The study's objective is to determine the feasibility of low-load resistance training with blood flow restriction in people who have advanced Parkinson's disease and impaired mobility using a mixed-methods convergent parallel design in a single cohort. The study's long-term goal is to develop clinically feasible exercise interventions that are effective at improving mobility, participation, and quality of life for people with advanced Parkinson's disease.

This study will use a mixed-methods convergent parallel design to determine the feasibility of low-load BFR training in 20 people with advanced PD symptoms and impaired mobility (Hoehn and Yahr Stage [H&Y] 3-4). All participants will receive low intensity resistance training (20-30% of 1RM) with BFR targeting knee extensor, ankle plantarflexor, and elbow extensor muscles 2x/week for 8 weeks. Intervention will be delivered by a physical therapist with specialized training in BFR. Pre-defined feasibility criteria will be assessed in the primary aim. Outcomes assessed before and immediately after the 8-week intervention will include quantitative muscle strength and mobility assessments, and quantitative and qualitative data on health-related QOL.

Aim 1: Determine low-load BFR training feasibility based on the following quantitative and qualitative criteria: 1) enrolling 20 participants, 2) retaining ≥80% participants, 3) obtaining ≥80% intervention adherence, 4) having no serious intervention-related adverse events, and 5) quantitatively and qualitatively measured acceptability.

Aim 2: Determine changes in 1) knee extensor, ankle plantarflexor, and elbow extensor muscle strength using fixed myometry and 2) instrumented functional mobility (30-second Sit-to-Stand, Timed up and Go, self-selected walking speed, and Berg Balance Scale) using a system of inertial measurement unit wearable sensors.

Exploratory Aim: Understand health-related QOL changes using the Parkinson's Disease Questionnaire-39 (PDQ-39) and semi-structured interviews to elucidate how components of the intervention translate into QOL changes through a mixed-method analysis of PDQ-39 constructs of mobility, activities of daily living, emotional well-being, social stigma, social support, cognition, communications, and bodily discomfort.

Inclusion Criteria:

• Adults ages 18-89 with neurologist-confirmed diagnosis of PD
• H&Y Stage 2 (bilateral involvement without postural instability) up to H&Y Stage 4 (severe disease)
• Able to provide informed consent

Exclusion Criteria:

• H&Y Stage 1 (unilateral involvement only) or less
• H&Y Stage 5 (wheelchair or bed bound)
• Unable to provide consent or diagnosis of dementia
• History of deep venous thrombosis/pulmonary embolism, peripheral vascular disease, thrombophilia or other clotting disorders; report of easy bruising
• Any comorbid conditions or pain that substantially affects ability to safely complete rehabilitation (e.g. neurologic, vascular, cardiac problems, orthopedic, or ongoing medical treatments) as determined by a neurologist or physical therapist
• Currently undergoing supervised resistance training with a physical therapist or other exercise professional
• Using Blood Flow Restriction currently or in the previous 3 months prior to enrollment
• Cannot tolerate BFR pressure cuff inflated to 60% of total limb occlusion pressure during baseline assessment
• PD-related medication change in the month prior to enrollment