As JohnO suggest..Breathing Squats: I made my best pure muscle gains using the 20 rep+ breathing squat. The ideas is to take a weight you can usually get 10 or 11 good reps out of. From there, push you body and mental capacity beyond to that goal of 20 reps. Add the 2 1/2 to 5 lbs every workout (probably twice a week). In my view the mental toughness is 50% (or more) when it come to working out with serious intent. At times, reaching the 20 reps, you may have reps to spare. Keep squating until you are pretty much fried. 30 reps are not out of the question. That taking advantage of the fact that your are breathing like a steam engine, do 20 or so deep breath BB/DB pullovers. Working for a full stretch at the bottom. Usually one set should take care of business with the breathing squat. I and a few other have done two sets at the most in that style program. Make no mistake though, you should be using very heavy weights with this system. Taking a weight that you normally get 10 reps out of and by pure force of will make 20 reps.
If your young enough (usually below 22-24 years as a mean average) the cartilage can expand some, allowing an increase in chest size. But this only when the cartilage is still in a younger and more elastic state. Before becoming more fixed and inflexable as we age. People get this confused with bone growth, which is not the case. The rib bones do not grow but the space (cartilage) between them can become somewhat expanded, with the heavy forced breathing and the pullover to follow. You will gain muscular weight if the good quality calorie intake is upped.
You may also get an 2" increase in chest size (at least) due to the muscular weight gained and the expansion of the rib box it's self. Give about 4 to 6 weeks on this style program. Another byproduct wil lbe outstanding stamina (endurance & strength). If you want to burn calories and gain pure size at the same time than give the breathing squat program a try.
I gained around 30lbs (attention SF) over the summer when I was 16, using the above program. For gaining strength and weight for football, it was perfect. Plus the stamina part. And actually lost a little around the waist. Best to work with a couple of other guy's for motivation. I had two very large Samoan gentlemen yelling in my ear while heavy squating. If I did not make one more rep they were going to shoot my dog and burn down my house. Motivation of the highest order. Good Luck.
