Dragy
Legend
Guys you forget torso rotation. Suppose just didn’t put it into posting rather than forget. It’s not solely upward drive, shoulder starts moving around simultaneously if not first. Arm pivots back and then down, circularly.
Early leakage reverses the direction of shoulder rotation gravity works against, which causes different muscles to support the position. Go too far, and you now contract ISR muscles to guide the arm instead of totally relaxing them and allowing free stretch cycle as racquet drops. Opposite, if you do like Macci and @Curious advocate: ESR-responsible muscles guide the prep all the way until the uncoil starts.
Regarding Serena, her forearm and racquet is still close to vertical when uncoil starts, so nothing dramatic.
The “continuous motion through trophy building up speed” story is an old myth from years when ISR loading (stretching) wasn’t understood yet, as far as I believe.
Early leakage reverses the direction of shoulder rotation gravity works against, which causes different muscles to support the position. Go too far, and you now contract ISR muscles to guide the arm instead of totally relaxing them and allowing free stretch cycle as racquet drops. Opposite, if you do like Macci and @Curious advocate: ESR-responsible muscles guide the prep all the way until the uncoil starts.
Regarding Serena, her forearm and racquet is still close to vertical when uncoil starts, so nothing dramatic.
The “continuous motion through trophy building up speed” story is an old myth from years when ISR loading (stretching) wasn’t understood yet, as far as I believe.