Why Is There a Time Cap?

Have you ever wondered why there is a 7 minute, 15 minute, 20 minute or other seemingly arbitrary time cap on your workouts? Have you ever wondered why you sometimes have a 3 minute workout, followed by a rest, followed by another 3 minute workout? Or some similarly formatted workout? There is a method to the madness. And here it is.

If you ever attend a CrossFit Level 1 Coach seminar you will learn that there are 3 main metabolic pathways. It was recently discovered that there are actually more than 3 metabolic pathways, but the 3 metabolic pathways we’re most interested in are: Phosphogen, Glycolytic, and Oxidative. I’m going to shorten the names of these pathways because I don’t feel like typing them out each time. We’ll call them Phospho, Glyco, and Oxidative.

The phospho pathway is used when we need a short burst of energy lasting a few seconds up to 30 seconds or so. When you complete a 1 rep max lift or even a 3 rep max lift, you’re in the phospho pathway. Your body is pulling energy from this pathway. We train this pathway each time we do work which requires a very short burst of energy, before resting. You can exert pretty close to 100% of your energy, but obviously that can only last for a very short time before you need to recover. This is the most “intense” pathway.

Efforts lasting anywhere from over 30 seconds up to about 2-3 minutes require you to pull energy from the glyco pathway. Short sprints and even repeats such as 4×400 meter run with 2 minute rest between efforts, fall into this middle pathway. It is less intense than the phospho pathway, but more intense than the oxidative pathway.

Long efforts such as the Filthy 50, where you are constantly working for more than about 3 minutes require you to pull energy from the oxidative pathway. It is impossible to be “intense” while in an aerobic state. You can move at a steady pace, but you will not be able to exert 100% of your energy for several minutes. These are long aerobic workouts. We pretty much live in the oxidative pathway. Every day, we walk around at a constant pace and pull energy from our oxidative pathway. Therefore, that is the least important metabolic pathway to train.

energy_systems2

When we train, we need to train where we are most uncomfortable. For most people, an all out effort for 3 minutes is very uncomfortable. If you are able to recover within the rest time we normally prescribe, which is no more than 90 seconds, you are still pulling your energy from the middle pathway – the glyco pathway. However, if you are unable to recover, you may move into the oxidative pathway. The goal, is to remain in the glyco pathway.

The majority of our programming falls into the phospho and glyco pathways because those are the pathways that most of us train the least. Before I was a CrossFitter, I ran. Or, I thought I was running, and now that I’m a CrossFitter, I realize I was jogging. I would go on long jogs, ranging from 30 minutes to an hour. I was always pulling energy from the oxidative metabolic pathway, which is the most comfortable because that is where we live. CrossFit was very uncomfortable at first because I was training different metabolic pathways. That, and I was weak and got my ass kicked by Fran.

Your coaches often have these metabolic pathways in mind when they suggest scaling for you. Just because you are able to do pull-ups without a band, doesn’t mean it’s always a good idea in a workout. We don’t want you to turn WODs into skill work. Sometimes it makes sense for you to grind through a workout in order to rx the workout, because it’s good for your state of mind. But many times, your coaches will ask you to scale the weight or movements, and it’s not that we don’t think you can do it. It’s the opposite – we know you can do it, and will do it, even if it takes you all night. That would change the workout, and there are times when we want you to expend all the energy you can in just 3 minutes, recover, and be able to do it again.

Besides that, the core and accessory work is just as important as your metabolic conditioning (metcons). The core and accessory work build your strength up so that you are more stable and therefore safer during your metcons. You can be strong as an ox, but stability is different than strength. You train stability under low intensity during your core and accessory work. We need you to have energy (and time) left to complete the core and accessory work in the manner it’s intended. If you are unable to pick up a kettlebell for Russian Twists or Turkish Get-Ups because you turned a 3 minute workout into a 20 minute workout, you’ve defeated the purpose of the programming.

Trust your coaches. They know what they’re doing!

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