Sea or River? Understanding the Triathlon course to maximise performance.

triathlon course

Not all triathlons are the same, and knowing the triathlon course means knowing what to expect in the water and on the road which can have a dramatic effect on your preparations and equipment. There’s no point spending months cycling up into the mountains if the race is flat!

Where is the swim on your triathlon course

In the swim, there are two broad categories, indoor and open water.

triathlon swim starts and triathlon course

This is the biggest error that first time races make with reacting to the triathlon course. We tend to spend so much time practicing in the pool that we are almost shocked when we get in to the water for the race, as we are used to nice, warm, clear flat water with a helpful line to show us where to go! Open water just isn’t like that.

Indoor pool triathlon courses are becoming less common, partly because they limit the number of entrants, are more difficult to organise as they require a large pool with space outside for transition and tend to be very warm, which places extra strains on the athletes due to the heat and the fact you are no longer wearing a wetsuit.

Open water swims are the norm for most races as they are plentiful and generally free to run! Unless the water is very warm, a wet suit is required however and they bring other environmental challenges, like visibility, current, tide, wind, animals, vegetation, temperature and a host of others.

Sea swims tend to be colder, affected by the tides and winds and require you to contend with the salt especially around the neck of your wetsuit.

River swims generally have an upstream and downstream section so need to be paced accordingly, but there is nothing better than surfing the flow on the downstream leg, however!! Like lakes, there is likely to be vegetation, and the depth will be dependent on the weather.

Lakes tend to have static water and can be deep, which makes them ideal if you’re a little uncertain. The lack of flow can make them cold, however, especially some of the deeper mountain lakes favoured by ironman events in Europe. But at least you know the water is fresh, clean and pure!

Finally, there are canal swims which are straight, have no current, and if active, tend to be kept clear of debris and vegetation.

Bike and run triathlon courses.

No matter what event you are signing up for, make sure you know the terrain and prepare accordingly. There is nothing worse than finding you’ve got a 500m climb halfway through an event that you’re not prepared for, but the grades and shape of the event can have as much of an effect for the unprepared.

triathlon run

The race website will probably have a map of both courses, and most will have a link to a mapping or training site like Strava, Komoot, or Ride with GPS, but if not, you should be able to easily copy the race map into one of these sites to get a clear sense of the type of terrain you are going over.


Traditional triathlon courses tended to be relatively flat, and are designed with consistent speed in mind. In these events, speed and endurance will be the focus and will favour the more aerodynamic bikes and riders ( more on this later). Be aware of the likely winds though as a strong, consistent headwind can be more energy-sapping than a range of mountains whereas side winds will impact on bike handling. Increased power on the bike is likely to come from increased cadence rather than power.


Rolling hills will require a more sustained effort at mid-range power outputs as longer hills with gradients in the 3-7% range will be the norm. Power endurance will be the key determinant of performance, and weight of the bike and rider will begin to affect performance more than aerodynamic efficiency.


The technique will become key in this area, both up and downhill. The key difference will be gradient and the ability to grind gears ( lower cadence but more power per stroke) and sustain high anaerobic effort will be required. You are likely to achieve a higher peak heart rate during these steep climbs as well. On the downhill sections, your courage and ability to tactically utilise your brakes and take sharp bends at speed will determine average speed.

Mountainous triathlon courses tend to be more common in Ironman events than shorter races, however, so you may not face too many on your first race.

Technical city courses

In cities, triathlon courses tend to incorporate short stretches of good pavement and lower average gradients. However, the turns will mostly be right angles and will bunch up the field, especially during the run.

Cross country triathlon variations are also becoming more popular especially with the mountain bike crew but these tend to be a more specialised event.