This is to prepare you for what happens in a real sprint at the end of the race. You never get to sprint from a "fresh" state. You always have to do at least 1-2 sprints to either hold your position or get into position for the sprint. So, this will be two sprints, the first at about 80% and then the 2nd at 100%, as if you are finishing a race and sprinting for the finish line. Be sure to rest and pedal easy between each for 3minutes, as you will want to be recovered for the next set!