A quick idea is that it doesn't have a damn thing to do with stomping and strengthening your hips in that way. There are things you need to do to connect your lower body to your upper body so you move as a unit. Even then there are things you do that are more old school to connect body parts that later lead to spiral energy.
Personally I like Robs answer to a guy who once said he did hundreds of them a day.
1. Your either a liar
2. Your not doing them right
3. Or I want to meet you and come train with you!!
Guess which one was the answer in reply?
I dunno.... I suspect that there are a lot of people out there who are sure they know what shiko does and how to do it. Yet probably there are missing parts from everyone's understanding, so it's probably more helpful to everyone who "knows" to discuss the exercise more openly, in case there's parts that they're missing.
The "I know a secret" stuff is what continually (through the centuries) causes this stuff to get lost and to degrade because people don't know as much as they think they do. It's an endless cycle.