PWO Nutrition Strategy for “Murph”

As we’ve discussed earlier, we’ll be doing a Memorial Day WOD. That WOD will be “Murph” in honor of Navy Lieutenant Michael Murphy. This is to be performed no earlier than the 23rd and no later than the 29th of May.

This workout will last, at the very least, 45 minutes. Obviously, this will depend on several factors like your level of fitness and whether or not you’ll be using a weight vest. Before we tackle the mechanics of PWO nutrition, a brief explanation of “Murph” is in order.

For those who don’t visit the main site as often as the avid (read: obsessed) CrossFitter (thrice daily, at the very least), this workout calls for a 1 mile run in the beginning and at the end of the workout. Sandwiched in between are some pull-ups, push-ups, and air squats- 100, 200, and 300, respectively. This is a lengthy metcon workout that will test your physical AND mental capacity. One of the most significant things going on as you progress through this workout is that you’ll be depleting muscular and, to a lesser extent, liver glycogen. Although the 1 mile runs at the beginning and end are physically demanding, most of the glycogen depletion will happen during the bodyweight exercises.

Glycogen is what fuels muscle contraction. Glycogen is stored in your muscles as well as your liver, among several other places. When you contract muscles, glycogen is more than likely what fueled that contraction (except in cases where the person is in ketosis). Because “Murph” is an extremely high-volume (lots of repetitions) workout, you’ll be depleting a significant amount of glycogen. Once glycogen stores in your muscles are depleted, your liver releases more of it to fuel your muscles. Once you’re glycogen stores in your liver have been depleted, your body is still capable of making the stuff, but at the expense of muscles. That’s right, once you’ve depleted glycogen in muscles and liver, your body will break down muscle tissue to make glycogen through a process called “gluconeogenesis.” This is not desirable, which is why, once you’ve completed “Murph,” it would be a good idea to consume some glucose-containing foods along with a good amount of protein. Your goal after this WOD is to refill muscle glycogen and prevent muscular breakdown. Doing the former prevents the latter.

So what does a “glucose-containing” meal look like? Well, it could take on several forms. Because we try to stay within the parameters of the paleo diet, it might look like a sweet potato and some kind of protein. One of the easiest meals is to cut a sweet potato in cubes, fry it in some olive oil, and throw in some tuna packets. If you’re halfway paleo, then your meal might look like some rice and some kind of protein. You could also do some fruit and protein, but some caveats are in order. Fruit contains fructose, not glucose. The reason why this is important is because your liver is one of the only places where fructose can be processed. Fructose gets to your liver first. Your liver then converts it into glucose for the muscles to use. On the other hand, glucose can be used by the muscles directly after digestion. It’s a faster way of refilling muscle glycogen.

We’ll cover pre-workout nutrition in a later post. Enjoy the workout.

CF671

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