IRONMAN 70.3 Westfriesland: Course, Route Profile & Map

Course & Elevation

The day opens with a 1.9 km swim before the 90 km bike loop heads out into the open polders. The profile is flat throughout: around 95 percent of the course carries no meaningful gradient, and the handful of vertical metres spread out as barely perceptible ripples. There is no climb worthy of the name.

The bike course is one large loop that runs past windmills and small West Frisian villages before returning to where it started. What defines it is not the terrain but the exposure: in the open landscape the wind meets you unshielded, and depending on direction fast tailwind stretches trade off against grinding headwind sections.

The closing half marathon covers 21.1 km through the centre of Hoorn and finishes on the historic market square, De Roode Steen. After the flat bike it is a pure rhythm section; there is no elevation left to ration, only whatever the legs still hold after 90 kilometres.

Pacing Strategy

On a course this flat there are no hills to set the pace for you; the evenness is something you have to impose yourself. Because you never coast downhill and recover, you are pedalling almost the entire time. A steady, controlled power band pays off more here than on any rolling course, since every lapse in the pedal stroke costs speed immediately.

The race is decided by how you handle the wind. Into a headwind the temptation is to push the watts up to hold your usual speed, and that is exactly what burns the reserves you need for the run. It is smarter to keep power constant into the wind and accept the lower speed, while in a tailwind you avoid drifting into a false rest and instead take the free speed on offer.

The most common trap is treating the flat bike as an all-out time trial and chasing groups. The flat half marathon does not forgive an overcooked bike leg: a conservative first run lap protects against the classic fade in the final third.

Training plan for IRONMAN 70.3 Westfriesland: 12-week build

An age-group finish over the middle distance takes roughly four and a half to seven hours depending on ability. The demand is therefore mainly one of aerobic endurance: holding a steady, sustainable intensity for several hours rather than putting in individual spikes.

The character of the effort on this flat course is remarkably even. With no climbs and no recovering descents there is no natural break in the pedal stroke: the legs work almost continuously in the same band, and it is precisely this ability to produce constant power over a long time that matters more than any explosive climbing strength.

The race is decided by the uninterrupted effort on the bike and the transition into the flat run on tired legs. Both call for durability rather than punch; power and carbohydrate stores have to last to the finish, and the body needs to be used to the seamless switch from 90 km of pedalling to 21 km of running.

Training therefore centres on long, even rides in an aerodynamic position, holding constant watts for hours, and brick runs off the bike. Because the wind is the real opponent here, it also pays to ride deliberately in windy conditions, practising constant power into a headwind instead of reflexively overreaching.