Originally, the tracksuit started life as an extra layer for athletes to sport (sorry) to warm-up in before starting their chosen event. Often made from jersey, the idea was that they would serve as a lightweight breathable solution to exercise in and also as a means of communicating which team a sportsperson represented.
Fast-forward to the 70s
, and the tracksuit became less about sport and more about being a sartorial mainstay. Two-pieces were created made from velour and terry loop fabric to give the sets a luxurious, casual feel to be donned as everyday wear.