Medical Daily has the details, or you can go straight to the research report. A quote from the former:
It’ll be an uncomfortable seven minutes, but it could be a more effective workout than hours spent running or weight training, Florida researchers say. In a new study published in the American College of Sports Medicine’s Health & Fitness Journal, two experts said that a combination of 12 exercises done over the course of seven minutes could be just as good for you as hours spent on other kinds of exercise….
It’s called high-intensity circuit training. These are body weight exercises, so you can’t blame lack of equipment as an excuse not to workout.