Justin Thomas’ Remarkable Ground Reaction Forces

Justin Thomas is known for his dynamic lower body, but what’s really happening under his feet?

In this video, TPI Co-Founder Dr. Greg Rose breaks down Justin Thomas’ swing using force plate data to show how elite players create – and sequence – ground reaction forces.

One of JT’s superpowers is not just the magnitude of the forces he creates, but the timing. This is a key concept that we discuss in our advanced Golf and Power courses. More info on our Certification courses here: https://www.mytpi.com/certification

Hey everyone, it’s Dr. Greg Rose. I’m here with Corey Coler. We’re here in the TPI lab and we’re looking at one of the best golfers in the world here, Justin Thomas. And I think it’d be really important for us to point something out because I think a lot of people see Justin’s footwork and they’re like, “Man, he does some really weird stuff, right? And it can’t be that biomechanically efficient.” So, I’ve got Corey, who’s our head biomechanist here, is going to help me with this. Cory, why don’t we take him to the top of the back swing? I want to show you what he does with his ground reaction forces. Now, one of the things you’re going to see if we get to the top of the back swing, this first graph that we’re looking at here is how hard he pushes lateral. So, this is kind of where he starts his weight shift. Most players start their weight shift before the top of the back swing. Now, you can see Justin starts his weight shift, but he doesn’t peak his weight shift until the down swing. So, in other words, he actually starts pushing lateral later than most people, which is kind of unusual because we usually see big hitters like Justin, they actually do their ground reaction forces earlier. He actually starts it later. But here’s what’s really interesting. Let’s go to his last ground reaction force, the vertical. So, normally when you’re using the ground, you’re going to weight shift, then you’re going to start to rock a little bit. You’re going to start to twist, and then you’re going to jump. And then all your ground reaction forces are done. And then you start transferring through your body to the club. Well, it takes time to do all those ground reaction forces. And the earlier you do that, the more time you have to transfer to the club. Now, I showed you Justin started his ground reaction forces a little later than most guys, but where he finished his ground reaction forces, notice where he is. His arm is horizontal and the shaft is already still behind us. It hasn’t even come down yet. That’s really, really early. So, what’s really unique about Justin Thomas is he starts his ground reaction forces late, but he finishes them early. So, he does them all in a very short period of time. So, by the time he’s done with his ground reaction forces, now think about it. The energy is coming up his body. So, it’s all the ground stuff has already happened. If you keep going a little farther forward, now’s when you start to see a lot of lower body action and heel coming off the ground going forward. And I think a lot of people go, “Man, I don’t really think he’s using the ground really well.” Well, here’s the key. He already did. It’s over, right? It’s now transferring through his body. It’s working his way up. So, what’s happening down here? We used to think it mattered a lot. I don’t think we think it matters that much anymore. And what’s really interesting is that he stays in sequence in that short period of time, you know, because he’s lateral, then he goes into rock, and then he goes into twist as he approaches that vert. Yeah. Even though it’s so short, he still keeps his sequence, which is pretty cool insight from one of the best hitters in the world.