What Causes Pelvic Rotation in the Early Downswing?

[JeffMann]

What do you think causes the counterclockwise pelvic rotation that happens in the early downswing between P4 and P5 in a professional golfer?

Do you think that it is caused by Dr. Kwon's theoretically-conceived Newtonian forces or do you think that it is secondary to the activation of particular pelvic girdle muscles?

See a discussion of this controversy in topic number 4 of this review paper -

http://perfectgolfswingreview.net/TylerReview.html

Edited December 11, 2018 by iacas
fixed link

[iacas]

I read just enough to see that once again you've made the same mistake you always seem to make in your "papers" and that is not understanding a basic frame of reference. It's the same mistake you made for years when not understanding that when people were talking about left tilt or side bend at A4 the frame of reference was the golfer and thus, left was toward the ball, not toward the target.

That whole episode was a hoot, and a complete waste of several years.

You're confusing counter-clockwise as viewed from above and face on.

[JeffMann]

1 hour ago, iacas said:

I read just enough to see that once again you've made the same mistake you always seem to make in your "papers" and that is not understanding a basic frame of reference. It's the same mistake you made for years when not understanding that when people were talking about left tilt or side bend at A4 the frame of reference was the golfer and thus, left was toward the ball, not toward the target.

That whole episode was a hoot, and a complete waste of several years.

You're confusing counter-clockwise as viewed from above and face on.

I think that the correct frame of reference for describing the direction of pelvic rotation during the early downswing is the golfer as viewed from a birds-eye viewing perspective. Using that frame of reference, the direction of pelvic rotation is counterclockwise. I think that it also counterclockwise when viewed from a face-on viewing perspective.

Irrespective of what frame of reference you prefer to use, the question remains - what do you think causes a rotary motion of a professional golfer's pelvis in that direction during the hip-squaring phase between P4 and P5?

Jack.

[iacas]

1 minute ago, JeffMann said:

I think that the correct frame of reference for describing the direction of pelvic rotation during the early downswing is the golfer as viewed from a birds-eye viewing perspective. Using that frame of reference, the direction of pelvic rotation is counterclockwise. I think that it also counterclockwise when viewed from a face-on viewing perspective.

You completely missed the point here.

2 minutes ago, JeffMann said:

Irrespective of what frame of reference you prefer to use, the question remains - what do you think causes a rotary motion of a professional golfer's pelvis in that direction during the hip-squaring phase between P4 and P5?

Muscles. Which Tyler and Dr. Kwon would say, too.

That, or magic fairy dust.

I don't like liars, Jeff, so goodbye.

[JeffMann]

1 minute ago, iacas said:

You completely missed the point here.

Muscles. Which Tyler and Dr. Kwon would say, too.

That, or magic fairy dust.

I don't like liars, Jeff, so goodbye.

According to Dr. Kwon, only "external moments" can cause an angular rotation of the body around its COM, and he states that those "external moments" are secondary to Newtonian forces generated by vertical GRFs. Which muscles do you think are used to create those vertical GRFs?

[iacas]

1 minute ago, JeffMann said:

According to Dr. Kwon, only "external moments" can cause an angular rotation of the body around its COM, and he states that those "external moments" are secondary to Newtonian forces generated by vertical GRFs. Which muscles do you think are used to create those vertical GRFs?

Again, you're completely misunderstanding things.

1. Dr. Kwon and Tyler are talking about counterclockwise in two perpendicular planes of motion.
2. Dr. Kwon would be the first person to tell you that the muscles are what create the forces and the reaction forces. They're "reaction" forces for a reason. The ground is inert.

Your "paper," as is typical of your work, is full of holes like the above, and horrible misunderstandings.

But hey, at least you didn't write "Jack" this time, Jeff.

[mchepp]

Jeff Mann returns again from out of the wilderness.