“Stopping your brain from compensating inferior technique is a major objective if you’re trying to develop a perfect swing.” – David Lee
The purpose of doing “Three-mode drills” is to prevent the brain from compensating and developing improper power technique. When you practice using the same mode in every shot, the brain “can” attempt to cover flaws by compensating what it felt may have been wrong in the previous swing. Changing modes with each swing eliminates the brain’s capacity to do this and helps
it identify and isolate proper mechanics. Three-mode drills can be done with or without a weight shift, and also with the feet crossed. First, hit a right-handed shot, followed by a left-hander, then a two-hander. The objective is to pay attention to the initial move in the backswing (the heave) and to make it powerful enough so that the backswing is not completed with a lifting motion. The heave should provide enough momentum to complete the backswing with the initial movement only. If the heave is too weak, it will create a tension backlash in the remainder of the swing and cause a miss-hit shot. If tension stays in the arms and shoulders too long in the backswing, it will cause you to sway laterally and create timing issues in the downswing.
Side note: Practicing these shots from varying contours around the green will help you with the geometry of alignment and ball position.