I think this type of punching was for the purpose of punching light body armor. The reason I say this is because the training for these punches is never thrown head height.
Now before the giggles come. This is the type of light armor I'm referring to.
Great for stabs and slashes but I bet one can still feel one of those deep power punches.
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It may seem silly but but there is validity in this. Similar protection used by TKD getting penetrated by punch energy. Keep in mind. TKD uses padding. The armour above doesn't had that same padding in mind. Good for knives and slashes but a solid puch with a conditioned hand will still get through.