Muscle Size vs. Mobility

About the Author: Eric Cressey

Q: At what point do you think that muscle size affects one’s range of motion? Just interested in your thoughts. I’m a golfer and my  flexibility is important; there isn’t much point for me to be really strong but not able to move properly.

A: Well, it would be joint- and population-specific. On the joint side of things, as an example, the elbow flexors (biceps, to the lay population) and knee flexors (hamstrings) can restrict elbow and knee flexion, respectively, if they get too big. Or, the pecs may inhibit horizontal adduction ROM. This list goes on and on.

I don’t feel that simply making a muscle bigger means that you lose range-of-motion in that specific muscle, as the improvements are to cross-sectional area. If this was the case, the elbow flexors would be restricting us in extension, and the pecs would be restricting us in horizontal abduction, but as the examples above show, that’s just not happening.

Provided that flexibility training is good, and structural balance is prioritized in programming, there is no reason to believe that you can’t be big and flexible.

Now, it’s important to consider the sporting population in question.  A powerlifter isn’t going to need as much mobility as, say, a baseball pitcher.  One guy needs to be efficient in a short range of motion, while the other needs to be efficient through a larger range of motion.

In pitchers, external rotation ROM is a good predictive factor for velocity.  On top of that, horizontal abduction at stride foot contact is huge, according to the research.

So, in order to have good pitching specific ROM, you need to have adequate length of the muscles that internally rotate and horizontally adduct the shoulders.  And, the big muscle that does this is the pectoralis major.  Bench until the cows come home, shorten it up, and then you’ll lose that ROM.

Now, ask anyone who has ever trained baseball pitchers, and they’ll tell you that pitcher gain external rotation over the course of a season simply from throwing.  Guys who don’t weight-train properly can certainly impede this velocity-aiding adaptation.

This, of course, is an example specific to baseball pitching, and demands would be different for golfers.