Instruction
What is “ Sway Gap ”?
And why it may be the cause of your direction problems
by SALVADOR ROCHA , PGA Associate , Eisman Golf Academy
The golf swing is one of the most complex athletic movements humans can make . Countless variables can affect the flight of your golf ball , from your body movements and club path to the relationship between the clubface and even weather conditions . That leaves us golfers with too many variables to address in order to improve , which is why many never rise above average . According to the USGA , roughly 70 % of male golfers in the United States have a handicap of 10 or greater .
One of the keys to improving your technique is finding the variable ( or variables ) that will have a significant impact on your game . Thanks to launch monitor technology , we are able to measure specific parameters of how the golf club moves in space , such as club path , face angle or low point .
But what about measuring specific data points for how our bodies move ? Until recently , getting this type of data was only possible by using a 3-D system like GEARS , which requires over 20 sensors attached to the club and body , plus several high-resolution cameras . The whole system is not cheap , costing around $ 30k .
This is where Sportsbox AI comes in . It is a “ marker-less and sensor-free 3D motion analysis studio ” that allows coaches and players to get data on body movements throughout the swing . It is an app , so it can easily be used on a phone or tablet .
One of the most relevant data points that Sportsbox has been able to measure is the “ sway gap ,” which refers to the “ horizontal distance between the center of the chest and the center of the pelvis .” In simpler terms , it tracks how much your chest is in front of or behind your lower body . The measurement is given in inches — the number is positive when the chest is in front of the pelvis and negative when the chest is behind the pelvis .
The interesting part about sway gap is that it has a very strong relationship to spin axis , which is the measure of the golf ball tilting immediately after impact . All things being equal , a positive spin axis creates a ball flight that curves to the right and a negative spin axis creates one that curves to the left . The larger the spin axis number , the bigger the curvature of the shot .
Sportsbox gathered swing data from Bryson DeChambeau , a partner of the company as well as a user , along with his current coach , Dana Dahlquist . They found that when Bryson ’ s sway gap at the top of his swing was -2.0 to -2.7 ( meaning his chest was behind his pelvis ), his spin axis became significantly more negative , resulting in shots with a greater curve to the left .
Sway Gap
Refers to the “ horizontal distance between the center of the chest and the center of the pelvis .” In simpler terms , it tracks how much your chest is in front of or behind your lower body .
The measurement is given in inches — it ’ s positive when the chest is in front of the pelvis and negative when the chest is behind the pelvis .
-3 "
INCHES
-2" -1" 0 " 1 " 2 " 3 "
Conversely , when Bryson ’ s swing gap at the top was between -2.0 and -1.6 , his spin axis was either neutral or positive , resulting in shots curving more to the right .
In other words , when Bryson ’ s chest was farther behind his lower body at the top of the backswing , it produced more of a draw ball flight . When his chest was not as far behind his pelvis , or more stacked on top of his lower body , it resulted in a fade or a straighter ball flight .
USING THIS IN YOUR OWN SWING It is important to note that these numbers were specifically for Bryson , so they are not a universal rule . However , after giving thousands of golf lessons , I have personally seen the following patterns among golfers .
Most golfers I have taught who slice the ball have two major issues : 1 . They are too stacked at the top with the upper and lower body — or sometimes the chest is even leaning more toward the target than the lower body ( reverse spine tilt ).
2 . They lack lateral movement of the pelvis in the downswing toward the target .
On other hand , I have seen the opposite trend with golfers who hook the ball excessively : 1 . They get their chest too far behind their lower body at the top .
2 . They have too much lateral movement of the pelvis in the downswing toward the target .
WHAT TO WORK ON If you slice the ball : 1 . Set up with the pelvis closer to the target ( bumping your lead hip toward the target but leaving the chest in place ).
2 . Focus on starting the downswing with a lateral move of the hips towards the target .
If you hook the ball : 1 . Set up with the pelvis more stacked with your chest .
2 . Focus on getting the lead hip more around / open instead of sliding it excessively in the downswing .
SALVADOR ROCHA
34 V IRGINIA G OLFER | M ARCH / A PRIL 2025 vsga . org