SECOND EDITION
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www.JACOBS3D.com
FOREWORD AND CONTRIBUTIONS FROM DR. STEVEN NESBIT
Copyright © 2020 by Michael Jacobs All Rights Reserved. This book or any portion thereof may not be reproduced or used in any manner whatsoever without the express written permission of the publisher, except for the use of brief quotations in a review. Printed in the United States of America First Printing, 2016 Second Edition, 2021 ISBN 9798714463303 Independently Published RSB Golf Inc. 105 Clancy Road Manorville, NY 11949 www.jacobs3D.com Second Edition designed by Keri Ello Reiter
DEDICATION
THIS BOOK IS DEDICATED TO DR. STEVEN NESBIT For his belief in my hard work and relentless desire to design a swing analysis system that connects his scientific discoveries to the world of golf. For the past nine years, we have put the mechanical meaning of the golf swing under a microscope, and his patience and open-mindedness have allowed me to take a journey that no other golf professional has been on before.
FOREWORD
Dr. Steven Nesbit
Right now, a golf instructor could spend around $100,000 and within a few weeks have a studio filled with motion capture and force measurement equipment that would have been the envy of any university mechanical engineering department in the country just a few years ago. That’s truly an amazing development.
Go back a little farther, to 1991, and information on what a golfer and the club really does during the swing—and the equipment to measure it—just didn’t exist. The USGA meant to change that, and they came to Lafayette College for some help with a project to draw computer models for golf clubs. They wanted to find out exactly what clubs contributed to distance—the first step in coming up with distance parameters in the game. I was relatively new to Lafayette at the time,and it was a project that the rest of the department didn’t think was that exciting. So it fell to me to meet with Frank Thomas of the USGA and come up with a solution. It was a subject that aligned very well with my expertise, in robotics, and one that I had a scientist’s interest in. The concept of biomechanics in golf was out there, but there hadn’t been much beyond the basics published about it—clubhead speed, how long impact
lasted. I could see there was room for some interesting research. Right before I made the trip to Far Hills, N.J. for the meeting with Frank, I saw a presentation from a friend of mine in the software business on a brand new motion capture system designed to analyze human motion. The concept of three-dimensional dynamics was fascinating to me, and it gave me an idea. When Frank and I met, I told him we could measure what happened with the club, but the technology now existed to biomechanically model the entire golfer—club included. We could figure out what was happening inside the swing in terms of motion, force and torque. Frank was one of the most open-minded scientists I had ever met. I was asking him to undertake a much more ambitious—and expensive—project than he had planned, on something that had never been tried before. By the time the meeting was over, we had a plan. Over the next several years, I used my background in robotics to devise what would become the USGA’s digital swing model—a comprehensive study of the three-dimensional dynamics of the body and club. We developed a database of kinetic and kinematic parameters, and Frank and the USGA were able to use that information in support of a new generation of equipment rules. The USGA research turned into my first two published papers on the golf swing, and I was able to get a grant at Lafayette to build my own motion analysis system. From there, I could study not only the golf swing, but also the movements from other sports like softball and tennis. What the motion analysis system and research has allowed us to do is look beyond what movements a person is making and study what actually makes them move. The golf swing is obviously very complicated—just like a serve is in tennis—but the method of analysis isn’t complicated. It is the fundamentals of mechanics, applied to the motion within the sport. When I started this research, I came in without any background in golf as a player or an instruc-
FOREWORD
tor. I had some sentimentality about the sport because it was important to my father, but I didn’t have any prejudice about what should happen, or a preconceived notion about what to expect. When I handed Frank Thomas the original results at the USGA and explained to him that the hub path— the route the nexus between the hands and handle of the club takes during the swing—wasn’t circular, he was ready to string me up. It went against what everybody had assumed about the golf swing for years—that the path was circular enough to call the radius pretty much constant throughout. I was just reporting what the physics told me. The information I collected and the research I did wasn’t any secret. It was out there for anybody to see and build upon. But Michael Jacobs and Brian Manzella were the first ones to come up to Lafayette to really try to understand it from the golf instructor’s perspective. Mike came into my office the first time with a notebook overflowing with printouts of all my articles. They were outlined, highlighted and full of questions. It was amazing, the level of study he had done. And from the questions he asked, it was clear he was deeply interested in not just the practical application of the information, but the quantitative side—what do the numbers mean, and how do you get to them? And on the other side of the equation, it was fascinating to learn from Mike the context of the kinematic fundamentals I had been researching. Looking at the data, I could make an observation that torque was really increasing at a certain point in the motion, and Mike could tie it into what was physically happening in the swing and how it was meaningful. I was excited to work on this project with Mike because so many people both inside and outside academia think that research papers get published and just sit on a shelf somewhere. This was an opportunity to show through Mike’s 3D software that the information we had been collecting and organizing had a practical application for golf instruction. And that’s what The Elements of the Swing (and Jacobs 3D) does. It gives any player or teacher the true “what” and “why” of the movement of the club in the swing. One of the first questions I get about kinetics
and kinematics related to a specific sport is about what the “optimum” motion is. Everybody wants to know how to do it perfectly. The answer might not be satisfying for a player or teacher, but it’s turned out to be a fascinating one for those of us interested in the science. The kinematics, kinetics and mechanics tell us that there isn’t one thing or one answer to it all. It’s complex, and the “answer” is many things, wrapped up together. Why is it that some small people with less obvious muscle power can produce more club- head speed than some large, strong people? It’s about energy, and how much energy you can put into the club with your body. The average person can produce more than enough energy to hit the ball a long way. But the people who hit it far are able to transfer more of that energy into the ball. They do it more efficiently, and more effectively. That’s part of what makes the Elements of the Swing—and Mike’s project in general—so interesting. He’s determined to use the science and research to start answering those how and why questions for every golfer—questions we’ve only been able to guess about before. It’s a fascinating road, and we’re just at the beginning of it. Soon, you’ll be able to look at the output from Mike’s software and see not just what’s happening to the club but what every individual joint and muscle group in the body is doing to contribute. Mike is right out in front with this—in the hardware it takes to build the best studio, the software to pull the data together and analysis on top of it. He’s driven, and he’s motivated to stay out front—a motivation I wish all my students at Lafayette had. They’re all gifted, but that’s meaningless without the drive and the desire to know more. Mike is never satisfied with what he knows at the moment. To me, that’s one of the highest compliments you can pay somebody in this field, and he unquestionably deserves it. It’s a pleasure to work on this project, and I hope you enjoy diving into the Elements of the Swing as much I enjoyed helping Mike with its construction.
INTRODUCTION
The Elements of the Swing
For more than 20 years, I’ve been looking for the “truth” behind the golf swing. More than just knowing how the best players move the club, I wanted to know why certain combinations of motions work better than others. Over the years, golfers have assembled a huge body of knowledge on the swing, and passing pieces of that information from mentor to student has been the main way we learn to play golf. I think there’s an important place for that mentoring, but it doesn’t mean we should stop there. We’re in the most exciting era in the history of golf instruction right now. Any full-time teacher with the desire (and funds) to invest some time, energy and resources into his or her craft can assemble a teaching studio more technologically advanced than anyone could have dreamed 20 years ago. Even if you leave aside technological leaps like the GEARS optical motion capture system, TrackMan and force plates—virtually all of us in the teaching business carry a device in our pockets that can do more than any teacher had at his or her disposal even in 1990. With an iPhone, I can record a student’s swing in regular speed and slow motion, use an app to mark it up and text it to him or her before we’re even done with the lesson. And we’re just scratching the surface of what the phone can do. But all the technology in the world doesn’t mean anything—and doesn’t help teachers and players get better—if the underlying swing theories behind it aren’t sound or are incomplete. Those theories need to be facts. I can use my GEARS optical motion capture
system to measure an amazing array of movements, and see in great detail how or what the right arm or the hips or the clubhead does during Rickie Fowler’s swing and compare it to Joe Hacker’s. GEARS now shows a functional skeleton, so it’s possible to see what individual segments are doing during the swing. Measuring movement is great, but what makes those movements happen? And what combination of movements is ideal for a given player? That’s where my software program Jacobs 3D comes in.
KINETICS VS. KINEMATICS Golf technology has gotten very good at measuring the kinematics—or movement—within a swing. We know how far the clubhead travels from address to the top of the backswing and down through impact. We can measure things like “turn” and “sway” and “swing plane.” TrackMan tells you an amazing amount of detailed information about how the club and the ball move. You can clip a small sensor onto your clubs, go play a round and come back with impressively accurate club head speed and distance measurements. You can think of kinematics as the speed and acceleration of that car going by you on the road in front of your house. But knowing how fast the car goes and how much it is speeding up (or slowing down) doesn’t tell you anything about what is making the car go. It doesn’t reveal anything about the engine under the hood. Kinetics is the study of force—what creates movement. In a golf swing, it’s useful to know what direction and how fast the club is moving. But what if you could identify the actual forces and torques that produce that movement? You could move back one step in the chain and learn from the source, instead of responding to a reaction several steps down the line. With Jacobs 3D, we can now identify and measure those forces and torques.
INTRODUCTION
WHAT IS JACOBS 3D? Every iteration of golf technology has pushed the boundaries of what we can measure in the swing. In my studio, I’ve worked my way up from radar to launch monitors, force plates, balance plates, pressure insoles and up to optical motion capture with the GEARS system. Each of those technological advancements had their merits, and offered a few pieces to the puzzle. But none of them brought it all together and gave me the answers I was looking for—even after consulting with some of the preeminent minds in the worlds of biomechanics and golf science. With the help of my good friend Michael Neff at GEARS Golf, I installed an upgraded Research and Development model of the GEARS system in my studio seven years ago. Using the data from that system and Optitracks as a jumping-off point, I started working with Dr. Steven Nesbit at Lafayette College to develop my own swing analysis software. Dr. Nesbit is the leading expert in bioengineering—the use of engineering principles in human applications—and was the lead scientist on the most comprehensive scientific study of the relationship between the human body and golf swing ever undertaken. Working on the team established by Frank Thomas at the USGA, Dr. Nesbit patented a system for the three-dimensional analysis of the golf swing that is to this day the industry standard. After spending years studying Dr. Nesbit’s three-dimensional analysis protocol, I approached him with the concept of Jacobs 3D. With Dr. Nesbit’s expertise in bioengineering and software design, he was able to create the algorithms to crunch the data and piece together a user-friendly software that finally answered the questions I had been posing all those years. For the first time, we can “look under the hood” of any student and understand not just the what, but the how and why of the swing. And more importantly, we can use that information to optimize a player’s swing more quickly and more thoroughly than ever before. In basic terms, Jacobs 3D shows the club’s movement through the swing and the forces and torques acting on that movement.
This information lets golfers focus their attention on techniques that actually change the way they force and torque the club. If some- thing a player is doing (or not doing) doesn’t impact those torques or forces in the desired way, that movement (or lack of it) isn’t contributing to the efficiency of the swing.
WHAT DOES IT MEASURE? Phase One of Jacobs 3D measures more than 115 “parameters” during the swing. These range from “standard” measurements you’ve heard before—like alpha, beta and gamma swing torques— to some new fundamentals I believe will become a basic part of golf instruction in the 21st century, like the hub path, center of curvature and the Relative Swing Plane. In this book, I’ll explain each of the fundamentals and what they mean for the swing, and offer a collection of swing “templates”—with their Jacobs 3D “fingerprint.” Teachers and players will be able to have a common language and understanding of the forces in the swing and what differentiates players of different power and skill levels. We now have the equivalent of a CT scan for the golf swing. To give two basic examples, think about what you know about how the club should line up through impact. Conventional teaching—and even biomechanical study—has long said that the centrifugal force of the swing acts on its own to extend the club through impact. Or, consider the movement of the club through transition. Do good players throw the club head immediately from the top? Do they start to “hold” or “create” lag? How many arguments have you read on the internet about those subjects, where well meaning teachers have used everything from personal experience to video to still photographs to prove or disprove some point? Now, we have quantifiable data that answers those questions and more.
THE ELEMENTS OF THE SWING
the studios of Ambassadors worldwide. But even though an ambassador location is the only place you can get your swing captured and then analyzed through Jacobs 3D, the overall concepts revealed through measuring hundreds of As good as technology has gotten over the last swings are too important to hide away and save for 20 years, teachers have still been guessing about a those who make the trip to our studios. lot of the things happening in a swing. And we’ve This manual will cover the basics of the Jabeen guessing about the exact movements and sequences of movements that separate good players cobs 3D Convention—the definitions and paramfrom great players and players who hit it 280 vs. 310. eters used within the software to provide the most With Jacobs 3D, we don’t have to guess anymore. complete dissection of a golf swing available today. The book will describe these parameters, what they So much of golf instruction is trial and error now—adjusting this knob and seeing what happens, mean and how they work together. It will also dethen tweaking another lever over here. With Jacobs scribe a new way of looking at the age-old concept of “swing plane,” but this time with the full weight 3D—and some basic training on how to interpret of mechanical research behind it. This Relative the fundamentals—teachers will have the ability to see problems and solutions much more quickly, and Swing Plane—the relationship between how the hub path and the clubhead path move—is one of to optimize a player in a fraction of the time. The practical application of this information to the most exciting new developments in golf instruction since the advent of drawing lines on video. make players better faster is my primary goal with With a basic understanding of what Jacobs 3D Jacobs 3D, but I also have an important secondary measures and how the parameters equate to the motivation in this process. movement of the club, any teacher or player will As the world of teaching evolves and changes gain a new understanding about the true causes with new ideas and new technology, those of us and effects in a golf swing. Not only will you be able interested in learning and teaching at the highto achieve that understanding without owning the est level can get there faster if we can agree on software—you’ll be able to get it with the naked eye a common “teaching language.” If you and I are and a half dozen swings on the range. arguing about the definition of angular and linear And better yet, if you get to the end and find movement in a swing, we’re wasting time we could yourself wanting more, don’t worry. It’s here, The be spending solving the real swing problems our Science of the Golf Swing, with complete descripstudents have. tions of every Jacobs 3D parameter is also available With Jacobs 3D, the hope is that the analysis for teachers and other dedicated swing enthusiasts. that comes from the software will help move us It really is the dawn of a new age in golf intoward a unified conversational convention—that struction. common teaching language. At the top levels of teaching, we should be able to talk about alpha, beta and gamma torques or the hub path the way MICHAEL JACOBS 15-handicappers talk about slices and hooks at the Top 50 Golf Teacher in America Golf Digest 2017 – Present driving range.
WHAT DOES JACOBS 3D MEAN FOR TEACHERS AND PLAYERS?
WHAT DOES THIS MANUAL DO, AND HOW SHOULD YOU USE IT?
Top 100 Golf Teacher in America
Jacobs 3D isn’t conventional software in the sense that you can buy it and run it on your own computer. The software is used exclusively in the teaching studio at Jacobs 3D Headquarters and at
PGA Teacher of the Year
Golf Magazine 2016 – Present
Best Young Golf Teacher in America Golf Digest 2017
Metropolitan Section 2012
PGA Horton Smith Award Metropolitan Section 2020
CHAPTER 1
Forces & Torques
Remember the car analogy we were talking about in the introduction? There’s a reason why I used it. When you’re watching a NASCAR race, it’s all right in front of you. All the cars start in a pack, and they go around a track over and over again, changing positions, accelerating and slowing down. Sometimes they crash into each other—or the wall— and at the end, one car goes over the finish line first. With photography, video and now 3D motion capture, we’ve spent more than 150 years watching golf swings like fans watch a car race on television or in the stands. How do the positions change? How does one piece look compared to the other? How fast does everything go? Let’s go back to the racecar garage and see how they put those cars together and you will get a different understanding of what makes certain teams win races and others stay at the back of the pack. The drivers are important, but the crews also have an incredible understanding of what goes on under the hood, and what makes that car accelerate, turn and stop. The terms they use—force and torque—are tremendously important in the world of high performance. In the simplest terms, a force is a push or a pull that causes that an object to move and a torque is a
twist that causes an object to rotate. As you’re about to discover, those terms are just as important in golf. With Jacobs 3D, we can now describe golfers and golf swings much like the way NASCAR engineers measure racecar performance. We can measure kinematic information with our optical 3D motion capture system—how the club and body move, and how fast. And for the first time in a golf lesson setting, we can take that positional data and calcuate a swing’s kinetic performance. It’s why the club moved in a certain way. 3D OPTICAL MOTION CAPTURE With eight cameras capturing the movement of 34 markers on golfer and club we can track the position and movements of the player. Based on that positional data and the path the markers move on, we can study the forces that produced those movements.
The basic camera on an iPhone and a $10 swing analysis app can show the change in a clubhead’s position from address to the top of the backswing and then down to impact. That’s like using a stop watch to keep track of how long it takes Jimmie Johnson’s car to make a lap around the Talladega Super Speedway. The kinetic outputs from Jacobs 3D show what forces and torques create those movements. Why is this important? Because body and club movements aren’t important for their own sake. Doing something with your body or the club— swinging “from the ground up,” or “lagging it” or “pivoting” or “transferring your weight” or “bracing your left side” only matters if you’re actually changing the way the club moves through space, and the
CHAPTER 1
energy it transfers to the ball. Until now, we could only guess at what kinds of forces and combinations of torque would change those club movements and energy transfer. In a way, we’ve been teaching backward all these years. We’ve been trying to get people to change and “improve” their movements to try to get the club to do something different to the ball. But that’s like telling Jimmie Johnson to steer the car a different way to make it win a race. Steering is part of the equation, and steering completely wrong will cause a crash. But if you don’t understand how to make the engine work at peak efficiency and the relationship between the car’s performance and how the steering system works, you aren’t even scratching the surface of true peak performance. It’s time to go deeper, beyond what your swing looks like. Let’s talk about the engine. We’ll start with the equations Isaac Newton came up with more than 300 years ago—one for linear motion and one for rotational motion: Force = Mass x Acceleration Torque = Inertia x Angular Acceleration What You’re Doing = What You Feel x What You See We’re going to get into what those terms actually mean in a golf swing, but at the most basic level, the two elements on the right side of each equation are the resistance (mass and inertia— what you feel) and what you see happening (acceleration and angular acceleration). Acceleration is the rate of change in an object’s velocity. To create this change in velocity, something has to influence an object to overcome its own mass (for linear movement) and moment of inertia (for rotational movement). For linear motion, that influence is a force. For rotational motion, that influence is a torque. You’ve almost certainly heard those terms before, but probably not in the golf sense. Let’s break them down. What is force, besides something Luke Skywalker is supposed to use? And what is torque, oth-
er than one of those numbers car companies use to brag about an engine? A force has both magnitude and direction and when unopposed will change the motion of an object. A great example of a force is something like pushing a car that is out of gas down the road. Just as a force is a pull or a push, a torque is the twisting of an object. Turning a door knob or tightening a bolt with a wrench are great exmples of torquing an object. When you twist a door knob to the right with your right hand your thumb works up while your fingers work down. When you twist the door knob to the left the opposite happens and your thumb works down and your fingers work up. The magnitude of the twist determines if you’re turning the knob slowly (as if you’re trying to sneak out), or hard (as if you’re angry and trying to leave!), or anything in between. You can categorize the movement of the club during the swing into two varieties—linear and angular movement. Imagine holding the club out in front of you, with the shaft standing straight up. If you push the whole club out from your chest and pull it back toward you without letting it turn or twist, that’s linear movement. If you turn or twist the club, that’s angular movement. How a player combines those forces and torques determines how the club moves during a golf swing. In order to understand these forces and torques and how they’re operating during a swing, you have to have a system to define and measure them. In the early 1990s, Frank Thomas of the USGA commissioned Dr. Steve Nesbit to figure out what a player’s physical contribution was to the swing. Steve describes some of that adventure in his foreword to this book. As Dr. Nesbit mentioned in the foreword, one of the most important findings in his research was the path the hub takes during a golf swing and how that is intertwined with the forces and torques applied by the golfer. In Chapter 2 we will discuss the hub in detail but let’s define it here: The hub is center point of where the golfer grasps the club. All the movements of the body culminate at this hub which is
FORCES & TORQUES
where the golfer applies his or her linear forces and rotational torques to the club. Let’s start with the linear force. It is the dominant action on the club and it changes direction and magnitude throughout the swing. During the downswing, the force begins outside the path of the hub and then changes direction to point toward the golfer by impact. As the velocity of the club increases, it requires more force from the golfer to change its curve. Every golfer moves the hub and applies force differently to the club. This explains why every player looks different when you’re watching golf on
THE HUB
TV or playing with your weekly foursome. There are some commonalities amongst the best players in the world and when we start to see trends they can be labeled as fundamental to an elite swing. Let’s take a look inside the Jacobs 3D software to see how different golfers apply their force to the club on the downswing. A major champion on the PGA Tour swinging a driver, an LPGA player hitting a 6-iron, a PGA Tour multiple winner using a driver, a club pro hitting a 7-iron, and a 20 handicap also hitting a 7.
The center point of the golfer’s grip is the hub of the swing. The hub is where the player imposes his or her will on the club, and where the actions of the body culminate. In Chapter 2, we’ll talk about how the movement of the hub influences the swing.
CHAPTER 1
FORCES & TORQUES
LINEAR FORCE
A golfer applies a linear force to the club, and that force changes direction and magnitude during the swing. The avatar left, of a PGA Tour player, shows the downswing with a yellow line representing the direction and magnitude of his linear force. Every player has different kinetics, but there are some common traits that are fundamental to every good player.
CHAPTER 1
MAJOR WINNER—DRIVER
The pink dots represent the path the clubhead takes from the start of the downswing to the follow-through. The yellow lines represent the shaft of the club, while the light blue arc is the path of the hub. The white arrows are called “quivers,” which illustrate the magnitude and direction of a player’s applied force. Notice the initial direction of the force, the shape of the hub, and how the player redirects the force in a spiral shape. We’re going to talk much more about all of these factors.