Utah-based ultrarunner Karl Meltzer has done some pretty crazy things with his endurance running prowess in recent years.

Not only is he the winningest 100-mile trail race winner in history, but he also covered the entire 2,064-mile length of the historic Pony Express route on foot over 40 days in 2010. Well, the 48-year-old runner, coach and race director is also a pretty good golfer and when he’s combined that with his endurance prowess, the results have been astounding.

On April 30, Meltzer broke his own world record for playing 12 hours of Speedgolf in the Ultra Speed Golf Challenge charity event at the Napa Golf Club in Napa, Calif.

In other words, in the time that most people wake up, get their day started, go to work, come home from work and find some kind of way to get some exercise somewhere along the way, Meltzer played 230 holes of golf and covered 100K (or 62 miles) on foot in the process.

Think about that for a moment: that’s more than 12 full rounds of golf in 12 hours without the use of a golf cart. “It was hard. I needed a break because my hands were cramping,” Meltzer admits.

Meltzer broke the world record of 229 holes that he set a year ago in the same event. He was encouraged to play in the Speedgolf World Championships a few years ago by former pro golfer Tim Scott, who used to play on the Web.com tour. At that event at Bandon Dunes Golf Course near Coos Bay, Ore., Meltzer finished 22nd among 27 players in the pro/elite division, shooting a pair of 89 rounds in 55 and 51 minutes, respectively. (Keep in mind that Meltzer has enough of a golf game to consistently shoot about a 75.)

Scott, the executive director of Speedgolf International, battled through ocular melanoma in 2012 and recovered, although his vision in one eye has been severely reduced. “He still nails it dead straight and long,” Meltzer says.

When the opportunity to help raise money for “A Cure in Sight”—a nonprofit organization that raises funds and awareness for those with ocular melanoma—arose at the Ultra Speed Golf Challenge charity event that Scott started last year, Meltzer jumped at the chance. He broke the previous world record of 221 rounds last year and came back to best that by one round this year. He also played a part in helping raise $35,000 for the nonprofit.

Meltzer was dressed like a trail runner for the Ultra Speed Golf Challenge, wearing a tech T-shirt, shorts and a pair of Hoka One One Speedgoat trail running shoes, a model that was named after his trail running nickname.

“The Speedgoat shoes were an incredible golf shoe too…go figure,” he says. “Traction makes a difference (on the golf course).”