Originally Posted by rkelley
... but the salient point is that most of the power comes from the legs and the core whipping the arm around, not from the arm muscles contracting without the loading from the legs and core.
Your statement contradicts with Bruce Elliott measured data http://www.ncbi.nlm.nih.gov/pmc/arti...81/table/tbl2/
Topspin forehand (forward direction)
Approximate contributions to impact racquet velocity (%)
Upper arm - Horizontal flexion 25
Upper arm - Internal rotation 40
IMO, shoulder means: power from legs, core, and etc.
This power produces just 15% of the racket velocity.
The arm and its parts create 85%.
Thus, the arm actions are much much much more important than legs, core, and etc actions!!!