Breath holding during the turn in competitive swimming.

Breath holding times were measured during competition and averaged 5.0 sec in the breaststroke events, 4.3 sec in freestyle, 3.7 sec in butterfly, and 3.3 sec in backstroke. These times represented approximately 30% of the total time of swimming breaststroke and freestyle races but only 20% of the time of backstroke and butterfly events. Pulmonary gas exchanges of O2 and CO2 were studied in eight male swimmers during the first turn after the start of a swim and during the third turn after continuous swimming. It was concluded that biomechanical considerations of optimizing a turn are in most circumstances not limited by the increased PCO2 and the decreased PO2 in the alveoli related to the brief period of breath holding. In turns which last longer than about 5.5 s, the swimmers may experience a strong urge to breathe. This "breaking point" sensation is brief and need not compromise the conclusion of a well-executed turn.