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Crawling or quadrupedal movement is a method of human locomotion that makes use of all four limbs. It is one of the earliest gaits learned by human infants, [1] and has similar features to four-limbed movement in other primates and in non-primate quadrupeds. [2]
Crawling is used mainly:
Infants sometimes "crawl" with their stomachs on the ground as early as 3 months, but this crawling is infrequent with the baby remaining stationary most of the time. True crawling with the stomach off the ground and the baby frequently on the move usually develops between 7 and 11 months of age and lasts anywhere from a week to 4 months before the child switches to walking. Even after taking their first unaided steps, most babies still crawl part of the time until they have mastered walking. While crawling, infants gradually practice standing, at first by using people or objects for support and, later, without support. Crawling babies are notorious for getting into trouble, so parents are often advised to childproof their house before a baby reaches crawling age.
Though crawling is an important developmental milestone in children, it is not necessary for healthy development. [3] Some babies skip crawling and go directly to walking. Others "bottom shuffle" instead of crawling (sometimes referred to as "bum-shuffling", or "scooting"). Bottom-shuffling babies sit on their bottoms and push themselves forward using their legs, and sometimes their hands, often in specially reinforced trousers. Babies that bottom-shuffle tend to walk later than babies that crawl.
Whether infants crawl is also culturally determined. European parents in previous centuries discouraged it as being too animal-like. [3] They kept their children in long dresses and other clothes that made crawling difficult or impossible. [3] Some cultures consider it to be dirty and dangerous. [3]
Crawling is a specific four-beat gait involving the hands and knees. A typical crawl is left-hand, right-knee, right-hand, left-knee, or a hand, the diagonal knee, the other hand then its diagonal knee. This is the first gait most humans learn, and is mainly used during early childhood, or when looking for something on the floor or under low relief. It can be used to move with a lower silhouette, but there are better crawls for that purpose. This is the most natural of the crawls and is the one that requires the least effort.
The bear crawl is almost identical to the standard crawl, but the feet are used instead of the knees, which creates an arched or squatted body posture. This works as a faster crawl but requires more effort to maintain.
This involves holding a gymnastic bridge and making small steps with the arms and legs. It is similar to a crab walk in that the body locomotes in a supine posture, but the arms are in shoulder flexion alongside the head.
Because of its unusual appearance, bridgewalking has been used in several horror films to suggest the demonic possession of a character. These have included The Exorcist and The Unborn . Wrestler Bray Wyatt does this.
Also known as "creeping", this is often a baby's first form of locomotion. At the same time the baby develops arm strength to lift their chests, thereby helping forward momentum.[ citation needed ]
The crab crawl is used in crab soccer. It starts by sitting down with the feet and hands flat on the ground, the hips are then raised off the ground and the chest faces the sky. It is similar to a bridge walk in that both have quadrupedal locomotion with a supine torso, but here the arms are held behind the torso, with the shoulder joint being in hyperextension. Due to its inefficiency, it is more commonly used as a form of exercise than actual transportation. Crabwalking builds triceps endurance [4] and arm and leg strength, and is a recommended exercise of various school athletic departments and soccer organizations, such as USA football. [5]
The crab crawl is also useful for descending steep slopes with poor traction. Its feet-first orientation ensures a low center of mass to prevent tumbling, while the inverted posture allows one to see where they're going.
The leopard crawl is a military-specific crawl. There are two versions, the leopard crawl proper and a modified version for when carrying weapons in the hands. This is a two-beat gait like a trot: an arm/elbow is advanced with the diagonal knee. This is designed for the smallest silhouette possible, and the body is often nearly or actually touching the ground, and although the elbow and knee are the main focus, most of the respective limbs touch the ground.
The tiger crawl is essentially a highly accelerated combination of crawl and leopard crawl. It uses the hands and the knees/feet depending upon the situation, while maintaining a silhouette almost as small as that of the leopard crawl. This is relatively fast gait but can take large amounts of energy.
Bipedalism is a form of terrestrial locomotion where an animal moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped, meaning 'two feet'. Types of bipedal movement include walking or running and hopping.
The foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws and/or nails.
Quadrupedalism is a form of locomotion where animals have four legs that are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four legs is said to be a quadruped. Quadruped animals are found among both vertebrates and invertebrates.
Walking is one of the main gaits of terrestrial locomotion among legged animals. Walking is typically slower than running and other gaits. Walking is defined as an "inverted pendulum" gait in which the body vaults over the stiff limb or limbs with each step. This applies regardless of the usable number of limbs—even arthropods, with six, eight, or more limbs, walk. In humans, walking has health benefits including improved mental health and reduced risk of cardiovascular disease and death.
Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency. Different animal species may use different gaits due to differences in anatomy that prevent use of certain gaits, or simply due to evolved innate preferences as a result of habitat differences. While various gaits are given specific names, the complexity of biological systems and interacting with the environment make these distinctions "fuzzy" at best. Gaits are typically classified according to footfall patterns, but recent studies often prefer definitions based on mechanics. The term typically does not refer to limb-based propulsion through fluid mediums such as water or air, but rather to propulsion across a solid substrate by generating reactive forces against it.
Horses can use various gaits during locomotion across solid ground, either naturally or as a result of specialized training by humans.
A gait is a manner of limb movements made during locomotion. Human gaits are the various ways in which humans can move, either naturally or as a result of specialized training. Human gait is defined as bipedal forward propulsion of the center of gravity of the human body, in which there are sinuous movements of different segments of the body with little energy spent. Various gaits are characterized by differences in limb movement patterns, overall velocity, forces, kinetic and potential energy cycles, and changes in contact with the ground.
Knuckle-walking is a form of quadrupedal walking in which the forelimbs hold the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles. Gorillas and chimpanzees use this style of locomotion, as do anteaters and platypuses.
Terrestrial locomotion has evolved as animals adapted from aquatic to terrestrial environments. Locomotion on land raises different problems than that in water, with reduced friction being replaced by the increased effects of gravity.
The Family That Walks on All Fours is a BBC Two documentary that explored the science and the story of five individuals in the Ulas family, a Kurdish family in Southeastern Turkey that walk with a previously unreported quadruped gait.
The Ulas family of 19 is from rural southern Turkey. Five of the family members walk on all fours with their feet and the palms of their hands in what is called a "bear crawl". Their quadrupedal gait has never been reported in anatomically intact adult humans. The gait is different from the knuckle-walking quadrupedal gait of apes. In 2006, the family was the subject of a documentary: The Family That Walks On All Fours.
Gross motor skills are the abilities usually acquired during childhood as part of a child's motor learning. By the time they reach two years of age, almost all children are able to stand up, walk and run, walk up stairs, etc. These skills are built upon, improved and better controlled throughout early childhood, and continue in refinement throughout most of the individual's years of development into adulthood. These gross movements come from large muscle groups and whole body movement. These skills develop in a head-to-toe order. The children will typically learn head control, trunk stability, and then standing up and walking. It is shown that children exposed to outdoor play time activities will develop better gross motor skills.
A facultative biped is an animal that is capable of walking or running on two legs (bipedal), as a response to exceptional circumstances (facultative), while normally walking or running on four limbs or more. In contrast, obligate bipedalism is where walking or running on two legs is the primary method of locomotion. Facultative bipedalism has been observed in several families of lizards and multiple species of primates, including sifakas, capuchin monkeys, baboons, gibbons, gorillas, bonobos and chimpanzees. Several dinosaur and other prehistoric archosaur species are facultative bipeds, most notably ornithopods and marginocephalians, with some recorded examples within sauropodomorpha. Different facultatively bipedal species employ different types of bipedalism corresponding to the varying reasons they have for engaging in facultative bipedalism. In primates, bipedalism is often associated with food gathering and transport. In lizards, it has been debated whether bipedal locomotion is an advantage for speed and energy conservation or whether it is governed solely by the mechanics of the acceleration and lizard's center of mass. Facultative bipedalism is often divided into high-speed (lizards) and low-speed (gibbons), but some species cannot be easily categorized into one of these two. Facultative bipedalism has also been observed in cockroaches and some desert rodents.
Uner Tan was a Turkish neuroscientist and evolutionary biologist. He is best known for his discovery and study of the human quadrupedal condition he named the Uner Tan syndrome. He taught at Çukurova University until his retirement in 2004 and had previously taught at several other institutions.
Uner Tan syndrome (UTS) is a syndrome that was discovered by the Turkish evolutionary biologist Üner Tan. People affected by UTS walk with a quadrupedal locomotion and often have severe learning disabilities. Tan postulated that this is an example of "reverse evolution" (atavism). The proposed syndrome was featured in the 2006 BBC2 documentary The Family That Walks On All Fours.
The evolution of human bipedalism, which began in primates approximately four million years ago, or as early as seven million years ago with Sahelanthropus, or approximately twelve million years ago with Danuvius guggenmosi, has led to morphological alterations to the human skeleton including changes to the arrangement, shape, and size of the bones of the foot, hip, knee, leg, and the vertebral column. These changes allowed for the upright gait to be overall more energy efficient in comparison to quadrupeds. The evolutionary factors that produced these changes have been the subject of several theories that correspond with environmental changes on a global scale.
Comparative foot morphology involves comparing the form of distal limb structures of a variety of terrestrial vertebrates. Understanding the role that the foot plays for each type of organism must take account of the differences in body type, foot shape, arrangement of structures, loading conditions and other variables. However, similarities also exist among the feet of many different terrestrial vertebrates. The paw of the dog, the hoof of the horse, the manus (forefoot) and pes (hindfoot) of the elephant, and the foot of the human all share some common features of structure, organization and function. Their foot structures function as the load-transmission platform which is essential to balance, standing and types of locomotion.
Human locomotion is considered to take two primary forms: walking and running. In contrast, many quadrupeds have three distinct forms of locomotion: walk, trot, and gallop. Walking is a form of locomotion defined by a double support phase when both feet are on the ground at the same time. Running is a form of locomotion that does not have this double support phase.
Arm swing in human bipedal walking is a natural motion wherein each arm swings with the motion of the opposing leg. Swinging arms in an opposing direction with respect to the lower limb reduces the angular momentum of the body, balancing the rotational motion produced during walking. Although such pendulum-like motion of arms is not essential for walking, recent studies point that arm swing improves the stability and energy efficiency in human locomotion. Those positive effects of arm swing have been utilized in sports, especially in racewalking and sprinting.
| Stages of crawling in a baby (1 minute video) | |
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 https://www.youtube.com/watch?v=f3xWaOkXCSQ |