3 jack,
You wrote-: “In other words, I believe Grober’s study on hand speed applies to both hitters and swingers because in reality all of us ‘pull then push.’”
I am astonished by your statement.
First of all, consider Grober’s thesis.
Grober stated that he found that harmonic noise from his clubshaft transducer had a certain pattern, and that he tried to correlate it with golf biomechanics. He then consulted a biomechanist at Yale and came up with the hypothesis that elastic energy in elite athletes is stored in the backswing and then released in the downswing. He used the analogy of a spring - where the spring is compressed in the backswing and then released in the downswing. He then stated that the speed of elastic (spring) release was inherent in a golfer’s torso. That thesis has nothing to do with the release pattern in a TGM-hitter, who releases power in the mid-late downswing by releasing PA#1 (which is a straightening action of the right arm - and which doesn’t involve elastic release forces in the torso).
Also, consider his hand speed versus club speed pattern.
See - perfectgolfswingreview.net/GroberHandSpeed.jpg
The first image shows his clubshaft speed (measured by by his clubshaft’s transducer).
The second image shows how he tries to correlate hand speed with the club’s movement in the downswing - hand speed is the bottom graph.
Arrow 1 shows the transition between the end of the backswing and the start of the downswing when hand speed is zero. The second arrow shows the time point when hand speed is maximum - which he claims occurs at the end of the early downswing. In fact, he is physically demonstrating the point in the downswing when he believes that hand speed reaches its peak speed - note that his left arm is roughly parallel to the ground (which is defined as the end of early downswing).
He then introduced the concept of a double pendulum swing model, which is a swinger’s model, and he then talked about the torque forces that would be needed to energize his swing model.
See - perfectgolfswingreview.net/GroberTwo.jpg
Image 1 shows the double pendulum swing action on the left side and the body torque graph on the right side (needed to activate the double pendulum’s central arm, which is equivalent to the left arm in a golfer).
Image 2 shows how he tries to correlate torque energy activation with left arm/club movement. The red arrow shows that he has applied about 70% of the torque and the blue arrow shows the position of the hands (peripheral hinge point) at that time-point .
Image 3 shows that he has applied 100% of the torque (red arrow) and the hands are at the end of the early downswing (blue arrow).
In other words, he claims that a golfer powers the golf swing with a body-energised torque force in the early downswing and that the torque force is maximally expended by the end of the early downswing (when the left arm is parallel to the ground). That is the time point when hand speed is maximal (in his model). From that time point onwards, he states that the club simply releases due to a centrifugal action.
Grober is simply describing a swinger’s action, where the pivot-action powers the swing. The pivot-action in a TGM-swinger applies its torque energy in the early downswing - as shown in the Grober model.
However, that Grober model cannot apply to a TGM hitter. In the early downswing, a triple-barrel TGM hitter only uses the pivot action to get the right shoulder (launching pad) closer to the ball. A TGM-hitter applies his swing power in the mid-late downswing by the release of PA#1. The hand speed pattern will be very different and there is no centrifugal release in a TGM hitter’s swing. The club is being ACTIVELY driven into impact in a drive-loading manner.
Jeff.
