World records are being obliterated at the Olympic velodrome. Here’s why

When Dr Brendan Gilhome was in the thick of developing the bike that helped deliver Australia’s men their first Olympic team pursuit gold in two decades, he modelled it to match the precise specifications of the Paris 2024 velodrome. Australia’s $100,000 Factor bike was not just designed to be the fastest the team had ever raced, its features were also chosen to harmonise flawlessly with the features of the track it was to race on.

Gilhome, the chief executive of specialist wind engineering aerodynamic firm L2T, was brought in by AusCycling in 2022. That same year, the former long-time head of aerodynamics for Formula 1 teams, including Mercedes and Red Bull Toro Rosso embarked on an intensive process of aerodynamic development followed by prototyping, refining, manufacturing and structural testing before calling for rider feedback to refine some more.

The search for perfect synergy also involved the help of another consultancy, Sync Ergonomics, along with other ex-F1 aerodynamicists, all tasked with analysing every bend and gradient with a part to play in Australia’s success.

“We were able to model based on a lot of the features of the track,” Gilhome says from Melbourne, where he has been watching his painstaking work pay off from afar. “The overall aerodynamic performance requires knowledge of the velodrome straights, corner radius and transition to ensure the best performance decisions are made. Stability is also a key consideration to ensure riders have confidence on the bike, which translates to speed.

“That’s certainly not to say the bike won’t be fast on other tracks; it just depends on the characteristics of that track and how they compare to this one.”

While this was all happening, the world’s other top nations were simultaneously working on their own secret creations to push cycling’s extortionate arms race to new limits over a new Olympic cycle. That, of course, included bikes but also helmets, skin suits, and anything else capable of adding an aerodynamic edge over the competition.

These latest space-age developments are, without doubt, playing a part in this week’s sorcery at the Saint-Quentin-en-Yvelines velodrome, where world records are dropping like flies. Already, 10 have been broken in the program’s first three days, with four days still to come.

So what is going on? It turns out a few things, all at once.

“The velodrome is a quick one,” Netherlands sprint coach Mehdi Kordi said this week. “The purists will say it’s a standard 250 metres, but it’s got big, steep bends, which means you can keep your speed a lot longer.”

It is true that the Saint-Quentin-en-Yvelines is the standardised length of 250 metres. But it was also built eight metres wide – a full metre wider than most others all over the world (while still conforming to UCI standards).

It sounds like a dream for sprinters, who can get higher on the banking and gain more momentum as they charge down. And it may help explain how the women’s sprint world record was broken on five separate occasions between champions Great Britain and silver medallists New Zealand on Monday.

The Netherlands also set two new world marks en route to gold in the men’s team sprint, and Matt Richardson and Dutch rival Harrie Lavreysen traded world records in individual sprint qualifying.

“The track itself is phenomenal, and particularly the flying 200 off the top because you’re so tall,” said British track cycling great and Team GB men’s sprint coach Jason Kenny. “It’s really quick – if anyone’s got any legs left.”

But that extra width does not really benefit the pursuit events, which renders the first-ever sub-3:41 in the men’s team pursuit – set by Australia in their first-round heat – somewhat more mystifying. Organisers did resurface the timber track before the Games, which may have lowered rolling resistance. But there are additional factors to consider.

“The shape is really fast,” said Conor Leahy, a member of the gold medal-winning men’s team pursuit quartet. “The bends are quite long, and long bends produces lots of speed, so that’s a mixing pot of fast conditions.”

Leahy’s teammate Kelland O’Brien said the squad had spent the preceding months preparing specifically for this track’s configuration. “We’ve known for the best part of eight or 10 years now that this track’s a really fast shape,” O’Brien said. “But also, for some reason, the atmospheric conditions here are really fast as well this time of year. So it’s just probably the complete opposite of the Olympic pool.”

The concept that indoor performances could be partly governed by meteorology feels slightly fantastical, but there is clear data behind the phenomenon.

The simple answer is that the weather conditions in and around Paris during the Games – hot and humid with some stormy nights – have decreased the air density, which means fewer air molecules providing resistance. And air density is affected by three key components: humidity, air pressure and temperature.

“Everyone packed into the venue is emitting heat and breathing out moist air, the humidity can increase,” Gilhome says. “As the humidity goes up, the air density comes down, and you’re not pushing through air as dense so you can go a lot faster.

“Then there’s the atmospheric pressure. When you have storms and unsettled weather, quite often, the air pressure will drop, and that also reduces the air density.

“Temperature probably has the most significant effect. If it’s warm outside, and you’re inside with a lot of people, the temperature inside can increase above the outside temperature. Over four kilometres, if you have a five-degree temperature difference, that can mean around one and a half seconds of time without changing anything. So it’s really significant. ”

This effect can be manufactured, too, in the way the London velodrome raised its temperature from 20 degrees to a fixed 25 degrees for the 2012 Games.

In Paris, the cyclists are coming in hot, and the fusion of factors almost mimics conditions at altitude despite being close to sea level, where the standard atmospheric pressure is 1013.25 millibars (mb). “The pressure’s been under 1000 this whole week, which is kind of rare,” said Kordi. “So it’s kind of the perfect storm to break the world record.”

The Izu velodrome, which staged the last Olympic track competition – at which many of the records now being broken were set – sits more than 300 metres above sea level and provided lightning-fast atmospheric conditions. That might still be the case today, if this Olympic competition were air-dropped from France to Japan mid-competition.

But those factors hold no regard for the advances in sports science that are constantly helping athletes become stronger and faster. To train and recover more efficiently, and eat and sleep better.

It is splitting hairs. But when the difference between gold and silver can be thousandths of a second, splitting hairs is what it is all about.

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