Editing Walking (section)

==Difference from running==
{{main|Running}}
{{See also|Jogging}}
[[File:1987WorldCupTrials.jpg|thumb|Racewalkers at the World Cup Trials in 1987]]

The word ''walk'' is descended from the [[Old English language|Old English]] ''wealcan'' 'to roll'. In [[human]]s and other [[biped]]s, 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. In contrast, running begins when both feet are off the ground with each step. This distinction has the status of a formal requirement in [[Racewalking|competitive walking]] events. For [[quadruped]]al species, there are numerous [[gait]]s 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.<ref name="Bie">{{cite book |last=Biewener |first=A. A. |year=2003 |title=Animal Locomotion |publisher=Oxford University Press |isbn= 978-0-19-850022-3 |url=https://books.google.com/books?id=yMaN9pk8QJAC&q=biomechanics+biewener }}</ref> 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. During walking, the centre of mass reaches a maximum height at mid-stance, while running, it is then at a minimum. This distinction, however, only holds true for locomotion over level or approximately level ground. For walking up grades above 10%, this distinction no longer holds for some individuals. Definitions based on the percentage of the stride during which a foot is in contact with the ground (averaged across all feet) of greater than 50% contact corresponds well with identification of 'inverted pendulum' mechanics and are indicative of walking for animals with any number of limbs, however this definition is incomplete.<ref name="Bie"/> Running humans and animals may have contact periods greater than 50% of a gait cycle when rounding corners, running uphill or carrying loads.

Speed is another factor that distinguishes walking from running. Although walking speeds can vary greatly depending on many factors such as height, weight, age, terrain, surface, load, culture, effort, and fitness, the average human [[Preferred Walking Speed|walking speed]] at crosswalks is about 5.0 kilometres per hour (km/h), or about 1.4 meters per second (m/s), or about 3.1 miles per hour (mph). Specific studies have found [[pedestrian]] walking speeds at crosswalks ranging from {{convert|4.51|to|4.75|km/h|mph|abbr=on}} for older individuals and from {{convert|5.32|to|5.43|km/h|mph|abbr=on}} for younger individuals;<ref>{{cite web|url=http://www.usroads.com/journals/p/rej/9710/re971001.htm|title=Study Compares Older and Younger Pedestrian Walking Speeds|publisher=TranSafety, Inc|date=1997-10-01|access-date=2009-08-24|archive-date=2009-07-03|archive-url=https://web.archive.org/web/20090703084118/http://www.usroads.com/journals/p/rej/9710/re971001.htm|url-status=dead}}</ref><ref>{{cite web|url=http://www.westernite.org/datacollectionfund/2005/psu_ped_summary.pdf|title=Establishing Pedestrian Walking Speeds|first=Karen|last=Aspelin|date=2005-05-25|publisher=[[Portland State University]]|access-date=2009-08-24|archive-url=https://web.archive.org/web/20051225181534/http://www.westernite.org/datacollectionfund/2005/psu_ped_summary.pdf|archive-date=2005-12-25|url-status=live}}</ref> a brisk walking speed can be around {{convert|6.5|km/h|mph|abbr=on}}.<ref>{{cite web|url=http://walking.about.com/od/measure/f/howfastwalking.htm|access-date=2012-08-17|title=about.com page on walking speeds|archive-date=2016-04-14|archive-url=https://web.archive.org/web/20160414183615/http://walking.about.com/od/measure/f/howfastwalking.htm|url-status=dead}}</ref> In Japan, the standard measure for walking speed is 80&nbsp;m/min (4.8&nbsp;km/h).
Champion [[racewalking|racewalkers]] can average more than {{convert|14|km/h|mph|abbr=on}} over a distance of {{convert|20|km|mi|abbr=on}}.

An average human child achieves independent walking ability at around 11 months old.<ref>{{cite journal |vauthors=Samra HA, Specker B |title=Walking Age Does Not Explain Term vs. Preterm Differences in Bone Geometry |journal=J. Pediatr. |volume=151 |issue=1 |pages=61–6, 66.e1–2 |date=July 2007 |pmid=17586192 |pmc=2031218 |doi=10.1016/j.jpeds.2007.02.033 }}</ref>