Pertaining to speedbag height, I believe it is conventional wisdom to line up the bottom of the bag about even with the bottom of your chin. Over several years, I have always taken it upon myself to raise it at least 6-8 inches to accustom myself to punching higher. Some have told me that this method is unnatural, while others have said it is a good idea. Since having a shoulder surgery over a year ago, it has been difficult bringing it back. My physical therapist described a move, similar to striking a speedbag overhead, as something NOT to do. That was over a year ago, and though that same physical therapist might be the one to ask, I am no longer in touch. Anybody have any insight or theories on speedbag height?
I suppose it would be different for each person. Whatever the "proper" way to do it is I'm not sure but I've always done it eye level.
