Interval Vs. Endurance Training

Leave Intense Interval Training For The Athletes

(AP)  The control group that did no interval training showed no change.

"From a muscle perspective, when you do long, slow endurance training, you are only recruiting part of your muscle fibers to do the work," Gibala said. "In high intensity exercise, you call upon all of your muscle fibers. They respond and adapt."

Gibala, who has worked with the NHL's Buffalo Sabres, says more research has to be done to determine what effects interval training can have on boosting heart, lung and blood flow capacity.

"We don't know all the other adaptations" someone's body makes after interval training, Gibala said. "Does heart size change? Is there more blood going to the muscles? Do your vessels become more elastic? Those studies have to be done."

An idea that's been around for about 80 years, interval training has been a mainstay of competitive athletes like cyclists and middle distance runners, said Ed Coyle, a professor of kinesiology at the University of Texas who has helped six-time Tour de France champion Lance Armstrong and the NBA's San Antonio Spurs.

Such training, he said, is not without its drawbacks.

"It involves a lot of suffering and requires high motivation," said Coyle, a former runner at Queens College in New York. "Unless it's done with a coach or teammates to ensure motivation and positive feedback it's hard to not quit. It's almost impossible not to quit."

He said it's not the best type of exercise for general health and fitness because it doesn't burn as many calories as exercise done over longer periods of time.