the thread is "ergonomic hammers"....I submit that to use a lump of metal on the end of a stick repeatedly all day long is not ergonomic, nor natural, nor even healthy......at least for most humans. The heavier the lump of metal the worse it is. One can train themselves to do a lot that otherwise would not be possible for a novice just starting out. That takes time, effort, and experience. The more you train yourself the easier it will become to do the job. Having said that, a 100 lb person will never effectively use a 10 lb hammer, it just ain't in the cards unless they train a long time. A person needs to know their limitations (thanks Clint) and work within them. Be happy you can even use a hammer.