Here is an article written by Gord Workum; a Titleist Performance Institute Instructor on why 3D Motion Capture (and Analysis) is better than simple 2D video analysis with regard to the golf swing. I like it and I will follow up with another article adding my point of view.
The only way to measure the efficiency of a golf swing is with 3D Motion Capture; with 2D one can just judge the style of the golfer’s swing. Yes, you can detect the big 12 swing characteristics with 2D, but with 2D you can not quantify any of the big 12 without being subjective. With 3D Motion Capture, you can also detect any of the big 12 swing characteristics, but you can quantify each one of them, objectively, and see if your client is improving their swing efficiency by improving or eliminating the swing characteristic that is causing them to have an inefficient movement. If you are only using 2D video with your clients then you have no way of objectively showing them that they are improving, all your conclusions will be subjective. By using a system that relies on you being subjective all the time can lead you and your client down the wrong path as you can not see how the client produces power in their swing and if it is efficient or not. With 3D motion capture you can never be wrong if you know how to read the information correctly and with 2D you are subjectively guessing and this will lead to a much lower success rate with your clientele. With 2D video, you can not tell if the client is using their body in a fashion that can create future pain and/or injury. With 3D you are able to see how the client produces power and if they are using the lumbar as a trigger to create power in their downswing which can lead to lumbar pain and/or injury in their future. This is an example of what you can not see with 2D video. The TPI physical screens that we perform will demonstrate; body limitations in positions that are not under load. They are great screens as they will show us a lot about the client’s body and help us connect the swing characteristics to the body limitations. But 3D will show us body limitations that the physical screens or 2D can not. The client might be able to pass the pelvic rotation test but in the downswing, their body is creating power, torque and moment of inertia and when these extra loads are put on the body, the pelvis might not rotate like we saw in the screen or the thorax stability might not be as good because of the load put on the body. With 3D we can see how the body reacts, dynamically, during the golf swing and this is objective information that we can use to quantify their efficiency. Then we can prescribe a combination of exercises and motor patterns changes to either give strength, mobility, stability or flexibility to a certain part of the body so the client can create a golf swing that is more efficient and this can give them more distance and/or accuracy. So if you are just using 2D video, stop guessing on what is needed to help your golfer and either invest in a 3D system or hire someone to capture the swings so you can have faster success with your clients with objectivity not subjectivity.