Petr Vabrousek is a highly accomplished endurance athlete with an impressive track record in triathlon. He also holds two notable world records: 81 top-10 finishes at official Ironman races and 21 top-10 finishes at Challenge full-distance races. At 51, Petr continues to inspire with his passion for ultrarunning, swimrun, and triathlon, balancing his athletic achievements with a love for travel, chess, and good food. Fluent in six languages and a proud member of Titan Trilife Zlín, he lives in Zlín, Czech Republic, with his family.
We’ve worked with Petr a couple of times in the past few years, including a recent testing session focused on finding which of two aero helmets was fastest for him. Here’s a rundown of that session.
Petr’s primary goal during the testing session was to assess the aerodynamic performance of two helmet options, ensuring they complemented his race position. In addition to focusing on helmets, he explored whether altering the placement of his bottle on the bike could impact performance. Though this wasn’t his primary focus, Petr wanted to confirm if small adjustments in bottle positioning might offer a subtle aerodynamic advantage alongside his choice of helmet for upcoming races.
Order of testing:
1. Testing first helmet
2. Testing second helmet
3. Testing second helmet with bottle down the jersey.
The tests were conducted on an out-and-back outdoor road in Nice, France, over multiple runs. For the initial two runs, the only variable was the helmet Petr was wearing, followed by a change in his water bottle placement.
Figure 1: The chart illustrates aerodynamic drag (CdA) for three setups Petr tested—Helmet 1 (R1), Helmet 2 (R2), and Helmet 2 with adjusted bottle placement (R3)—and the corresponding watt savings:
Key takeaway: The switch to Helmet 2 significantly improved aerodynamics, while changing his bottle placement on the bike in R3 further enhanced performance. Further testing could now be done to explore which bottle placement set up would further enhance the savings Petr could make over his Ironman cycle leg.
Figure 2: The following graph illustrates the rider's weight distribution across the entire bike. Understanding this distribution is valuable as it provides insight into where your weight is applied, which can impact power output, comfort, and injury prevention.
Key Takeaway: One change we have repeatedly noticed with athletes is that a bottle down the jersey tends to alter their pedalling stroke. This can be seen here, as Petr puts more weight on his saddle and less on his pedals, for the same power output
A next step would be to conduct further testing of bottle placement, as the "down the jersey" option is now unusable for future races. Identifying an alternative, optimised placement will ensure Petr continues to enhance his aerodynamic efficiency, saving valuable watts and time during the bike leg of his races.
I really enjoyed the Body Rocket testing session in Nice was an unforgettable experience and really brought to life what you can achieve using the system. I've always been interested in becoming more aero, and it was incredible to see measurable insights in real time! The results confirmed my suspicions around my position and apparel, but it was interesting to see the actual time savings from the changes were even greater than I expected, especially as it was only a single session. Feeling the difference is one thing, but seeing the hard data I collected made it even more valuable, helping influence my apparel decision for the season ahead.
