Bumping into the bump - how does it feel?

Similar to stubbing your toe into the kitchen table - whenever somethings hits one of those knee-bumps when im not knowing it, i feel like i cant move for some seconds. Like i freeze, feeling like my knee has been made to a iron beam without screws. In that moment i feel like even my head freezes aswell.

I may be explaining this horribly, but anyone else got this sensation? (Im 20, with 2 eight year old big bumps)