Especially form the stabilizer muscles. Those objects are awkward and unbalanced. I was a granite worker for a few works and had to move some crazy big pieces and it was tough. Very hard.
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Member of DaJoGen MMA school under Dave Hagen and Team Chaos fight team under Denver Mangiyatan and Chris Toquero, ran out of Zanshin Martial Arts in Salem Oregon: http://www.zanshinarts.org/Home.aspx,