Terminology reference
Triathlon Glossary
Clear, practical definitions of triathlon terms — from race formats and swim/bike/run vocabulary to pacing, nutrition, and training concepts.
Race formats
Sprint triathlon
Short-distance race: typically 750 m swim, 20 km bike, 5 km run. The most accessible entry point for new triathletes.
Olympic triathlon
Standard Olympic-distance race: 1.5 km swim, 40 km bike, 10 km run. Also referred to as Standard distance.
70.3 (Half Ironman)
Half-distance race: 1.9 km swim, 90 km bike, 21.1 km run. Named for the total distance in miles (70.3).
Ironman (140.6)
Full-distance race: 3.8 km swim, 180 km bike, 42.2 km run. The longest standard triathlon distance. Total 140.6 miles.
Ultra triathlon
Any triathlon longer than Ironman distance. Common formats include double, triple, and deca Ironman distances.
Duathlon
Run-bike-run race format, typically 5 km run, 30 km bike, 5 km run for standard distance. No swim leg.
Aquabike
Swim-bike race format with no run leg. Popular among cyclists who want to skip the run.
Aquathlon
Swim-run race format with no bike leg. Often used as an entry point for new multisport athletes.
Swim
Sighting
Lifting the head briefly during freestyle to look forward and swim in a straight line. Critical in open water without lane lines.
Bilateral breathing
Breathing to both sides (every 3 strokes) during freestyle. Helps balance stroke mechanics and sighting in open water.
Drafting (swim)
Swimming close behind or beside another swimmer to benefit from reduced water resistance. Legal in most triathlon swims.
Open water swim
Swimming in a natural body of water (ocean, lake, river) rather than a pool. Involves waves, currents, cold, and navigation challenges.
Wetsuit
Neoprene suit worn during the swim for buoyancy, insulation, and hydrodynamics. Legal when water temperature is below a race-specific threshold.
Swim buoy
Inflatable safety float tethered to the swimmer for visibility. Required in some open-water events but not in race competition.
Positive split (swim)
Swimming the first half of the distance faster than the second half. Often a pacing mistake in triathlon.
Chop (swell)
Irregular wave action in open water. Makes sighting, breathing, and stroke rhythm more difficult than flat water.
Bike
Aero position
Low, aerodynamic body position on a triathlon bike or TT bike using aerobars. Reduces frontal area and wind resistance.
Aerobars
Forward-extending handlebar attachments that allow the rider to assume an aerodynamic, forearms-resting position.
Drafting (bike)
Riding in another cyclist's slipstream to reduce wind resistance. Illegal in most non-draft-legal triathlons.
FTP (Functional Threshold Power)
The highest average power (watts) a cyclist can sustain for one hour. Used to set training zones and race pacing.
IF (Intensity Factor)
The ratio of your average power to FTP during a ride. IF of 0.85 means you rode at 85% of FTP.
TSS (Training Stress Score)
A composite score that combines ride duration and intensity. 100 TSS = 1 hour at FTP. Used to quantify training load.
NP (Normalized Power)
A power metric that accounts for intensity variation during a ride. More representative of effort than average power.
VI (Variability Index)
The ratio of Normalized Power to Average Power. A lower VI (closer to 1.0) indicates more even pacing.
Cadence
Pedal revolutions per minute (rpm). Typical triathlon cadence ranges from 80–95 rpm for most athletes.
Disc wheel
A solid, flat rear wheel that significantly reduces aerodynamic drag. Used in time trials and triathlon racing.
Crosswind stability
A bike's resistance to being pushed sideways by wind. Deep-section wheels and lightweight frames are more affected.
Run
Brick workout
A training session where biking is immediately followed by running. Simulates race-day transition and teaches the legs to adapt.
Running off the bike
The experience of running immediately after cycling. The legs feel heavy and uncoordinated until they adapt — typically 1–3 km.
Negative split (run)
Running the second half of the race faster than the first half. A disciplined pacing strategy for long-course triathlon.
Strides
Short (20–30 second) accelerations to near-maximum speed with full recovery. Used to improve running form and leg turnover.
Cadence (run)
Running steps per minute. Optimal cadence is typically 170–180+ steps/minute to reduce ground contact time and injury risk.
Bonk (hitting the wall)
Severe fatigue caused by glycogen depletion. Results in dramatic slowdown, weakness, and reduced coordination. Preventable with fueling.
Transition & gear
T1
Transition 1: the zone between swim and bike where athletes remove wetsuit, put on helmet, glasses, shoes, and mount the bike.
T2
Transition 2: the zone between bike and run where athletes rack the bike, remove helmet, change shoes, and start running.
Flying mount
Mounting the bike while already in motion. The athlete runs alongside, then hops onto the saddle. Saves a few seconds over a stationary mount.
Flying dismount
Dismounting the bike before coming to a complete stop. The athlete swings a leg over and runs alongside before dismounting.
Race belt
A lightweight belt that holds the race number. Rotated from back (bike) to front (run) during T2 for visibility.
Elastic laces
Shoelaces that do not need tying. Used in triathlon to save transition time. Also called speed laces or quick laces.
Timing chip
An electronic ankle strap that records split and finish times as the athlete crosses timing mats on the course.
Pacing & strategy
Goal split
A target time for each segment (swim, T1, bike, T2, run) that adds up to the total finish-time goal.
Cutoff time
The maximum allowed time to complete the swim, bike, or entire race. Athletes who exceed cutoffs are pulled from the course.
Even pacing
Maintaining a consistent effort or speed throughout a segment. The most efficient pacing strategy for long triathlons.
Course buffer
The time cushion between a planned finish and the official cutoff. A larger buffer reduces cutoff anxiety.
Surge
A sudden, short increase in effort. In triathlon, surging on the bike often compromises the later run.
Effort-based pacing
Pacing by perceived exertion rather than by watch or power meter. Useful on courses with variable terrain or conditions.
Nutrition & hydration
Carb loading
Increasing carbohydrate intake in the days before the race to maximize muscle glycogen stores for endurance.
Gel
A concentrated carbohydrate gel typically containing 20–30 g of carbs. Consumed during the race for quick energy.
Electrolytes
Minerals (sodium, potassium, magnesium, calcium) lost through sweat that must be replaced to prevent cramping and maintain function.
Sodium
The primary electrolyte lost in sweat. Sodium targets range from 500–1500 mg per hour depending on sweat rate and conditions.
Hyponatremia
A dangerous condition caused by low blood sodium levels from drinking too much water without enough electrolytes. Can be fatal.
Gastric emptying
The rate at which the stomach processes food and fluids. Limited to about 60–90 g of carbs per hour during intense exercise.
Aid station
A designated point on the bike or run course where athletes can pick up water, sports drink, gels, and snacks.
Sports drink
A beverage containing carbohydrates and electrolytes. Provides both hydration and energy during exercise.
Training & physiology
Aerobic base
The foundation of endurance fitness built through low-to-moderate intensity training. Improves fat utilization and cardiovascular efficiency.
Lactate threshold
The exercise intensity at which blood lactate begins to accumulate faster than it can be cleared. Key predictor of endurance performance.
VO2 max
The maximum rate of oxygen consumption during intense exercise. Measures aerobic capacity and potential.
Periodization
Structuring training into phases (base, build, peak, taper) to systematically develop fitness and peak for race day.
Taper
A period of reduced training volume before the race. Allows the body to recover and super-compensate for race-day freshness.
Overtraining
A state of chronic fatigue and performance decline caused by excessive training without adequate recovery.
Recovery
The period between training sessions when the body repairs tissue, replenishes energy stores, and adapts to training stimulus.
Cross-training
Using other sports or activities (yoga, swimming-only, strength training) to supplement triathlon training.
Heart rate zone
A percentage range of maximum heart rate (typically 5–7 zones). Used to target specific training intensities.
RPE (Rate of Perceived Exertion)
A subjective scale (1–10 or 6–20 Borg scale) for rating exercise intensity. Useful when power or heart rate data is unavailable.
Functional strength
Strength training that targets movement patterns relevant to swimming, biking, and running to improve performance and reduce injury.
Mobility
Range of motion around joints. Good mobility in hips, ankles, and shoulders is important for efficient triathlon movement.
DNS (Did Not Start)
An athlete who registered but did not begin the race. Common reasons: injury, illness, or last-minute withdrawal.
DNF (Did Not Finish)
An athlete who started the race but did not complete it. Can result from cutoff, injury, equipment failure, or voluntary withdrawal.
Trust and methodology
How this page should be used
Last updated
July 13, 2026
Maintained by
M Imtinan Farooq
Status
Planning estimate, not a race guarantee
Formula summary
Finish time = swim + T1 + bike + T2 + run, with related tools for risk checks.
Key assumptions
Entered paces, distances, transitions, and condition choices are race-realistic.
Limitations
Weather, course profile, water conditions, equipment, and execution can change results.