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Submitted by Robert Roy Britt

Until you’ve seen it done, you might think the whole concept of a martial artist breaking through concrete blocks with their bare hands is some kind of magical trick. But as John Rennie, former editor of Scientific American (“Martial arts are my hobby and explaining science is my job”) explains, it’s all about physics.

Renne puts it succinctly in a recent blog post that debunks other explanations that claim methods such as there being some pull-back involved, as though hesitancy could bust concrete. Rather, Renne busts that myth. Breaking a board, or a stack of concrete blocks, is all about follow-through. As he puts it:

“When you break a board, or concrete, or a Louisville slugger or anything else routinely used these days in demonstrations of tameshiwari (breaking), you have to follow through on the strike. Indeed, advice commonly given to students learning to break is that they should aim at an imaginary target several inches beyond the actual object, for two reasons. First, doing so helps to make sure that the actual strike occurs closer to the movement’s point of peak biomechanical efficiency. Second, it helps to override our natural tendency (partly psychological, partly reflexive) to slow down ballistic movements such as punches and kicks before they reach full extension, which helps to protect the connective tissues around our joints.”

If you plan to try and break a board, or a concrete block, take Renne’s advice. If you see an explanation that claims “making the blow fast and pulling back” works, don’t believe it. I’ve watched the kids in my son’s Tae Kwon Do class break boards, and those that believe they can do it and follow through usually succeed. The tentative ones get hurt.