The internal power folks will tell you that the lessons aren't actually the same, that IP focuses on manipulating the structure of your own body, while athletes manipulate the outside world. They will also point out that internal strength continues to develop as people age, while athletic strength inevitably declines.
I understand that the "IP folks" say lots of things. They may or may not believe that the lessons are actually different, but this is still not a reason. Why are they different?
Saying that internal focuses on manipulating the structure of your own body, but athletics doesn't is not logical. Athletics is about properly aligning, moving and using the body. It teaches the principles of proper use of the physical body. There is absolutely no doubt that athletics focus on manipulating the the structure of your own body.
If internal martial arts don't manipulate the outside world, how do they interact with it? If internal martial arts don't have an effect on the world outside of the body, then how are they useful for anything, let alone martial arts.
Athletics have proven time and again to help people into old age. Look at Jack Lalanne (who passed this weekend at 96) He could do things that no internal martial artist could even touch. At 80 yeas of age he swam 1.5 miles, pulling 80 boats, each with 80 people in them. At half his age, 80% of people couldn't do that. Everyone dies, Ueshiba and Lalanne, who do you think was stronger at 80?
I find it strange that all the "internal people" who possess so much "internal power" are also athletes. Perhaps they are simply telling you that it's not athletics, but something else. Ark has more videos than any of the other internal people, he's also an ex gymnast and kickboxer (I'm sure he's done a few other athletic things as well). Strange that the more athletic they are, the more things they show.
As far as using the elastic nature of the body, sports people discuss this all the time. The language is different but they are talking about the same thing.
Athletics take less time to learn, are more clearly explained, more widely available, and demonstrate more effective ability.
Why is "internal" different then athletics? What can an internal martial artist do that a good athlete cannot?