Definitely a good exercise. I've been following Charles Poliquin since I discovered him when he was writing for Muscle Media 2000 back in the fun 1990's.
Another strengthening exercise for the shoulder girdle are straight arm shoulder retractions. These are performed when you are sitting at a weighted row station [not rowing machine where the seat moves] then pull the weights off the rack straight armed then retract your shoulders. Its like performing a standing shoulder shrug but instead of shrugging upward you are shrugging straight back. This is a very therapeutic maneuver. I learned this from John Boos who I interviewed about 17 years ago for this, I think my first E-zine piece for Gene.
http://www.kungfumagazine.com/index....le&article=421
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