As shown in the picture, biceps brachii is one set of muscles in your upper arm.
Both these heads can be emphasized differently since the long head is bi-articulate (crosses the 2 joints: shoulder & elbow joint.).
| Fri July 22, 2011 
@JC
The grip width is related to rotatory movement of the arm. Essntially, when arm is medially rotated, long head is preferentially used over short head (our arm is slightly medially rotated in close-grip stance) and vice versa.
As with shoulder, whatever the movement, long head is always active, since it arises from supraglenoid tubercle (passing from above the humerus) and has to stabilize shoulder during all resistance flexion movements at elbow. Where it shares any co-activity with the short-head, less stress is put on it though. So I can tell you two positions in which short-head is active (and as a result of which long head is less active). These are:
1. Shoulder externally rotated during flexion (described above)
2. Shoulder extended (extended shoulder stretches the short head of biceps, effectuating stretch-reflex and automatic contraction of the stretched muscle).
Hope it helps!
Anoop | Fri July 22, 2011 
Hi Harris,
Thanks for the comment.
Which head helps in shoulder flexion or raising the arm to the front? Short head or long head? Look at the picture of that helps.
Anoop | Sat July 23, 2011
HI JC,
The long head crosses the shoulder and elbow joint. When you shoulders are raised like in preacher curls, your long head has already contracted to raise your arm, now it doesn’t have much fibers to do the flexion job. So the short head is recruited. Does that make sense?
| Sat July 23, 2011
Hi, Anoop,
I want to point out the basic mistake here. In preachers, the shoulder is NOT raised (not abducted). It is FLEXED. Flexion and Abduction are two different movements. Abduction is when you raise your arm towards your head, i.e cranically. Flexion is when you make arm moves closer to your body. Shoulder flexion is the job of pectoralis major and anterior deltoid, but short head also contributes slightly, as it comes from coracoid process and is closer to shoulder joint than long head. That puts this short head into active insufficiency, and shifts the work load to long head. I agree that if you were to flex your elbow in a raised shoulder (i.e abducted shoulder), some of long head will be used to stabilize shoulder rather than perform elbow flexion, but in preachers, the shoulder is flexed and is very stable. Preachers is almost always a long-head and brachialis exercise, muscles on the lateral aspect of arm, and very much less so of short head.
Secondly, I would also like to point out that even in a raised shoulder, long head DOES contribute to elbow flexion. Shoulder abduction is primarily the job of deltoids, trapeizus and serratus anterior, and if these muscles are strong enough, little of long head is needed for shoulder stability.
We have studied several MRI researches in our anatomy classes (needless to say but I am a medicine student), and most studies have clearly demonstrated the fact that long head is ative in almost ALL flexion movements across elbow joint. Short head is less so. partly because of it’s medial and hind position in the arm, and partly because it has yet another job to do, an even more important one than elbow flexion or shoulder flexion: SHort head of biceps is the strongest supinator of the forearm.
Given so many functions of the short head, it would be a stronger muscle than its brother long head, but then it also would be next to impossible to ever isolate this muscle in exercises completely.
Anoop | Sat July 23, 2011
I am not sure what you are saying. Flexion involves raising the arm towards your the front of your head and abduction involves raising the arm towards the side of your head head.What is the mistake here?
And almost all the studies have shown long head of the biceps brachii to be atleast more involved in shoulder flexion. Can you show me studies which shows short head to be more involved in shoulder flexion? I am assuming there are quite a few from what you are saying.
| Sat July 23, 2011
I guess you have not had much anatomical background behind your claims. But that coming from a commonplace man is understandable.
To save our time, please visit: http://en.wikipedia.org/wiki/Biceps_brachii_muscle
here it says: “The short head of the biceps brachii also assists with horizontal adduction (bringing the arm across the body) when the arm is internally (or medially) rotated.”—That is the shoulder position when long head contributes to elbow flexion, and this is what I’ve been telling on in my posts repeatedly.
Still think it’s not enough?
Please visit the most well aclaimed muscular kinesiology website on web:
http://www.exrx.net/Muscles/BicepsBrachii.html
It reads:
“The triarticulate biceps brachii muscles, particularly the short head [2 ] enters active insufficiency through the completion of elbow flexion when the shoulders are more flexed (brachialis becomes more active) or through the completion of shoulder flexion when the elbows are more flexed.”
If you intend still to stay deadset and back up your claims behind reference-absent opinion, then you are welcome. Otherwise, not few but many would know the real story otherwise.
Good luck and Farewell!
Anoop | Sun July 24, 2011
When did medical schools use wikipedia and exxrx.net as scientific reference? (:-
Let me repeat the question again: Do you have any studies to show that short head is largely involved than long head in shoulder flexion?
I am posting an excerpt from one study for you:
Function of the long head of the biceps at the shoulder: Electromyographic analysis. Andrew S. Levy, MD,a Bryan T. Kelly, MD,b Scott A. Lintner, MD,c Daryl C. Osbahr, BS,d and
Kevin P. Speer, MD,d Summit, NJ, New York, NY, Indianapolis, Ind, and Durham, NC
These 11 electromyographic studies have shown the long head of the biceps to be a shoulder flexor in 7 studies,a shoulder abductor in 3 studies, a shoulder internal rotator in 2 studies, an external rotator in 1 study,a shoulder extensor in 1 study, an anterior stabilizer in 1 study, and an abductor only with resistance in 1 study.2-8,17,24,28,29.
The short head has been rarely studied compared to the long head. There are lot of studies on the biceps long head and it’s functions.
Thanks for the comments.
| Tue August 02, 2011 
Debates are always fun, but let’s put this to the practical use.
Which exercise(s) are best for isolating (as much as possible) the long (outer) bicep head?
Close grip db/bb raises
Incline db raises
Preach Curls
Alternating Curls
<insert other>
How would we rank the above, or feel free to add your own suggestion.
| Sat September 03, 2011 
i hav a short headed biicep and it is nt very much visble in t shirts…wat can ii do
| Wed September 14, 2011 
Dear me, some medical students have real bad attitudes. A good, healthy debate should not have deteriorated by way of such condescending comments being posted by one side.
| Fri November 18, 2011 
When did medical schools use wikipedia and exxrx.net as scientific reference? (:- ..........lol ,i liked it
really felling sorry for the fate of patients who is going be get treated by this medical student in future after he becomes a doctor.. lol
| Sun November 27, 2011 
May I suggest Gironda Curls as an excellent isolation exercise for brachialis and long head of biceps?
Except of course for who shoulder internal rotation is a problem.
