I do short hill repeats for 2 reasons the first goal, and most obvious, is to gain physical strength. Since strength is in our sport is often interchangeable with speed I see why it seems strange for a marathoner to be doing this type of a workout especially with such frequency. I mean why try to get a faster top end speed when even to run a world record I only need to run 4:45 or 4:46 a mile. The first reason is that every race is a race of speed, meaning that no matter how long the race is the fastest person over the distance wins. But that alone doesn't justify hill repeats one to three times a week. The real reason is strength and speed over the short distance equal efficiency. By doing these hills and getting stronger and faster in the maxim. I teach my body to consume less glycogen, and less oxygen when moving at sub maximal speeds. The less of these "fuels" the body consumes at a given pace the longer I can hold that pace.
the 2nd reason I do short hills is that they drive my heart rate way up in an extremely short period of time, to within 10 beats of max or higher in 10 seconds or less and then because my heart rate hasn't been up that long and no acid needs to be flushed out of my system (it takes 15 seconds of an exercise to begin to produce any lactic acid) my heart rate basically plummets back down to a relatively rested level, 120 to 130 beats per minute, in a short time 20seconds to a minute. This exercise on the heart teaches the heart efficiency as well meaning it takes less energy to pump more blood.
Now if I was training for the mile I would still do short hill repeats for the same reasons I have listed above but I would probably try to go a little longer (say 13 to 15 seconds rather then my usual 8 to 12) and I would try to do it on a slightly less steep hill and with better footing. Why? Because a miler would want to improve there efficiency, muscular as well as heart but he/she would also want to work more specifically on there top end speed and running uphill but with your form closer to that which you use to run over flat ground is a spectacular way of doing that.
Finally the greatest advantage of short hills is that you can reap huge long term benefits without having to sacrifice much of anything. They are very easy on the body and mind. Sure you run all out but only for a few seconds so they really are not hard and because little or no acid is accumulated in the system they take little recovery at all. This is why if I had one thing I would recommend to all runners to add to there program right now short hills would be it. They improve your basic speed, improve your efficiency and strengthen your heart and if you do them once or twice a week your body won't be any more tired or worse for the wear. It’s a win win situation. I am convinced that these, progression runs and the use of circuit training are the biggest reasons the Kenyans are so far beyond us here in the