I've noticed a big difference between comic book characters, anime/manga characters, and hw they go about gaining there powers....
Let me start by mentioning the concept of the peak human. In American comics, specifically DC and Marvel, people have a physical and mental maximum that that they are capable of achieving without outside influence. Captain America and Batman's bodies are only capable of so much because at the end of the day they are only men... and cannot get any more powerful through training because they have already reached their body's limits. Unless their is something that can make a human better wether it be tech, genetic variation (X-Gene, metagene, etc), or mystical enhancements... humans in american comics cant becoming superhumans just because they want to.
Anime/Manga characters on the other hand are not portrayed the same way. They are without previously imposing limits... even if most of them are natural humans. Most of them train themselves to superhuman levels of capacity, which in itself doesnt make any sense because by definition.. superhuman should be something than a human isn't capable of achieving naturally. Some exmaples include the humans from DBZ or the ninjas from Naruto. They superimposed lesser limits on themselves through training and made themselves capable of doing the impossible. The funny thing is they keep getting more powerful with time and "training" and arent held back by anything but their own wills.
Now im not saying I have a problem with either.. it is just something i have noticed... am I wrong? any thoughts?