Changing the Kinematic Sequence with Biofeedback Drills

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.

Although she transitions in the correct order; pelvis, thorax, arm, club; you can see that she pauses with her hips before transition (the red curve flattens out), also her transition period is too long, there is minimal downswing loading of any joint and her turning speeds are fanning early in the downswing.  This pause really limits the speed contribution of the “stretch-shorten cycle” of the muscles.  In and ideal stretch-shorten cycle there should be virtually no time between the eccentric/concentric contraction phases of the muscle; this “amortization” phase or pause should be as short as possible.  The lack of downswing joint loading means she is leaving a lot of power on the table and the fanning of the curves means that the relative speed between the body segments is increasing, reducing the amount of force that can be produced in each muscle; (see my article on amm3d.com regarding Riding, Stretching, Fanning, I’ll post it soon on this blog too).

So while she was still in the AMM3D system we began using real-time audio biofeedback to see if we could change the sequence and teach her not to pause at the top; hence allowing the smooth acceleration into and out of transition and improving the stretch-shorten cycle.  We set the audio tone to sound if she achieved a good core stretch at the beginning of downswing and worked on half backswing drills.  Very quickly she was able to coordinate her downswing loading (aka “X-Factor Stretch”) and the curves became smoother before and after transition.  We also saw that thorax, arm and shaft “rode” up together (good energy transfer); however, her total transition time was still very long.  This means that the drill was definitely successful but that we still need to work on lessening the transition time from about 0.17 seconds to about 0.8 seconds.  This will require a combination of half swing drills and strengthening of the core muscles so they can support fast pelvis firing without leaving the thorax behind.  Check out the kinematic sequence graph below, this is from one of the half swing drills. 

Drills can definitely change the kinematic sequence very quickly, but conditioning exercises will also need to be done in the gym to support the change.  The trick will be to transfer this to the full swing.