There is no doubt about it, the guys and gals on tour have found something in the ground—and that something is power and speed. I’m sure by now you have heard of “ground reaction forces”—and I’m not talking about how you “shift your weight” during the golf swing.

Ground force in the golf swing: Pressure and force are not equal

With respect to ground force in the golf swing, it’s important to understand the difference between pressure and force. Pressure is your perception of how your weight is being balanced by the structure, in this case, the human body. Your body has a center of mass which is located roughly one inch behind the belt buckle for men and about one inch lower in women. When we shift (translate and/or torque) the center of mass, we create a pressure shift as the body has to “rebalance” the mass or body. This pressure shift can help us understand some aspects of the golf swing, but when it comes to producing power, force and torque are where it’s at.

Pressure can only be expressed in relation to the mass or weight of the body. Therefore, if you weigh 150 pounds, you can only create 150 pounds of pressure at one time. However, when we direct that mass at a larger object than our mass, all of a sudden that larger mass directs an opposite and equal reactionary force. So now, when a human being “pushes” their legs against the ground and “feels” 150 pounds of pressure, they now get 150 pounds of force directed back towards them from the ground, creating a total of 300 pounds of force that allows them to jump off the ground in this scenario.

If ground reaction forces don’t have anything to do with the “weight shift,” then what do they affect? Everything!

Most people use the same basic ingredients to make chocolate chip cookies. However, almost everyone has chocolate chip cookies that taste slightly different. Why is that? That is because people are variable and use the ingredients in different amounts and orders. When we create a golf swing, whether we are aware of it or not, we are using the same basic ingredients as everyone else: lateral force, vertical torque, and vertical force. We use these same three forces every time we move in space, and how much and when we use each force changes the outcome quite a bit.

Welcome to the world of 3D!

Understanding how to adjust the sequencing and magnitude of these forces is critical when it comes to truly owning and understand your golf swing. The good news is that most of our adjustments come before the swing and have to do with how we set up to the ball. For example, if an athlete is having a hard time controlling low point due to having too much lateral force in the golf swing (fats and thins), then we narrow up the stance width to reduce the amount of lateral force that can be produced in the swing. If an athlete is late with their vertical force, then we can square up the lead foot to promote the lead leg straightening sooner and causing the vertical force to happen sooner.

While we all will need to use the ground differently to play our best golf, two things need to happen to use the ground effectively. The forces have to exist in the correct kinetic sequence (lateral, vertical torque, vertical force), and the peaks of those forces need to be created within the correct windows (sequencing).

• Lateral force – Peak occurs between top-of-swing and lead arm at 45 degrees
• Vertical torque – Peak occurs between lead arm being 45 degrees and the lead arm being parallel to the ground.
• Vertical force – Peak occurs between lead arm being parallel to the ground the club shaft being parallel to the ground.

While it may seem obvious, it’s important to remember ground reaction forces are invisible and can only be measured using force plates. With that said, their tends to be apprehension about discussing how we use the ground as most people do not have access to 3D dual force plates. However, using the screening process designed by Mike Adams, Terry Rowles, and the BioSwing Dynamics team, we can determine what the primary forces used for power production are and can align the body in a way to where the athlete can access his/her full potential and deliver the club to the ball in the most effective and efficient way based off their predispositions and anatomy.

In addition to gaining speed, we can help athletes create a better motion for their anatomy. As golfers continue to swing faster, it is imperative that they do so in a manner that doesn’t break down their body and cause injury. If the body is moving how it is designed, and the forces acting on the joints of the body are in the correct sequence and magnitude, not only do we know they are getting the most out of their swing, but we know that it will hold up and not cause an unforeseen injury down the road.

I truly believe that force plates and ground reaction forces will be as common as launch monitors in the near future. Essentially, a launch monitor measures the effect and the force plates measure the cause, so I believe we need both for the full picture. The force plate technology is still very expensive, and there is an educational barrier for people seeking to start measuring ground reaction forces and understanding how to change forces, magnitudes, and sequences, but I’m expecting a paradigm shift soon.