Binding fit as related to knee injuries

Just curious what the school of thought is. I am a relatively new wakeboarder and at the tender age of 40, want to protect my knees as much as possible. I have always been a little afraid to crank down on my bindings...my thinking being that if I fall really hard I want to come out of them to save my knees. A friend of mine rides and mentioned that he cranks his down so he will not come out on a hard fall. He is afraid if he keeps them loose maybe only one leg comes out on a fall and then you are asking for trouble. That makes sense to me now that I think about it. What does everyone think is best?


Thanks