Have you had any injuries?

You may want to check this in with the doctor. When you knees just give out, it could indicate acl problems. How long has this been happening? How old are you?

hehe that's pretty gross with your leg. Hyperextension can also cause strain on the acl though, so don't do it too much especially if you're knee gets sore afterwards.
Keep me posted!

Thanks for replying. I'm only 19 and i've never had any injuries. My mum did have acl problems, but she hurt it playing netball. Its been happening for the last 6 months, but never before that. And the first time was just walking home one day.

As for the hyperextension, its always happening. When i stand up they automatically lock backwards. Apart from looking kinda creepy it usually doesn't cause problems. After a few hours of standing they do get pretty sore, but i just figure thats cos i dont do much standing.

Ugh, I just wrote you a huge thing and then I had to log in again... lame

Anyways, to sum it up. You hyperextend your knees when you stand(like you said) and I figure you probably do it when you walk as well. Hyperextension DOES strain your acl and your knee giving out definetly indicates ligament issues. I think you may just have a weak acl-- I think-- there's a lot of stuff going on in your knee so its hard to tell.

So stregnthen your leg muscles, especially the quads. Getting more muscle can help prevent more injury too. Sometimes all you need is a little muscle and your symptoms will just kinda go away-- its what happened to my mom anyways, and I know my knee hurts more when I'm in the off season when I spend a lot of time on the couch

Try not to let your legs lock quite so much when you stand. And be sure to ice and rest your leg when its sore!

Good luck, and sorry you kind of got the short version. let me know if you need anything else or something doesn't make sense.

hi
just recently i got out of bed & tryed to walk to my alarm clock but it seemed asif my knees gave way because i had no control on my legs & i just collased. When i tryed to stand up my legs went like jelly & could not surport me & i fell to the floor again i did this several times but finally mangage to get the surport back in my legs & got up & carried on as normal... any ideas what this could have been ?
thanks x