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Triathlon terms explained: The ultimate jargon-busting guide

From bonking to brick sessions, we have you covered...

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Tri247’s ultimate triathlon jargon buster for beginners will enable you to hold your own in any triathlon conversation.

From referencing some of the sport’s greats to understanding the difference between Vo2 max and threshold, we have you covered. But first, a short guide to being able to smell triathlon BS, or real talk.

What triathletes say, and what they likely mean…

Triathlon and triathletes are very inclusive and welcoming. However, that doesn’t stop them from being prone to exaggeration or understatement, and humble brags. The following are classic comments made by triathletes which are often not what they seem:

“That [run or ride] on Strava was only tempo/steady” – Means the activity was far harder than real ‘tempo’, and closer to ‘threshold’ or harder. Don’t be intimidated by such claims!

“I finished in X place …..[in my age-group]….” – It is possible the result is objectively impressive, however a top 10 overall can be very different to finishing top 10 in your age-group (which could be far further down the field).

“I have barely trained this week…” – Means an athlete has still trained far more than the average person, but not as much as their normal high standards. Don’t be fooled.

“If it isn’t on Strava it didn’t happen” – Means if you trained and raced, but failed to upload the activity to Strava, did it really happen? Of course it did!

“Today’s race was just training, I didn’t taper…” Don’t let an athlete convince you that they have not raced their hardest. If you are on the start-line, you are there to race.

Anyway, now we’ve given you a few stock triathlete sayings, we’ll get to the meat of this and our extensive glossary of tri terms. It should serve you well as you go deeper into the sport that is swim/bike/run.

Triathlon terms explained

These are just some of the terms and phrases you will come across when you take up triathlon. We’re here to help you learn all about swim, bike and run – so here goes:

Age-group (AG)

You will hear people say “I finished in X place overall,  and [an impressive] X in my age-group”. In amateur triathlon the vast majority of races are split into five-year age-groups, for example 20-24, 25-29, 30 -34 and so on. This is one of the attractions of triathlon, that even if you aren’t competing for the overall honours you can compare yourself to people of a similar age. Unless you are racing in the elite category, you will be an age-grouper.

Aero helmet

You must wear a helmet when cycling. When people say ‘aero helmet’ they will mean either (i) a helmet with a profile similar to a classic road lid, which has been stream-lined and aero-optimised, or (ii) a ‘time-trial’ specific helmet which has a longer shape, akin to a teardrop, which is designed to fill the gap between your head, neck, and upper back when cycling in an aggressive position.

Angry Bird

The nickname given to Swiss long-distance specialist Daniela Ryf.


Normally a swim followed by a run. See our full guide to aquathlon for more details.

Base training

Training at low intensity, designed to improve aerobic capacity and enhance endurance. Base training is relatively longer and slower.

Battle braids

The iconic hairstyle used by Lucy Charles-Barclay when it comes to race day.

‘Big Blu’

The nickname given to individual male triathlon gold medallist at the Tokyo Olympics, Norwegian Kristian Blummenfelt.

Bilateral breathing

Breathing every three strokes when you are swimming.

Breakaway (or exploder) zipper

Some wetsuits have a special zipper designed to help you get your wetsuit off as quickly as possible. Unlike a conventional zip which requires you to pulling the zip all the way down, a breakaway zipper splits open when you tug at the top and easily separates to help you swiftly pull down your wetsuit.

Brick session

A training session including two disciplines which are carried out one after the other. The classic is a bike session immediately followed by a run. “Run off the bike” is a phrase often used in this context.

Brownlee brothers

Alistair and Jonny, the two British (and global) triathlon superstars from Leeds, UK.

Alistair Brownlee / Jonathan Brownlee
The Brownlee brothers – trailblazers for triathlon in Britain.

Bonking (to bonk)

Bonking in a triathlon context is not as fun as it might sound. In fact, to bonk is an unpleasant experience where you completely run out of energy during a race or training session. Fuelling is crucial to avoid this – beware, often by the time you realise you are bonking it is already too late to do anything about it.


This refers to your leg speed or pedal revolutions, for running and cycling.

Calf guards

These are sleeves that fit tightly around your lower legs, rather than long socks. Depending on their design they might be used for compression and recovery, and/or aerodynamic gains when cycling.

CdA (coefficient of drag area)

This technical term is used when talking about aerodynamics on the bike. It stands for coefficient of drag area. A very aero rider on a time trial bike will have a CdA of around or below 0.2. In short, the smaller your CdA, the more aero you are and the better the results you are likely to get.

Clip-on bars

Rather than buying a triathlon or time-trial bike, attaching clip-on aero/tri bars or extensions to your road bike can be a more affordable way to achieve an aero position on the bike leg. Clip-on bars can be short and stubby (they do not protrude beyond the hoods of your road bike) with a bridge joining the bars together to comply with draft-legal race requirements or longer independent extensions.

Clipless pedals

The name is confusing. The term clipless pedals refers to cycling pedals without straps and classic toe-clips. However, they do mean pedals that you clip your bike shoe into and out of. If you are serious about improving your cycling and triathlon performance you will need to start riding with clipless pedals.

Challenge Family

The Challenge Family is a competitor of the IRONMAN brand, offering high-quality international races predominantly over the full and half-distance. The most popular race is Challenge Roth in Germany – which regularly draws huge fields and crowds.

Cross triathlon

Triathlon races with an off-road bike leg and often a trail run.

Disc wheel

This could mean one of three things:

  • A wheel for a disc brake-equipped bike (which is a wheel with a rotor for braking)
  • A rear disc wheel that has no visible spokes and is designed for aerodynamic gain
  • Both

Dismount line

The line, often marshalled by a volunteer, by which you must have stepped off your bike before crossing and entering T2. Most importantly when returning to T2 you should ensure you are not going too fast to safely get off your bike.


Means not finishing a race. Grim stuff, three letters nobody wants after their name.


As you might expect, it is failing to start a race.


To swim or cycle behind, or to the side of, someone reducing your required effort by benefitting from their slipstream or them blocking the wind. Drafting is permitted in nearly all open-water swims. However, when it comes to cycling, triathlons are distinctly split into races which allow drafting and those that do not.

If you watched last year’s Olympics in Tokyo you’ll likely have noted that drafting is allowed in short-course racing – not uncommon to see big groups of riders together on the bike sharing the work. Drafting is not allowed in the bike leg in Ironman races though.


Most commonly a run, bike, run. See our full guide to duathlon for more details.


For many, ‘elite’ is used instead of or along with ‘professional’ (for example, Alex Yee, Georgia Taylor-Brown and co.). However, in reality, ‘elite’ is often far more accurate – as many triathletes who are classed as ‘elite’ do not make their money exclusively from triathlon.


Interval training and fartlek training mean intense sessions which involve varying paces and efforts, alternating between harder sections and easier recovery sections.

Flying squirrel mount

It sounds simple, but getting onto your bike quickly in a triathlon is quite a skill. It requires a lot of practice. A flying squirrel mount involves running with your bike and attempting to seamlessly jump over your saddle and onto your bike. Not easy…

Flora (Duffy)

The individual women’s triathlon gold medallist at the Tokyo Olympics. The first ever Bermudian to win Olympic gold in any event.

Flora Duffy / Tokyo 2020
Flora Duffy en route to Olympic triathlon gold in Tokyo.

Forefoot strike

To run landing on your forefoot (rather than your mid-foot or heel) – a style popular with elite runners.


The nickname given to German triathlete Jan Frodeno. For many, Frodeno is the GOAT of triathlon having won gold at the Beijing 2008 Olympics and then dominating long-course triathlon.

Front crawl or freestyle

This is the most common swim style used in triathlon (however, you will occasionally see people using other strokes, like breaststroke).

FTP or Threshold

On the bike this is referred to as functional threshold power – it is the power you can average for an hour. When running, it is the pace you can maintain for an hour.

Full distance

Means a race over the iron distance = an Ironman (check out our full guide to triathlon distances).

A race over the full Ironman distance consists of:

  • 3.8k swim
  • 180k bike
  • 42.2k run (full marathon).


The greatest of all time. All sports have raging debates about theirs and triathlon is no different.

‘The Grip’

The nickname given to six-time IRONMAN World Champion Mark Allen – the GOAT in the eyes of many experts…


This is a cycling term and it means the components on your bike which are involved in braking, changing gear, or running the drive train. This means your brake calipers, brake levers, gear shifters, front and rear mechs (derailleurs), crankset, bottom bracket, chain and cassette (sometimes called block). The main groupset providers are Shimano, SRAM, and Campagnolo.

Half distance

Half-distance means a race over triathlon’s middle distance or 70.3. It consists of:

  • 1.9k swim
  • 90k bike
  • 21k run (half marathon).


Means a heart rate monitor. Classically this is a sensor which is strapped across your chest. However, depending on the type of HRM, the sensors can be included in a watch or a band around your arm.

Interval training

Another term for fartlek training.


Despite often being used to mean or refer to full iron-distance racing (that is: 3.8k swim; 180k bike; and 42.2k run), Ironman is really just a brand. IRONMAN the brand provides high-quality events internationally, predominantly over the half and full-distance. You will notice triathletes with tattoos of the Ironman M-Dot logo, often on their calf.

Many athletes who take up the dream of finishing a full-distance race do so to hear the famous words ‘You are an Ironman’ as they cross the finish line.

The ‘Iron War’

The epic 1989 IRONMAN World Championship on Kona, Hawaii which saw great rivals Mark Allen and Dave Scott locked together for more than eight hours before Allen finally managed to surge ahead to claim a famous victory.


Means the International Triathlon Union, the former name of World Triathlon. World Triathlon is the international governing body of triathlon – although it does not govern all forms of triathlon racing (for example, IRONMAN, Challenge Family, and Super League), which often causes race scheduling challenges and conflicts.


Kona, Hawaii is the iconic location of the Ironman (the brand) World Championships held every year in October. On May 7, 2022 though there is an additional World Championship at St. George, Utah.

Lactate threshold

Not to be confused with Vo2 Max and FTP. Your lactate threshold is the point of exercise or intensity at which your body is creating more lactate in your blood than it is able to remove.


British triathlete Lucy Charles-Barclay. LCB is redefining what people thought was possible in triathlon and defying convention: an athlete starting their career in long-course, continuing to race in the top echelons of long-course, and simultaneously excelling at short-course racing!

Lucy Charles-Barclay / IRONMAN 70.3 World Championship 2021
Lucy Charles-Barclay, or ‘LCB’ (Patrick McDermott/Getty Images for IRONMAN)

Mandatory foot down

Some races require that during the bike leg, when you are approaching a busy or dangerous junction, you slow down, come to a stop, and put your foot down before proceeding.


Maui, Hawaii is the location of the annual XTERRA cross triathlon world championships.

Mixed relay

Introduced to great effect at the Tokyo Olympics, with Team GB winning gold. The format was female / male / female / male but that’s switching round from the 2022 Commonwealth Games onwards.

Mount line

When coming out of the T1 transition, you must not get on your bike until you have passed the mount line.

Negative split

To finish the second half of a race faster than the first half.

Olympic distance

Also known as the standard distance, this is a race over:

  • 1.5k swim
  • 40k bike
  • 10k run

Open water swim

A swim in a lake, river, or the sea (including swims in a harbour).


Simply put, overtraining means training too much without adequate recovery. The result can be sustained fatigue or burn-out.

Power meter

A power meter is fitted to a bike to record and monitor the rider’s power output. The advent of power meters has revolutionised bike training and racing. There are different types of power meters, which record your power output from different places on the bike – such as: pedal, crank, and rear-wheel hub.


The Professional Triathletes Organisation. It is in effect a union for non-drafting professional triathletes (predominantly middle and long-distance specialists). The PTO has supported many events by increasing the available prize money and has hosted its own events – notably the Collins Cup. In 2022 there is the inaugural PTO Tour.

PTO World Rankings

The PTO has designed a system with the aim of objectively rating and ranking athletes. The ranking system has caused some debate but is that really such a bad thing?

The Rankings also carry a $2million bonus pool at the end of each year, handed out to the athletes in the top positions.

Sweet spot training

This is a cycling term and it refers to efforts which are at circa 88-95% of your FTP or around 75-85% of your maximum heart rate. It can be described as being slightly harder than tempo efforts.


As the name suggests, swimrun involves swimming and running. Normally raced in pairs, competitors swim then run, and then swim and run some more multiple times. The biggest swimrun event organisers are Otillo Swimrun and Breca Swimrun.


This is looking where you are going when you are swimming in open water. For example, gauging where you are in relation to the race route by looking at landmarks on the coastline or trees on the edge of the lake. A really handy skill to have.

Sprint distance

A triathlon raced over the following distance:

  • 750m swim
  • 20k bike
  • 5k run

Super shoes

Shoes with a carbon blade which have revolutionised running. You may have heard of Nike’s Vaporfly, but there are many other competing options such as the Asics Metaspeed (which is popular amongst pro triathletes)._

Super sprint distance

The shortest common triathlon distance, namely:

  • 400m swim
  • 10k bike
  • 2.5k run

Super League Triathlon

Exciting, short and fast. The made-for-TV series of races includes the best short-course (and occasionally long-course specialists) racers in the world competing over bespoke triathlon formats (the races are not always swim, bike, run!) across the globe.

Marten Van Riel Alex Yee Super League Triathlon Malibu 2021
Super League Triathlon is attracting a new breed of fan.


To recover and reduce your training load before a big race.


It can mean slightly different things to different people. Generally, it is an effort that should be comfortably hard or a challenging pace that is sustainable. That is, slower than both race pace and the speed you do hard intervals, but faster than your recovery jaunt.

Time trials

A common phrase in swimming, cycling, and running. In swimming and running this is generally racing over a fixed distance as fast as you can. However, in cycling, this is opening your eyes to a whole other world!

Cycling time trials tend to be over fixed distances (10 miles, 25 miles, 50 miles, 100 miles) on set out-and-back courses; but, there are courses with bespoke distances. Some courses are circular or multi-lap, and there are even events over 12 and 24 hours where the aim is to ride as far as you can in the allotted time.

‘The Man With The Halo’

Tim Don, a legend of triathlon. Multiple world champion, three-time Olympian, and ‘the man with the halo’. This is the title of a documentary about his battle with the serious injury he suffered, and the halo he wore during his recovery.

Track session

This is commonly a running phrase and means a running session using a running track.


A popular online platform used by athletes and coaches to record training and race performance. There are other similar platforms, such as Today’s Plan.

Transition – T1 and T2

Triathlon is a non-stop race, meaning you need to go from swimming to cycling to running. You do this via transitions. There are two transitions in a race: T1 is the exit from the swim and preparing for the bike; T2 is finishing the bike and starting the run.

Normally, T1 and T2 are in the same place/are the same place, meaning this is where your bike is racked and where you swap kit between disciplines; however, some events will have a split transition, which means T1 and T2 are in different places, and importantly your run kit will be in T2 whilst you bike gear will need to start off in T1.

Time trial bike

Triathlon bikes and time trial bikes are both designed to make you as aerodynamic as possible. Their geometry is such that the rider sits further forward over the bike’s bottom bracket.

The bars normally consist of a flat base bar and two long extensions/skis (often called tri-bars). The design and shape of time trial bikes are restricted by the rules imposed by cycling’s governing body (the UCI); whereas, triathlon bikes have no such restrictions, which can result in some radical designs.

In general, without lots of practice, triathlon bikes and time trial bikes are less comfortable and less nimble than a normal road bike.

Triathlon relays

There are several variations and formats for triathlon relays. Broadly there are three are main structures to a triathlon relay:

(i) A team mate each completes one of the disciplines (one full triathlon, normally with a classic distance, is completed by the team)

(ii) Each team member completes a full triathlon (usually a short triathlon, similar to a super-sprint) before passing onto the next team mate

(iii) The first team mate completes the swim and passes onto the next team mate to complete their swim and so on, this is then repeated for the bike and the run (again, the distances are usually similar to a super-sprint).

Tri shoes

This refers to the shoes you wear when you are cycling during a triathlon. They have the same style sole and cleat design as a cycling shoe. However, they tend to have a wide opening, one-wide strap (rather than a ratchet, wires, or laces), and a hoop on the heel – all designed to help you get your shoes on and off as easily as possible.


This is a piece of clothing which can be worn for the whole triathlon, the swim, the bike, and the run. Most tri-suits have a small insert/pad to make the cycle-leg more comfortable. Often tri-suits are a one-piece either with or without sleeves. However, some people favour a two-piece tri-suit with separate shorts and top.

Race belt

Usually an elastic belt which you attach your big race number to. Then, rather than having to pin a number to your back and front, you can simply slide the number attached to your race belt from your back to your front when moving from the bike to the run.


The app used by many athletes to record and share their training and race performances.

Swim skin

Thinner and less buoyant than a wetsuit, a swim skin can be worn over a trisuit for a non-wetsuit swim (that is, when the water is too warm for a wetsuit). They are tight fitting, often with a similar shape to a tri-suit, but are notably quicker through the water than if you were to just wear a trisuit.

Vo2 Max

For a long time considered the best indication of endurance sport prowess, but now acknowledged as just being one of many contributing physiological factors.

Vo2 max is the maximum amount of oxygen your body is able to use during exercise. Vo2 max is a relative measurement, it is the maximum volume of oxygen in millilitres which is consumed per kg of body weight per minute (that is, in units of ml/kg/min).

Elite athletes often have a Vo2 max north of 70 ml/kg/min.


The unit of power often referred to when riding a bike. Understanding your watts and power on the bike can be a useful metric when you are training and racing.


A popular stationary bike which offers variable resistance and power data (amongst other metrics).

Wind tunnel

This is something which generates airflow and is used by cyclists to optimise their position on their bike to reduce drag and save watts.


The World Triathlon Championship Series – World Triathlon’s top tier of short-course racing. Athletes such as Jess Learmonth and Taylor Knibb are regulars on the circuit.


The main international series of cross triathlon. Rather than road riding and running, XTERRA has off-road mountain biking and trail running disciplines.


The popular online training app which allows you to run and cycle in a virtual world. In addition, Zwift sponsors the Zwift Academy Tri Team (a team of long-distance focused amateur triathletes with the goal of succeeding at Kona).

Written by
Chris Hovenden
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