A participant, called a musher, races in the 33rd Aviemore Sled Dog Rally in Aviemore, Scotland January 23, 2016. The Siberian Husky Club of Britain is holding its annual sled dog rally over the weekend. (Photo by Russell Cheyne/Reuters)

Cyclists compete during the UCI BMX World Championships Elite Women's Moto Race on May 29, 2016 in Medellin, Antioquia department, Colombia. (Photo by Raul Arboleda/AFP Photo)

Britain Horse Racing, Royal Ascot, Ascot Racecourse on June 17, 2016. Chelsea pensioners with a racegoer posing between them. (Photo by Toby Melville/Reuters/Livepic)

A person poses on the track during a fashion competition at the Durban July horse racing event in Durban, South Africa, July 2, 2016. (Photo by Rogan Ward/Reuters)

Fallon Taylor of Collinsville, Texas, slips and falls with her horse in the barrel racing event during the Calgary Stampede rodeo in Calgary, Alberta, Canada July 8, 2016. (Photo by Todd Korol/Reuters)

Jockeys spur buffalos during the Makepung buffalo races at Jembrana in Bali, Indonesia on October 23, 2016. Makepung is a tradition for farmers to celebrate a bumper harvest in Bali. (Photo by Kadek Raharja/Xinhua/Barcroft Images)

Couples participate in the “Running of the Brides” race in a park in Bangkok November 29, 2014. Seventy-five husbands and wives-to-be wore their wedding dresses and running shoes and competed in an event for a combined prize worth 1 million Thai baht ($30,460). (Photo by Damir Sagolj/Reuters)

Swimmers prepare to take part in the annual Christmas Day Peter Pan Cup handicap race in the Serpentine River, in Hyde Park, London, December 25, 2015. (Photo by Andrew Winning/Reuters)