By philcheetham on 1/18/2010 4:43 PM

Introduction This article is meant as an introduction to the basics of measuring position in both two dimensions and three-dimensions; specifically to the golf swing.  I wrote it a while ago but would like to bring it back and then continue the idea.

Position Measurement in Two-Dimensions When we want to measure the position of something on a flat plane, say a piece of paper or the screen of a computer, we can use two perpendicular axes, one along the bottom and one along the left side of the paper. Lets give each of these lines a name, lets call the bottom one the X-axis and the one on the left side the Y-axis. These two lines join at the bottom left corner of the paper and we call this point the origin or (0, 0). It is zero feet along the X-axis and zero feet along the Y-axis. To place a point on the paper we can simply measure a specific distance along the X-axis and a specific distance along the Y-axis and write is as: (x, y). These two numbers completely define a point anywhere on our piece...

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By philcheetham on 12/12/2009 4:42 PM

I am currently working with an LPGA player to improve her efficiency in the kinematic sequence and get her more swing speed.  Remember that the kinematic sequence is the graph of turning speed of pelvis (red), thorax (green), arm (blue) and club (brown).  It is measured in degrees/second along the vertical axis and shows time through the swing along the horizontal axis.  (Check my earlier blog articles for more detail or amm3d.com).  After capturing her swing with the AMM3D golf motion capture system, I analyzed it with the TPI 3D biomechanics report.  Below is the graph of her kinematic sequence with a driver.  There are many “expert” characteristics in the graph; transition order is good, peaking order is good, accelerations and decelerations generally look good too.

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By philcheetham on 11/26/2009 11:43 AM

An article I did earlier this year on where in the downswing the pelvis rotation speed peaks and then decelerates.  The interesting this is how early it happens.



The Kinematic Sequence is an indicator of swing efficiency and speed. If you look at just the downswing phase of the swing (the center section) the graph above displays how fast you turn or swing each part of your body for about 0.25 seconds before impact. During the downswing each part accelerates then decelerates in a smooth and sequential order. In an...

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By philcheetham on 11/23/2009 5:55 PM

I recently captured the swings of a young female playing professional on the AMM3D golf full-body motion capture system using TPI 3D analysis. She had some issues with the kinematic sequence peaking order, it was not optimal; her thorax was peaking before her pelvis. I noticed from the graphs that she had both a little excessive sway in the backswing and a reverse spine angle at the top. After the analysis we worked on some real-time biofeedback; we set it so if she swayed more than an inch the computer would beep; after about 15mins of practice we again captured her swing. She was able to maintain stability without swaying; she also stopped the reverse spine action. Look what happened to the peaking order of her kinematic sequence; perfect!  She and her coach were both thrilled. Check out the kinematic sequence graphs below.

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By philcheetham on 11/19/2009 11:38 AM

This article is a very good introduction to the Kinematic Sequence.  It discusses the downswing, the transition and gives a few examples.



In sports such as golf that need to create maximal speed of a distal segment or implement (club, bat, racket etc.), it is generally found through motion analysis techniques, that there is a precisely timed sequence of body segment motions progressing from the proximal (inner), large segments to the distal (outer), smaller segments. In the biomechanics literature this is often called "proximal-to-distal-sequencing", "kinetic linking" or the...

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By philcheetham on 11/19/2009 11:37 AM

Welcome to my first post on my new blog.  This blog will post to several different places, AMM3D website, and Blogger being the first two.  I will discuss topics related to AMM3D motion analysis, TPI 3D golf swing biomechanics, the kinematic sequence, the body-swing connection and real-time biofeedback training.