Why Aaron’s Rodgers’s Arm Isn’t Enormous

The offseason dead-zone is winding down, but there’s still not much to talk about, so I’m reflecting on a question raised a while back on the Packers Insiders Inbox: Why isn’t Aaron Rodgers’s arm much bigger considering how far he can throw?

Conversely, can David Bakhtiari, with tree-trunk arms bigger than my head, throw it farther than Aaron Rodgers? No? Well why not?

I’ve often wondered about this based on comparing various quarterbacks that I played with over the years. Here’s a small sampling:

• McNabb – He was a, uh, stocky fellow… ok, he was a fat guy from Wisconsin who stepped off the bus looking like a walking hangover. He got his nickname because one time we had a noon kickoff on a road game and he got so hammered the night before that he threw up on the field during the coin toss (we still won). He was a wreck. He didn’t exercise, he didn’t look like an athlete, he played with a full lip of chew, but he could launch a ball farther than anyone I ever played with. I could never understand this.
• Pixie – He was really quick and built like a high schooler who lettered in chess. He got his nickname from opponents who laughed at his appearance in pregame. He must have had the skinniest arms on the team. He did a lot of cardio and isometrics, but never really lifted weights, and it showed. However, he could flat out chuck a deep ball farther than anyone he ever played against. I was always shocked at how much farther he could throw it than I could.
• Google – This guy was the real deal. He made it to the Combine and eventually the NFL and when opponents trash talked him, he responded with “Google me, b!tch” (which is how he got his nickname). He was a Tight End, a workout warrior with a monstrous, powerful build. He was always begging for an option gimmick where he got to throw the ball. The thing was, he couldn’t throw it very far. He was built, and a football player through and through, but he couldn’t throw the ball nearly as far as McNabb or Pixie. It was mind-boggling.

If you saw these three guys next to each other, you’d laugh in my face if I told you Pixie or McNabb could throw it farther than Google (side note: never judge people by their appearance).

This always confounded me.

So I did some digging and learned why. Why couldn’t I just life more weights and throw farther? Why couldn’t I just keep practicing my motion and get better?

The answer was: the glenohumeral joint in the shoulder.

Throwing distance is more about the shoulder joint than the arm muscle. It’s about generating torque. In some ways like a golf swing, but with more genetic limitations.

You know those giant Mr. Universe guys that can bench press a truck? Most of them can’t do a single pull-up. You know why? Because their fingers are still just normal fingers and they can’t maintain a grip with all their extra body weight. This is how muscles can be misleading in something like throwing torque.

You can lift weights to get a “stronger” arm, but there’s still going to be huge genetic limitations on how far you can chuck a football.

Meanwhile, some genetic freaks – sometime a short stocky guy or a little skinny guy – have the glenohumeral joint to let them launch it.

I’m guessing pretty much every top QB in the league, in addition to having a giant, well-trained powerful body, also has a glenohumeral joint in the 98th percentile. 

This is one more of the many genetic gifts that goes into making a NFL QB.  

It’s just another reason I’m in awe of the absolutely freakishness of these guys.