looking at the two examples, clubbell vs. Tetsujo (i guess thats what it's called), and the muscle groups used are completely different.
with the clubbell, most of what you'll be working out is the
flexsor pollicis longus (index finger forearm muscle)
triceps
deltoid (shoulder),
the spine erectors
and to a lesser degree the hand and quads. the biggest difference when you look at the two though is tension of the rest of the body. the clubbell work out is using the absolute minimum muscle tension to acheive the motion, every other muscle in every instance possible is in a relaxed state, only flexing to stop the motion or start it again.
the tetsujo requires you to control the weight and motion at all times, and to stop the motion in a dead stop, rather then letting the momentum cusion down and redirect. stopping a 10lb weight at a dead stop requires -huge- amounts of muscle strength and effort, where as slowing the item down and letting it swing to reduce speed and motion requires much less.
if you wanted to get specific muscles toned, and perhaps increase job performance at a given motion the clubbell would be great. but if you want just pure all around bulk, with hand and forearm strength as the main focus - the tetsujo wins out.
if I had a 4x4 peice of wood that big I'd totally go make one...
