Sam Alvis never liked formal workouts, but started biking with friends and decided to complete a half-triathlon distance for fun. Courtesy of Natalie Bartels A 70-year-old man completed a half-triathlon thanks to habits that made fitness fun, not a chore. He said running, biking, and swimming in scenic locations helped him enjoy the process. Exercising with friends kept him motivated, even when the training felt challenging. Sam Alvis does not enjoy workouts . Still, he'll ride his bike for hours along the California coast, run for miles, and play golf, pickleball, and plenty of other active hobbies. But the word "work" doesn't appeal to him, and never has. "If you called it playing a game, I was all over it," he told Business Insider.…