Parkinson's Disease (PD) is a brain disorder that affects movement. This study aims to see if using special cuffs to reduce blood flow during exercises can help people with PD improve their balance and strength. The exercises are called instability resistance training (IRT). There are two groups in the study: one group uses the cuffs for Blood Flow Restriction (BFR) during IRT, and the other does IRT without BFR. Each session is about 45 minutes long. Researchers will look at how these exercises affect walking, balance, and endurance. They will also use a non-invasive (does not go inside the body) method to test nerve function. Eligibility: Participants should be 40-85 years old, diagnosed with PD, and meet certain health criteria. People with serious heart conditions or other major health issues cannot join.

• Each session lasts 45 minutes.
• Participants will be in either the BFR or non-BFR exercise group.
• No surgery planned in the next 2 months.