why cant all humans be double jointed?
473139
Because then how would I know a guy really loved me for ME?
1081536
you might be double jointed
123300
i would say, based on the human body being symetrical, if we only had one hand, it would have to be in the middle of our chest. that could be dangerous i think.
23569
Because human beings need two muscles to separately extend each of our thighs for such activities as walking, running, Tae Bo, or driving a car with a manual transmission in the hopes that will impress the ladies slightly more than an automatic.
910036
Otherwise certain internal organs and networks within the body would not be able to function.  For example, the joints between your vertebrae can move only slightly.  They move enough so that they can absorb impact, but if they were more flexible in their range of movements, not only would they not be able to protect your spine, they would actually damage it.  Another example, if your knee joint were a ball and socket one, the muscles, tendons, ligaments, nerves and blood vessels would become tangled and cease to function, essentially shutting down your foot as a functional appendage.
482376
The joint with the greatest degree of freedom in rotation and angles achievable would probably be the shoulder joint where the humerus connects to the scapula in the glenoid fossa.\n\nThe degree of motion in this joint is remarkable, and is probably a legacy of the brachiation ability of our ape forebears.\n\nThe flexibility of this joint also probably costs us too, as it is probably one of the most easily injured joints.  Dislocated shoulders and torn rotator cuffs are probably a result of this flexibility, as the joint is not well protected with connective tissue, large slabs of muscle or shelves of bone.
690865
Hello,\n\n    Simply, we're normally stronger in one arm!!! Hence, if your left one is stronger, the right arm will be tired first!!!\n\nBut don't worry, the more you train, the more that discrepancy will disappear!
113685
Yeah its very common for most humans to lift more than 4 times there own body weight on there legs.
578743
Ok, I would normally be ofended by such questions, but there is a perfectly logical answer: Lets see you swing that club with a couple melons hanging inside your shirt. Seriously. Try it. It's incredibly hard. We need to bend out knees and arch our backs in a totally different way, just to get our arms straight.
314544
Joints\n\nA joint, or articulation, is the place where two bones come together. There are three types of joints classified by the amount of movement they allow: immovable, slightly movable, and freely movable.\n\nImmovable joints are synarthroses. In this type of joint, the bones are in very close contact and are separated only by a thin layer of fibrous connective tissue. An example of a synarthrosis is the suture in the skull between skull bones.\n\nSlightly movable joints are called amphiarthroses. This type of joint is characterized by bones that are connected by hyaline cartilage (fibro cartilage). The ribs that connect to the sternum are an example of an amphiarthrosis joint.\n\nMost of the joints in the adult human body are freely movable joints. This type of joint is called a diarthrosis joint. There are six types of diarthroses joints. These are:\n\nBall-and-Socket: The ball-shaped end of one bone fits into a cup shaped socket on the other bone allowing the widest range of motion including rotation. Examples include the shoulder and hip.\n\nCondyloid: Oval shaped condyle fits into elliptical cavity of another allowing angular motion but not rotation. This occurs between the metacarpals (bones in the palm of the hand) and phalanges (fingers) and between the metatarsals (foot bones excluding heel) and phalanges (toes).\n\nSaddle: This type of joint occurs when the touching surfaces of two bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement. The only saddle joint in the body is in the thumb.\n\nPivot: Rounded or conical surfaces of one bone fit into a ring of one or tendon allowing rotation. An example is the joint between the axis and atlas in the neck.\n\nHinge: A convex projection on one bone fits into a concave depression in another permitting only flexion and extension as in the elbow and knee joints.\n\nGliding: Flat or slightly flat surfaces move against each other allowing sliding or twisting without any circular movement. This happens in the carpals in the wrist and the tarsals in the ankle. \n\nP.S.  does this help you?
506601
because we are made differently and can have multiples.
1052663
i have a friend that says that all the time, but really i don't notice.  it is just like any other part of the body,  for example my left calf is one inch bigger than my right, and my left wrist is smaller than my right.  our bodies are asymmetrical
981770
Its movements would depend entirely on joints on the limbs, like most robots. It would be more difficult to share the body's weight and vertical acceleration loads among the limbs. and without spinal flexibility the impact loads would be much worse. Different gaits (e.g., a horse's walk, canter, trot and gallop) would be difficult since spine motion can assist in implementing fore-and-aft limb motion differences.
917134
Some people are naturally more flexible than others. Its just the reality that you may not be able to do them as well as the other girls.\n\nIf it really bothers you, enroll in gymnastics -- your trainer will help you increases flexibility and teach you the proper ways to do splits, flips, stretches and such.
377496
I can't do it. I think double jointed people can.
893201
Generally, double jointedness describes people who can stretch their joints further than 'normal'.\n\nCauses include: abnormally-shaped ends of one or more bones at a joint, weak or stretched ligaments, low muscle tone, abnormal joint proprioception (an impaired ability to determine where in space parts of the body are, and how stretched a joint is)\n\nSuch 'hypermobility' may not be indicative of any underlying medical conditions, and (natural) double jointedness is genetic in origin. Having said that, people who are double jointed can be prone to injury to the joints and muscle problems (since muscles have to stretch further with the movement of the joint).
186111
It is possible if you are born with a strange mutation such that you have hundreds of fingers.  If you only have ten fingers you could do one digit at a time and just remember if you need to cary one over.