text: i was in the martial arts when i was 8 to 13 .. and i dont think he will take injuries anymore because his abs are trained to take that punishment ... now dont get me wrong i bet he puked the first few times and had a sore stomache. But most likely he didnt just jump into heavyweight girls, he most likely started with a lightweight girl, and as his abs got used to the beating he raised the weight. Its all about conditioning and practice in the martial arts. in fact, chinese monks can bend a metal pipe with their throats and do two fingered push-ups because they condition their bodies to take that abuse.