Originally Posted by luvforty
from the end of the backswing, to about when the ball gets to the baseline, the arm/torso relationship is the same...... then she stops the torso and let the arm go forward by itself.
pause the video and go frame with the right arrow on the key board.
so the arm never had to 'catch up'.... it is always in sync (by design anyways), then at the last moment it goes ahead of the core.
the arm is moving slightly. she's using arm. she's not arming it
. there's a difference. if it were no arm there would be lag. that's why the atp guys have a lag. the guys rotate and the racquet stays back until it's pulled around.