My left and right arms are not equal. The left measures about 40.5 cm and the right about 41.5 cm. The difference isn't that noticeable, but I know it's there and it's really annoying to me just the same. My right arm even has a more noticeable vein than the left one. The left arm also seems a little bit stronger than the right; on the last two reps in any bicep exercise, the right arm can keep going but the left gives out. I train biceps with two exercises, one barbell, bilateral, and one with dumbbells, one arm at a time. I train the triceps always with two arms at a time. Is there anything I can do about this difference?
Yes, this is almost always correctable. First of all, uneven development is natural; it's actually more common to have one side more developed than it is to have both perfectly even. Having 100% even development (without intentionally training for balance) is about as common as being ambidextrous.
The best way to balance out uneven arm development is to use primarily dumbbells and unilateral (one arm at a time) movements.
Unilateral training can be done with dumbbells, one arm cable movements or unilateral machines like Hammer Strength iso-lateral equipment. You can even do unilateral training on most conventional machines by using one arm instead of two.
If you really want your bicep development to even out quickly, do a lot of dumbbell and unilateral training for your entire upper body, including chest, back, shoulders, triceps, biceps and even forearms.
One arm dumbbell preacher curls
Dumbbell concentration curls
One arm standing or seated dumbbell curls
Alternating dumbbell curls
One arm Cable curls
One arm overhead tricep extension
One arm lying tricep extension
Alternating two dumbbell lying extensions
One arm cable pushdowns
One arm dumbbell rows
One arm cable rows
One arm pulldowns
Hammer Strength isolateral row
Hammer strength isolateral pulldown
One arm Dumbbell bench presses
One arm machine presses
One arm cable flyes
Hammer strength unilateral presses
Alternating dumbbell bench presses
One arm dumbbell press
Alternating dumbbell presses
One arm Lateral raises
One arm cable lateral raises
Hammer Strength Isolateral shoulder presses
You don't have to do every exercise one arm at a time, either. Doing nothing but one arm dumbbell exercises can become quite time consuming. Just the practice of using dumbbells in general will improve the right to left balance because each arm has to work equally and independently. Alternating dumbbell exercises will work well too.
If you do the majority of your exercises with dumbbells or in a unilateral fashion, you'll be surprised how quickly your arms even out in size and strength.
Avoid machines for the most part until you’re satisfied with your muscle balance. On most bilateral machines (like a two hand seated chest press on a single pulley/cable machine), your dominant side will take over and do most of the work. Dumbbells force both sides to do equal work.
A word of caution: The most common reaction people have to unbalanced development is to do extra sets for the lagging side. This is NOT a good idea because you may end up overtraining the smaller side. This could have the opposite effect: the overworked arm could stop growing or even get smaller!
It's much wiser to simply work harder on the same number of sets you would normally do. Increase the intensity, not the volume.
Right and left side imbalance is not just a muscle development issue; it's a neurological issue. When you’re right handed, its only natural that your mind to muscle connection is stronger on the right side. The late bodybuilding trainer Vince Gironda recommended using your weaker side in daily life to do things like open doors, lift objects, turn on faucets, and everything else you can think of. He said that if you worked on becoming ambidextrous, your muscle development would quickly even out.
There's also a mental aspect: If you train with increased mental concentration and focus on the weaker side, this will tend to improve the neural connection between your brain and weak side, which will increase the strength of muscle contraction and eventually balance out your development.
If you have a difficult time with this mental focus concept, simply slow down your exercises, hold the contracted position and squeeze. Get your mind into the muscle. Arnold Schwarzenegger wrote about this frequently in his autobiographical and training books.
Give these techniques an honest trial, then drop me another note in a few months. I won't be the least bit surprised if you’ve achieved 100% even development… or your weak side has actually become your strong side!