If there's one thing that I've been left a little unsatisfied with in all the literature that I've read about BW, it's defining all of the different types of BW. So, as I understand and see it, these are the types of BW:
This one lacks the clearest definition. What Richard Simmons does IS NOT calisthenics. I couldn't even find a definition in a dictionary. So, examining all of the exercises that I know are calisthenics, I cam up with this one: Any exercise where you use a combination of body's gravitational pull and leverage to supply resistance to your muscles.
2. Self Resistance
These exercises use an opposing body part to supply resistance to the muscles. A good example of this is the bicep curl. Rather than using a weight, simply place your opposite hand in the curling arm's hand and press against it. Your muscles respond to tension from resistance, it doesn't matter if it's coming from a weight or your own body.
3. Visualized Resistance
This one may be the hardest to believe that it will actually build muscle but it does. Instead of using gravity, leverage, or an opposing body part, you're actually going to use the body's opposing muscle group. Muscles act much like a rope on a pulley: One pushes, the other pulls. So, if you tense the opposing muscle very tightly, it will supply resistance to the other muscle. Go back to the bicep curl. Instead, tense your triceps very hard and try to curl your arm. Pretend you're lifting a weight. Visualized resistance at work. Very effective.
The word literally means "one length". Isometrics are any exercise where the muscle is tensed and held in a specific position. There are several ways to practice isometrics and here are three:
A. You can use an opposing limb but remove all movement. Push so hard that no
movement occurs. Actually, any immovable object will work.
B. You can use the opposing muscle groups to provide resistance. Once again apply so
much tension that no movement takes place.
C. You can remove all movement from a choice calisthenic and instead hold the position for
a count. I've heard of it referred to as positional isometrics.
Of course there are more to each of these four exercises but this is a general outline of the strength building exercises that BW offers.