Quote:
Originally Posted by
Scott O 
This is actually pretty complicated. Sorry but I have spent the last fifteen years understanding the question of "why" in the training world. The why in this case could stem from several variables. I work as a trainer and one of my best diagnostic tools is postural photographs. The imbalances we have come from several factors or variables. The biggest one I have found is genetics. I tried so hard to believe this was not as big of a deal as many believed but after working with different generations of families it is. The muscular system and patterning of your parents does have a major impact on your own. Im not a geneticist I just have seen too many kids who structurally look exactly like their parents to not think it can play a big part. Next is injuries. Take a broken leg for example, if you break your right leg lets say and it needs to be in a cast for 8 weeks, during that time your body will adapt to the stimulus you are giving it. This means that for 8 weeks you will unconsciously learn to put more pressure on the left side of your pelvis since your right leg cant take any weight. Now when the cast comes off and you begin training you are doing so with a huge compensation. You are now going to be putting pressure on one side of your body even if you do not want to. So if one side of your pelvis is accepting more weight, the other side will then raise itself up due to muscular atrophy. Now this changes the angel in the spine which in turn changes the elevation of your shoulders. This might sound crazy but I could show you thousands of client pictures where this is the case. So it is the skeletal misalignment that will cause your muscles to be different in size and shape. To fix it I highly recommend avoiding barbells moves. Do everything with dumbbells so you can strengthen each side independently. Also do lots of one leg movements like lunges or one leg squats to try and get your body to correctly accept weight on both sides. I realize this is a long comment and I apologize but like I said it is not an easy answer. Oh, and yes I have shown clients how to overcome it. but I do believe once you achieve it if you do not continue to supply the stimulus to your muscles to maintain it, you will go right back to your imbalance.
I am currently recovering from a broken patella. It happened 10 weeks ago and I just did some light squatting the other day to get it back to old form. I have been stationary biking for 20-30 mins a few times per week for the past couple weeks. I am the OP and the left leg used to be my strong one. The calf is still much bigger, as I have been walking since a week after the injury, just not using any quad, mostly hamstring and calf. What should I be doing to avoid a permanent quadriceps asymmetry? I now use my right leg for standing up, which I am trying to change, but the left knee still hurts when I ascend stairs and run. I should probably be going to PT but insurance won't cover me until I move back home in 3 weeks. Another odd thing is my jaw muscles. They exhibit the same asymmetry as the rest of my body. My left jaw is more muscular and is pulling the jaw bone over, about 5mm so far (which is about 2 front lower teeth off center, quite a difference). I am considering a procedure to fix it, but it is a pretty complicated issue.