I hope that someone can shed some light on a debate I have been having with two of my friends. My friends told me during a discussion that locking your knees for an extended period of time can cause a person to pass out. While I have heard that you should not lock your knees while standing for an extended period of time, I do not believe that locked knees can make a person pass out. I ran track in high school and was always told not to lock my knees after running b/c if I do pass out from being winded, I will injure myself more than if my knees were not locked. If a person passes out with locked knees they will fall straight forward of backwards and likely hit their head. However, if they pass out with knees unlocked, they will fall straight down which will cushion the fall and likely cause a less severe injury. However, I believe that my friends are wrong in their belief that locking your knees will make you pass out. Could someone help me out here. If I am wrong, I will bow down to my friends. However, if they are wrong, I would like to have something in writing to prove it :d thank you