The International Cycling Union (UCI) is reportedly planning more rigorous clothing inspections for female cyclists competing in events like the Tour de France Femmes. This follows concerns that some riders might be padding their bras to gain an aerodynamic advantage by altering their body morphology.

The UCI issued a warning about clothing that “could modify riders’ morphology,” citing article 1.3.032 of its regulations, which prohibits any non-essential elements in clothing or accessories that change a rider’s shape. The rule states, “Clothing and other items or accessories worn by a rider (including but not limited to helmets, glasses, shoes or in-race communication devices) may not modify the morphology of the rider. Moreover, any non-essential element which is added on (or under) or integrated in any clothing, or other item or accessory worn by a rider shall be forbidden.”

Dutch outlet Wielerflits first reported several instances where female cyclists appeared to have noticeably larger busts during time trials compared to road races. They highlighted a rider from the 2024 Paris Olympics whose bust size seemed larger than usual. The photo was shown to Bert Blocken, a professor of aerodynamics at Heriot-Watt University in Scotland and LUT University in Finland.

The practice, known as “chest fairing,” involves placing material inside a cyclist’s jersey to alter chest shape, redirect airflow, reduce pressure on the thighs, and lower aerodynamic drag. This technique can benefit both male and female cyclists but has been banned by several sports governing bodies, including some in cycling.

At the 2025 World Championships in Rwanda, Belgian riders reportedly wore radios on their chests rather than their backs without penalty, illustrating some inconsistencies in enforcement. Additionally, cyclists have been known to tuck water bottles inside their jerseys, a practice the UCI has recently begun to crack down on.

The UCI’s announcement emphasized that particular attention will be paid to compliance with the morphology modification rule, including all nonessential elements and clothing or accessories worn by riders.

Sources