Glossary

Triathlon in 28 words.
Defined simply.

Brick, T1, sighting, drafting, FTP, zone 2, VMA, DNF — triathlon vocabulary can feel intimidating. It's all here, sorted by category, explained in one or two sentences.

Whether you're prepping your first discovery triathlon or your tenth Ironman, here's the essential vocabulary you need to know. Each term is defined simply, without unnecessary jargon.

Distances and formats

The main triathlon and multisport formats.

Sprint (S)Sprint triathlon, S format: The shortest official triathlon format: 750 m swim, 20 km bike and 5 km run. The classic discovery format, doable in 1 to 3 h depending on level.
Olympic distance (M)Olympic, Standard: Also called Olympic distance: 1,500 m swim, 40 km bike, 10 km run. The reference triathlon distance, raced at the Olympic Games since 2000.
Long distance (L)L distance: Intermediate format between M and Half-Ironman, with variable distances depending on the event (often around 2 km / 80 km / 20 km). Sometimes called Half or Middle distance by international organizers.
Half-Ironman70.3, Ironman 70.3, Half: Official mid-distance format: 1.9 km swim, 90 km bike, 21.1 km run — 70.3 miles total. Effort of 4 to 8 h depending on level.
Ironman140.6, XL, Full Ironman: The ultimate format: 3.8 km swim, 180 km bike, 42.2 km run — 140.6 miles. Effort of 9 to 17 h depending on level, generally prepped over 6 to 12 months.
AquathlonAqua-running: Swim + run combo (no bike). Often used as a discovery format or in pre-season to prep the triathlon T2.
DuathlonBi-athlon, run-bike-run: Run + bike + run combo (no swim). Format suited to non-swimmers or cold seasons when open-water swim isn't possible.
SwimrunSwim&run: Scandinavian discipline turned popular: alternating open-water swim segments and trail running in teams of two, with no formal transition. Gear (shoes, wetsuit, pull buoy) stays with the athlete throughout.

Transitions

Triathlon's 4th sport: switching disciplines fast.

T1First transition, swim-to-bike: Transition between swim and bike. Includes water exit, wetsuit removal, putting on bike shoes and helmet, grabbing the bike. A good T1 takes under 1 min on short distance.
T2Second transition, bike-to-run: Transition between bike and run. Includes racking the bike, removing bike shoes, putting on running shoes, removing helmet. Faster than T1 — 30-45 s for good triathletes.
BrickBrick workout, Bike-run combo: Specific workout chaining two disciplines back-to-back, usually bike + run. Goal: train the body to handle 'jelly legs' after the bike. Essential ingredient of any triathlon prep.

Swim

Terms specific to swimming in triathlon (mainly open water).

Open waterOWS, Open water swimming: Swimming in natural environments: lake, sea, river, managed swimming area. Different from pool swimming: wetsuit, sighting, currents, variable conditions.
SightingHead-up check: Technical move in open-water swimming: briefly lifting the eyes out of the water (every 4 to 8 strokes) to check your trajectory. Avoids zig-zagging between buoys.
Swim draftingWake, slipstream swim: Swimming right behind (in the feet) or next to another swimmer to benefit from the wake. Energy savings of 10-25%. Legal in triathlon swim, unlike bike in most races.
WetsuitNeoprene: Neoprene suit (3-5 mm) used in open water. Provides warmth (water < 20 °C) and buoyancy (athlete floats better, loses less energy). Often mandatory below certain temperatures, banned above 22-24 °C depending on federations.
Pull buoyPull, leg float: Small foam float held between the thighs that lets you swim with arms only (legs immobilized). Training tool to work arm propulsion and body position.

Bike

Essential cycling terms applied to triathlon.

AerobarsAerobar, TT bars, time-trial position: Handlebar extension that lets you go into aero position (forearms on pads, hands forward). Major aerodynamic gain (up to 30 W), but less maneuverable position. Standard on triathlon bikes.
Bike draftingSlipstream, wake: Riding very close behind another cyclist to benefit from the slipstream. Energy savings of 20-40%. Banned in most triathlons (Sprint, M, amateur Half-Ironman and Ironman) except draft-legal format (Elite World Championships).
CadenceRPM, pedaling frequency: Number of crank revolutions per minute. An efficient triathlon cadence sits between 85 and 95 RPM — high enough to save the legs for the run.
FTPFunctional Threshold Power, Threshold power: Maximum power you can hold for one hour of sustained effort, in watts. The central marker to define your bike training zones (Z2 = 56-75% FTP, Z4 = 91-105% FTP, etc.).
Elevation gainD+, positive elevation, climbing: Total positive elevation of a route, in meters. Flat long bike ride = 200-400 m, hilly route = 800-1500 m, mountain = 2000 m+. Useful to assess the difficulty of a session or race.

Run

Paces and concepts specific to running in triathlon.

Marathon paceM-pace, half-marathon pace: Pace sustainable over 42.2 km (or 21.1 km for half). Typically 10-15 s/km slower than your 10k pace, and 20-30 s/km faster than your easy jog. The target run pace of an Ironman or Half-Ironman.
Threshold paceT-pace, tempo pace, lactate threshold: Pace sustainable for about 1 h in isolated effort. Located in zone 4, just below lactate accumulation. Reference pace for tempo runs and cruise intervals (4×10 min threshold with short recovery).
Stride / CadenceFoot turnover, SPM, step rate: Number of steps per minute (counting both feet). An efficient cadence typically sits between 170 and 185 SPM. Too low a cadence (< 160 SPM) increases injury risk.

Physiology and training

Key concepts to structure your sessions.

Zone 2Z2, base endurance, easy: Low to moderate intensity, at 60-75% of max heart rate. Conversation pace: you can talk without panting. The king zone to build aerobic base. At least 60-80% of weekly volume in triathlon.
Zone 4 / Lactate thresholdZ4, threshold, LT: High intensity at 85-90% max HR, corresponding to the lactate threshold. Sustainable for about 1 h continuous. Threshold sessions (tempo, cruise intervals) raise the percentage of VO2max you can hold long.
Zone 5 / VO2maxZ5, VO2max, short intervals: Very high intensity (90-100% max HR), sustainable only a few minutes. Target of short interval sessions (30/30, Billat, 3×3 min) that develop maximum oxygen consumption. Physiological ceiling of aerobic performance.
VMA / MAVMaximum Aerobic Velocity, vVO2max: Speed at which you reach your VO2max, in km/h. French concept widely used in running. A 30/30 interval session is done at 100-110% VMA, the 10 km is run at 85-90% VMA.
FartlekSpeed play (Swedish): Unstructured training session alternating fast and easy pace freely based on terrain or feel (e.g., accelerating from pole to pole). Playful format that builds base without the rigidity of a timed interval.

Mental and unexpected

Triathlon is also a head sport.

DNFDid Not Finish: Abandoning mid-race, for injury, physical failure, mechanical, hypothermia or personal decision. A DNF isn't a failure: sometimes it's the right call to preserve your health and finish the season.
The wall / BonkHitting the wall, energy crash: Major energy crisis when glycogen stores run out (typically after 90 min to 2 h of sustained effort without fueling). The athlete crashes dramatically — heavy legs, blurry vision. Avoided by regular nutrition (60-90 g carbs/h) during effort.

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Chargement…

Triathlon in 28 words.Defined simply.

Distances and formats

Transitions

Swim

Bike

Run

Physiology and training

Mental and unexpected

Make triathlon a team sport

Triathlon in 28 words.Defined simply.

Distances and formats

Transitions

Swim

Bike

Run

Physiology and training

Mental and unexpected

Make triathlon a team sport

Triathlon in 28 words.
Defined simply.

Triathlon in 28 words.
Defined simply.