Also known as microcycles, these recurring seven-day workout schedules typically include three designated hard days, which are buffered on either side by at least one day of lighter training. Two of the three hard days feature moderate-intensity or high-intensity runs while the third is reserved for a longer run, which is done mostly or entirely at

way they were programmed to do it. They could not learn to do it better or alter their movements in response to changes in their environment (such as encountering a slope). Also, the movements of the first walking robots just didn’t look human. They were missing a certain grace and fluidity.

If your ultimate goal is to become the best runner you can possibly be, then you’ll want to continue to increase your running volume until your current limit merges with your final genetic limit. This is the point beyond which there is no possibility for further improvement by means of additional running.

If currently you run only three or four times per week, set a goal to run six or seven times per week. According to the World Health Organization, daily aerobic exercise is required for maximum all-around health. As a runner, you might as well meet this requirement by running. Not only will your health improve but your running will too.

RULE #6: PRACTICE STEP CYCLES Step cycles take the hard-easy principle to a broader time scale. Also known as mesocycles, step cycles are multiweek training blocks in which the running workload is intentionally varied from week to week. In a step cycle, each week of training is slightly more challenging than the preceding, until the last week of

TEMPO RUNS A tempo run is a sustained effort in Zone 3 sandwiched between a warm-up and a cool-down. Tempo runs are a very effective means of enhancing a runner’s ability to sustain relatively aggressive speeds. They are emphasized in the peak phase of training for races of all distances from 5K to the marathon.

They figure that running thirty miles per week mostly at moderate to high intensity will make them just as fit as running sixty miles mostly at low intensity.

Seiler’s rule also helps runners by explicitly defining low intensity. The boundary between low intensity and moderate intensity, according to Seiler, falls at the ventilatory threshold, which is the intensity level at which the breathing rate abruptly deepens.

First, they teach us that high-intensity training is essential, but that a little goes a long way.