my 4.5 year old could not sit still for longer than two seconds without being reminded to sit still. It's normal in all kids that age. I have four nieces and five nephews who are all the same age and have the same problem. I only have one other neice who will sit still for as long as you want, but that's because she spends hours at a time watching tv at home and that's not what is good for her. Kids will learn as they are taught. But we gotta remember to be patient rather than frustrated and try to discover more ways to get the point through to them.
What I do with my son is give him a minute of still quiet time. If he makes it without moving he gets a star for his sticker book and a great big hug and comment of approval. I like to make the comment more of an award rather than the object. But either way, now he is at 10 minutes without wiggling or moving and I can sit down and have a conversation without him getting distracted. It has turned out to be a very rewarding effort for both of us.
I would be more worried if your son didn't wiggle as annoying as it can get! Good luck friend!
my son is 8 and he still cant sit still at certain times lol. boys are like that. and at that age. when mine was younger and i would take him places that required him to sit still for more than a few min, i would take a toy, or even his gameboy. i know its not the best idea, but i was less stressed about it.
And I know very few little 4.5 year old boys who like to sit still!!
Has he been checked for scoliosis? If he can sit still for long periods of time when on his knees, and doesn't seem to have any other real focusing issues, it sounds like there's a real comfort problem in sitting with his hips square.
When he stands, does he often put his foot up on something, like step?
My oldest has a very slight curvature, and he liked to sit with one knee up. So, he would sit in a chair but put his right food on the chair, and his knee would be up by his chest.
Best wishes.