Trying to get it with straight arms takes longer with most kids, because in trying to keep their arms straight, they push their upper body away from the bar (opposite of what is necessary). I've had those perfectionist kids who take forever to learn a kip, because they insist on keeping their arms straight. I prefer when they keep them straight when I am spotting, but muscle a few up on their own until they "get it." Once they have a muscle kip on their own, I alternate spotting and letting them work alone until they have a straight arm kip on their own (doesn't take long if the foundation has been properly laid). There are not too many skills that I like a kid to learn incorrectly and then go back and fix it, but the straight arm aspect of the kip is one of them. I don't allow any cheating on the jump position, glide-extension position and the kip action itself, but I do let them muscle over the bar a few times to get what it feels like to put it all together.
