[nkozyra]

I'm still not sure I understand the logic of that; the only rotation I see is in the supine in the 'correct' version. The 'wrong' version doesn't require any rotation at all, even using the illustrations. It's simply lifting the front limbs up, allowing the hands to rest.

[maxerickson]

Imagine a chicken flapping its wings forward at a cat or something.

[brmgb]

If you want to bring it in front of you in the zombie like position most people use, you should have a notable rotation of both the elbow and the wrist.

[nkozyra]

This is true, but I notice similarly if I attempt a hands up position.

I should mention how excellent and detailed this article is. Anyone with a young child knows how fascinating they find this stuff and I have some corrections from this article to share with mine.