The truth about Bruce Lee's one-inch punch

If you had never heard the term 'one-inch punch' before, it might sound like the description of an ineffectual hit from a weak fighter or a devastating insult for a man's lovemaking. But when the legendary Bruce Lee debuted the move on a kung fu TV show in 1967, it sounded more powerful than a freight train barreling at you at 30 miles an hour. Well, okay, maybe not quite that powerful. Vice reports that the the show's announcer claimed "Lee's punch had more force behind it than a car" traveling at about 30 miles an hour. 

When Bruce Lee let his short-range fist of fury fly, the man it struck "[flew] back at least five meters (16.4 feet)." That's nearly 200 times the distance his fist traveled. After a feat like that, if someone said Bruce Lee could bruise the air just by shadowboxing, we'd believe it. How on Earth did he punch that hard?

Bruce Lee's crazy one-inch punch

Popular Science spoke with Jessica Rose, a biomechanical researcher at Stanford University, about the underlying dynamics of the iconic punch. Rose explained, "When watching the one-inch punch, you can see that his leading and trailing legs straighten with a rapid, explosive knee extension." The force from his legs enables his hips to twist faster, "which, in turn, lurches the shoulder of his thrusting arm forward." From there his fist and wrist do the rest. Just as soon as he lands the blow, Bruce Lee pulls away, compressing the force and increasing the impact.

Obviously, that level of bodily coordination requires immense physical training. But the key ingredient is a well-trained brain. Neuroscientist Ed Roberts — whose work was also covered by the aforementioned Popular Science article – studied the brains and brawn of martial artists. He found that performing withering, precise strikes like the one-inch punch (or, in his research's case, a two-inch punch) depends on "a beefed-up glob of white matter" in the brain's supplementary motor cortex, which controls coordination between the muscles in your limbs. Bruce Lee's white matter was undoubtedly well-developed, allowing him to flow like water and punch like a tsunami.