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Walking: the story on HearLore | HearLore
Walking
The human body vaults over a stiff limb with each step, a mechanical strategy known as an inverted pendulum that defines the very essence of walking. This biomechanical principle applies to creatures with six, eight, or more limbs, proving that the mechanics of ambulation are far more universal than the simple act of moving from point A to point B. While the average human walks at a speed of 5.0 kilometres per hour, the physics of this motion involve a complex trade-off between kinetic and potential energy. As the leg strikes the ground with the heel and rolls through to the toe, the calf muscles contract to raise the body's center of mass, storing potential energy. Gravity then pulls the body forward and down onto the other leg, transforming that stored energy into kinetic energy. This process saves approximately 65 percent of the energy used by relying on gravity rather than constant muscle power. The distinction between walking and running is not merely a matter of speed but of the center of mass height; during walking, the center of mass reaches a maximum height at mid-stance, whereas in running, it is at a minimum. This mechanical difference holds true for locomotion over level ground, though the rules shift when walking up grades above 10 percent. The word walk itself descends from the Old English wealcan, meaning to roll, hinting at the ancient, rolling motion that has sustained life for millions of years.
The Energy Advantage
Bipedal walking emerged as one of the first defining characteristics of hominin ancestors, predating other traits of the Hominidae family by millions of years. Fossil evidence from footprints discovered on a former shore in Kenya suggests that ancestors of modern humans were walking in ways similar to the present activity as long as 3 million years ago. This evolutionary leap provided a selective advantage due to metabolic energy efficiency, allowing early humans to travel further with less effort than their quadrupedal counterparts. A 2007 study revealed that the energy spent in moving the human body is approximately 75 percent less costly than that of chimpanzees. While chimpanzees expend one-hundred and fifty percent of the energy required for travel compared to true quadrupeds, humans utilize an upright posture that places ground reaction forces at the hip and knee to reduce muscle use. The energy efficiency of human locomotion is further enhanced by longer legs and short dorsally oriented ischia, which result in longer hamstring extensor moments. Even early hominins like Ardipithecus ramidus, which possessed both terrestrial and arboreal adaptations, developed an energy-efficient means of bipedal walking while maintaining the ability to climb. The presence of long femoral necks means that hip muscles do not require as much energy to flex while moving, and lengthened Achilles tendons increase energy efficiency in bipedal locomotor activities. This evolutionary shift allowed humans to become the dominant means of locomotion among early hominins, saving energy that could be used for other survival tasks.
Common questions
What is the biomechanical principle that defines the human walking gait?
The human body vaults over a stiff limb with each step using a mechanical strategy known as an inverted pendulum. This principle applies to creatures with six, eight, or more limbs and defines the mechanics of ambulation as a universal phenomenon.
When did fossil evidence show that hominin ancestors were walking in ways similar to modern humans?
Fossil evidence from footprints discovered on a former shore in Kenya suggests that ancestors of modern humans were walking in ways similar to the present activity as long as 3 million years ago. This evolutionary leap provided a selective advantage due to metabolic energy efficiency.
How many steps per day reduce the risk of dying from cardiovascular diseases according to a 2023 study?
A 2023 study by the European Journal of Preventive Cardiology found that walking at least 2,337 steps a day reduced the risk of dying from cardiovascular diseases. The study also found that 3,967 steps a day reduced the risk of dying from any cause.
Which city opened the first purpose-built pedestrian street in Europe and when did it open?
The first purpose-built pedestrian street in Europe is the Lijnbaan in Rotterdam, which opened in 1953. This development marked a significant shift in urban planning to prioritize walking over motor vehicles.
What is the average speed of a human walk and how does it compare to the speed of a racewalker?
The average human walks at a speed of 5.0 kilometres per hour. Champion racewalkers can average more than 14 kilometres per hour over a distance of 20 kilometres, a feat that requires immense endurance and technical precision.
How many years ago did neural mechanisms for walking evolve in little skates?
Little skates 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. This occurred before vertebrates set foot on land and represents an early form of walking.
Competitive racewalking presents a unique paradox where athletes must maintain a speed comparable to Olympic 800-meter runners while adhering to the strict rule that one foot must appear to be in contact with the ground at all times. This formal requirement distinguishes the sport from running, where both feet leave the ground during each step. To achieve these competitive speeds, racewalkers must attain cadence rates that rival elite runners, yet they must do so for hours at a time during Olympic events like the 20-kilometer race walk. The history of this sport traces back to pedestrianism, a popular spectator sport in the British Isles during the late eighteenth and nineteenth centuries. By the mid-19th century, competitors were expected to extend their legs straight at least once in their stride and obey the vague commandment known as the fair heel and toe rule. Newspaper reports from that era suggest that trotting was common in events, and racers were usually allowed to jog to fend off cramps, with distance rather than code determining the gait. The sport eventually evolved into modern racewalking, with the first codification occurring in the last half of the 19th century. Champion racewalkers can average more than 14 kilometres per hour over a distance of 20 kilometres, a feat that requires immense endurance and technical precision. The distinction between walking and running in these events is so critical that it is measured using motion capture or force plates to determine the height of a person's center of mass at mid-stance.
The Health Wonder Drug
Walking has been described by James Leiper, associate medical director at the British Heart Foundation, as a wonder drug if its benefits could be sold as medicine. A 2023 study by the European Journal of Preventive Cardiology, the largest to date, found that walking at least 2,337 steps a day reduced the risk of dying from cardiovascular diseases, and that 3,967 steps a day reduced the risk of dying from any cause. The Centers for Disease Control and Prevention reported that those with diabetes who walked for two or more hours a week lowered their mortality rate from all causes by 39 percent. Women who took 4,500 steps to 7,500 steps a day seemed to have fewer premature deaths compared to those who only took 2,700 steps a day. Even a light walk after a meal offers benefits in reducing postprandial glucose spikes in people with or at risk for type 2 diabetes. Sustained walking sessions for a minimum period of 30 to 60 minutes a day, five days a week, with the correct walking posture may improve health, including memory skills, learning ability, concentration, mood, creativity, and abstract reasoning. Regular, brisk exercise can improve confidence, stamina, energy, weight control, and may reduce stress. The benefits of walking extend to mental health, with studies showing that it improves the mind's ability to function. The average human child achieves independent walking ability at around 11 months old, marking the beginning of a lifetime of health benefits that continue to be discovered and quantified by modern science.
The Ancient Origins
The theory that walking originated underwater with air-breathing fish that could walk underwater gives rise to the plethora of land-dwelling life that walk on four or two limbs. 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. While terrestrial tetrapods are theorized 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. The fossil record indicates that among hominin ancestors, bipedal walking was one of the first defining characteristics to emerge, predating other defining characteristics of Hominidae. The ability to walk on land was a crucial adaptation that allowed early life forms to transition from the ocean to the terrestrial environment. This evolutionary leap was not immediate but occurred over millions of years, with various species developing different walking gaits to suit their environments. The walking gait of humans is unique and differs significantly from bipedal or quadrupedal walking gaits of other primates, like chimpanzees. 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. This evolutionary history is a testament to the adaptability and resilience of life on Earth, with walking serving as a fundamental mode of locomotion for countless species.
The Walking Varieties
The figure of the flâneur, a person with leisure time that strolls the city streets observing city life and architecture, appeared with the development of large cities with a bourgeois class, such as Paris. The concept of walkability has arisen as a measure of the degree to which an area is friendly to walking, allowing commuting, shopping, and recreation to be done on foot. The first purpose-built pedestrian street in Europe is the Lijnbaan in Rotterdam, opened in 1953, and the first pedestrianised shopping centre in the UK was in Stevenage in 1959. Central Copenhagen is one of the largest and oldest pedestrian zones, converted from car traffic into a pedestrian zone in 1962. The world's largest multi-day walking event is the International Four Days Marches Nijmegen in the Netherlands, an annual walk that has taken place since 1909. Numbers have risen in recent years, with over 40,000 now taking part, including about 5,000 military personnel. In the U.S., there is the annual Labor Day walk on Mackinac Bridge, Michigan, which draws over 60,000 participants, while the Chesapeake Bay Bridge Walk in Maryland draws over 50,000 participants each year. These events highlight the importance of walking as a form of tourism and community engagement. The development of specific rights of way with appropriate infrastructure can promote increased participation and enjoyment of walking, with examples including pedestrian malls and foreshoreways such as oceanways and river walks. The pedestrian village, a compact, pedestrian-oriented neighborhood or town, represents a modern approach to urban planning that prioritizes walking over motor vehicles. Venice, Italy, is essentially a pedestrian village with canals, while the canal district in Venice, California, combines the front lane/rear street approach with canals and walkways. These urban planning efforts reflect a
The Urban Walker
growing recognition of the benefits of walking for both individual health and community well-being.
The study of walking extends beyond biology into the realm of robotics and mathematics, where scientists attempt to replicate the complex mechanics of human locomotion. Generally, the first successful walking robots had six legs, but as microprocessor technology advanced, the number of legs could be reduced, and there are now robots that can walk on two legs, such as ASIMO. In 2009, Japanese roboticist Tomotaka Takahashi developed a robot that can jump three inches off the ground, named Ropid, which is capable of getting up, walking, running, and jumping. Despite 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. Multiple mathematical models have been proposed to reproduce the kinematics observed in walking, including rule-based models, weakly coupled phase oscillators models, control-based models, and phenomenological models. Rule-based models integrate the past literature on motor control to generate a few simple rules which are presumed to be responsible for walking, while coupled oscillator models explore the view of walking as a set of weakly coupled phase oscillators. Control-based models start with a simulation based on some description of the animal's anatomy and optimize control parameters to generate some behavior, and phenomenological models model the kinematics of walking directly by fitting a dynamical system. These models help scientists understand the neural coding underlying walking behaviors and the biomechanical properties of locomotion. The study of walking in animals, from horses to elephants, provides further insights into the diversity of walking gaits. Horses use a four-beat gait that averages about 5.5 kilometres per hour, while elephants can reach a top speed of 25 kilometres per hour, using their legs much like other running animals. The
The Mechanical Mind
ability to walk efficiently is a crucial adaptation for survival, and the study of walking continues to reveal new insights into the mechanics of locomotion.