January 20, 2019- by Steven E. Greer, MD
Along with the advent of modern golf analysis technology is the downside of data overload. What do we do with all of that TrackMan and Boditrak data? How can 3D images of the golfer’s swing help them play better?
Bryson DeChambeau is best known for his unusual swing that he devised based on his theories of physics as they apply to the golf swing. He was a physics major. Is he winning because of his physics theories or despite them?
Sasho MacKenzie (see video at top) is a well-respected Sports Biomechanics professor in Canada. He earned his PhD from The University of Saskatchewan and teaches at St. Francis Xavier University. He calls himself “doctor”, much like Dr. Phil. He too uses physics to explain the golf swing. Are his theories of cause and effect with the golf swing valid? Has he tested them in a scientific manner? Is he appropriately applying the right formulas?
The YouTube algorithms must have thought that I would want to see a Sasho MacKenzie video. I watched one and immediately spotted a common problem that even most medical doctors are guilty of doing. He was making conclusory statements about cause and effect, then backing them up with fancy physics formulas. The data he is collecting from all of his gadgets are leading him astray, in my opinion.
Let us step back for a moment. Who am I and why should anyone believe what I have to say?
As a pre-med student, I took advanced chemistry and physics. I got straight A’s in Physics.
As a student of biology and human medicine, I am also aware that mathematical formulas are rarely used by medical researchers (I spent several years in different medical research labs from Ohio State to Michael Longaker’s respected lab at NYU. He now runs the surgery research efforts at Stanford. During that time, I was awarded large government grants for my clinical trials on wound healing). Medical research requires basic math, of course, but it is not an endeavor to prove a formula correct. Mathematicians and physicists prove formulas.
However, biology cannot be predicted by formulas. Even the study of genetics, where one would think that formulas would apply, defies formulas. The only way to investigate biology is to use the scientific method to experiment, see what works or fails, and then move forward, inch by inch. Most of the advances in medicine have been the result of accidents or unforeseen outcomes.
Now, let us get back to the application of technology and data collection to swing theories based on physics.
The reason that simple physics cannot predict or explain most aspects of the golf swing is that our bodies are highly complex and biological. Our musculoskeletal systems are comprised of different types of muscle fibers and amazingly dynamic joints.
All of that is controlled by our brains and spinal cords. We are all born with the ability to swing a golf club because we have a vestibular system in the brainstem and a cerebellum. Our exquisitely sensitive inner ears and eyes give balance and visual input into that super computer allowing our bodies to make elaborate motions while maintaining a steady head. That vestibular system was a crucial part of evolution to allow vertebrates capture prey and hunt (Watch video of birds keeping heads still as they hunt).
Modern robots from Boston Dynamics can do back flips. But they are controlled by simple computer code formulas, relative to our brains, and have simple joints, compared to our musculoskeletal system. They might look like a human at first glance, but the day when we have robots that can fool us as being human, such as in HBO’s Westworld, is far far away.
No robot has been devised that can swing like a human. When one is made, it will achieve a swing using mechanisms different from human golfers.
Regarding Bryson DeChambeau, I would argue that he plays well despite his quirky same-length irons and “one plane” swing. He clearly has a good vestibular system and strength enough to win the 2018 PGA Championship Long Drive competition. Admittedly, I have no data to support my hunch. It just seems intuitive to me that his short game suffers from having 7-iron shafts.
Regarding Sasho MacKenzie, I do have some facts to support my argument that he is wrong in his theories of physics as they apply to case and effect in the swing. However, I should clarify that I have never met the man and have seen a grand total of one of his videos.
In the video, he explains that a longer backswing with a longer downswing leads to “more work on the club”, which leads to faster clubhead speed at impact. However, that is wrong. Work is the wrong parameter to measure and think about.
Work does not have to translate into speed. But Sasho, and apparently the entire golf instruction community that he has misled, thinks that the two parameters, work and speed, are one in the same.
To illustrate this point, for examples, one can bench press 300-lbs for many repetitions and do a great deal of work. But they develop almost no speed. In contrast, a single punch into a boxing bag will generate good fist speed at impact with a fraction of the work that it took to bench press. One can swing a club underwater, put in more work to the club than above ground on dry land, and yet achieve very slow clubhead speeds. In real golf scenarios, one can be wearing many layers clothes in cold weather, which requires more work to produce a swing, and yet have slower clubhead speeds.
The typical bad golfer puts a tremendous amount of work into their swing and yet develops slow clubhead speed of under 100-mph. They even look like they are working hard. It is painful to watch. They chop wood rather then elegantly swing a club.
Work does not translate into speed unless it is efficiently converted into force on the ball. Most golfers dissipate the energy and lose speed when the left arm is horizontal. “Golf Scientists” are making huge errors by assuming that work is converted into speed.
If longer backswings generating more work meant, by definition of simplistic physics equations, that the end result of clubhead speed at impact would be greater, then how does one explain the tour-leading distances from players with only 3/4-length abbreviated swings, such as John Rahm, J.B. Holmes, or Tony Finau?
Rather than work, force is the proper physics term to focus on with the swing. Force equals mass times acceleration. If Justin Thomas, at 5’10” and 145-lbs, can swing the club fast, he can apply the same force to the ball as 6’4” Dustin Johnson. However, most women on the LPGA could out-bench-press Justin and create more work.
In the Sasho video, he also explains that the average force applied in the downswing, times the length of the hand path, is the work that one puts into the swing. This is misguided for two reasons.
First, the average force of the downswing is meaningless because it is so misleading and variable from player to player. Most of the acceleration of the club and, therefore, the force created on the ball, is generated in the last two or three-feet of the clubhead. It is the acute angle between the left forearm and the club shaft that causes this acceleration when the angle is released and the right arm throws the grip like skipping a stone across water.
The work applied to the club prior to this acceleration is mostly ineffective. It is a placeholder, time filler, before the wrist whiplash at the bottom. The average work generated by the total downswing is not meaningful. In fact, the best swings have slow transitions and initial downswings.
The big backswings seen from John Daly, Freddie Couples, or Ernie Els help those players have a good tempo and transfer weight to the left side. They are not getting their acceleration from the first half of the swing.
Also, the top of the swing is the danger zone, as I call it, for most golfers because humans want to start swinging as fast as they can from the very beginning. If the golfer applies too much acceleration too soon, the wrist angle will release and the acceleration will dissipate before the club gets to the ball. Also, the centripetal and centrifugal forces of the club will pull the golfer to the right, move the head, disrupt the vestibular system, and then result in catastrophic fat or thin shots.
One key physics principal that is relevant to the swing are these centripetal and centrifugal forces of the club. They are powerful and will move the body all over the place, lifting the spine-axis, pulling players to their right. The best players have learned to “tame the shaft”, as I call it. They do this by using the wrists to get the club shaft into a very flat downward plane. This way, the force vectors are not pushing upward on the shoulders as much and the player can turn rather than lift up.
Many athletic golfers can have only a ¾ abbreviated backswing and still generate enough acceleration to be PGA Tour driving leader. As mentioned above, J.B. Holmes, Tony Finau, and Jon Rahm are three great examples. I have recently adopted this style as well to avoid the danger zone of a full backswing.
It is true that Long Drive champions have huge backswings. But they are also atrocious golfers who are lucky to hit a single drive in play with 10-attempts. They lose their center of gravity by swinging too hard too soon.
I would argue that the ideal swing requires the least amount of work as possible while maximizing the force transferred into the ball. If a player can achieve the same clubhead speed with a ¾ swing as they do with a lazy long Ernie Els swing, then they should strive for the shorter swing.
I spoke with “Doctor” Sasho via email. He replied arrogantly, “I’m struggling to follow your logic. If you would like to brush up on your understanding of physics as it relates to the golf swing, then please take a look at my free videos on Vimeo.” He then provided this fancy looking “scientific” chart stating, “You might want to start with the one on work and energy. The graph below is from a current study I’m writing-up for publication. It was part of my keynote presentation at the World Scientific Congress of Golf this summer. The total work done on the club by the golfer perfectly predicts clubhead speed….as would be expected by theory.”
That smug reply exposes him for being too unaware of real science to even know that he is unaware. No experiment ever perfectly validates what a researcher “predicted” unless the researcher is conducting junk science experiments flawed by bias.
I asked him for the abstract of this paper so that I could learn his methods. He refused.
How did he measure “work”? Did he have pressure sensors on the arms and body? Did he measure the weight of the arms and torsos? That would seem to be impossible. His most important endpoint in this paper, which is work, is likely just estimated by equations using speed. That method would be fraught with error. The only way to measure true work of a golfer would be to somehow place them into a robotic swing harness and measure the resistance.
Sasho MacKenzie’s list of publications are in junk science journals. The World Scientific Congress of Golf is just a bunch of snake oil salesmen.
What Sasho did not realize is that I have been a Wall Street financial analyst and portfolio in the biotech and medical device space for 20-years. It is my job to forensically analyze clinical trial data and spot how the companies have misled the FDA with inappropriate methods and statistical analysis. I spot junk science. These “golf doctors”, such as Sasho, have shady PhDs and are not doctors. They publish in small junk science journals to give the appearance of peer review.
Most golf instructors who use this modern swing analysis technology commit systematic error of bias (often by sampling and measurement bias), if they even conduct an “experiment” at all. In most cases, the instructor convinces himself that he is right and then reverse-engineers the rationale using misapplied formulas. They inappropriately apply simple physics concepts to the complex biological human swing.
Having said all of the above as a cautionary prelude, modern swing analysis technology is great, if properly used. For club fitting, this new technology is most useful. We can now fine tune driver shafts, etc. to deliver the right spin and launch angles.
If a teacher can diagnose swing ailments with new technology in ways not otherwise seen by the eye, then they might be able to prescribe a remedy. But therein lies the biggest problem in golf instruction. Very few teachers can prescribe a remedy. They stand back for an hour, mutter a few words of wisdom, and only diagnose the problem.
Because they do not understand the neurology involved in the swing, they often misdiagnose symptoms as underlying root causes. It would be like going to the doctor, being told you have a fever, and receiving only Tylenol but no antibiotics. The infection will spread.
The fact is that some of the greatest golfers ever to play, such as Ben Hogan and Bobby Jones, lived many decades ago. They had none of this technology. They rarely even saw their own swing. Yet they managed to understand the important swing fundamentals. Without realizing it, they were analyzing their brain circuity and devising mental images to trigger the autopilot vestibular system we all are born with.
My concern is that there is now a misuse of technology. It has developed a mistrust of golfers toward lessons. Many top golfers, such as Bubba Watson and Xander Schauffele, are afraid to ever use a swing coach because they instinctively know that there are too many false prophets out there, like Sasho MacKenzie.
Technology in the wrongs hands is not good for golf. Instructors need to understand that the body is not a robot easily explained by engineering and physics. The human golf swing is fluid, dynamic, and controlled by autopilot neurocircuitry.