Walking is generally distinguished from running in that only one foot at a time leaves contact with the ground: for humans and other bipeds running begins when both feet are off the ground with each step. (This distinction has the status of a formal requirement in competitive walking events, resulting in disqualification at the Olympic level.) For horses and other quadrupedal species, the running gaits may be numerous, and walking keeps three feet at a time on the ground.
The average human child achieves independent walking ability around 11 months old.
While not strictly bipedal, several primarily bipedal human gaits (where the long bones of the arms support at most a small fraction of the body's weight) are generally regarded as variants of walking. These include:
Mankind evolved because he was a long distance animal--and walking is at the core of our being.
For humans, walking is the main form of transportation without a vehicle or riding animal. An average walking speed is about 4 to 5 km/h (2 to 3 mph), although this depends heavily on factors such as height, weight, age and terrain. A pedestrian is a person who is walking on a road, sidewalk or path.
Human walking is accomplished with a strategy called the double pendulum. During forward motion, the leg that leaves the ground swings forward from the hip. This sweep is the first pendulum. Then the leg strikes the ground with the heel and rolls through to the toe in a motion described as an inverted pendulum. The motion of the two legs is coordinated so that one foot or the other is always in contact with the ground. The process of walking recovers approximately sixty per cent of the energy used due to pendulum dynamics and ground reaction force.
Walking differs from a running gait in a number of ways. The most obvious is that during walking one leg always stays on the ground while the other is swinging. In running there is typically a ballistic phase where the runner is airborne with both feet in the air (for bipedals).
Another difference concerns the movement of the center of mass of the body. In walking the body 'vaults' over the leg on the ground, raising the center of mass to its highest point as the leg passes the vertical, and dropping it to the lowest as the legs are spread apart. Essentially kinetic energy of forward motion is constantly being traded for a rise in potential energy. This is reversed in running where the center of mass is at its lowest as the leg is vertical. This is because the impact of landing from the ballistic phase is adsorbed by bending the leg and consequently storing energy in muscles and tendons. In running there is a conversion between kinetic, potential, and elastic energy.
There is an absolute limit on an individual's speed of walking (without special techniques such as those employed in speed walking) due to the velocity at which the center of mass rises or falls - if it's greater than the acceleration due to gravity the person will become airborne as they vault over the leg on the ground. Typically however, animals switch to a run at a lower speed than this due to energy efficiencies.
Fitness walkers and others may use a pedometer to count their steps. The types of walking include bushwalking, racewalking, weight-walking, hillwalking, volksmarching, Nordic walking and hiking on long-distance paths. Sometimes people prefer to walk indoors using a treadmill. In some countries walking as a hobby is known as hiking (the typical North American term), rambling (a somewhat dated British expression, but remaining in use because it is enshrined in the title of the important Ramblers' Association), or tramping. Hiking is a subtype of walking, generally used to mean walking in nature areas on specially designated routes or trails, as opposed to in urban environments; however, hiking can also refer to any long-distance walk. More obscure terms for walking include "to go by Marrow-bone stage", "to take one's daily constitutional", "to ride Shank's pony", "to ride Shank's mare", or "to go by Walker's bus." Among search and rescue responders, those responders who walk (rather than ride, drive, fly, climb, or sit in a communications trailer) often are known as "ground pounders".
The Walking the Way to Health Initiative is the largest volunteer led walking scheme in the UK. Volunteers are trained to lead free Health Walks from community venues such as libraries and GP surgeries. The scheme has trained over 35,000 volunteers and have over 500 schemes operating across the UK, with thousands of people walking every week.
Professionals working to increase the number of people walking more usually come from 6 sectors: health, transport, environment, schools, sport & recreation and urban design. A new organization called Walk England launched a web site on the 18th June 2008 to provide these professionals with evidence, advice and examples of success stories of how to encourage communities to walk more. The site has a social networking aspect to allow professionals and the public to ask questions, discuss, post news and events and communicate with others in their area about walking ,as well as a 'walk now' option to find out what walks are available in each region.
The world's largest registration walking event is the International Four Days Nijmegen. The annual Labor Day walk on Mackinac Bridge draws over sixty thousand participants. The Chesapeake Bay Bridge walk annually draws over fifty thousand participants. Walks are often organized as charity events with walkers seeking sponsors to raise money for a specific cause. Charity walks range in length from two mile (3 km) or five km walks to as far as fifty miles (eighty km). The MS Challenge Walk is an example of a fifty mile walk which raises money to fight multiple sclerosis. The Oxfam Trailwalker is a one hundred km event.
In Britain, the Ramblers' Association is the biggest organization that looks after the interests of walkers. A registered charity, it has 139 000 members. Regular, brisk cycling or walking can improve confidence, stamina, energy, weight control, life expectancy and reduce stress. It can also reduce the risk of coronary heart disease, strokes, diabetes, high blood pressure, bowel cancer and osteoporosis. Modern scientific studies have showed that walking, besides its physical benefits, is also beneficial for the mind — improving memory skills, learning ability, concentration and abstract reasoning, besides reducing stress and uplifting ones' spirits. Source
"Walking is convenient, it needs no special equipment, is self-regulating and inherently safe. Walking is as natural as breathing". John Butcher, Founder Walk21, 1999
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. Some communities are at least partially car-free, making them particularly supportive of walking and other modes of transportation. In the United States, the Active Living network is an example of a concerted effort to develop communities more friendly to walking and other physical activities. Walk England is an example of a similar movement.
Walking is also considered to be clear example of sustainable mode of transport, especially suited for urban use and/or relatively shorter distances. Non Motorised Transport modes such as walking, but also cycling, small-wheeled transport (skates, skateboards, push scooters and hand carts) or wheelchair travel are often key elements of successfully encouraging clean urban transport (Source: Non Motorised Transport, Teaching and Learning Material). A large variety of case studies and good practices (from European cities and some world-wide examples) that promote and stimulate walking as a means of transportation in cities can be found at Eltis, Europe's portal for local transport.
However, some studies indicate that walking is more harmful to the environment than car travel. This is because more energy is expended in growing and providing the food necessary to regain the calories burned by walking compared to the energy used in the operation of a car These studies have been criticised for using inefficient food sources (i.e. those that use large amounts of energy to produce) such as milk or meat to skew the results..
When distances are too great to be convenient, walking can be combined with other modes of transportation, such as cycling, public transport, car sharing, carpooling, hitchhiking, ride sharing, car rentals and taxis. These methods may be more efficient or desirable than private car ownership, being a healthy means of physical exercise.
The development of specific rights of way with appropriate infrastructure can promote increased participation and enjoyment of walking. Examples of types of investment include malls, and foreshoreways such as oceanways and riverwalks.