Biceps: Big Arms, Big Total?

Choo-Choo!
All aboard the gains train, am-i-right?
Suns-out-guns-out.
Curls for the girls and all that nonsensical bro-menclature has lead to the demise of one of the most influential muscles of the shoulder.

Somehow every other muscle in the body is deemed as useful, but the short and long head of the biceps brachii has pledged a fraternity and been stamped with the label of “non-functional”.
All Show-No Go.

DISCLAIMER: This isn't going to be some "5 Easy Steps To Sleeve Busting Arms" article. So if you're here for the easy fix, do me a favor, leave my article and don't dawn the doorstep of any of my content again. ' Cause guess what, this shit isn't easy, it's arduous, painstaking and it has no room for half measures.

I digress...

"Non- Functional" my ass...

Let's examine the role of the biceps, shall we?
Most people know the role of the biceps as a flexor of the elbow, some people will understand its action as a supinator of the wrist, and even fewer people know it as a secondary flexor of the shoulder. But what if I were to tell you that the biceps has three other functions, two direct and one indirect, which could arguably bring this muscle out of the frat house and into the first chair when it comes to the order of importance in training for health and longevity of the shoulder.

Starting with the two indirect benefits to bicep training in isolation. As mentioned prior the biceps act as a supinator of the wrist, as it inserts onto the radius, which allows us to turn our palms to the ceiling.

As you read this put your arms at your sides, elbows at 90 degrees and move your wrist in and out of supination, you’ll see as your palm begins to face-up (supination) your bicep will begin to shorten, with no further intent of elbow flexion than the 90 degrees flexed starting point.

Now, this role of supination becomes very important for screening the overall function of the shoulder. The supination of the wrist can manifest itself in two ways.

1)  The action of the bicep as it acts on the radio-ulnar joint.

2)  A distal expression of external rotation of the shoulder.

It’s that latter manifestation that becomes a great screening tool and an indirect way to keep your shoulders healthy and strong over time.

Enter in the mixed-grip deadlift debate...

For as long as people we’re deadlifting with a mixed grip (one hand over – one hand under, or one wrist supinated and on wrist pronated) there has been zealots on one side of the injury aisle saying your should never deadlift with a wrist in the supinated position in fear of tearing the bicep at the radius. This is a cogent, well-founded argument if we are basing supination of the wrist purely off the action of the bicep as it acts at the radius.

However, if we consider that second manifestation of supination of the wrist as an expression of external rotation of the shoulder then this becomes a safe way to deadlift with a supinated wrist position (underhand).

The fear being with the first scenario that if the shoulder is flexed (a secondary role of the bicep), the elbow is extended, the end range of motion where the bicep is at its weakest, and then the bicep also has to act as a supinator of the wrist in order to grab the bar and make up for any lack of that supination coming as a manifestation of diminished external rotation of the shoulder then that bicep tendon as it attaches to the radius is in a very compromised position.

How To Screen

Standing with your feet shoulder width apart, flex both shoulders right out in front, with your elbows in full extension stopping at 90 degrees, as the forearms begin to run parallel with the floor. From here, try and have both palms facing the ceiling. You should be able to actively externally rotate the shoulder enough that the position of the hand is fluid and full expression of that shoulder external rotation without having to utilize the bicep to make up for any deficiencies of external rotation.

If the shoulder is deficient in any external rotation in that 90-degree shoulder flexed position then it will be visible through the hand that the bicep is trying to take over in generating torque at the elbow in order to appease the visual criteria of turning the palms to the ceiling, often time the subject will flex their pinky finger to give the illusion that full external rotation has been achieved. A dead give away the bicep is playing a tertiary role.

It’s this indirect function of the bicep that makes it a very telling predictor of the overall long-term function of the glenohumeral joint.

Can the distal trajectory of the hand and wrist be fully expressive of the intent of the ball and socket of the glenohumeral joint in the motion of external rotation? Or does the bicep have to play a compensatory role at the elbow in order to make diminished external rotation of the shoulder manifest itself as supination of the wrist? If the latter is the case than an intervention must be taken to improve external rotation of the shoulder in order to ensure for the long-term health of the bicep.

Now examining the indirect function of the biceps is for fringe cases, looking to protect against distal bicep tendon ruptures, mostly in those looking to deadlift mixed grip or do a single arm pull-up. The direct role of the bicep is often overlooked, and much more applicable and pertinent to a wider demographic of people.

Glenohumeral Depression

We've briefly outlined the actions of the bicep:  supination of the wrist, flexion of the elbow, flexion of the shoulder. We're now going to talk about the function of the bicep (This is a distinction we'll be going into more details in coming articles).

The biceps direct role at the shoulder is through a function called "glenohumeral depression", which is a shared function of both the biceps and the rotator cuff. Essentially, glenohumeral depression is achieved when the humeral head travels downward, away from the glenoid fossa of the scapula. This is an integral function in offsetting the net forces of "glenohumeral superior translation" and keeping at bay the dreaded plight of anterior impingement syndrome

In cadaveric research studies, there is a  0.6mm superior translation of the humerus when the long head of the bicep tendon is severed. 0.6mm may seem like a trivial amount of movement, but as far as your body is concerned, that may as well be a country mile.

Conclusion:

I admit this might seem like a lot of detail, some might say, an unnecessary amount of detail. But in a sport where torn biceps are as common as ripped callouses and bloody noses, it might be time we take bicep training a little more serious.  In coming articles, I'll be going over some more sophisticated approaches to training the biceps to help decrease the risk of injury but also to help improve performance.

Stay Strong,

Dr. Jordan Shallow D.C

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