What is Loft?

Loft is the increase or decrease in Loft (the angle of the putter face relative to the vertical plane) between the start of the stroke and impact with the ball, measured in degrees.

Assuming the putter face is flush with the ground during the start of a stroke, pushing your hands towards the hole will decrease Loft and drive the ball into the ground. Pulling your hands away from the hole will increase Loft and send the ball into the air. In a biomechanically efficient putting stroke, there should not be an increase or decrease in Loft.