Fatigue-Inducing Protocols in Parkinson's Disease: Implications for Gait Assessment and Rehabilitation: A Systematic Review.

Background: Fatigue is a common and disabling nonmotor symptom of Parkinson's disease (PD), which significantly impacts gait and overall mobility. In spite of its clinical significance, the biomechanical consequences of different fatigue induction protocols on gait performance in PD are not yet well understood.

Objective: To systematically review fatigue induction protocols in gait studies of individuals with PD and to examine how different types of fatigue (local, general, and cognitive) and assessment methods influence gait outcomes.

Methods: In accordance with PRISMA guidelines registered under PROSPERO (CRD420251038246), five databases were systematically searched from January 2004 to March 2025. Seven studies met the inclusion criteria and were reviewed and analyzed through descriptive synthesis.

Results: Repeated sit-to-stand tasks were the most effective in inducing lower-limb fatigue and produced consistent changes in gait, including reduced stride length, slower speed, and impaired turning. General aerobic or functional tasks had inconsistent effects, and no study directly tested cognitive fatigue on gait. Fatigue assessment methods varied widely, including force decline, perceived exertion, and fatigue scales. Gait outcome measures were also heterogeneous, limiting comparability.

Conclusion: Targeted lower-limb fatigue protocols are effective in revealing gait impairments in PD. There is a clear need for standardized fatigue induction procedures and gait evaluation methods to improve consistency and comparability across research. Clinically, assessing gait under fatigue conditions may uncover subtle mobility impairments and inform more personalized rehabilitation strategies.