>>>Jack, "Gaining Forward Velocity", "Shifting the COM", and "Weight Shift(Transfer)" are all the same thing. Weight is a measurement of Mass, and is being shifted in space. Why are attempting to make a distinction that doesn't exist?
Bonds and Pujols absolutely shifts their COM/Weight/Mass forward prior to swing initiation, and MORE IMPORTANTLY to your "thread subject", is still shifting COM/Weight/Mass forward during launch intitiation and prior to blocking. Notice in my clips, the rear/front shoulder and bathead begin rotation in the last frame of transfer shown in these clips.
IMO, your analysis of this fact is flawed as indicated here of Bonds and Pujols shifting the COM and initiating his launch during the end of that shift.<<<
Gaining Forward Velocity", "Shifting the COM", and "Weight Shift(Transfer)" are "not" all the same thing. The video clearly shows that the forward velocity and development of momentum attained during the stride slowed to a stop "before" weight shift started (front foot is still off the ground). During the weight shift phase of the swing, the forward velocity of body mass (and momentum) remained zero as the body rotated about a stationary axis.
A frame-by-frame analysis of all high level swings will exhibit the same principles as described above. These hitters will generate varying amounts of body mass velocity and momentum during their strides. However, all the forward velocity and momentum attained will slow to a stop before rotation and weight shift (weight going from back to front foot) takes place. -- Conclusion: Forward velocity and momentum is generated during the stride but not during the "weight shift" and rotation phase of the swing.
The question then becomes: Since "weight shift" and rotation are occurring at the same time, does weight shift generate rotation? Or, does the rotation of the body cause the weight to be shifted from the back-foot to the front-foot? -- I choose the latter.
Giambi - Momentum & lead leg
I thank you for your input. The readers can now study the video and compare your analysis with mine. This is what informative discussions are all about.