What is a triathlon?

A triathlon is a multisport event consisting of 3 elements, always in the same order:

  • A swim
  • A cycle ride
  • A run

Each element follows the other without a pause other than to change into the necessary kit. The change from one discipline to the next is known as “transition” with t1 being the transition from swim to bike where you take off your wetsuit, don cycle helmet and shoes and jump on your bike, and t2 being the transition from bike to run where you ditch the bike and swap to trainers.

The swim can either be in a local swimming pool, or a lake/river/reservoir, or even the sea. For openwater swims it is usual to wear a wetsuit (there are temperature rules which make the wearing of wetsuits compulsory below certain water temperatures and illegal above a set temperature).

The bike section is usually on road (occasionally on closed roads, but most often shared with traffic). There are off road triathlons too for which mountain bikes are the modus operandi. Almost all triathlons are “non-drafting” races which means that on the bike section you are not allowed to slipstream other riders. Professional “Olympic distance” triathlons, on the other hand, allow riders to work together in a pack producing a very different tactical race.

The run can be either on road or trail depending on the location, and some triathlons will involve fell running at the more extreme end of things.


Although the concept of three sports making up a single event is at least 100 years old, triathlon in its current form dates from the mid 70s with the first event taking place at San Diego in California in 1974 (I wish I had known when I visited that fine city). The first running of the iconic “Ironman” event (now Ironman World Championship) took place on Hawaii in 1977. Triathlon didn’t become an Olympic event until Sydney 2000 and then only at Olympic distance (see table below).

For more on the history of triathlon, checkout this excellent page on Wikipedia.

Famous British Triathletes

Until 2012, no British triathlete had ever won a medal at the Olympic games (Triathlon was introduced to the Olympics at Sydney in 2000). Tim Don did win the ITU World Championships in 2006 at Olympic distance, but then massively blotted his copybook by falling foul of the athletes whereabouts system for dope testing by carelessly (and there doesn’t seem to be any question about that) missing 3 tests. The current top British male triathlete is Alistair Brownlee who famously won gold at London 2012 and was world champion in 2009 and 2011. He backed up gold at London with a further gold at Rio in 2016 with his brother Jonny (bronze in 2012) taking silver.

However, dwarfing the achievements of these guys is the quadruple Hawaii Ironman World Champion and Ironman distance world record holder, Chrissie Wellington. At Kona (Hawaii) in 2009 she broke the 17 year old women’s course record, and in July 2010 she broke her own Ironman world record (for any course) by over 12 minutes. She retired in 2012 with a perfect record at Ironman distance. Her record as Britain’s only winner on the Big Island didn’t last too long, though as her mantle was taken up admirably by Leanda Cave who took the women’s title in 2012. I wonder when a British male will take the top step at Kona?


There are at least 4 standard distances for triathlon listed below from sprint (and even super sprint for juniors and novices) right up to the iconic Ironman distance. Because events take place on public roads and are subject to local conditions, actual distances from race to race can vary quite considerably so it’s quite difficult to compare times meaningfully between different events.

Distance ? –Swim– ?–Bike– ?–Run–
Sprint Distance 750m 20km 5km
Olympic Distance 1500m 40km 10km
Half Ironman or middle distance 1900m 90km 21km
Ironman or long distance 3800m 180km 42km