T Nation

Muscle Fiber Recruitment at 80% and Above

Hi Coach,

I have a question regarding muscle fiber recruitment. You have mentioned in several of your articles that a person reaches maximum muscle fiber recruitment if the load represents roughly 80-82% of his or her “relative max” (Max relative to the current level of fatigue) .

If you need to produce more force, no more motor neurons and therefore no additional muscle fibers will be recruited instead the increase in force production comes from a higher firing rate.
Is this correct?

This results in my question: How are elite lifters able to recruit ca. 90% (number may vary depending on mastery) of their muscle fibers during an action?

Do you know some recommendable literature so I can read that up?

I appreciate your time.

Because there are a lot of percentages involved it might be confusing.

Everybody, at any given experience level, can recruit a specific amount of muscle fibers. When I say that when the load is around 80-82% of what they can lift at that moment, you can recruit all your recruitable fibers, I don’t mean that you can recruit all of your fibers.

I mean just that: you can recruit all of the fibers that YOU are capable of recruiting under normal circumstances.

The percentage of muscle fibers someone can recruit will vary depending on many factors. For example training experience, genetics, neurological state, etc.

Normally, people with less experience lifting heavy weights will not be able to recruit as any of their fibers as someone with a lot of experience under heavy bars.

A beginner could have the potential to recruit 60% of his fibers while an elite strength athlete could recruit 90% of his fibers.

This means that when each of these athletes train, and use a load that allows them to recruit ALL OF THEIR RECRUITABLE fibers the beginner in our example would recruit 60% of his muscle fibers and the elite athlete, 90%.

Over time you can improve your capacity to recruit fibers, which increases your number of recruitable fibers.