Bolt's Achilles tendon is 42cm. These legs are made for sprinting. 42cm long is simply beyond the limits of human beings. And in good health. Tai Sen has a thick neck. Tai Sen is the strongest boxing champion in the world. Not only can he hit 800 kilograms with one punch, but his fighting ability is also first-class. His neck is thicker than the average person's waist. The physical structure of these athletes simply goes against common sense.