The BAL.ON Impact drill
Please mind: this is the Impact drill for irons!
Creating the correct pressure distribution at the moment of impact is one decisive factor shaping the quality of your shot. As with all other drills, measure precisely, but also sharpen your senses as to how this distribution feels. The more you get this feeling grounded, the easier it is to reproduce the motion.
Place the ball slightly left of center (for a right-handed player).
Assume a balanced set-up, watching the heatmap.
Now bring ~80% of your pressure to the lead side.
Check with the heatmap. Allow yourself a little time perceiving how these 80% feel.
During all following motions, keep the pressure at ~80% in the lead leg.
Prepare a half swing, i.e. in backswing, stop when your lead arm is parallel to the floor.
Swing through, hit the ball first, then the ground.