Podcast, Season 4, Swing

Ground Reaction Forces and the Reason to Pay Attention

With all the buzz about “GRF” and “center of pressure” what do the different terms mean and what does the research say about the golfers interaction with the ground? In this episode we learn from Dr Mike Duffey and Dr Scott Lynn about the forces going on with the ground and talk about what ground reaction forces actually are.

Ground Reaction Forces

Ground Reaction Forces is the force exerted by the ground on a body in contact with it.

So when you are trying to move in the golf swing, you have to push on the ground and the ground then pushes back on you at the opposite direction which causes your body to move.
Dr Scott Lynn

It’s simply the reaction force to what we are doing to our bodies against the ground. If you like, Newton’s law for every action there is an equal and opposite reaction so every force that we apply against something, there is an equal force pushing back. Dr Mike Duffey

If you take away the ground and loose ground reaction forces you can see that things go haywire pretty quickly.

Listen into the entire episode and learn more below

About our guests

Dr Scott Lynn

Dr. Scott K. Lynn, PhD was born in Toronto, Ontario, Canada and has been involved with sport, physical activity and exercise throughout his life. He played on the varsity ice hockey, baseball, golf and football teams during high school and also had a keen interest in science which brought him to Queen’s University in Kingston, Ontatio, Canada to pursue a dual undergraduate degree in both Physical and Health Education (BPHE) and Life Sciences (BSc). During his time at Queen’s he was also a member of the varsity golf, football and lacrosse teams.

Following his playing days, he continued his involvement in varsity athletics as an assistant coach of the men’s and women’s varsity golf teams. After his undergraduate degree, he continued on to do an MSc followed by a PhD in orthopedic biomechanics at Queen’s University.

His research concentrated on examining the mechanical factors that are involved with the development and progression of knee osteoarthritis and how this process may be slowed through exercise and modifications to basic activities of daily living. He then went to the University of Waterloo to do a six month post doctoral fellowship that concentrated on examining whether those with knee osteoarthritis make compensations in their movement patterns that may put their back at an increased risk of injury.

Also, during his doctoral and post-doctoral studies, he worked in several clinical and fitness settings doing exercise prescription for a variety of clients from the frail older adult to the elite athlete.

Dr Mike Duffey

Dr Mike DuffeyDr. Mike Duffey is a faculty member in the Department of Kinesiology at Pennsylvania State University and Biomechanist for the Golf Teaching & Research Center (GTRC).

Mike completed his Master’s in Exercise Science at Wake Forest University; his thesis examined how lower body 3D kinematics and ground reaction forces influence running injuries. He completed his PhD in Biomechanics at Penn State where his research focused on upper body kinematics and muscle activity during resistance exercise.

In 2006, Dr. Duffey returned to Penn State University as a faculty member in the Department of Kinesiology and began collaborating with the Professional Golf Management Program. That collaboration has led to the development of the Golf Teaching and Research Center. Dr. Duffey’s roles in the GTRC include detailed swing assessment, instructor education, and conducting research. The research focus of the center is to develop a better understanding of the mechanics of the golf swing with the goals of improving performance at all playing levels as well as reducing the injury in golf.

Links / Resources

Article on Vertical Forces mentioned in episode

Penn State online biomechanics course

Scott Lynn’s level 1 certification with Swing Catalyst

This Episode’s Sponsor

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Music Includes

Simple Hop by Broke for Free
Drop of Water in the Ocean by Broke for Free
It’s a Mystery by Lee Rosevere

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Founder and chief curator of the Golf Science Lab. Documenting what's going on in the world of research and beyond that can help you play your best golf on the golf course (when it counts). Join the movement of researched based coaching over trusting beliefs and what worked for one person a few decades ago. Follow on Twitter