I don’t actually do a lot of bag work, I generally try to train on other people. This is because the bag doesn’t react like a person, it doesn’t move, cover, double-over, tense-up, twist in different planes and so on. The bag is a simple piece of equipment, it has it’s benefits when you don’t have a partner as hitting something with some resistance provides some feedback for you. The bag should be moderately heavy, heavy enough to provide resistance but no so heavy as not to move.
The video is on my facebook account but should be accessible via the link below