IRONMAN Switzerland Thun: Course, Elevation & Route Profile

Course & Elevation

The swim covers 3.8 kilometres in Lake Thun before the 180-kilometre bike loop heads into the green hinterland. The profile is rolling rather than high-alpine: almost half the course is flat, yet the metres between the rises constantly ask to be pedalled anew.

The notable climbs sit in the middle third of the bike loop, roughly between kilometre 42 and 72: short ramps of one to two kilometres at three to nearly seven percent, none of them long, but together making up the bulk of the 2,100 metres over the whole ride. There is no single marquee ascent; the difficulty lies in the repetition.

The closing marathon runs flat along the shore of Lake Thun and is covered in several laps. After the rolling bike it is a rhythm section; the climbing is done, and now what is left in the legs decides.

Pacing Strategy

On a rolling 180-kilometre ride, evenness decides everything: the short climbs tempt you to press hard each time, but across hundreds of such rises those matches add up to an expensive account. Take the ramps at steady power and avoid over-riding the flat sections, and you reach transition with your legs intact.

The race is shaped by the middle and back of the bike, with its clustered climbs, and by the switch into the flat marathon. The most common error is treating the rolling bike like a time trial and burning the reserves you need to run.

The marathon itself is flat and split into laps; here the restraint shown on the bike pays off. A steady, rather conservative pace on the first lap guards against the classic collapse in the final third.

Training plan for IRONMAN Switzerland Thun: 12-week build

An age-group finish over the full distance takes roughly nine to fourteen hours depending on ability. The demand is therefore above all one of aerobic endurance: holding a steady, sustainable ride-and-run intensity over a very long stretch rather than setting isolated peaks.

Despite the 2,100 metres of climbing, the character stays predominantly steady and aerobic. Because the climbs are short and moderate, it depends less on explosive climbing power than on the ability to work through hundreds of small rises without spiking the wattage.

The race is decided by the rolling back half of the bike and by the marathon on tired legs. Both require strength and carbohydrate stores to last to the end, durability rather than a punchy kick.

Training therefore centres on long rides with many short climbs, brick runs off the bike and a rehearsed fuelling plan. A flat, lapped marathon additionally rewards practising steady running paces over long distances.