I keep reading online development things, of what they should be doing. my 8 month old is sitting but making no attempt to move (crawl bum shuffle etc) plus have looked after my friends little girl today who is a week younger and she is rolling about and going into crawl position(not going anywhere) I just feel really worried and I keep encouraging him to go on his belly but he just cries. when he was younger he used to roll from belly to back, but now wont even do that. In every other way he is happy healthy and talking(?) to me. He is clapping and doing everything else intellectually a 8 month should be, but really worried about not rolling and moving about.
We do lots of things swimming once a week, baby club(sure start run so, lots of thing to see touch and do) baby yoga, and even been to baby ballet, music class ( singing at library)
Is there anything I can do to encourage movement?