T Nation

Left Pec Takes More Strain Than Right


So i've had the most annoying problem for the past year or so...

Whenever doing chest movements etc. my left pec takes more 'strain' than the right pec, and it is gradually getting bigger and bigger than the other one.

Now I know it's due to a weakness of some sort in my left arm/shoulder area, but I don't know what exercies to do to fix it...

It started when my elbow kinked the wrong way at the top of a DB press, I have a hell of a time locking out with my left arm, then I get a twinge that runs up my arm into the back of my shoulder.

I'm guessing my left arm stays partially bent at the top keeping more strain on the left pec?

If anyone who is smarter than me can just tell me whats going on here and what I could do to fix it, it'd really help.

I'd go see a therapist but it's a) really expensive, and b) they will just give me a couple of stretches/exercises to do anyway that may or may not work...


I agree that a therapist is probably a bad idea; unless you are experiencing some sort of pain. You said you get a twinge that runs up your arm and down your shoulder. Was that just once, or repeated?

If it keeps happening, then youve gotta figure out what it is, even if you have to go to a PT. But if you are benching all of the time and dont have any problems other than this weakness, then you should be able to figure things out on your own.

Here are a couple things I would think about:

-Check your righ/left tricep strength/endurance with DB skull crushers
-See if the problem is the same with a standing press or incline press

-So your idea that the left shoulder arm/shoulder might be weak seems plausible. Are you noticeably smaller in the left arm/shoulder? If not, maybe just do extra work to bring up your right chest.

Also, how is your grip strength on the left side?

So IMO if you aren't experiencing any pain/numbness then just try to figure out what is wrong or strengthen your left side. But if you are experiencing pain/numbness then you should probably see a PT to get evalutated.


What kind of bench presses are you doing? You might try focusing on dumbbells, and work in some unilateral presses to ensure you are working both sides equally.


It's really all chest work.

Bench press (powerlifting style), DB press, incline press.

I am 100% sure that there is no possible way I can 'do extra work' to bring up my right pec to my left.

First this imbalance (whatever it may be) has to be addressed, then I'm sure they will balance themselves out over a few months of training.


I have had that same Problem!! and i dident do anything about it till a couple weeks ago... what i did was do
single arm shoulder press to see that left shoulder was way weaker than my right [ my left pec is bigger than
my right] and do single arm tricep pushdowns [ again my left tricep was weaker] hope this helps


These questions will probably help me a lot, thanks.

  • I'd have to say my tricep strength and it's endurance is slightly less than the right side.

  • Theres no real issues with overhead pressing, although it has stalled significantly recently, which is probably due to this problem.

  • The problem is pretty much the same with incline pressing yes. HOWEVER, I do not do incline BARBELL bench because my left posterior delt tightens up to such an extent that I can't bring the bar to my upper chest.

So far my plan so far is to just do hundreds of pushups every day to see if it points anything out... lol.

Theres no fucking way im changing my regular training, did that before, ended up wasting a year. Training/not training doesn't make a difference. So I gotta do something.


Forgot to mention:

When nearing the point of fatigue on pull ups I get a bad strain on my upper arm/rear delt, which is definitely related!

I just wish I was smarter with this physiology stuff.


ya, he said he notices the lockout problem on DB presses.

I still say if you aren't having pain or some sort of noticeable motor control problem, then check your triceps to see if there is a weakness from left to right.

Another thing that might reveal something is to pre-exhaust your chest with something like the peck deck. Then go on to bench, if something is weak in the movement this might make it more noticeable.

The only other thing I could think of would maybe be overactive/tight biceps but I dont think it would be this noticeable.

And you could always do an extra set or two on your right side.

Hope you find a solution.


I too have the exact same issue! Left side is bigger and stronger than my right. I have been doing the single arm presses as well as the single tricep exercises and it seems to be helping some. It's pretty weird, almost like the right side is built differently. I know it is not but the mechanics seem so different in order to feel the same contraction as the left side.


WOW! Its actually noticeable in your avatar. OP this is another possible scenario. There may not be anything "abnormal" you may just have less fat or muscle tissue there due to genetics. But since you stated there is a noticeable strength difference and lockout problem, I would think it has something to do with your training.

I read your previous post and am a little confused about your posterior delt issue. It sounds like you have a lot of issues going on and you might need to get in eventually to see a PT.

When you say you are doing pullups and experience something with your posterior delt, im assuiming you are doing WIDE GRIP PULLUPS? I'd drop these for a while and see if anything changes. Go with a overhand grip that is about shoulder width.

I'd find a way to see a PT. If you cant afford it, maybe find one that would be willing to give you their best guess through e-mail or something similar. Over at www.thefitcast.com one of the hosts is a PT or studying to be one and would possibly give you some areas to look at. It just sounds like you have a lot going on and it could really be anything from your big toe, to your neck, and people here that aren't PT's just aren't qualified to make guesses.

Good luck!


Try switching it up a little.
select slightly lighter dumbells,one a little heavier than the other (i.e. 25kg in one hand,22kg in the other)
Do a set,then swap them round.
experiment with this for a few workouts over the course of a month or so.
Without getting too technical,it's basically gonna wake up your CNS (Central Nervous System) and expose it to new stimulus,forcing it to activate new areas of the muscle that have been dormant.
Your CNS has become so used to the same workouts,when you pick up the dumbells,it's basically 'ho hum,here we go again' for it.
When you switch it up with different weights,even though you have come down in weight,it's a lot more stimulus,you don't have that balance of the same weight in each hand,you have to stabilise yourself more.

If this gets too easy,you can gradually switch it up again-use 2 DB's with a bigger difference between them (i.e. 25kg & 18kg) then heavier weights nearer your usual load.
And try one-arm DB press with lighter weights and only half your body on the bench-it's a lot harder,you have to grab the bench for support and take a wider stance and really activate all muscles to stabilise yourself.


You need to define 'strain' do you mean PAIN? this changes things....


no no no just the strain you get from lifting weights during your set.

Anyway, I got out some 10lb dumbbells and did some movements and found a few things:

Overhead press: Both sides equal
rear delt raise: Both sides equal
standing external rotations: Left side weaker
lateral raise: Left side weaker (got throbbing pain after I did this)
Front raise: Left side weaker
Dumbbell triceps extension, supinated grip: Left side weaker

Did each movement for 30-60 reps.

I'm guessing I should just keep doing these movements until both sides are the same and that will fix everything.


By the way,I notice the abbreviation PT gets thrown around a lot,I know this sounds anal,but please clarify what you mean,especially if advising someone to go to one.
I am a PT-a Personal Trainer.
But PT can also mean (as in this case) Physical Therapist (U.S.) or Physiotherapist (U.K.) often shortened to Physio.

It does happen,and you would be surprised how many clients fill out a medical clearance form,mention no injuries or twinges/spasms/sprains during my consultation,despite me grilling them,then when training,I notice something unusual and pick them up on it,and they just make a throwaway comment like 'Oh yeah,it always hurts when I do that' or 'Oh,I can't do that' because of this injury or trauma and so on.
I'm like 'gee,thanks for wasting my motherfucking time,it's back to square one' okay,I don't say that,but I think it sometimes.


Thats good that your are figuring things out. You may also want to do a similar diagnostic with heavier weights in the rep ranges you normally use. Because an imbalance at 30-60 reps is not necessarily an imbalance at 5-10 reps.

And the fact that you got a throbbing pain from the lateral raises is something to be concerned about. Try to figure that out as well.

***Oh and I didn't mention it earlier, but read the article on pushups, face pulls, and shrugs. I think it might apply to your situation a bit.


Whoa! easy,tiger!
This is the key word I was looking for-PAIN.
I don't think it's your pec.It sounds like a rotator cuff injury.
It's a complex joint,but the pain with the lateral raise is worrying.
Do your utmost to contact a physio,see if you can get refererred by your GP first if no luck online.
Or someone qualified in sports massage.


This might sound like a weird solution, but I'll let you hear it anyway. When I get under a certain body weight I usually end up pulling out my right back and my left shoulder. This usually happens in the summer, as I work outdoors and tend to loose about 10 pounds every year. Try beefing up a little. Put a little meat on( 10 pounds) and see if the problem goes away.


-Soft tissue work
--Tennis or lacrosse ball for posterior shoulder joint (infraspiatus, teres minor esp. . .)
--Stand up straight, push your shoulder as far forward as possible. Maintain that position and feel for the front of your shoulder blade in your arm pit. Here's a visual of what you're looking for: http://z.about.com/d/exercise/1/0/G/k/subscapularis.jpg Massage that with your thumb. It may be painful, but that's because that muscle works hard all the time, and it has developed scar tissue as a result.
--Shoulder girdle (rhomboids with duct taped tennis balls, sure this is mentioned somewhere around here in an article)

-Balancing out the foo-foo stuff
--You've already discussed imbalances in external rotation, this is an indication of weakness of muscles such as infraspinatus and teres minor, which work hard to depress the head of the humerus into the glenoid fossa when you are benching. You see, pectoralis major has a tendency to produce a 'gross' type of motion on the humerus, which sort of acts to pull the upper arm bone out of its socket. An imbalance of activation, strength, and/or length of these 'external rotators' can cause pec major to get over worked and more hypertrophyed (as you've noted).

-Strengthening the foo-foo stuff
--Start working on prone internal rotations on the side where your pec is larger. Your pec may be working harder than it should be, which could eventually lead to strains and all kinds of lame stuff. Getting subscapularis (the muscle worked when you do prone internal rotations) stronger will take some of the load off of pec major and keep that shoulder joint going hard.

-Understand this takes time. . .
--You've mentioned this is something that has been going on for some time. It will also take some time to fix.

If I could see you in person I'd be able to do specific tests to figure out exactly what the problem is. Over the internet, I can tell that you need to do soft tissue work for just about everything and specific strengthening work for your rotator cuff. So take the day after your pressing day and spend time working on cable external rotations, prone internal rotations, and scapular stability stuff. It'll take you 15 minutes to do that stuff, and if you spend 5 minutes a day on the tennis ball and foam roller and stay away from stupid shit in the gym, this issue will resolve.

Also, I know you don't want to make huge changes in your training, but it may be a good idea to take the weight down and REALLY iron out any form discrepancies you may have. If you are leaning more to one side on the bench, this can reinforce a triceps/pec/intrinsic shoulder imbalance you have.

Listen to your body, man. If you go into the gym and your warm ups are hurting. . . That should tell you something.

Great luck man, I know you'll resolve this!


I always thought, and have been told, that lifting with different weight in each hand was like a mortal sin. I don't have any concrete article to reference other than my memory. May want to look into that idea before trying it...


Thank you all for the great help on this thread.

I'm going to be spending a lot more time focusing on my benching form, and i'll start working on internal/external exercises.

Probably going to drop military presses and just add in more raise variations to see if that helps also.