Hi.. i was doing an gymnastic trick called "monkey jump" which is building up to a cartwheel. what you do is put both arms on floor, trampoline etc to the side then legs behind it then jump your legs over(infront) of your arms.. i locked arms straight like your suppose to and all of a sudden my arm gave out(collapsed)and now my elbow is trobbing with pain and cant bend it up i have to keep arm straight