Tour de France Femmes riders are facing allegations of gaining an advantage through the use of padded bras.
The women’s edition of cycling’s biggest race began on Saturday and will run until Monday (AEST) across nine stages and 1,174 kilometres.
On Tuesday, the 21km time trial stage took place which consists of each rider setting off individually in a race against the clock.
Watch the biggest Aussie sports & the best from overseas LIVE on Kayo Sports | New to Kayo? Join now and get your first month for just $1.
Aerodynamics plays a crucial role in a time trial performance, with the skinsuit, rider position, helmet, and a host of other factors taken into account to optimise the flow of air around the body.
One of the areas that can create aerodynamic drag is around the chest — hence why the cyclists tuck into a position where their arms are outstretched in front of them.
Belgian and Dutch cycling publication WielerFlits has reported there have been several complaints from cycling’s WorldTour teams alleging that padded sports bras are being used for aerodynamic advantage.
They claim riders are faking a larger cup size to reduce their drag through the air.
Padded bras are banned under the rules of cycling’s world governing body, the Union Cycliste International (UCI).
Teams reportedly called for inspectors to be introduced to check riders in a closed tent before time trials to “ensure they are not hiding anything in their bras or under their aero clothing”.
This was then approved by the Tour de France Femmes as riders appeared for bike and outfit checks 10 minutes before their start time on Tuesday.
Bert Blocken, professor of aerodynamics at Heriot-Watt University in Scotland and LUT in Finland, has published the theory that a rounder chest is advantageous when it comes to aerodynamics.
He labelled the concept of placing an object inside a jersey or skinsuit to reduce aerodynamic drag and improve airflow around the body “chest fairing”, and said it can reduce drag by 3.6 per cent.
Professor Blocken said: “We are talking about a Chest Fairing, which alters the airflow around the body, thereby reducing overpressure on the thighs. As a result, the rider experiences less air resistance.
“It is not that you gain a benefit of tens of seconds with this in a time trial, but in a ride of 20 to 30 kilometres, it can yield seconds that can be decisive.”
Swiss rider Marlen Reusser won the time trial to take the leader’s yellow jersey.
She has a 14-second advantage over pre-race favourite Demi Vollering.