Astronauts have staged orbital sports before. In fact, for the last Olympic Games, the 2010 Winter Olympics in Vancouver, Canada, the 11 astronauts aboard the space station and the space shuttle Endeavour, which was docked there at the time, recreated the event in orbit. (Video: Sports in Space)
The spaceflyers tried their hand at space skiing, the zero-G luge and weightless figure skating, all the while beaming a video of their orbital Olympics to Mission Control.
"You are officially the only folks who are able to get more hang time than Shaun White," the American gold medal-winning snowboarder, Mission Control radioed to the astronauts.
This time around, the spaceflyers are still working out which orbital events to stage, given their limitations.
"We just thought it would be something fun to do on orbit," Hoshide said."We have limited space and limited equipment."
HSW: How the First Olympics Worked
Williams herself has participated in weightless workouts before, when she ran along with the Boston marathon on the treadmill aboard the International Space Station in 2007. She completed the marathon in four hours, 24 minutes, all while orbiting the Earth at some 17,500 miles (28,163 kilometers) per hour.