I was curious about doing heavy body conditioning like in kung fu like doing long horsestance holds, hitting and kicking eachother arms and legs against eachother to build strength and putting on dit da jow after for bruises. Same goes for any other style for body conditioning where you hit areas on the body. Is all this conditioning not good to start doing at a young age like mid teens cause it will develop problems later on? Or is it better to wait when older to do? Thanks.