My male ckcs is six months younger than my female but at least twice the size of her he has a habbit now and then when they are at the park of running to her but not stopping very well so they both go flying My oh and i took them out today and he did this and ran straight in to her but this time she was running too and the colision was quiet something he started screaming and she seemed a little shocked when my husband got to him he discovered Milo had bit his lip and Cindy seemed quiet upset aswell I carried her home where she was checked over but perked up quickly so no harm but a bit of a shock for her but my oh kept an eye on her while i was at work.  Any ideas how to stop Milos behaviour i am hoping the injury he recieved may make him see sense but if not my only other option is to not allow them both of the leads together as Cindyloo could get damaged she is so delicate.  Is Milos behaviour normal?
Any ideas please

Yes, this is normal puppy behaviour. :) He will have had a bit of a fright this time so might not be quite so rough next time, but pups have to learn things, and this is the only way for them. Have you had his eyesight checked? CKCS's do have a problem in some cases (MRA ? ). This could be partly why he isn't seeing your bitch until it's too late. :(

Oh dear, poor things! My 2 often end up having head-on collisions, but luckily have never actually injured themselves. Hope they both feel better soon.

It's a great game that a lot of adolescents like to play, most of them do actually ram into each other when playing like this so you have been lucky so far that it has only happened this once.  I've always used distraction tactics to stop this unsavory game and will take a ball or frisbee for a dog to play with making them forget their favourite not so healthy game.