College Strength and Conditioning Coaches
Hi, I am currently studying for my CSCS exam in the UK. In the NSCA book and the study questions at the end of chapter 1 there is a question asking,
Which of the following muscle fiber types is the MOST beneficial for a marathon runner?
a) Type I
b) Type IIa
c) Type IIx
d) Type IIc
now the answer in the back says it it c) Type IIx
Do you agree with this? Is it not a) Type a
Any Explanation stating why Type IIx would be true would be very helpful
Sorry if i have posted this in the wrong place.
In review of the textbook, the answer is correctly identified as: a) Type I.
The question does pose a discussion though and the following information may help:
When working with the majority of marathon runners whose times are in the range of 3 to 4 hours, Type I fibers are the predominant fiber utilized: slow contraction speeds with high fatigue resistance.
When working with highly elite marathon runners whose times are closer to 2 hours or just over 4 minute miles, then Type IIa fibers are more predominant: fast contraction speeds with intermediate fatigue resistance.
Furthermore, with endurance training it has been found that Type IIx gradually convert to Type IIa thereby providing a greater number of muscle fibers that can contribute to aerobic endurance performance. (p129, Essentials of Strength Training and Conditioning, 3rd edition)
I hope this helps!
(NSCA Education Coordinator)