Boxing may seem like an unlikely sport for a Parkinson's disease patient, but experts believe it could help delay the disease's symptoms if practised regularly.
And once you shake off the dominant image of aggressive pre-fight chat ("I want your heart, I want to eat your children") or equally aggressive post-fight brawls, it's clear why.
As a sport, boxing requires strong reflexes, agility, endurance and speed, which means it not only maintains physical fitness but stimulates the mind.
At Rock Steady US doctors hope to help Parkinson's sufferers through boxing.
Dr Elizabeth Zaube, neurologist for the charity says: "People involved in the organisation can see a difference - as well as outlook and confidence."
See Also: What Triggers Parkinson's Disease?
There is lots of research to show that exercise helps symptoms of Parkinson's disease, she explains, but it is not clear which form of exercise is best.
"Our sense is that Rock Steady is an extremely good exercise because it combines such a diverse group of forms of exercise," says Dr Zaube. "It is so varied -- everyday is a different type of routine so people don't get tired or bored."
Mary Yeaman, a Parkinson's patient and Rock Steady attendee says of the class: " I don't know what I would do without it."
Rock Steady classes are divided into four levels based upon each individual’s unique Parkinson’s symptoms and overall level of fitness. Those in the first class have mild Parkinson's symptoms that are inconvient but not debilitating and are able to reach maximum heart rate, where as those in the fourth class have more severe symptoms such as rigidity and cognitive impairments.
Former champion boxer Muhammad Ali is one of the most high profile Parkinson's sufferers and was diagnosed with the disease in 1984, aged just 42.