by Dr. Phil Maffetone.

When all the training ingredients are in place, and your diet and stress are under control,your aerobic base. And as your workout pace increases, you develop more aerobic speed. This means you’ll be able to run at a faster pace with the same effort or heart rate. And, you’re successfully developing your metabolism so you convert more fat to energy. In addition, as your aerobic system functions better, you’ll be healthier.

With more aerobic speed, two training techniques can be added to your aerobic base routine. These can even be performed during the anaerobic phase of training if it fits your schedule. These include downhill workouts and aerobic intervals.

 While building your aerobic base, you can help develop more leg speed without the need to train anaerobically by doing downhill workouts. I refer to them as such because I first employed them with athletes running downhill. This workout allows you to go at a faster pace without the heart rate rising. The increased pace is accompanied by a quicker leg turnover.

For example, at a heart rate of 145, if you can run at a 7:45 pace on flat ground, then running down a hill at the same heart rate will force you to run much faster, perhaps at a 6:55 pace depending on the hill’s slope and distance.

Using a long downhill that’s not too steep, you can train your brain to turn the legs over much more quickly than would ordinarily occur during a run on a flat course—all while staying aerobic. If you have a long steady downhill that takes you ten minutes or longer to complete, you can derive great neuromuscular benefits. It’s important to be sure the downhill is not too steep a grade, which may force a runner to overstride, putting too much mechanical stress on the feet, knees, hips, and spine. Even on the right grade, your stride length should be about the same as if you were on level ground.

If the downhill run is short, such as five minutes, you can do downhill repeats, walking or slowly running up the hill while staying aerobic to start your downhill interval again. Some treadmills can be adjusted to slant downhill, which is a nice alternative for runners.

I often suggest one or two downhill workouts per week, not on consecutive days, during the base period. Even though you’re aerobic, this workout does add more good stress to your body, and it’s best to assure recovery by not using the technique on consecutive days. When properly done, most athletes don’t feel much different from any other workout, but some may feel a slight or mild soreness in some muscles indicating the new activity. This workout need not be very long—runners can go forty-five minutes. These workouts will also help you further develop more aerobic speed.

This essay is excerpted from Dr. Phil Maffetone’s “The Big Book of Endurance Training and Racing.”