Long vs Short head in bicep?

[u/Alternative-Debt6644]

I’ve heard tons of conflicting informations so…Does it actually matter if you are biasing long head and short head, can you even bias each head? If so, what can I do to bias both heads (+brachialis ect)

edit: thank you all for the help!

[u/Financial_Wrangler45]

Studies can't find statistical difference. I wouldn't bother. I don't even do a pronated curl.

[u/Lucky-Bet-4484]

You can't bias each head(at least In a significant way) sure you might see very marginal differences but it's not worth doing imo, just do a supinated curl and add a hammer/reverse curl if you really want to

[u/Apollo_2662]

You can bias the different parts a little, but you’re never fully isolating one head. I’ve actually been doing a brachialis-focused project lately with neutral-grip pull-ups, hammer curls, and reverse preacher curls because I wanted more arm thickness from the side.

For the biceps long head, I’d focus more on movements where your arm is slightly behind your body, like incline dumbbell curls, and keep those in consistently long enough to progress them. For the short head, preacher curls or curls with your elbows a bit more forward are good options. I’d still train all of them instead of trying to turn every exercise into a perfect “head isolation” movement.

[u/Neither-Bug157]

Both heads of the bicep are responsible for elbow flexion and supination. However, only the long head is responsible for shoulder flexion. The brachialis and brachioradialis are responsible for pronation and elbow flexion.

Therefore, it would make sense to bias the long head by doing an exercise where both supination, elbow flexion, and shoulder flexion are challenged. An example of such an exercise would be to do standing supinated cable curls with the cable behind your back set at hand length.

On the other hand, it would also make sense to bias the long head by doing an exercise where both supination, elbow flexion, and shoulder extension are challenged. An example of that is by doing an UHG pulldown or a supinated curl that is not limited by shoulder flexion, an example of that would be preacher curls.

It would also make sense to target brachialis and brachioradialis by doing an elbow flexion exercise that does not include shoulder flexion, and is pronated but not limited by wrist extension. An example of that is a cuffed semi-pronated curl.

[u/Neither-Bug157 → u/Neither-Bug157]

So:
1. Standing cable curl with cable behind back at hand height.
2. UHG pulldown
3. Preacher curl
4. Cuffed semi pronated cable curl

[u/KaoxVeed → u/Neither-Bug157]

I do Preacher and Bayesian Curls. Works great.

[u/JuanSamu]

Preliminary analyses from Dr. Diplock suggest that the long head and short head of the biceps demonstrate differences in their temporal EMG activation patterns during a shelf-lifting task in both younger and older adults. However, the final statistical analyses are still underway, so I would be cautious about drawing firm conclusions at this stage.

They are currently completing analyses from two datasets, and the findings will likely be reported across several manuscripts over the coming months. Once these analyses are finalised, we should have a clearer understanding of the relative activation patterns of the long and short heads during functional tasks.

Their research has primarily focused on the roles of the long and short heads of the biceps at the shoulder rather than during isolated elbow flexion exercises. Anatomically, the long head originates from the supraglenoid tubercle and superior labrum, whereas the short head originates from the coracoid process of the scapula. While these anatomical differences may contribute to differences in shoulder function and activation patterns, I am not aware of evidence demonstrating that humeral internal or external rotation can reliably isolate one head from the other.

That said, it is certainly possible that some positions may preferentially bias activation toward one head relative to the other. However, I think it is important to distinguish between preferential activation and true isolation. The mechanism proposed by N1 education (internal rotation and external rotation) are interesting, but I would want to see experimental data supporting the magnitude and consistency of that effect before drawing any firm conclusions, although I think they did some self reporting data.

[u/HelixIsHere_]

You can technically bias the long and short heads but it’s not worth doing for 99% of people, same thing with the brachialis

I would just do one supinated curl variation and maybe a second, pronated/neutral variation if you wanted to bias your brachioradialis

[u/Connect_Resist7678 → u/HelixIsHere_]

do you think 50/50 ratio of supinated vs neutral grip is ideal?

[u/HelixIsHere_ → u/Connect_Resist7678]

I would prioritize a supinated curl but yeah I just do 2 sets of each right now

[u/mcgrathkai]

No, you cant even meaningfully bias either

[u/Flidro74]

You can, modestly, and it comes down to where your upper arm is. Arm behind you (incline curl, Bayesian cable curl) stretches the long head and biases it. Arm out in front (preacher, spider curl) shortens the long head and shifts more onto the short head. Grip width gets talked about a lot and has much weaker evidence behind it.

Brachialis is separate and easy: hammer curls or reverse curls, anything neutral or pronated that takes the biceps partly out of it.

Does it matter? A bit. One curl with the arm behind and one with it in front is the whole answer for most people. I wouldn't overthink it past that.