IRONMAN has updated its list of prohibited shoes for all its events, including the IRONMAN World Championship.
The M-Dot brand now adheres to World Athletics’ Shoe Regulations applicable to road events and there are more details below on the history of how that came to be the case.
All of which now means the current rules state:
“For the avoidance of doubt: Running shoes with a stack height sole thickness (as defined in World Athletics: Athletic Shoe Regulations 10.3-10.5) of greater than 40mm are prohibited and will result in disqualification.
“Shoes containing more than one plate rigid structure (as defined in World Athletics; Athletic Shoe regulation 10.6) are prohibited and will result in disqualification.”
How we got to this point
We’d seen a similar scenario in swimming around the 2008 Beijing Olympics when full-body LZR swimsuits massively reduced drag and improved buoyancy.
They had been unveiled in February of that year and a staggering 94% of all swimming races at the Games later that year were won by those wearing the LZR Racer. In terms of total medals that figure rose to 98% – and 23 of the 25 world records broken in Beijing were won by swimmers wearing the suit.
But not long later, in 2009, there was an outright ban and some sweeping rule changes.
And in terms of super shoes, it was in the build-up to the 2020 Tokyo Olympics when World Athletics prohibited from road-race competition any shoes with a stack height – which is the thickness from the ground to the foot – of more than 40 millimetres. Or shoes with more than one rigid embedded plate or blade as set out above.
In triathlon terms though, it then got complicated.
For it took until the start of 2023 for World Triathlon to follow that policy.
The October before at the IRONMAN World Championship in Kona, Norway’s Gustav Iden had won the men’s race in a record-breaking time when wearing a pair of ON prototype shoes in the marathon.
All within the rules but not for much longer as IRONMAN would soon adopt the new policy.
Which shoes are banned?
Which brings us to this week’s latest update which “as of February 6, 2025” has the following list of prohibited shoes:
- Adidas: Adizero Prime X / Adizero Prime X Strung / Adizero Prime X 2 Strung
- Asics: SUPERBLAST / Novablast 4 / Nova Blast 5
- New Balance: FuelCell SuperComp Trainer
- Saucony: Kinvara Pro
But even now there is the occasional grey area – Challenge Roth in the past, where both the men’s and women’s world record full-distance times have been set in recent years, has allowed some leeway in terms of prototype shoes for example.
And there’s also an obvious question as to how rigidly the rules are enforced, especially on the Age-Group side.
For clarity, the IRONMAN rulebook states: “Athletes are subject to random shoe control before, during, or after any Race.
“For any shoe that cannot be identified, each piece of information (and maybe the shoe itself) will be required to be sent to the World Triathlon headquarters for verification within 7 days after the Race it was worn. In the official results, the athletes under shoe review will have the note ‘Result Under Review’ added to the results footer notes. If the shoe is confirmed as legal, the note will be removed. In any different case, the athlete will be disqualified.”
Switching to a waxed chain could take minutes off your Ironman bike split, without riding any harder – and here’s why
