Riders collapsed into the grass from heat exhaustion after the finish of Friday's race at the Trek CXC Cup due to temperatures that climbed over 30 degrees Celsius. The unseasonably warm weather took a toll on both the men's and women’s fields, knocking out several riders, including World Champion Sanne Cant (Beobank-Corendon.)
"For me, it was too hot to race," Cant told Cyclingnews Friday. "The second lap I became dizzy, and I crashed three times, and the last time it was a really hard fall on my head, so I had to stop with a big headache."
High temperatures also affected the World Cup in Iowa City a week earlier, and many riders came to Wisconsin hoping the forecasted rain would soften up the dry parcours and cool things down. Despite thundershowers, Thursday night temperatures stayed steadily in the 30-32 degree Celsius range.
By Friday, most riders were racing with cages and bottles on their bikes and showing up at the start line with ice vests and improvised ice socks. Sunday's World Cup in Waterloo included a sprinkler section, which riders could ride through to get some relief before they headed up Factory Hill. Organisers in Waterloo also provided plentiful water around the course for the 8,000 spectators they were expecting to come watch the race.
"Cyclocross in this kind of weather is almost like a different sport," said Elle Anderson (Cycling.be-Alphamotorhomes). "The preparation is different and the warm-up is different. The whole strategy of racing in high temperatures just feels so different from normal cyclocross racing and has a lot of staying cool and managing your energy. Personally, I feel like I can't go into the red as much because there is always that risk of heat stroke."
Katie Compton (KFC Racing-Trek) won Friday by a comfortable margin but said the heat added an element of unpredictability to the racing.
"I feel good, but hot days make everything different," Compton said. "People who are generally fast can struggle."
Though many European riders lamented the hot weather, it was hard to see a significant impact on the results. Dutch and Belgian riders dominated the men's races throughout the week. Some riders like Quinten Hermans (Telenet Fidea Lions), who placed third at the Iowa City World Cup, were acclimated from their summer training in Majorca.
Others like Mathieu van der Poel (Beobank-Corendon), who won the Iowa City World Cup and the World Cup and C2 races in Waterloo, banked more on preparation. Van der Poel was one of the few riders to show up at the Iowa City World Cup with a cage and bottle. After his win on Friday Van der Poel crossed the line, grabbed a fresh bottle of water and began to douse himself.
Sunday's World Cup winners, Van der Poel and Cant, seemed to have their temperature regulation techniques dialed in. Cant attributed her improvement through the week to steady acclimation and getting sprayed with water at strategic spots around the course. Van der Poel attributed his continued success to detailed preparation.
"I didn't feel particularly that warm, but I think we made a good decision to race on Friday with the team," Van der Poel said after his win at the Waterloo World Cup. "It was a lot hotter then, and I think that was an advantage today. We went with ice vests to the start, we were well prepared I think, and we couldn't have done anything more. The heat wasn't an issue for me today."