For more information about Rock steady boxing and PD here are some links.

Rock steady boxing.org page https://www.rocksteadyboxing.org/#go_here

Michael J Fox Foundation https://www.michaeljfox.org/

https://parkinsonsdisease.net/living/rock-steady-boxing/

https://health.usnews.com/health-news/patient-advice/articles/2016-06-15/punching-out-parkinsons-boxing-training-improves-symptoms