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A week or so ago, a known pot-stirrer who rarely (never?) offers anything of his own kicked up another storm on some instructor Facebook groups. He had problems with the photo in this article: https://www.golfdigest.com/story/swing-by-numbers-new-study-unlocks-6-swing-secrets. Specifically with this image: The pot-stirrer's issue is that the image looks a little too much like S&T. The data from GolfTec shows that the average Pro's "pelvis"* moves 3.9" toward the target on the backswing, while the average amateur's moves "only" 2.55" (toward, also). The paragraph accompanying the picture makes it clear that the "hips" or "pelvis" are measured at the tailbone, which even if it rotated 45° while the center of the hips remained in place, would move about 2.8" (assuming the tailbone is about 4" from the center of the pelvis). Measuring the hip sway at the tailbone is a pretty bad way to go about it, I agree, because again rotation alone will result in "sway" toward the target even if the center of the hips is actually swaying the other direction, away from the target. But regardless, GolfTec's data said that the tailbone moved 3.9" toward the target in good players, and 2.55" in amateurs. It showed a strong correlation to ability, and ~1.4" is reasonably significant. But pot-stirrer had a problem with the actual PHOTO. Does the blue guy look a little left? Well, his torso is tilted away from the target. So I like that. But his right leg is close to "locked out straight" (then again, so is Red Guy's). That doesn't look like 1.35" difference, either. Perhaps it would have been better had GolfTec simply shown the hips of the golfers and shown their starting position and a little dot on the tailbone where the thing is actually measured. Better yet, GolfTec could put an additional sensor on the front of the golfer's hips, by his belt buckle, to measure the center of the pelvis a bit more so (this may require an adjustment for a very fat person). Anyway, pot-stirrer's issue was with the picture. Not the actual data. Several commenters said the 3.9" was misleading, but it was made pretty clear in the article that the measurement is from the tailbone, so even if the sensor is 4" from the center of the hips, and the hips rotate 45°, that's 2.8" of movement right there. But… let's look at what the hips actually do during the golf swing. Here's a tweet with some basic information. A larger version of that image is here: Not that it matters, but here are what the terms are. 01 BA = Breakaway (when the clubhead moves off the ball) 02 MB = Mid-Backswing 03 LB = Late Backswing 04 LBA = Late Backswing Arms 05 EPR = End of Pelvis Rotation 06 TB = Top of Backswing 07 EDA = End of Delivery (Arms, ~A5) 08 ED = Early Delivery (roughly A6) 09 MD = Mid-Delivery (roughly A6.5) 10 BI = Ball Impact 11 MF = Mid-Followthrough Forward/Backward (thrust) is relative to the ball: closer to the ball or away from the ball. Toward/Away (sway) is relative to the target: toward or away from the target. Upward/Downward (lift) is vertically. The middle line is the mean (average), and the lines on each side of the graph are one standard deviation away. Some data points in mean (EPR) format for the green values, in centimeters (cm), are: EPR: 1.2 (2.7) TB: 3.0 (2.9) EDA: 6.8 (2.9) Between BA and MB (points 1 and 2), the pelvis can be seen swaying backward slightly. How slightly? If EPR (5) is 1.2 cm, then the max sway back away from the target is about 1.6cm. As 2.54cm = 1 inch, 1.6cm is about 0.6". This very small sway back is used by some to "kick start" the forward motion: at EPR (5), it's 1.2cm forward, at TB (6, A4) it's 3.0 (or 1.2"). From 7 to 10 (impact), the mean is about 7.4cm @ 7/EDA, 8.4cm @ 8/ED, 10cm at 9/MD, and 10.95cm at 10/BI/A7 (impact). So… the hips move back about half an inch in these elite players hitting driver, before they pivot and sway slightly forward during the backswing. During the downswing, BAM, the pelvis slides to about 11cm forward of their starting location: almost 4.5". Again… And… BTW, these numbers are pretty darn close to what we wrote in the 5SK Instructor training manual back in 2012 or so.
Nick Clearwater, a buddy of mine (and @mvmac and @david_wedzik and others) is the head instructional guy at GolfTec these days, and generally has good information. Though I'm not always a huge fan (I'll explain why a bit later) of using "Tour averages" to teach average players, the numbers are still illustrative. Let's take a look at each, with the numbers and a brief note on each. Hip Sway (Backswing) Pros: 3.9" toward the target Ams: 2.55" toward the target Notes: This measures the tailbone and how much it moves toward the target during the backswing. As the tailbone is at 12 o'clock, and as it rotates toward 3 o'clock, that's toward the target. Amateurs often sway the hips back as they rotate, robbing them of some of this distance. Example: Shoulder Tilt at the Top Pros: 36° downward (lead shoulder) Ams: 29.6° downward Notes: This is just how "flat" or "steep" your shoulders turn at the top of the backswing. Keeping your chin up, standing too tall at address, rotating and lifting up are all causes. Example: Charley Hoffman's shoulder tilt matches spine angle: Hip Turn at Impact Pros: 36° open to the target line Ams: 19.5° open Notes: Amateurs stall for a lot of reasons, but one of the bigger ones is that they stall so that they can try to drop the club inside a little and get the clubhead down to the ball. Often this isn't something you worry about until you're a lower handicap golfer, but good golfers almost all rotate through impact - you won't find many PGA Tour pros who are relatively "square" at impact. Example: Dustin Johnson and Jim Furyk are wide open at impact: Hip Sway at Impact Pros: 1.6" toward the target Ams: -0.4" toward the target Notes: This is measured relative to the setup position, and remember, the hips are rotating here and this measurement is still at the tailbone. So a tailbone that has AWAY from the target (think 12 o'clock at setup to before 11 o'clock at impact, or 36° per the above), has also slid several inches - the difference between 10:48 and 12:00 is made up for, PLUS an additional 1.6". The average golfer is not only rotating less (11:21), but they're not sliding their hips forward much if at all (11:21 may be close to -0.4"…). Example: Rose at Setup and Impact (tailbone marked): Shoulder Tilt at Impact Pros: 39° upward (face-on view) Ams: 27.5° Notes: This is a measure, as seen from face-on, of how much shoulder tilt from the trail to the lead shoulder the average player has versus the PGA Tour player. Because PGA Tour players are more forward and more open, it follows that this number will be greater, too. Example: Tiger Woods and Fred Couples demonstrate this well here: Shoulder Bend in the Follow Through Pros: 32° back bend Ams: 3.2° back bend Notes: This is a measurement of how far forward your hips are versus your head. If you're straight up and down, the measurement would be 0°. If you're doing a "morning stretch" and really arching your back, pushing your "belt" out and forward and up, you'll get a higher number. Example: Zach Johnson and Adam Scott show this off quite well: As to why I don't like teaching averages… Dustin Johnson and Jim Furyk are very open. They're both one of the longer and shorter hitters out there. Averages are just that - an average - and players exist across a pretty wide spectrum. If the average AoA with a 7-iron is 4.1° down, you'll find PGA Tour players winning millions of dollars at 5° down and 2° down… and both can work well. Everyone's built differently. Averages account for all body types, all shot shapes, all types of swings. You know how if they take the average measurements of models and build a "model model," it's not all that attractive? The same can be true of striving to get the "average PGA Tour golf swing numbers." You might end up with something that's pretty, but you'd never get Cindy Crawford's mole.