Lesson in Physiology

Since my girlfriends and I started running this year, we have tried to get our husbands to join us. The first race we ran was a 4 miler called Love to Run. This race was the day before Valentine’s Day and you could sign up as a couple with your significant other. I asked the hubs to sign up with me, and without any hesitation he said, “No. I don’t love to run.”

I asked him to join me in the other three races I’ve done after Love to Run, and I’ve gotten the same answer every time. No way.

There is really only one way that I can get him to do something he really, really does not want to do. That is by making a bet!The bet…

…if I can run a 5K under 24 minutes sometime during the beginning of the summer, he will run a 5K with me by the end of the summer.

Can I do it? I really don’t know. I’ve never ran that fast before…like…ever! Since I’ve been back in school taking prerequisites for nursing, I have learned a lot about anatomy and physiology of the human body…some of which makes me think that a sub-24 minute 5K is possible for me, and some that makes me think it could be impossible.

Now on to the lesson and why I think that it is possible.

There are three different kinds a fatigue that a person can experience, not just the kind that is caused by the buildup of lactic acid. The first kind is psychological fatigue. This is when you perceive that you are tired (like when you have just finished the fifth mile of your long, eleven mile run) and you don’t want to do something anymore. This type of fatigue you can overcome.

When I started running this year, I kept this little fact in my mind. This helped me keep going, even when I did not want to go anymore.

The second kind of fatigue is neurological fatigue, and it usually does not affect the muscles.

The third kind of fatigue is physiological fatigue. This is the type of fatigue that is caused by a buildup of lactic acid. An increase in acid in the muscle fibers causes a drop in pH and alters the oxygen carrying capacity of the myoglobin, which leads to oxygen deprivation in the muscles. This also leads to a buildup of carbon dioxide in the muscles. The body cannot overcome this kind of fatigue.

Not many people get to the point of physiological fatigue. I know I have never been there.Lesson two…

…there are three types of muscle fiber types in the human body. There are fast twitch glycolytic muscles fibers. This type has the fastest response time, they are the largest in diameter, they create very forceful contractions, and they fatigue quickly. They require less oxygen than other muscle fiber types. When you think of fast twitch glycolytic, think of body builders.

The second type of muscle fibers are called fast twitch oxidative. This is an intermediate type that is between fast twitch glycolytic and slow twitch oxidative.

Slow twitch oxidative muscle fibers have a slower response time, they are the thinnest in diameter, they get tired more slowly and sustain contractions for a longer period of time. They require more oxygen than the other muscle fiber types. When you think of slow twitch oxidative, think of elite marathon runners.

And now why I think it just might be impossible for me to run a sub-24 minute 5K…every person has a unique mixture of muscle fiber types, but the ratio what you have is all about genetics. (Only the intermediate fibers have the capability of converting to fast twitch fibers.) If I have mostly fast twitch glycolytic fibers, then I’m never going to have the highest endurance. Vice versa, if I have mostly slow twitch fibers, I’m never going to be a body builder (well, I guess I probably already knew that!)

The thing about it is, I don’t know what muscle fiber types my body is made of…but what I do know is I have been surprising myself lately, so I’m going to find a race sometime in June, and try my gosh-darn hardest to run it fast!



4 thoughts on “Lesson in Physiology

  1. I am rooting for you!!! ha!

    I think you can do it! Hubby will be running a 5k with you soon! ha!

    Love ya girl! Thanks for your always sweeter than ever comments!!

    xoxo ❤

  2. Pingback: More Than Just A Race Recap |

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