Fairly steep hills that take you between 30 and 60 seconds to get up can also replace striders as a way to improve your basic speed. These are a staple of Kenyans’ training; everyone from milers to marathoners do, say, 15 repeats up a 30-second hill. It’s OK on these workouts to not be fully recovered between repeats so that you can also get cardiovascular benefits from the session. As always, though, you want to be getting up the hill with quick, efficient form, and that’s not going to possible if you run the first few all-out.