From the article:

“We have shown that interval training does not have to be ‘all out’ in order to be effective,” says Professor Martin Gibala. “Doing 10 one-minute sprints on a standard stationary bike with about one minute of rest in between, three times a week, works as well in improving muscle as many hours of conventional long-term biking less strenuously.”

HIT means doing a number of short bursts of intense exercise with short recovery breaks in between. The authors have already shown with young healthy college students that this produces the same physical benefits as conventional long duration endurance training despite taking much less time (and amazingly, actually doing less exercise!) However, their previous work used a relatively extreme set-up that involved “all out” pedaling on a specialized laboratory bicycle. The new study used a standard stationary bicycle and a workload which was still above most people’s comfort zone -about 95% of maximal heart rate – but only about half of what can be achieved when people sprint at an all-out pace.