Triathlon is the kind of sport where people casually say things like “I bonked in T2 because my FTP dropped,” and you’re expected to nod like you didn’t just hear a made‑up spell from Harry Potter. If you’re new, don’t worry: this glossary is here to translate the triathlon tribe’s secret language into plain human.
TL;DR:
- Triathlon has three disciplines plus two transitions—yes, the “in-between” counts.
- Most chaos (and time gains) happens in T1/T2, not in your heroic suffering.
- Learn a handful of key rules (helmet, lines, drafting) to avoid collecting penalties like souvenirs.
Triathlon terms you’ll hear five minutes after you sign up for your first race
Let’s start with the basics—because “just swim-bike-run” is the biggest understatement in endurance sports.
Triathlon
A multisport race with three legs: swimming, cycling, and running, done continuously. The clock does not stop for transitions, bathroom breaks, existential crises, or your sudden desire to become a chess player instead.
Multisport
The umbrella term for sports that mix disciplines: triathlon, duathlon, aquathlon, aquabike, cross triathlon, winter triathlon, and other ways adults choose discomfort on purpose.
The three disciplines
- Swim: usually freestyle (front crawl), in open water or a pool.
- Bike: road bike or tri/TT bike.
- Run: typically on road, paths, or mixed surfaces.
Triathlon distances (a.k.a. “How long is this suffering, exactly?”)
Different events use standardized distances. You don’t have to memorize them, but it helps when someone says “It’s just a sprint” with a straight face.
| Distance | Swim | Bike | Run | Who it suits |
|---|---|---|---|---|
| Super sprint | shorter than sprint | shorter than sprint | shorter than sprint | first-timers, test runs |
| Sprint | ~750 m | 20 km | 5 km | beginners, fast day out |
| Olympic/Standard | 1.5 km | 40 km | 10 km | intermediate, club racers |
| Half (70.3) | 1.9 km | 90 km | 21.1 km | long-course curious |
| Full (Ironman) | 3.8 km | 180 km | 42.2 km | the “I hate free time” crowd |
Transitions: where minutes vanish like your dignity
Transitions are the glue between disciplines—and the place where beginners donate time to the universe.
Transition / transition area
The “transition area” is where your bike, helmet, shoes, and gear sit. “Transition” is the act of switching disciplines. The clock is running the whole time.
T1 and T2
- T1: swim-to-bike.
- T2: bike-to-run.
Mount line vs dismount line
Two lines that exist solely to prevent chaos.
- Mount line: you may get on the bike only after this line.
- Dismount line: you must get off the bike before this line.
If you ignore them, you might get a penalty—or a front-row seat to the volunteer’s disappointed stare.
Starts: the art of not getting kicked in the face
Wave start
Athletes start in groups (by age, gender, ability). Less crowding, fewer panic hugs in the water.
Rolling start
People start in a steady stream, a few seconds apart. Great for calmer swims and for anyone who prefers “orderly chaos” over “mass mayhem.”
Rules you should not learn the hard way
You can be fit and still get penalized for something silly. Triathlon is generous like that.
Drafting
Riding close behind another cyclist to save energy.
- Draft-legal: drafting allowed (common in elite/Olympic formats).
- Non-drafting: keep the required distance (common in many amateur long-course races).
Penalty
Time penalty or disqualification for breaking rules—drafting, unfastened helmet, incorrect number placement, mounting early, etc.
Cut-off time
The maximum time allowed to finish a leg or the whole race. Miss it and the race politely (or not) removes you from the course.
Aid station
A fueling point on course: water, isotonic drinks, gels, fruit, and sometimes the emotional support of a volunteer who calls you “champ.”
Training jargon: what your coach says while smiling too much
Warm-up, main set, cooldown
- Warm-up: easy start to prepare the body.
- Main set: the key work.
- Cooldown: easy finish to downshift.
Intervals / reps / speedwork
Faster efforts broken into repeats with recovery. The goal is speed and efficiency, not seeing your ancestors.
LSD (Long Slow Distance)
Long, easy endurance. Looks boring, works brilliantly.
Brick / multi-brick
- Brick: two disciplines back-to-back, usually bike→run.
- Multi-brick: multiple switches in one session (for people who enjoy logistics with their suffering).
Negative split
Second half faster than the first. The opposite of the classic beginner strategy: “go out hot, regret everything.”
Effort metrics: pace, cadence, HR, FTP
Triathletes love numbers. Sometimes more than they love joy.
| Term | What it means | Where you’ll see it |
|---|---|---|
| Pace | speed, usually min/km | running (and sometimes swimming) |
| Cadence | pedal revolutions per minute (RPM) | cycling |
| HR | heart rate (bpm) | all disciplines |
| HRM | heart-rate monitor | training + racing |
| FTP | functional threshold power (~1h sustainable power) | cycling training zones |
Common “why do I feel like this?” terms
Bonking
Sudden energy collapse from low glycogen and/or dehydration. Feels like hitting a wall. The cure is fueling earlier, not heroic suffering.
Cramp
Muscle spasm—often from fatigue, electrolyte imbalance, or cold.
DOMS
Delayed-onset muscle soreness 24–48 hours after effort. A reminder that stairs are optional until further notice.
Gear glossary: what you need vs what you’ll impulsively buy
You can absolutely start with basic gear. The internet will still try to sell you a disc wheel and “marginal gains.” Stay strong.
Swim gear
- Wetsuit: neoprene suit for warmth and buoyancy in open water (allowed up to certain water temperatures).
- Tri-suit: one kit you can wear through the whole race.
- Goggles: swim goggles.
- Swim cap: often mandatory, usually provided.
Bike gear
- Road bike: standard drop-bar bike.
- Tri/TT bike: aero geometry, aerobar position, designed to help you run better after.
- Aero bars: forearm rests and extensions for aerodynamics.
- Disc wheel: aerodynamic rear wheel, used in time trial/tri.
- Clipless pedals (e.g., SPD): shoes clip into pedals.
- Bottle cage: holds bottles on the bike.
Run + transition gear
- Race belt: elastic belt for the number; rotate from back (bike) to front (run).
- Running shoes: often with elastic laces for quick entry.
- Visor/cap: sun and sweat control.
Safety basics (because penalties are optional, injuries aren’t)
- Helmet: mandatory on the bike; must be fastened whenever you have the bike.
- Race number: typically on back for the bike, front for the run.
- Draft distance: often ~10–12 m in non-drafting races (check the race briefing).
- Follow officials and volunteers: especially in water and transition.
Practical internal links (so you can keep pretending you’re “just browsing”)
- Find triathlon events: https://uzjudek.lt/events/by-sport-triathlon
- Explore swimming events: https://uzjudek.lt/events/by-sport-swimming
- Explore cycling events: https://uzjudek.lt/events/by-sport-cycling
- Explore running events: https://uzjudek.lt/events/by-sport-running
FAQs
Do I need a triathlon bike for my first triathlon?
No. A road bike is totally fine. Comfort, safe handling, and a decent fit beat “aero” if you’re still learning.
Are transitions really that important?
Yes. They’re “free speed.” You can save minutes with simple practice: layout, helmet first, shoes ready, and don’t wander like you’re in IKEA.
What’s the biggest beginner rule mistake?
Helmet strap. People forget to fasten it, or unfasten too early in T2. Officials notice. Always.
What’s bonking and how do I avoid it?
It’s an energy crash. Avoid it by fueling early and consistently (fluids + carbs), especially on longer distances.
Conclusion
Triathlon isn’t complicated—people just enjoy making it sound like an exclusive club with abbreviations. Once you know the core terms (T1/T2, drafting, cut-offs, bricks, FTP), the sport becomes much less intimidating and a lot more fun. Learn the language, respect the rules, practice transitions, and you’ll spend less time confused—and more time doing the thing you signed up for: swim, bike, run, repeat.