Elite training for the homeless

WikiHow has instructions for making weight training equipment out of pretty much anything that resists gravity. My favorite suggestion is to "use canned goods that fit in your hands as simple hand weights." This one seemed like an especially great suggestion given the synergy it has with local canned food drives. I was a little confused though by the warning to "always consult with a doctor or qualified health professional before beginning an exercise program." If you're using a sock full of beans to workout, how good can your health coverage be?