This exercise helps develop a better shoulder plane and more stable posture during the swing.

Get in a good 5-iron golf posture with your arms crossed over your shoulders.

While trying to limit your lower body from moving, take a full backswing keeping your shoulder plane from flattening out at the top. 

From here, return to the impact position, once again with little lower body motion. 

Finally, rotate your whole body through to the finish; once again maintaining a good stable posture and shoulder plane throughout.

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