223/365 Muscles 101

Friends and Fitness Enthusiasts,

After two days of skiing, my legs are feeling the burn. This has never been an issue for me but, having become a runner of some degree, I can understand now why this is cropping up.

Your muscle make up was pretty much set the day you were born though there is small room for flexibility to changing it. We humans have 3 kinds of muscles that we've found so far (some say that there's a 4th, type IIx but for now we'll stick to the following three). There's type I, type IIa, and type IIb.

Type I: Think about your favorite Fido. Dogs can run for days because of the muscle fibers they have. These muscles are your aerobic fibers meaning that they are best for endurance. The main fuel source for these muscles are your fat stores. Think back to those cross country runners in high school, skinny as rails right? Their healthy, aerobic activity, dedication, and genes are to thank for that.

Type II: Now think about your favorite feline. Cats start out on the floor and in one single bound they're on top of the piano. They are anaerobic, able to create a lot of power very quickly but, only in short bursts. These muscles are for sprinting. From type II, you get IIa and IIb; one is quicker to contract than the other. One is also argued to be able to change its type so that it can be more anaerobic or aerobic based on how you train it.



My point in sharing this lesson with you is that some of us are genetically predisposed to be better sprinters or better endurance runners. Still, you can only let your genes define you to a certain extent. I used to think I was a sprinter on account of my large thighs as a kid but, now I think I could be more of an endurance person. The only difference between me and my younger self is that I've given myself the chance to be good at one or the other.

In health,

Lauren