Pistol,

I don't think you jacked the thread. I think you responded the jack. Definitely post.

In the edit I did on this youtube:

http://uk.youtube.com/watch?v=oh184bHGkpM

Whilst accumulator 4 has not started to release (ie. the initial move before frame by frame segemnt) the left shoulder moves left without much vertical motion...John Schlee (and hence Tom Bertrand) always go on about moving "level left".

Then there is much more vertical motion in the next sgement (frame by frame)...

Obviously it is all blended....but the pivot is much more complicated than just pure rotation. I'm sure that Jeff could do a great job with his Spline tool on the motion of the left shoulder and left knee....maybe "j" shaped...?horizontal during lateral weight shift and preliminary rotation (about 45 degrees) then much more towards vertical when the axis tilt kicks in ???

Maybe?

GBD

You wrote-: ".but the shoulders can move and alter the left arm in a different manner...? maybe redirecting the power package or actually adding force??"

Let's presume that the right shoulder can add thrust force (push-pressure or added weight) to the right forearm/wrist/hand in the late downswing and at impact. Would it make the ball travel faster?

Not according to this collision review paper.

http://nmgolfscience.tripod.com/collisions.htm

Jeff.

I am not saying that the right shoulder adds force through impact resistance...just by increasing arm trhust PRIOR to impact...

If the left arm is blasted off the chest by rotation of pivot...does the left arm continue to accelerate in a pure swing...??

If the left arm is blasted off then is given an extra force prior to impact...will that increase hand speed - and perhaps more imortantly alter hands path - prior to impact resulting in more clubhead speed at impact?

Get a copy of "golf-o-metrics" - it should be part of your journey. If you want to document the perfect swing as well as all swings - as Mac O'Grady wishes to do, by all accounts - then you should at least follow his footsteps to see where he is right or wrong. The book is written by his students...it is very hard to read...makes TGM seem like kindergarten stuff:laughing9

Mac liked Norwood alot (gave him a very complimentary review on his video)...but he apparently gave Joe Norwood a copy of TGM... Mac likes both apparently...

too many "apparently" - I am such a gossip!:laughing9

GBD

Here is a graph showing the arm speed of an excellent golfer.



Note that arm speed increases after the shoulders decelerate. However, arm speed decreases prior to impact. Note that clubhead speed increases all the way to impact (slope of the clubshaft curve represents its rate of acceleration).

Let's presume that one could prevent the left arm from slowing down in this kinetic sequence by some supplementary biomechanical maneuver (eg. increasing right shoulder thrust). Would that be advantageous and increase clubhead speed at impact?

I think not - because the arms have to slow down to allow for the complete release of PA#2 and PA#3 in a swinger's action. Accelerating the left arm in the late downswing will interfere with the club's release phenomenon, and actually decrease clubhead speed into impact.

I think that the only practical method of increasing clubhead speed is to increase the speed of evolution of the entire kinetic sequence. In other words, Tiger Woods performs this entire kinetic sequence much faster than the average amateur golfer, who is skilled enough to get the kinetic sequence correct.

Where can I get a copy of golf-o-metrics?

Jeff.

Not sure about all the bursting stuff . . . . I just think the segments in the pivot go from flexion to extension . . . . it's like full lever extension of the pivot . . . extending the segments from the feet all the way through . . . extending the entire radius. Tiger blew out his knee from over-rotation not extension. Sure the shoulders rotate but I think the speed is from the fast arms and the extension . . . .

A lot of this has to do with the sequence with which this happens . . . You can get a transition like Hogan/Sergio but you can't just let the pivot pin the left arm and have it drag it over or under plane . . . .it has to go FAST to stay on the plane. The hands have to go down plane FAST. #4 releasing . ..

Cool . . . you can really see #4 releasing there.

look similar . . check the extension . . .

This is what this cat had to say about hitting . ..

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In our experience, the answer is almost certainly no … if they continue doing what 95% of the hitting world – both baseball and softball – from youth league coaches to college and professional coaches - is telling them to do. However … with dedication on the part of both the hitter and his parent or coach and an understanding of the principles and movements taught by Steve Englishbey, we have seen mediocre hitters develop swings that are pretty damn good. And we are pretty damn critical. The success stories are inside this website. We invite you to join our forum, spend some time browsing the website, and take an informed look at whether EnglishbeyHitting swing instruction might be the answer to your young athlete’s hitting aspirations.

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I agree with most of your stuff about kinetic sequence. But can I just check that I see the same things as you in that chart?

When you say the shoulders decelerate - do you mean time point green diamond?

I am not convinced that the arm rotational velocity increase much between green diamond and blue circle (time point for max arm speed)... the arm speed trace seems to plateau at about the same time as the shoulder rotation...approximately.

The thorax does increase in rotational velocity after peak pelvis rotational speed - That I do accept.

What interest me is the relative lack of vertical motion in the early DS pivot (top of BS -ie. pre red square - to green diamond) relative to the period in later DS ( green diamond to impact).

This is where the piston shoulder bit comes in I think... as i said earlier - it may be hand path that is effected most...your graph shows rotational speed...the shoulders move less in rotation in some DS segemnts and more in vertical direction it seems ...?

For Joe Norwood material i will PM (it is commercial so can not post on LBG)

not sure this would translate to golf but pretty interesting . . . maybe swing a dowel fast . . .

http://www.bigcat844.com/increasing_bat_speed.html