Building muscle is all about progressive resistance. That is, ever growing force acting against your muscles over a period of time; weeks, months, years, etc.
That’s why building muscle with dumbbells and barbells is so efficient. Pop the collar off, slide a plate onto the bar, and away you go… easy.
For whatever reason, some people prefer the idea of building muscle without using traditional weights. But, the law of progressive resistance still applies – whether that’s more and more books in a backpack while you do squats or push ups or whatever.
If you do choose to do calisthenics, if you are an untrained beginner, when you first start out you can probably put a bit of muscle on – just as if you had a hard laborious job you’d develop a certain amount of extra muscle. But, it’s pretty limited. For instance, just because you worked as a removal man lifting refrigerators once or twice every day, doesn’t mean you’d get to the size of Jay Cutler.
What normally happens is, a certain amount of muscle mass is developed, or a certain amount of fat is burned, depending upon the amount of calories taken in, of course.
There are an abundance of calisthenics exercises, and there are enough for a complete body workout. But, rather than developing enormous strength (i.e. lifting a car), callisthenics tend to only help you develop endurance, so don’t expect to get huge muscles.
Push ups, for example, are a great calisthenic exercise. Push ups are basically an inverted bench press, and just about all of the same muscles are involved: triceps, front deltoids, pectorals, abs and the lats.
Push ups can be performed in different ways to hit different muscles. For instance, a wide hand placement would hit the chest more, whereas a narrow hand placement would hit the triceps more.
Don’t forget, just because you are doing calisthenics, it doesn’t mean you can’t add some weight into the mix in the form of something. If you want to continue gaining size, I recommend using a backpack filled with increasingly heavier objects to provide more resistance, and performing 12-15 push ups for around 5 sets, with a maximum of 1 minute’s rest in between.