At 38, five-time world champion paratriathlete Matt Perkins is still training as hard as ever, focused on a sixth world title and perhaps a trip to sport's Paralympic debut in 2016

Matt Perkins has been a wrestler and Paralympic-class skier, but has had his greatest success since become a paratriathlete. The determined Perkins -- who lost his left leg as a boy -- is known for his killer workouts and attention to detail. "He'll swim until he throws up," says one training partner. Now, at age 38, he's trying to stay a few steps ahead of the sport's growing number of younger, terrific athletes. My story for ESPN.com's Endurance Sports section: http://espn.go.com/sports/endurance/story/_/id/9601673/endurance-sports-paratriathlete-matt-perkins-chasing-another-world-title