Nervous Training, Extreme Power

Recently I’ve read a few articles and forum discussions that have left me with that “I’m not mad, I’m just disappointed” feeling.  Despite writing about this a few times already, it seems that people still do not understand the difference between muscle recruitment and muscle activation.

Recruitment refers to the beginning of force production from additional motor units.  A motor unit is a motor neuron and all the muscle fibers it innervates.  For the sake of simplicity, just think of motor units as muscle fibers and recruitment as more muscle fibers producing force.  In most cases, in small muscles, recruitment is MAXIMAL by 65%; in large muscles, recruitment is MAXIMAL by 80%.  This means that you DO NOT recruit additional motor units (or muscle fibers) above these percentages.  If you read somewhere that doing this or that will improve motor unit recruitment or the recruitment of fast twitch fibers, they are probably lying to you.  The exception, of course, is that below these percentages a rapid concentric contraction can lower the recruitment threshold of these motor units, meaning they are recruited below 80% (in big muscles, for example).

When most people refer to recruitment, they actually mean activation.  Activation is an all-encompassing term that includes both motor unit recruitment AND rate coding.  Rate coding simply refers to the firing rate of a motor unit.  For any given motor unit, a faster firing rate results in higher levels of force production.  Therefore, despite maximal motor unit recruitment at 80% in large muscles, maximal force production can increase due to changes in firing rate.  The total change in motor unit recruitment AND in firing rate properties is referred to as activation.  Increases in activation occur as a result of strength training.  Increases in recruitment do not.  There is essentially no evidence that untrained people cannot recruit all their motor units.  There is ample evidence that they cannot fully activate their motor units.  It’s not just semantics; it’s actually important.  Next time someone tells you to perform some form of exercise because it will increase your recruitment, ask them for a reference!

Power, defined as force production over time, is arguably the most important variable of training for athletics.  I never used to think there was such a thing as too much power.  Today I changed my mind.  Today I was doing a series of medicine ball throws against a brick wall as part of a conditioning workout (Side Note: I hate traditional conditioning.  All my conditioning sessions involve slideboards, medicine ball throws, barbell complexes, farmers walks, and sled pulls).  Today it looked like:

3 Times Through:

A) 1 x 10 Overhand MB Floor Throws

B) 1 x 30s Heavy DB Holds w/ Added Perturbation

C) 1 x 10 (Each Side) Side-Standing MB Wall Shot-Puts

D) 1 x 10 Underhand MB Wall Toss

On my first rep of the underhand MB wall toss, I threw my hips back, and rapidly thrust them forward as I threw the ball against…well, over the brick wall, into the ceiling pipeline, and straight down into a water pump.  The take home: Maybe too much power CAN be a bad thing.  Either that or I should stick to hockey and leave ball-throwing for someone with better aim.

Last week I had another article published on T-nation.  If you haven’t already, check it out here: Fight the Injury Blues: Keep Lifting.  Remember, if you’ve suffered an injury or are dealing with nagging pain (and the article doesn’t clear things up for you), feel free to email me and I’ll get a response back to you ASAP.  No one on my newsletter list stays hurt!

I leave for Denver tomorrow evening to relax for a few days in the mountains.  It’ll be nice to take a break from everything.  I hope you all get to relax a bit this weekend as well.  Enjoy the holiday.

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