High Intensity Interval Training. sprints, then a break then sprints etc etc etc. its not a constant high heart rate, its elevated then you allow it to drop then elevate it again. Better than sustained moderate or high heart rates. You did what I would consider a version of HIITWhat is that? We did 5 5's. 5 sprints then a minute of x core thing, repeat. So it's 25 sprints with leg lifts, side planks, full plank and then ended with 20 pushups. then we had to sprint and tackle some bags as well. it was nice though