Why do people roll when they hit the ground form a high jump?

Im wondering cuase ive been playing GTA 4 and when i do a high jump a land on the ground rolling. Why is that? I know gta iv uses euphoria a program that makes things seem like real life so there's probably a logical reason. So why? is it safer?|||You can realize the answer by thinking of two cases:





a) A guy falls falls and absorb all the impact by bending this legs but not moving forward.


b)Same as above but as he bends he lets himself fall toward into a roll.





In b) some of the energy of the fall has been converted into forward motion. As such the legs of guy b) don't have to take such a strain. Therefore he is likely to get hurt less





As anyone who messed up a parachute landing will tell you converting pure vertical motion into forward motion is very hard (you basically land with you legs back abit and roll forward as your legs compress).





It's harder the faster you fall so don't think this will mean you can go jumping from 6 storeys. That said if you look up parkour you can see videos of guys using this technique to jump from incredible heights. |||well in layman's terms, if you jump and land on you two feet (even if you crouch) the reaction from the ground will be MANY MANY times more that what it will be if you fall down and start rolling... that is the easiest explanation i can give..





hope it helps :-)|||To give less impact to the blow and to save their legs. It's safer as long as you don't land on your head.