8 x 300m levee sprints. About 120m is uphill, the rest is flat. Easy jog back to the start for about 2:00 rests. Trying to extend my speed endurance in prep for later work. I treated it sort of like a flag drill and tried to beat my spot each rep. Focused on running fast and relaxed. It hurt after the 3rd rep and by 8 I was really gasping for air.