Hours on a rowing machine. A bicycle race. Push-ups followed by dead lifts. A mini-triathlon of swimming, paddle boarding and running.

In the decathlon, athletes compete in 10 track and field events. In the CrossFit Games, the namesake competition of the gym and exercise franchise, the athletes go further: 13 to 15 events, with most involving multiple disciplines.

Now in their 13th year, the CrossFit Games are being held this week in Madison, Wis. In the opening event on Thursday, athletes ran a quarter-mile, climbed a rope three times without using their legs and quickly lifted 185 pounds (for men) or 130 (for women) seven times. Then they did the sequence three more times, with a 20-minute total time limit. Later the same day there were competitions in rowing, kettlebell lifting and handstand walking.

The event attracts about 20,000 paying customers a day and are streamed on YouTube. At the conclusion on Sunday, the winners will be named the “fittest man and woman on Earth,” and each will receive $300,000.