As in the medley relay, no individual may swim more than one leg of the relay. Many races are lost in poor starts and turns. In the start, the swimmer is called to starting position by the starter who visually checks that all swimmers are in the down positions and still. Then, once the starter is satisfied, the race is started by either a gun or electronic tone. If the starter feels that one of the swimmers has jumped early, the race will be recalled and the offending swimmer disqualified.
Quick turns are essential to a good race.
In all events the swimmer must touch the wall, but in the freestyle and the backstroke, the swimmer may somersault as he or she reaches the wall, touching only with the feet. In the other two competitive strokes, the swimmer must touch the wall with one or both hands before executing the turn. The 200-meter events require the swimmer to have a sense of pace as well as the ability to swim a controlled sprint. This distance is considered by many swimmers to be the most difficult to master. Swimming the first portion of the race too fast can sap a swimmer's strength and cause a poor finish.