Running Faster-Slow Twitch vs. Fast Twitch Fibers

"Behold the turtle. He makes progress only when he sticks his neck out."– James Bryant Conant

How many of you want to run faster? I do. There are many supplements to consider as well as testosterone, HGH etc. in fact just yesterday, San Francisco Giants major league baseball player Milky Cabrera got suspended for the rest of the season because of his testosterone levels. Different training regimes such as intervals, tempo runs, high mileage, heavy strength training and plyometrics are other things to consider.

We know that some runners have superior speed while others have exceptional endurance and  the differences is likely due to the different types of fibers that make up the different  muscles. Do you have a majority of slow twitch fibers which are good for aerobic running? Do you have majority of fast twitch fibers which are best for short or high-intensity sprinting? Apparently some distance runners may have 90% slow twitch and 10% fast twitch fibers i.e. marathoners while others may have 60% slow twitch and 40% fast twitch fibers i.e. milers.

One way to evaluate your fiber type was found in the May 2011 Edition of Trail Runner. When you race, A) Are you able to hang with your competitors during the middle stages, but get out kicked in the last quarter to half mile?  B) Do you have a hard time maintaining the pace during the middle stages, but can finish fast and out kick others?  Answer A. is associated with more slow twitch fibers while answer B is associated with more fast twitch fibers

Which type of workouts feels easier and more natural?  A) Long intervals such as 800 m to mile repeats, long runs and tempo runs. B) Short, fast intervals such as 200 and 400’s.  Answer A. is associated with more short twitch fibers. Answer B) is associated with more fast twitch fibers.

Which workouts do you look forward to more?  A) Long intervals and tempo runs. b) Short fast intervals.  A. is associated with more short twitch fibers. Answer B. is associated with more fast twitch fibers. According to the article, we tend to get excited about tasks in which we excel while being more anxious about tasks that are difficult.

Hopefully, you are more aware now of your fast or slow twitch fibers. One rule of thumb is the more slow twitch fibers you have the more you’ll benefit from aerobic training. Also, the more fast twitch fibers you have the more you’ll benefit from speed work.  In other words with more slow twitch fibers the emphasis should be on mileage and   with more fast twitch fibers the emphasis should be on interval training.

Stay tuned as there are other ideas to improve speed. Remember, keep moving.