with daily step count (r = .502, p < .05). After controlling for disease stage, trunk mobility significantly contributed to TUG performance (β = -.445; p = .036), while trunk AROM did not. Disease stage remained the strongest predictor of functional outcomes.

Conclusions.
Trunk AROM and trunk mobility are significantly limited in PwP, even in early-stage disease. Trunk mobility during task execution is more strongly related to functional outcomes and participation in PA than isolated trunk AROM. These findings highlight the clinical importance of trunk mobility and support rehabilitation approaches that integrate trunk mobility into functional tasks to enhance mobility, PA participation, and independence in PwP.