Why do I need to run slow to race faster? Part 1: Energy


One of my running clients recently asked me to answer one of the Big Questions in running: “Why do I need to run slower to race faster?” It sounds counterintuitive- crazy, even- when I oh-so-often tell my runners to SLOW DOWN after analyzing their data. But running slowly is an important part of meeting your goals- just as important as running hard during a speed session or other “effort” workout. For all the nerds (like myself) out there, I’m going to break this answer down into a 3-part series: Energy, Adaptation, and Effective Training.

To begin understanding why running slowly is an effective part of training, here’s a crash course on how your body converts and uses ENERGY. As heterotrophs, all of our energy comes from the food we eat. Adenosine triphosphate, or ATP, is the energy in your body originally derived from all that food. There are 3 systems in place that your body uses to access ATP: the phosphagen, anaerobic glycolysis, and aerobic glycolysis.

The phosphagen pathway uses the tiny amount of ATP stored in your muscles or synthesizes it using creatine phosphate and can provide immediate energy lasting up to 30 seconds. A short sprint, flipping a tire, and jumping out of a chair when you see your toddler holding out her food for the dog each activate the phosphagen energy pathway. Running anything more than a 100 yard dash requires additional energy systems. Your body knows when it’s time to switch gears automatically.

Next up- anaerobic glycolysis, which breaks down glucose in the body to produce more ATP without the use of oxygen. This allows for a slightly longer yield of energy- anywhere from 30 seconds to 2 or 3 minutes– but is still insufficient for most activities, such as running longer than 400 meters. This system IS important when we talk about improving your lactate threshold, but we’ll get to that in a later post. What your body needs now…is oxygen.

Aerobic glycolysis is the body’s ability to convert energy stored in fat and carbohydrates in the presence of oxygen. Even though all 3 energy systems work together in any kind of exercise, this is the primary energy system for the endurance to last more than 2 to 3 minutes- i.e. distance running. The aerobic system depends on the circulatory system to deliver oxygen and while it is slower, it is much more efficient at providing you with long term energy than the previously mentioned pathways. Therefore, the best way to improve your capacity to run long distance is to increase your aerobic base. In order to increase your aerobic base, you need to run more. But we’ll get to that in the second part of the series. In the meantime, may the wind be at your back!


Erica Marina

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