Why shouldn't you use calfs if your doing flips?
Never heard that one before

First off, im not arguing anything at all about how nice and tight you can get each type of strapping. (and if i was calf cuffs seem to do a better job) what I am talking about is protection for the knee itself. that is why im talking about flipping, as when you flip, (especially when performing flips like the back, front 180 or back 360- ones you come down facing the way you came)
then if you fall you are more than likely going to land with your knees taking a lot of impact.
Cuffs offer very little if no impact protection when you fall. the knee bar does the opposite, it offers a very high level of protection from impacts. I think i would be better off with a diagram of the knee bar to explain how this exactly works, but basically it is designed very well to deflect the vast majority of impact pressure away from the knee and onto the stilt. as your knee hits the ground the big foam padding soks up the inital impact pressure, and then the metal bar inside takes the rest. the metal then transfers that impact down the bars and away form the knee itself, pushing the impact down the stlt rather than directly onto the persons knee/legs. At the moment im doing some new flips and during practice I have fallen a few times onto my knees and i know that if I was wearing he calf cuff my knees would have taken impact they are just not designed to take.
um... no, i flip with cuffs they're fine, don't jhulv and chris use cuffs on their 7's?
They hold your leg in great, and dont hinder the flip at all i agree. but no safety incase of a fall (See above) and juhuv uses the knee bar.
Basically heres how it is in my opinion.
Cuffs = Great comfort
great strapping to connect the user to the bock
very little protection from impact
Knee bar = Satisfactory comfort
Good strapping to connect the user to the bock (when adding some extra straps like pinheads)
Awesome protection from impact
and as i can fix the first 2 things (Comfort/strapping) to make them more than adequate i will always take the kneebars due to the much larger safety you just do not get with the cuffs