noun - T1 is a transition area area used in a triathlon. T1 is a staging area between the swim leg and bike leg. Athletes and a few officials are usually the only individuals allowed in the T1 transition area. Athletes enter transition areas two times during triathlons: T1 occurs between the swim and bike; T2 takes place between the bike and run.
The T1 and T2 transition areas are positioned both between the swim and bike segments, and between the bike and run segments and are used to store bicycles, performance apparel, and any other accessories needed for preparing for the next stage of the race. The time spent in T1 and T2 is included in the overall time of the race. Transitions areas can vary in size depending on the number of participants expected for the race. In addition, these areas provide a social headquarters prior to the race.