Sprinting 5 days a week is too much. It does not matter that it is only 120-150 seconds a day. Ideally, you should have multiple paces of running each week. Recovery-based, slow jogs, sprints for speed and form, tempo work for threshold increases, as well as hill work for hamstring flexibility, VO2, and general determination. read more
Instead of running six days a week, you could jog three days, cross-train two days, and take the other two days off. If you have a vacation planned, you could take the whole week off of running so you can enjoy swimming in the ocean or hiking in the mountains. read more