Shadowboxing is an exercise used in the training for combat sports, especially, as its name implies, in boxing. It is used mainly to prepare the muscles before the person training engages in stronger physical activity. In shadowboxing, only one person is required to participate; the participant throws punches at no one in particular. Muhammad Ali once performed a now famous shadowboxing routine next to Howard Cosell for ABC's Wide World of Sports television cameras. Black Nova Scotian boxer George Dixon is widely credited for developing the technique.