[mondocat]

Thinking about this more, I'd say the convention wisdom on body-weight exercises is completely backwards. They're terrible for beginners, but can be valuable for people already strong enough to do them. Why are they terrible for beginners? Two reasons, either their potential for improvement is too low, like the pushup or squat, where the average person can get to 5-10 reps pretty quickly- the point at which a given resistance is no longer able to elicit strength gains. Or, the first step is so large that it's effectively unreachable. Pull-ups are great, but if you are a beginner, doing your first pull-up by doing only pull-ups is a great challenge, compared to going to the gym and doing pull-downs or assisted pull-ups starting at an appropriate weight, and making incremental progress. In short, body weight exercises can certainly be challenging, think of a gymnast, but they offer very little in the way of incremental improvement from any starting point, which is what beginners need most.