I will repost here what I posted on facebook:
While they addressed a few points ( bio mechanically) about the strike, they did leave out one crucial element on how Lee ( and most southern hand practitioners) deliver the "inch punch" and that is with the striking arm 75% extended already ( extended bridge). This allows for far more force to be produced because the arm muscles are at their strongest also. The also did not address the whole body tension/relaxation factor that adds the "BAM" into short distance strikes.
Psalms 144:1
Praise be my Lord my Rock,
He trains my hands for war, my fingers for battle !