Tan Shie Boon, founder of Movement.sg, teaches parkour to older adults in Singapore. Provided by Tan Shie Boon. On a sunny Friday morning, a group of nine people gathered at an exercise corner in one of Singapore's public housing blocks. Clad in workout wear and sneakers, some rolled their shoulders and stretched their calves. Others stood together in small circles, chatting beneath the morning sun. Over the next hour and a half, the conversation continued flowing as they hopped across concrete