Burning Question: Why Do We Need To Run Slowly?

One of the most frequently asked questions that I hear in our little group is “Why do we need to run so slowly?”

Class of 2016 – Our group of amazing runners

As you might have guessed, in this our first week of training, I’ve asked the group to run slowly…extremely slowly. To a point where I barely broke a sweat after an hour of running.

I took this idea from one of Matt Fitzgerald’s books (80/20 Running, I believe) where he suggested the idea of the Week of Slow. This is more to get runners used to the idea and feeling of taking it easy. Truly easy. Not the kind where we think it’s easy but are actually working fairly…medium.

Outside of the Week of Slow, however, it’s very important to keep easy paces easy. It’s much more difficult to do than people think because we tend to run harder than intended and continue to call it “easy”, especially in a group setting where the slower runners are pulled forward by the faster ones.

By my definition, easy paces or efforts range from recovery (where no pace is too slow) to aerobic (which is about 20 seconds or more slower than marathon pace). From a heart rate perspective, this is generally at 70% max HR or less.

This kind of easy running has been shown to provide several benefits:

  1. Improves aerobic endurance – higher weekly mileage (up to a point, of course) has been shown to be a key factor in marathon success. by spending more time on your feet running, both slow-twitch and fast-twitch muscle fibers get a workout. Running at an easy pace allows us to run for longer periods of time. Our slow-twitch muscles are activated first in endurance runs and once they are depleted, our bodies recruit fast-twitch muscles to help. This is one way to force our bodies to adapt to distance running. Running harder than this (into the so-called Middle Zone) also depletes slow-twitch muscles but since we can’t run as long, our bodies don’t get around to depleting the fast-twitch muscles.
  2. Improves oxygen utilization – by pushing out a large volume of blood, our bodies adapt by becoming more efficient at using oxygen and breaking down fuel. Our capillary (tiny blood vessels beside or arteries and veins) network expands to accommodate blood volume to muscles and our cells are able to become more efficient at breaking down and using stored glycogen and fat as fuel.
  3. Helps recovery – Taking it easy gives our bodies a chance to recover more quickly and fully from hard workouts, which results in fewer injuries as well as harder efforts when it counts. Research has shown that the middle zone (which falls between half-marathon and marathon paces) isn’t as effective in developing aerobic endurance or lowering lactate threshold as slow and hard efforts respectively. Running in the middle zone usually occurs when we run our intervals or tempos before we are recovered from our previous run(s). As a rule, I mostly book-end hard runs with easy runs to ensure that we are fresh enough to achieve threshold paces or faster, which helps improve specific endurance, speed, and power.

There are more reasons why running slowly helps but the above three are why a lot of successful coaches and athletes promote the idea of slowing down…for at least 80% of the time anyway.


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