Tri jargon buster for beginners

From aerobars to zones, DOMS to HIIT, here's your essential starter guide to decoding some of the terms you'll come across in multisport…

Triathlete in transition

At some point on your journey to becoming a triathlete you’ll have a conversation with a fellow athlete and have absolutely no idea what they’re talking about.


Don’t worry. It’s all part of the learning curve, and before long you’ll be throwing terms together that’ll make newbies’ eyes water. To help you on your way, here’s a list of some of the key terms to help ease your transition into tri…


Also known as tri-bars: the special aerodynamic handlebars used in racing.


The use of oxygen in the body’s energy-generating process. Aerobic exercise involves or improves oxygen consumption by the body. Exercise intensity is usually moderate.


When your body produces energy without utilising oxygen, stimulated by exercise that’s at high intensity.

Base training

Low-intensity training that stimulates your aerobic system and helps develop endurance.

Bilateral breathing

Breathing on alternate left/right sides in swimming, typically every third or fifth stroke.


A rapid drop in energy caused by the depletion of glycogen in the muscles and liver. Also called ‘the wall’ by runners, it can be accompanied by nausea, dizziness and even hallucinations.

Brick session

A session that combines multiple sports, usually bike and run.


The rate at which you’re pedalling, expressed in revolutions per minute (rpm).

Core stability

The ability to control the position and movement of the central portion of the body. Training targets the abdominal muscles.


The very top and bottom of your pedal stroke, where you produce little power.


Delayed onset muscle soreness. Typically kicks in 48hrs after a hard session or a race.


Hitching a ride in someone else’s slipstream – a strict no-no in most age-group races but allowed in elite ITU racing. Penalties vary per race. At the London Triathlon, for example, you have 15secs to pass through their 3 x 7m ‘draft zone’.


The amount of turbulent displaced air that an object creates, resulting in a slowing effect. Smooth ‘aero’ objects create low drag, while things like round tubesets, a bad bike fit, vented helmets and kit flapping in the wind increase drag.


An electrolyte solution contains acids, alkalis or salts. They’re used to replenish the body’s stores of various substances lost through sweating during exercise.


Functional threshold power. The highest average power you can maintain for one hour on the bike.

Half-iron distance

Also known as 70.3 (for official Ironman-branded races) or middle, and refers to the total distance of the race in miles. In km, it’s a 1.9km swim, 90km bike and a 21km run.

Heart-rate monitor

A device that monitors how many times your heart beats per minute. Allows you to monitor effort in real time. Often written as HRM.


High intensity interval training.


Your maximum heart rate, measured in beats per minute.


A deficiency of sodium in the blood, which can cause cramps, nausea, vomiting, headache and fatigue.

Interval training

Intensive training using repeated on/off efforts for faster results than a single sustained slog.

Iron distance

Also know as Ironman (for officially branded races), or long distance. Involves a 3.8km swim, 180km bike and a 42.2km run.

Lactic acid

Produced in the muscles during high-intensity workouts, it can inhibit oxygen movement and slow you down.

Midfoot strike

When running, your front foot strikes the ground flat, as opposed to toe or heel first.

Mount zone

An often-chaotic area just beyond transition for mounting your bike before starting the bike leg. On the return leg, this is where you must dismount before entering transition.

Negative splits

A training method where successive sets are completed faster than the previous one. Or, in a race, where you pace yourself to race the second half faster than the first.

Olympic distance

Also known as standard distance, this refers to a race that follows the format of the Olympic-recognised triathlon: 1.5km swim, 40km bike and a 10km run.


Common symptoms of training too much with insufficient recovery include insomnia, headaches, moodiness, loss of enthusiasm for the sport and increased illness due to a suppressed immune system.


The natural ‘turning in’ of the foot. Some athletes overpronate excessively, often when tired.


Rate of perceived exertion. A measure of exercise intensity, where one is easy and 20 is extremely hard.

Sprint distance

Half the distance of an Olympic-distance triathlon: 750m swim, 20km bike, 5km run.

Super sprint distance

Half the distance of a sprint: 400m swim, 10km bike, 2.5km run.


When you reduce your training in the days just before a big race, giving your body a chance to get ready for the big push.


The portion of the race where you’re moving between disciplines. T1 is between swim and bike; T2 between bike and run.

Turbo trainer

A frame that attaches to your bike and provides resistance to the back wheel as you pedal, turning the bike into a static trainer.


A measure of the body’s maximal ability to use oxygen to produce energy. Those who are fitter will have a higher VO2max.


The unit of measurement in which power is expressed.


A way of figuring out how hard you’re working in a session using a percentage of your HRmax. Exactly what percentage constitutes which zone and how many zones there are can vary between systems, but they usually fall in the range of 60-100% of HRmax.

(Main image: Delly Carr/ITU)


Which terms have we missed? Let us know in the comments below!