It's a technique that's been used for years by sports teams and athletes. But is it useful to an average overweight person? Probably not. It doesn't burn many calories.
And it requires so much suffering that you're almost destined to quit, one expert said.
The study, published this month in the Journal of Applied Physiology, was done by researchers at McMaster University in Hamilton, Ontario.
It looked at 16 college students who exercised regularly, but are not competitive athletes, said Martin Gibala, associate professor of kinesiology. Half of the volunteers did two-week sprint interval training, cycling in 30-second bursts going "all out" in four to seven sessions. Each burst of cycling was followed by four minutes of rest. The workout was done three times a week for two weeks.
The other half of the test group did no specific training, but continued their normal activities, including basketball, jogging or aerobics, depending on the individual.
Endurance capacity in the sprint group nearly doubled from an average of 26 minutes to 51 minutes. They also showed a significant increase in the enzyme citrate synthase in their leg muscles, indicating an increased ability to use oxygen, Gibala said.