I used to do pushups every morning and night before school (before i started lifting). Once did circuit of 30 normal,30 wide 30 close. like 20nsec between them.vvv hard,i lay on the floor after for a while,then did situps etc lol.
Some rugby buddies of mine use pushuips alot, they do bench with weight they can just get 6 reps with,then take weight off and just do bar for as many reps as poss (sometimes 80), then try and do 10 pushups (vvv hard), then put weight back on little lighter than b4, and repeat again. I suppose this can b used for most exercises. They said it built strength and endurance etc. Who knows as iv never done it.
davie