Double Pendulum Model

It has been said that, “Few sports provide as many physics problems as the game of golf."   When physicists study the golf swing they use the double pendulum as a model.  This model has been used extensively in determining the effect of various alterations on the club head speed.  The two pendulums are in tandem, with the top pendulum representing shoulders and arms and the second pendulum beginning at wrists involving the hands and club.

Thinking of the golf swing as a double pendulum may help golfers better understand the swing.  If you were swinging a double pendulum you would rapidly learn you could not “hit” the ball.  You would learn that you would have to use hips and body and delay the swinging of your arms so the second pendulum could “catch up” to the first and be ready to snap or release at the proper time.  The top pendulum represents the shoulders and upper arms the second pendulum is the wrists and club.

Golf Swing Photos

female golfer

 

female golfer

 

female golfer

Top of swing, weight on right leg, and hips turned away from ball, wrists fully cocked.

 

One-half way through down swing, weight switching to left side, hips turning and weight shifting to left side.

 

Impact, wrists uncocked, weight on left foot, hips turned to left, and obvious pulling with left arm and upper body pulling against lower body and centrifugal force of club head.

 

 

 

 

 

Follow through, obvious pulling on club with upper body, completely turned with weight on stiff left leg and circle is complete.

male golfer

 

male golfer

Top of swing, weight on right foot, hips turned away from ball, wrists fully cocked.

 

Hips turning and weight shifting to left side, wrists cocked.
 

male golfer

 

male golfer

Weight shifting to left side, hips turned to left side and wrists uncocking illustrating upper body working against lower body.

 

Impact, weight entirely on left side, hips entirely turned, stiff left arm pulling on club, wrists uncocked, again illustrating upper body pulling against lower body.


Baseball swing

The forces in the baseball swing and the golf swing are almost identical.  The advantages of studying the baseball swing are that the forces are more exaggerated and thus easier to see.

  understanding golf swing

This illustrates how similar the golf swing and baseball swing are.  His position is that of a golfer completing his swing. 

  Tiger at impact.

The difference is that in baseball the ball is moving and in golf the ball is fixed.  The swing in baseball starts with the bar over the shoulder so there is no back swing.  The baseball swing illustrates how baseball hitters “step into the ball.”   This action is just as important in the golf swing but is referred to as “getting to left side.”

baseball swing

 

baseball swing

 

baseball swing

Right leg lifted and ready to "post," step into ball.  

Impact, weight is on right leg, hips turned and upper body pulling against right leg and centrifugal force of bat.

  End of swing illustrates strong pull against centrifugal force of bat and weight on stiff left leg.  You can see the pull.


Complete Baseball Swing

baseball swing

 

baseball swing

 

baseball swing

Left handed batter posting, with left foot elevated and ready to step into the ball.

 

Ready for the pitch, weight on right foot, entire body twisted back.

 

Beginning to unwind with weight shifting, hips turning and bat coming around.
 

baseball swing

 

baseball swing

  baseball swing
Weight getting to left  foot and hips turning.   Everything coming around to left side just prior to impact.  

Impact complete, still pulling against weight on left foot and centrifugal force of bat.  Swing complete, still pulling against club head and weight on left foot.

From the Complete Book of Hitting, False, and Fixes, Contemporary Books

What Not to Do During a Swing

 

       

baseball swing

This illustrates what not to do.  Although weight has shifted, left leg is not stiff so it cannot provide a post or axis to rotate around.  Results is a weak swing, with no pull and no power.  Appears to be "hitting" and is all arms, like a girl throwing a ball.

Contact O'Tar Norwood with your thoughts and opinions:  otar@understandingthegolfswing.com

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