How do I stop "sliding hips" on backswing
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You could try placing an umbrella / alignment stick in the ground so it's just next to your back hip. Then when you make your backswing, try not to touch it with your hip.
Great tip, was that ben hogan? You can also use a piece of 1x4 instead of a golfball, its a little easier to work with.
Actually, where I first saw it was Woody Austin on a Nationwide tour event driving range back in the 90's. A 1x4 works fine, as does the grip of another golf club laid down perpendicular to the target. Anything to get that feeling of the weight never going to the outside.