Your Hair and Clothing Choices Could Hold You Back in Long Jump and Sprint

Professor Bert Blocken, head of Heriot-Watt University’s aerospace programme, School of Engineering and Physical Sciences, has a knack for discovering competitive advantages in athletic competitions. In the past, he, along with other researchers, used CFD to reveal how a cyclist's position in a peloton could affect his or her chances of winning. Recently, he turned his attention to the hair styles and clothing choices of long-jump athletes.

A Small Margin Could Make a Difference

According to the World Athletics website, “the long jump is a track and field event that requires competitors to sprint along a runway until they reach a take-off board. From here, they jump as far as possible into a sandpit.”

Ahead of the Summer Olympics, Blocken and his team published their research paper titled “Numerical-physical modelling of the long jump flight of female athletes: Impact of jump style, hairstyle and clothing.” In it, they revealed, “Jump style only impacts flight distance by 1 cm or less. Hairstyle and clothing however can cause drag to vary by more than 25% and flight distance by more than 10 cm, mostly by impacting the take-off speed.”

Thierry Marchal, Chief Technologist for Healthcare & Sport for Ansys in Europe, the Middle East and Africa, said, “Sporting victories are determined by increasingly small margins, and using simulation to improve factors including aerodynamics can provide the competitive advantage to deliver a winning performance.”

Blocken said, “There’s a surprising misconception that persists up to the present day among some athletes and their coaches that aerodynamic resistance would not be significant in track and field events. This is compared to faster sports such as cycling, speed skating and skiing – where the impact of clothing and even hairstyle has been firmly established over the past decades. But our research shows this opinion is fundamentally wrong and that hairstyle and clothing can cause significant drag in long jump and 100-meter sprint events. In both events, the impact on performance is enough to lose out on a gold medal.”

Physical and Digital Mannequins

For their research, Bloken and his team examined 10 different hairstyles and 20 different clothing styles. The wigs ranged from braided hair, straight long hair, curly long hair, to tied long hair. The outfits ranged from body-hugging to loose-fitting. They put them on a mannequin and run wind tunnel tests. Ansys also created digital female mannequins in 28 different postures to be used in computer simulation.

“CFD and wind tunnel (on full-scale mannequin) did not overlap but supplemented each other. The focus in the CFD simulations was on the different postures during the long jump, which are quite pronounced with stretched out arms and legs. We studied the aerodynamic drag of 28 postures in CFD. In the wind tunnel, for CFD validation, we considered a few of these postures by quarter-scale wind tunnel models,” explained Blocken. 

The mannequin was a much better choice than a real human athlete for the tests, Bert pointed out. “No person would probably be willing to serve as reference—that is, to jump naked and with shaved head, etc. Also, no real person can jump twice exactly in the same way. No real person can even stand in the wind tunnel twice in exactly the same way,” he explained. In contrast, the required postures were much easier to produce with the mannequins and digital models. 

Based on their findings, Blocken and his team suggested, “From the viewpoint of aerodynamics, one could consider the introduction of hair caps and low-drag clothing to reduce the athlete’s aerodynamic resistance and to level the playing field.” However, he also observed, “We wouldn’t expect caps to be introduced any time soon. Even in cycling, the introduction of helmets took many years, and initially the riders even protested.”

The Counter-Intuitive Braids

Blocken also found something counter-intuitive about braided dreadlock-style hair. “While these look like ‘heavier’ hairstyles, during the sprint and the first half of the long jump flight, they tend to be positioned more behind the back of the athlete— so are more sheltered from the wind than loose, curly hair—and more aerodynamic as a result,” he noted.

The research was also supported by the University of Southampton, which provided their wind tunnel facilities; the School of Engineering at Oxford Brookes University in Oxford, which provided some of the wind tunnel models; and Tailormold, a Belgian mold-making specialist. 

At the 2024 Summer Olympics, women's long jump was held in Paris, France, on 6 and 8 August 2024. 

Ansys software was also used to examine how the fit of swimwear could affect a swimmer's performance. For more read “CFD Making Waves in Olympic Swimming (Again),” August 2012.

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