Swimming

Triathletes will often use their legs less vigorously and more carefully than other swimmers, conserving their leg muscles for the cycle and run to follow. Many triathletes use altered swim strokes to compensate for turbulent, aerated water and to conserve energy for a long swim. In addition, the majority of triathlons involve open-water (outdoor) swim stages, rather than pools with lane markers. As a result, triathletes in the swim stage must jockey for position, and can gain some advantage by drafting, following a competitor closely to swim in their slipstream. Triathletes will often use "dolphin kicking" and diving to make headway against waves, and body surfing to use a wave's energy for a bit of speed at the end of the swim stage. Also, open-water swims necessitate "sighting": raising the head to look for landmarks or buoys that mark the course. A modified stroke allows the triathlete to lift the head above water to sight without interrupting the swim or wasting energy.
Because open water swim areas are often cold and because wearing a wetsuit provides a competitive advantage, specialized triathlon wetsuits have been developed in a variety of styles to match the conditions of the water. The Springsuit, for example, sleeveless and cut above the knee, was designed for warmer waters, while still providing buoyancy. Wetsuits are only legal in sanctioned events with a water temperature equal to or below 78 degrees Fahrenheit (25.5 degrees Celsius). Some events allow wetsuits regardless of water temperature, and sometimes they are required. Or, in a single event, wetsuits may be allowed for "age groupers" but not for professionals, as the temperature rules differ slightly between the two groups.