T Nation

Pecs vs Delts

I’ve read that some people claim that bench press is dominated primarily by the front delts and triceps and not much good for pec development. I got to looking at the size of the muscles, the origins and insertions, directions of pull, and mechanical advantage (leverage) of each of them.

The front delt is quite a bit less massive than the pec, it is a shorter muscle, it pulls nearly straight into the shoulder joint. The pec is bigger, longer, and has a huge leverage advantage at rotating the arm forward and downward towards the centerline of the body. I think in the bottom of the bench the pec outpulls the delt by a good amount, although they do work together. Of course once your upper arm gets a bit higher than parallel to the ground your tricep is the dominant force.

What do you all think?

you made part of the point yourself, if the pec is bigger and stronger than the front delt which one will give out? which one is “the weekest link” goodbye

I think you know your shit.

i was just watching a bench video by JM blakely and he tries to limit almost all contributions from the shoulder.

Okay I’m seeing your reasoning. Here’s the deal though: If delts are weaker muscles, obviously they are going to fatigue faster. But the Pecs are still doing the bulk load of the work. Therefore, if the delt fails, the Pec still hold a mechanical advantage and can continue to fire through the exercise. The Pecs and the Ant delt are both acting on the same joint so if the “weakest link” fatigues, that juggernaught pec is gonna keep firing on it’s own. Lifting can continue and the Pec is properly taxed. Your Ant Delt should never be the failure point (or be doing the bulk of the work) in a flat bench, it just doesn’t have the leverage. Theoretically, if your delts are causing failure in flat bench, then they are doing the bulk of the workload and your pecs are “the weakest link” – Goodbye.

well I’m sure we both agree that the tri’s are realy the weakest link in just about any pressing exercise. My point about the bench vs. dips is not that the bench can’t build a big chest its just that I think that dips are better, when ever I think of a muscle I try to find a movement that streches the muscle the most and then an exercise that contracts it the most. there are few exercises for any bodypart that do both, for back maybe the rv.chins to chest or hammer/nautilus pullovers, there are none realy for bi’s or tri’s that do both, quads either, hams have the glute/ham raise, front delts have the standard overhead press (first half atleast), the pec do have an exercise that comes close to doing both. the DIPS, the fully contracted position is w/elbows down, close together right in front of the body, the fully streched position is w/elbows up high behind the body, just like dips, the pecs primary movement is to pull the arms DOWN and together, not across the body, that is not how they “function best” the first about third of a dip (from bottom) is almost all pec, then the delts come in then the tris, if there is an exercise that works the pecs better I think it would be the LOW decline bench, but a barbell prevents a full strech and db’s, due to the amount of balance needed, prevent optimum overload ,I know some will dissagree but I think there is a fine line between the benefits of free wts. and the decrease in overload due to the “stabalizer” muscles being involved, I think barbells are the almost perfect compromise between db’s and machines but they limit the range of motion in a decline press and db’s can also once you go over about 120’s (atleast for me) unless you use a hammer grip, which is great I just do not find the hammer grip to be very comfortable for myself. again I think you can build a great big chest w/benches I just think there is a better way. and I understand your point about “if your delts are causing failure in the bench, then they are doing the bulk ot the work, and they are the weekest link” I can w/ rows for example concentrate on pulling from my elbows and almost not use by bi’s at all but I think it is next to impossibe in free wt. pressing movements (for myself atleast) so you are always limited by the weekest muscle, and delt strength has not been a prob for me, I have always been able to incline almost as much as I bench. there is another prob w/ the power curve that most use when they bench (which is why some people feel the db bench more that the bb bench) but I have taken up toooo much space w/my ramblings already. peace