How we walk is a perfect example of a system that nobody has thought to challenge. Why not? Because that’s how we’ve always done it. QED, the current method is the best possible. I’m going to prove that false, and selectively supply information culled from a third party source linked at the bottom of this post to provide a better method.
The basic problem with the current mode of locomotion is the reliance on the shoe. Though humans evolved to deal with the ground barefoot, it seems an obvious pain-reliever to put some protection underneath the sole. However, the natural human mode of walking is intended to deal with the ground by first “testing” the ground to see if it’s safe to tread there using the front of the foot. With shoes on, however, this test is discarded and we begin to walk with the heel. When you walk barefoot, your walking mode switches hugely. You start to walk with bent knees and relaxed calf and thigh muscles. The arch of the foot is used to effect to lift the back of the foot, and the toes are used to provide forward stability. Moreover, your center of gravity is shifted forwards. This is to greater effect when running, so you are in effect falling forward slightly to propel yourself forward.
Naturally, the foot is an excellent shock absorber when walking with the front of the foot, because the ankle converts the jarring upward shock into rotational force, which the heel and achilles tendon steady. When walking with the heel- Anthropik calls this “cow walking,” which I quite like- this jarring upward force is carried directly up through the heel, ankle, and leg. Apart from long-term health concerns, hip and back pain, and arthritis or osteoporosis of legs or hips, the major problem that this produces is is a greatly reduced ability to walk or run. Each leg has to move farther to place the heel vertically underneath the leg, and then the fact that it is vertical, with knees locked, causes the shock to extend all the way up the leg and to jar your internal organs. This tends to manifest itself as a stitch in the side, when the liver or kidneys are knocked around too much. Also, the natural tendency for right-handed people is to breathe in when the right foot hits the ground. This especially aggravates the shockwaves to the kidney since it faces heightened internal pressure from above as well, resulting in a stitch in the side after you’ve run hardly a mile. Shoeless societies such as the Kalahari Bushmen or Navajo indians appear to be impossibly good runners. Bushmen hunters run for days continuously to catch a gazelle- the creature collapses from exhaustion (four-legged runners may be faster, but when they run they constrict their lungs and can’t breathe as well). And Bushmen do this regularly, unlike marathon runners.
Humans are natural-born runners. We can run for longer than any other creature alive. Ostriches are exclaimed in National Geographic to be able to run at 40 mph for up to five hours. Humans can run at 10 mph for up to three days. Obviously, there is conditioning and fitness required on top of just being human, but those Kalahari Bushmen don’t lift weights or run around a track. They hunt a gazelle every few days just to eat.
More depth on the subject, including physiological deformity as a result of common walking practice, and seemingly extreme physical feats of shoeless runners dismissed as commonplace in shoeless societies such as the Native American Indians, can be found here.