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Athlete Partner Kristian Blummenfelt - Sierra Nevada Case Study

Updated: May 2

A man cyling in an aerodynamic position
Kristian Blummenfelt testing the Body Rocket system in Sierra Nevada

April 2023 - Sierra Nevada, Spain


Name: Kristian Blummenfelt @kristianblu

Experience: Tokyo 2020 Olympics Triathlon Gold Medalist, 2021 Ironman World Champion, Ironman 70.3 World Champion

Specialty: Long Course and Olympic distance triathlon


  • Test Body Rocket’s field install process

  • Demonstrate live CdA display capability

  • Achieve significant gains for Kristian

In late April, in Sierra Nevada, Spain, we met up with Body Rocket athlete partner and all-round superstar Kristian Blummenfelt to show everything we had been working on since our previous session at Barcelona velodrome in 2022.

Armed with learnings and enthusiasm from our recent success in Marrakech with test rider George Gray, who was able to adjust his behaviour on the bike based on the live data being fed to his Garmin head unit, we set out to show Kristian just how big of an improvement a day with Body Rocket could offer an athlete - even one at the very top end of the sport.

The first part of the day consisted of establishing his performance in the baseline position he finished last year with. Believe it or not this was the first time he’s been on his long course bike since winning St. George, underlining how little time athletes at this level have to switch between their long and short course objectives.

This would be the first time that Kristian had seen our new live Garmin experience in person, having previously only had access to post-ride analysis on our laptop based portal. His coach, Olav Aleksander Bu, would then crunch the numbers and see where improvements could be made.

Olav and Kristian, along with their multiple equipment partners, have spent many hours in wind tunnels and on velodromes during the course of their work together, testing which position and kit is most efficient for the course and conditions. For anyone with a busy training and racing schedule, not to mention the other commitments which come along with being a world-class athlete, frequent visits to a wind tunnel, whilst hugely important, don’t match the convenience of having a direct drag force system integrated into your bike.

Also, as Olav pointed out during our webcast in 2022, if you work with an athlete who has found the most efficient position for them in a wind tunnel, riding in short bursts, and then ask them to replicate this position out on the road during an Ironman, you’re likely to find some differences.

Knowing that Kristian’s baseline would already be at such an elite level, coming from a squad renowned for turning over every stone in pursuit of performance gains, made for an exciting challenge!

Eric Degolier and Kristian Blummenfelt

The Tests

We had a very tight remit for this test session. Clothing and helmet had already been selected for the Ibiza PTO race. We would need to make all our gains simply by getting Kristian in a stable, aerodynamic position. As with George, testing with Kristian began with a baseline run of 3 laps at race pace using his standard Ironman position, to give us a reference point.

From there, we trialled various adjustments to his position, including changes to bar angle and height, throughout the testing period.

Conditions on the day were actually windier than those at the Kona Ironman World Championships in 2022 but the Body Rocket system allows us to look specifically at the data taken between +5 and -5 degrees yaw, better approximating the Kona conditions where Kristian finished 3rd.


Throughout the course of one day, we were able to improve Kristian’s race pace efficiency by more than 15.5W versus his baseline. That’s a significant 5% improvement from an already very high starting point.

Had he been in this new position at Kona 2022 he could have expected to save 4 ½ minutes on the bike leg, without any extra effort. Kristian ultimately finished that race 3 minutes behind eventual winner, and teammate, Gustav Iden.

The Body Rocket testing team noted that there’s room for yet further improvement on Kristian’s new position, identifying some repeated head movements which, if eliminated, has the potential to double the gains made during this testing session.

The Rider Experience

‘Being able to test on open roads meant I had a much better understanding of how comfortable and stable a position was by the time I was over a longer period, in a realistic scenario. That’s something that’s always missing from wind tunnel testing.

The system was really easy to use but Eric and Callum were there to run everything, which helped a lot. I’m looking forward to testing the system without their assistance next time to get a similar experience to that of a consumer.

We, as a team, have developed a reputation for utilising the best technologies available in pursuit of peak human performance. Body Rocket is no different in that respect.

I was surprised by some of the results from this session. Not everything that felt faster was, but that’s why we test. Fortunately, the position I ended up in is faster and comfortable.

Once Body Rocket is for sale this is going to close a huge gap between the tools that pros have to get faster and what you can achieve as an amateur, without access to the world’s top wind tunnel facilities.’

Kristian Blummenfelt


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