I was wandering. Is it possible to build any appreciable mass solely through bodyweight training? Obviously its not gonna turn a person into Arnold or anything like that, but would it be possible to add a stone or so over a year? Also, how important is stretching before and after a workout, and what sort of stretches do you guys do? Im only about 9 stone, and I'm aiming for 10/10 1/2. Do think its possible through just bodyweight exercises, or do I have to hit the weights?