Triathlon Terms
This glossary defines concepts created specifically by combining running, cycling, and swimming: race format and distance, transitions, discipline crossover and pacing, and multisport nutrition. Individual-sport terminology, including brick session’s counterpart references, lives on the Running, Cycling, and Swimming glossary pages rather than here.
Quick answers
What is age-group in triathlon?
Age-group is the classification of amateur triathletes into bands defined by age and gender, used for both race results and qualification into events with limited entry, including roll-down slots passed to the next-placed athlete when a qualifier declines.
What is an aid station in triathlon?
An aid station is a designated point on the bike or run course where race organisers provide water, sports drink, and food to competitors.
What is bike-in in triathlon transition?
Bike-in is the point where a rider dismounts and enters the transition area at the end of the bike leg, moving through to their bike rack position.
What is bike-out in triathlon transition?
Bike-out is the point where a rider exits the transition area with their bike before crossing the mount line to begin the bike leg.
What is bike-to-run crossover (running off the bike)?
Bike-to-run crossover, or running off the bike, describes the distinctive adaptation period in the first kilometre or two of the run leg, when legs accustomed to cycling adjust to running mechanics.
What is a brick session?
A brick session is a training session that combines two disciplines, most commonly cycling immediately followed by running, used to practice the physiological transition athletes face on race day. For the full breakdown of brick session structure and purpose, see this site’s guide to building an effective brick.
What is carbohydrate intake rate?
Carbohydrate intake rate is the amount of carbohydrate consumed per hour during a race or long training session, typically expressed in grams per hour.
What is cardiac drift in a multisport race?
Cardiac drift in a multisport context is the gradual rise in heart rate at a constant effort level across the swim, bike, and run legs, driven by accumulated heat and fluid loss over the race.
What is a cutoff time in triathlon?
A cutoff time is the maximum elapsed time allowed to complete a discipline or the overall race, beyond which a competitor is withdrawn from the results.
What is the dismount line?
The dismount line is the marked point before the transition area where riders must be off their bikes before entering T2 on foot.
What is draft-legal triathlon?
Draft-legal describes a race format in which cyclists are permitted to ride in the sheltered wake of other competitors during the bike leg.
What is a duathlon?
A duathlon is a multisport event combining a run, bike, and second run, sharing the same transition structure as triathlon without a swim leg.
What is electrolyte replacement?
Electrolyte replacement is the intake of sodium and other minerals lost through sweat during a race, taken to offset cramping and maintain fluid balance.
What is exogenous carbohydrate oxidation rate?
Exogenous carbohydrate oxidation rate is the physiological ceiling on how much ingested carbohydrate the body can actually absorb and use for fuel per hour, a limit that governs realistic race-day fueling targets.
What is a flying dismount?
A flying dismount is a technique for exiting the bike while it is still moving, used to save time entering T2 rather than coming to a complete stop before dismounting.
What is a flying mount?
A flying mount is a technique for getting onto a moving bike at the mount line, used to save time exiting T1 rather than starting from a stationary position.
What is gut training?
Gut training is the deliberate practice of consuming race-day quantities and types of nutrition during training sessions, to condition the digestive system to tolerate fueling under race effort.
What is the triathlon helmet rule?
The helmet rule requires a triathlete’s helmet to be fastened before touching the bike at the mount line and to remain fastened until after the bike is racked at the dismount line.
What is hyponatremia?
Hyponatremia is a dangerously low blood sodium level caused by excessive fluid intake relative to sodium replacement during a long race, a serious medical risk in endurance multisport events.
What is middle-distance triathlon (half-iron / 70.3)?
Middle-distance triathlon covers the approximately 1.9 km swim, 90 km bike, and 21.1 km run format, commonly known by the branded terms half-iron distance or 70.3. For the full breakdown of standard triathlon and duathlon distances, see this site’s simple guide to sprint, Olympic, and iron distances.
What is the mount line?
The mount line is the marked point after the transition area where riders may get on their bikes to begin the bike leg.
What is multisport pacing?
Multisport pacing is the strategy of distributing effort across the swim, bike, and run legs so that fatigue in one discipline does not disproportionately compromise performance in the next.
What is a negative split in a triathlon leg?
A negative split applied to a triathlon leg means completing the second half of that discipline faster than the first, the same concept defined generally under Running applied to a single leg of a multisport race.
What is non-drafting triathlon?
Non-drafting describes a race format in which cyclists must maintain a minimum distance from other riders and are penalised for drafting.
What is a number belt?
A number belt is an adjustable belt worn around the waist to carry a race number, allowing it to be moved from back to front between the bike and run legs without repinning.
What is Olympic distance (standard distance) triathlon?
Olympic distance, also called standard distance, covers the 1.5 km swim, 40 km bike, and 10 km run format. For the full breakdown of standard triathlon and duathlon distances, see this site’s simple guide to sprint, Olympic, and iron distances.
What is on-course nutrition?
On-course nutrition is fuel and fluid provided by race organisers at aid stations, as distinct from nutrition an athlete carries themselves.
What is a penalty box (draft zone)?
A penalty box, tied to draft zone infringements, is a designated stop where a competitor serves a time penalty for drafting violations in a non-drafting race.
What is a race-day fueling plan?
A race-day fueling plan is an athlete’s predetermined schedule of carbohydrate, fluid, and electrolyte intake across all three disciplines, developed and tested in training.
What is race morning nutrition timing?
Race morning nutrition timing is the planned schedule of food and fluid intake in the hours before a race start, designed to arrive at the swim start neither underfed nor still digesting.
What is a relay (team triathlon)?
A relay, or team triathlon, is a race format in which different athletes each complete one discipline as part of a shared team result.
What is run-out in triathlon transition?
Run-out is the point where an athlete exits the transition area on foot to begin the run leg.
What is special needs nutrition in triathlon?
Special needs nutrition refers to a personal nutrition bag, permitted at longer-distance events, that an athlete pre-packs and collects at a fixed point on the bike or run course.
What is sports drink concentration?
Sports drink concentration is the ratio of carbohydrate and electrolytes to water in a race-day drink, a variable athletes adjust based on temperature and personal tolerance.
What is sprint distance triathlon?
Sprint distance covers the shorter end of standard triathlon racing, roughly a 750 m swim, 20 km bike, and 5 km run. For the full breakdown of standard triathlon and duathlon distances, see this site’s simple guide to sprint, Olympic, and iron distances.
What is super sprint triathlon?
Super sprint is a shortened race format below sprint distance, often used for beginner or team events.
What is swim-to-bike crossover?
Swim-to-bike crossover describes the physiological adjustment from horizontal swimming effort to the seated, upright effort of cycling, including the pacing decision of how hard to swim without compromising the bike leg that follows.
What is T1 in triathlon?
T1 is the first transition, from swim to bike, including removing swim gear and preparing to ride.
What is T2 in triathlon?
T2 is the second transition, from bike to run, including racking the bike and preparing to run.
What is the transition area?
The transition area is the designated zone where athletes’ bikes and equipment are racked between disciplines.
What is a transition bag?
A transition bag is a bag used at longer-distance events to organise and store an athlete’s gear for a specific discipline, collected or dropped at a designated point rather than left on an open rack.
What is a transition rack?
A transition rack is the physical rack structure within the transition area where bikes are hung by their saddle or handlebars between the bike and run legs.
What is transition time in triathlon?
Transition time is the elapsed time spent in T1 and T2, counted as part of a competitor’s overall race time.
What is ultra-triathlon?
Ultra-triathlon covers formats exceeding full iron distance, such as double or deca iron distance events, undertaken by a small specialist ultra-endurance field.
What is variable pacing across triathlon legs?
Variable pacing across legs is the deliberate allocation of uneven effort across the swim, bike, and run, typically holding back slightly on the bike to preserve run capacity.
What is a wetsuit strip?
A wetsuit strip is the act of removing a wetsuit quickly on entering T1, sometimes assisted by volunteer wetsuit strippers at larger events.
