Parkinson's Disease (PD) affects movement and can make daily activities harder. This study is testing if a smartphone app can help people with PD exercise more over 12 months. Exercise is good for health, but it can be tough for people with PD to stay active daily.

The study will include 452 participants from the Netherlands. They need to have PD and be able to walk on their own. Participants should have a smartphone and not have other health issues that affect movement. They also shouldn't live in a nursing home or have trouble using the app.

Participants will be randomly placed in groups to increase their activity to different levels based on their current activity. The app will aim to help them exercise more, and researchers want to see if this improves their fitness and PD symptoms.

• The study lasts for 12 months.
• Participants need a smartphone to use the app.
• Researchers will observe changes in fitness and symptoms.