In-play betting, also known as live betting or run betting, is the process of placing a bet during an event. This could be, for example, during a football match, horse race, golf tournament, or any event that carries a betting market.
It depends on the sport. Play is for games and sports where you're competing directly against another person or team in a mock battle: football, tennis, chess, billiards. Sports where you're ultimately competing against a clock or the like (most track and field events, swimming) are do .