The video above is a feature on the ground mechanics of Justin James, with terrific analysis provided by Grayson Zacker of Jim McLean Golf School. Justin finished third at the World Long Drive Championships last fall. Like all long drive competitors, he employs fascinating ground mechanics to generate speed. Some of them exaggerated techniques of what we see on professional Tours, others are unique to long drive competitors.
Justin is a ridiculous athlete with a unique pedigree for long drive success. His father, Gerry, is a former bodybuilder (won Mr. California several times), professional football player and two-time World Long Drive Champion in the Senior Division. In high school, Justin was a standout golfer, but chose to pursue baseball in college and professionally. Like many of golf’s longest hitters, Justin’s athletic background has prepared him for success in golf, both in terms of his raw physical ability and sport specific technique (more on this later).
Grayson’s entire analysis is great, but we wanted to highlight a few points.
1) – 1:20 – Justin has 100% of his pressure on his trail foot early in the backswing. He’s able to do this because he lifts his lead heel, an extremely common move in Long Drive that’s less prevalent on professional TOURs. This lateral move sets up everything he does in his golf swing to generate power.
2) – 2:02 – While coiled and loaded on his trail leg, Justin initiates his explosive downswing by aggressively pushing off his trail leg and transferring pressure to his lead leg. Here’s where his baseball background really starts to show up. Justin spent eight years in pro baseball as a hard-throwing a right-handed pitcher, making his MLB debut for the Oakland Athletics in 2010. His move to shift weight to the lead side by driving pressure to his trail foot is not dissimilar from a pitcher pushing off the rubber to begin their delivery towards home plate. Obviously, golfers don’t stride like pitchers do, but the similar move of using the inside of the trail foot to generate arm speed is one reason why baseball players can be powerful golfers. At the 2:20 mark of the video, Grayson points out that Justin’s peak velocity measured an absurd 510 cm/sec. Peak velocity is the measure of how quickly a golfer transfers pressure from the trail leg to lead leg. While peak velocity doesn’t always correlate with swing speed, Justin’s is on the high-end of golfers we’ve measured, a reflection of how violently he transfers pressure.
3) – 2:45 – How Justin receives/responds to the pressure with his lead leg is probably the most important factor in his power generation. Additionally, it’s further evidence that his baseball background has prepared him for long drive success. Watch the action of his lead leg, specifically his knee, as the weight shift occurs. Instead of absorbing his weight and going in to flexion (bending) with his left knee, Justin extends his knee, exerting tremendous pressure through the ground with his left toe. Lead leg extension isn’t a characteristic that’s unique to long drive. In fact, it’s something we observe in many big hitters like Justin Thomas or Rory McIlroy. One of the trends that we’ve found in our data collection is that the longest hitters generally maximize ground reaction force in the lead leg, especially at the point that the shaft is vertical on the downswing. By responding to weight transfer with pressure (and not absorbing the weight), Justin is able to increase ground reaction forces and generate more speed. This is a move that’s consistent in baseball pitching as well. Studies around pitch velocity in baseball have found that the relationship between velocity and trail leg push off is negligible, while the plant leg ground force is vital (h/t Kyle Boddy of Driveline Baseball ).
So what does this tell us about golf? Like baseball, golf is a sport where athletes put force into the ground to create maximum arm speed. Therefore, if you want to generate maximum speed, the ground force you create with your lead leg is massively important.
We often talk about the propensity of big hitters to lift their pelvis during the downswing. This is an example of them pushing into the ground to use vertical force to maximize speed and optimize launch conditions (you can read more about this in our analysis of Justin Thomas’ CoP trace).
Thanks to Justin and Grayson for sharing this trace with us. There’s so much we can learn about using the ground to generate speed. As a sport, golf is just scratching the surface.