Apolo Ohno is taking on a new challenge in retirement, one of the greatest challenges in sports.
The most decorated U.S. Winter Olympian ever is training to compete in the World Ironman Championships in Kailua-Kona, Hawaii, in October.
Ohno will attempt to swim 2.4 miles, bike 112 miles and run a marathon back to back to back. Ohno, 31, won eight Olympic medals from 2002 to 2010 never skating at an individual distance greater than 1500m.
The world’s best athletes take more than eight hours to complete an Ironman. Ohno’s longest short track races took a few minutes.
“I’m still not entirely sure I can grasp the difficulty of this,” Ohno told The Associated Press.
Retired Pittsburgh Steelers wide receiver Hines Ward and celebrity chef Gordon Ramsay entered last year’s World Ironman Championships.
Video: Meb Keflezighi stuns to win Boston Marathon
Puma has introduced the “BeatBot,” a self-driving, line-following robot that runners can program to move at a specific pace around a track.
That means one could race against a robot-version of Usain Bolt‘s 100m world record of 9.58 seconds, with BeatBot’s top speed at just over 27 miles per hour.
The BeatBot can also navigate track curves, as shown in the video above.
Puma plans to roll out BeatBot to various track programs around the world over the year.
MORE: Bolt, Ashton Eaton set for showdown
Several U.S. Olympic champions highlight the Penn Relays and Drake Relays fields, live on NBCSN and NBC Sports Live Extra on Saturday.
At the Penn Relays in Philadelphia, the U.S. 4x100m, 4x200m and 4x400m pools include:
Justin Gatlin: 2004 Olympic 100m champ
Tyson Gay: Olympic 100m, fourth place
Carmelita Jeter: Olympic 100m silver medalist
Jeremy Wariner: 2004 Olympic 400m champ
Sanya Richards-Ross: Olympic 400m champ
Also competing will be two-time Olympic 100m champion Shelly-Ann Fraser-Pryce, 2008 Olympic 100m silver medalist Kerron Stewart and 2015 World 200m silver medalist Elaine Thompson for Team Jamaica.
STREAM: Penn Relays: 12:30-3 p.m. ET
Next is the Drake Relays in Des Moines, Iowa, including:
- 2008 Olympic champion LaShawn Merritt versus 2012 Olympic champion Kirani James in the 400m
- World Indoor champion Vashti Cunningham in the high jump. Cunningham, 18, is the daughter of retired NFL Pro Bowl quarterback Randall Cunningham.
- 2008 Olympic champion Dawn Harper-Nelson versus 2013 World champion Brianna Rollins in the 100m hurdles.
STREAM: Drake Relays: 3-5 p.m. ET
MORE: Full NBC Olympic trials broadcast schedule