Walking
In humans and other bipeds, walking is generally distinguished from running in that only one foot at a time leaves contact with the ground and there is a period of double-support.
For quadrupedal species, there are numerous gaits which may be termed walking or running, and distinctions based upon the presence or absence of a suspended phase or the number of feet in contact any time do not yield mechanically correct classification.
[2] The most effective method to distinguish walking from running is to measure the height of a person's centre of mass using motion capture or a force plate at mid-stance.
[7] Scientific studies have also shown that walking may be beneficial for the mind, improving memory skills, learning ability, concentration, mood, creativity, and abstract reasoning.
[10] "Walking lengthened the life of people with diabetes regardless of age, sex, race, body mass index, length of time since diagnosis and presence of complications or functional limitations.
[15] While terrestrial tetrapods are theorised to have a single origin, arthropods and their relatives are thought to have independently evolved walking several times, specifically in hexapods, myriapods, chelicerates, tardigrades, onychophorans, and crustaceans.
[16] Little skates, members of the demersal fish community, can propel themselves by pushing off the ocean floor with their pelvic fins, using neural mechanisms which evolved as early as 420 million years ago, before vertebrates set foot on land.
[19] Judging from footprints discovered on a former shore in Kenya, it is thought possible that ancestors of modern humans were walking in ways very similar to the present activity as long as 3 million years ago.
Human walking has been found to be slightly more energy efficient than travel for a quadrupedal mammal of a similar size, like chimpanzees.
[22] The energy efficiency of human locomotion can be accounted for by the reduced use of muscle in walking, due to an upright posture which places ground reaction forces at the hip and knee.
[22] When walking bipedally, chimpanzees take a crouched stance with bent knees and hips, forcing the quadriceps muscles to perform extra work, which costs more energy.
[22] They found that the energy spent in moving the human body is less than what would be expected for an animal of similar size and approximately seventy-five percent less costly than that of chimpanzees.
[24][22] Longer legs also support lengthened Achilles tendons which are thought to increase energy efficiency in bipedal locomotor activities.
[24] Humans have long femoral necks, meaning that while walking, hip muscles do not require as much energy to flex while moving.
[23] These slight kinematic and anatomic differences demonstrate how bipedal walking may have developed as the dominant means of locomotion among early hominins because of the energy saved.
The process of human walking can save approximately sixty-five percent of the energy used by utilizing gravity in forward motion.
Some people prefer to walk indoors on a treadmill, or in a gym, and fitness walkers and others may use a pedometer to count their steps.
In terms of tourism, the possibilities range from guided walking tours in cities, to organized trekking holidays in the Himalayas.
[37] Many also walk the traditional pilgrim routes, of which the most famous is El Camino de Santiago, The Way of St. James.
The LDWA's annual "Hundred" event, entailing walking 100 miles or 160 km in 48 hours, takes place each British Spring Bank Holiday weekend.
[40] There has been a recent focus among urban planners in some communities to create pedestrian-friendly areas and roads, allowing commuting, shopping and recreation to be done on foot.
[41][42] Shared-use lanes for pedestrians and those using bicycles, Segways, wheelchairs, and other small rolling conveyances that do not use internal combustion engines.
[41][43][44] Walking is also considered to be a clear example of a sustainable mode of transport, especially suited for urban use and/or relatively shorter distances.
Although there has been significant advances, robots still do not walk nearly as well as human beings as they often need to keep their knees bent permanently in order to improve stability.
Finally, such models are typically based fully on sensory feedback, ignoring the effect of descending and rhythm generating neurons, which have been shown to be crucial in coordinating proper walking.
However, they need to be heavily constrained to fit to data and by themselves make no claims on which gaits allow the animal to move faster, more robustly, or more efficiently.
Control-based models start with a simulation based on some description of the animal's anatomy and optimize control parameters to generate some behavior.
[56][57] However, the lack of underlying mechanism makes it hard to apply these models to study the biomechanical or neural properties of walking.
However, a rider will almost always feel some degree of gentle side-to-side motion in the horse's hips as each hind leg reaches forward.
[59] In walking, the legs act as pendulums, with the hips and shoulders rising and falling while the foot is planted on the ground.
