To prepare for his first marathon last year, Michael Nolan trained for six months with the New York Road Runners Club, running up to 20 miles a day five days a week.
Nevertheless, he finished with an average speed of about 11 minutes a mile, a full 60 seconds a mile off his target pace. This year, he vowed to be faster. "I didn't want to take that long again," he said.
So he got a personal trainer. Now as Mr. Nolan prepares for this year's New York marathon, he is leaner, stronger and "easily" averages eight-and-a-half-minute miles on training runs, he said.
Mr. Nolan's new workouts are not coached by a running guru, but by iPhone applications that show video workout instructions and tabulate every set of burpees, a full-body exercise for strength training, and step-ups.
The sports and health industries are just beginning to tap the computing power of smartphones. Applications range from simple calorie counters to heart-rate monitors that use complex metabolic calculations.
These apps can help an athlete achieve a personal best, but some doctors say that more important is their ability to produce no-fail routines for the sedentary and obese, which could improve health and drive down medical costs. Here are some of the popular fitness apps out there.
