During a relay race, members of a group or team take turns swimming or running (generally with a baton) parts of a circuit or performing a certain action. The Relay races take the form of professional races and the amateur games. In the Olympic Games, there are lots of types of relay races that are part of track and field.
Based on the speed of the runners in relay, the generally accepted strategy used in setting up a 4 person relay team is: the second fastest, third fastest, slowest, then fastest (anchor). Each segment of the relay race is referred to as a leg.