Adding hill running to your training is a great way to get more fitness bang for your workout buck. A hilly 5-mile run will challenge you more and improve your fitness more than a flat run of the same distance. Specifically, running uphill develops aerobic capacity and leg strength. There are plenty of ways to incorporate hills into your training. You can do your weekend long run on a hilly route, run a set of intervals uphill or downhill, or do a few 10-second uphill sprints! Don’t hit the hills every day, but be sure that not a week goes by without some hill running.