okay, all. i'm not going to argue. every single one of those videos shows every single one of those athletes with straight arms. as i alluded to above, the hypermobile elbow gives the 'illusion' of a bent arm but the elbows are NOT actually bent.
what you are seeing is the elbow joint go from a suppunated to pronated position. the elbow rotates in and then out as the load is placed on the bar. the elbow joint is NOT bending.
and Munchkin3, yes, i'm comparing kips whether they are compulsory or elite. doesn't matter what level. they should have straight elbows. this is why i have explained to coaches here to not tell the kids to "lean their shoulders" forward when attempting the kip cast to handstand. rather, tell them to place their elbows over the top of the bar when completing the kip. the first instruction will cause the elbow to bend. the second, not.
as i alluded in the above post, the kids have to be taught to pronate their elbows when casting. it's not a natural occurrence. and those with hypermobile elbows have a harder go of it because of the way their elbow joint rotates compared to an athlete who is hypomobile.
then, of course, those that are hypomobile give the illusion that their elbows are bent. and they are not. usually, and i mean usually, the judges know the difference. but many do not. same goes with knees. they might look bent but they are not.
moreover, the best bar workers in the world would NOT be able to do any of the difficulty required of them if their arms were bent. bending arms on bars means loss of pressure against the rail. and loss of pressure against the rail, which can throw the body out of alignment, means epic failure or falling off. that's all.