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A gait is a pattern of
limb Limb may refer to: Science and technology *Limb (anatomy), an appendage of a human or animal *Limb, a large or main branch of a tree *Limb, in astronomy, the curved edge of the apparent disk of a celestial body, e.g. lunar limb *Limb, in botany, t ...
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 Bipedalism is a form of terrestrial locomotion where an organism 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' (from Latin ''bis'' 'double' ...
, biphasic forward propulsion of the center of gravity of the human body, in which there are alternate
sinuous Sinuosity, sinuosity index, or sinuosity coefficient of a continuously differentiable curve having at least one inflection point is the ratio of the curvilinear length (along the curve) and the Euclidean distance ( straight line) between the ...
movements of different segments of the body with least expenditure of energy. Gait patterns are characterized by differences in limb-movement patterns, overall velocity, forces, kinetic and potential energy cycles, and changes in contact with the ground.


Classification

Human gaits are classified in various ways. Each gait can be generally categorized as either natural (one that humans use instinctively) or trained (a non-instinctive gait learned via training). Examples of the latter include
hand walking Hand walking is an unusual form of human locomotion in which a person travels in a vertically inverted orientation with all body weight resting on the hands. It can be executed with legs fully extended or with variations such as stag, straddle or ...
and specialized gaits used in
martial arts Martial arts are codified systems and traditions of combat practiced for a number of reasons such as self-defense; military and law enforcement applications; competition; physical, mental, and spiritual development; entertainment; and the pre ...
. Gaits can also be categorized according to whether the person remains in continuous contact with the ground.


Foot strike

One variable in gait is ''foot strike'' – how the foot contacts the ground, specifically which part of the foot first contacts the ground. * ''forefoot strike'' – toe-heel: ball of foot lands first * ''mid-foot strike'' – heel and ball land simultaneously * ''heel strike'' – heel-toe: heel of foot lands, then plantar flexes to ball In sprinting, gait typically features a forefoot strike, but the heel does not contact the ground. Some researchers classify foot strike by the initial center of pressure; this is mostly applicable to shod running (running while wearing shoes).Lieberman, Daniel
''Running Before the Modern Running Shoe''
Harvard University. Retrieved 2 December 2020.
In this classification: * a rear-foot strike (heel strike) has the initial center of pressure in the rear one-third of shoe length; * a mid-foot strike is in the middle third; * a forefoot strike is in the front third. Foot strike varies to some degree between strides, and between individuals. It varies significantly and notably between walking and running, and between wearing shoes (shod) and not wearing shoes (barefoot). Typically, barefoot walking features heel or mid-foot strike, while
barefoot running Barefoot running, also called "natural running", is the act of running without footwear. With the advent of modern footwear, running barefoot has become less common in most parts of the world but is still practiced in parts of Africa and Latin Am ...
features mid-foot or forefoot strike. Barefoot running rarely features heel strike because the impact can be painful, the human heel pad not absorbing much of the force of impact. By contrast, 75% of runners wearing modern running shoes heel strike;Lieberman, Daniel
''Modern Running Shoes & Heel Striking''
Harvard University. Retrieved 2 December 2020.
running shoes are characterized by a padded sole, stiff soles and arch support, and slope down from a more-padded heel to a less-padded forefoot. The cause of this change in gait in shoe running is unknown, but Lieberman noted that there is
correlation In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistic ...
between the foot-landing style and exposure to shoes. In some individuals, the gait pattern is largely unchanged – the leg position and foot position are identical in barefoot and shoe running – but the wedge shape of the padding moves the point of impact back from the forefoot to the mid-foot. In other cases, it is believed that the padding of the heel softens the impact and results in runners modifying their gait to move the point of contact further back in the foot. A 2012 study involving Harvard University runners found that those who "habitually rear-foot strike had approximately twice the rate of repetitive stress injuries than individuals who habitually forefoot strike". This was the first study that investigated the link between foot strike and injury rates. However, earlier studies have shown that smaller collision forces were generated when running forefoot strike compared to rear-foot strike. This may protect the ankle joints and lower limbs from some of the impact-related injuries experienced by rear-foot strikers. In a 2017 article called "Foot Strike Pattern in Children During Shod-Unshod Running", over 700 children aged 6–16 were observed using multiple video recording devices, to study their foot strike patterns and neutral support. Rear foot strike was most common, in both shod and unshod running, and in both boys and girls. There was a significant reduction in rear foot strike from shod to unshod: boys shod - 83.95% RFS, boys unshod - 62.65% RFS; girls shod - 87.85% RFS, girls unshod - 62.70% RFS. As-of 2021 there was a very low level of evidence to suggest a relationship between foot strike pattern and runner injury. Studies used retrospective designs, low sample size and potentially inaccurate self-reporting.


Control of gait by the nervous system

The
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all pa ...
regulates gait in a highly ordered fashion through a combination of voluntary and automatic processes. The basic locomotor pattern is an automatic process that results from rhythmic reciprocal bursts of flexor and extensor activity. This rhythmic firing is the result of
Central Pattern Generators Central pattern generators (CPGs) are self-organizing biological neural circuits that produce rhythmic outputs in the absence of rhythmic input. They are the source of the tightly-coupled patterns of neural activity that drive rhythmic and stereot ...
(CPGs), which operate regardless of whether a motion is voluntary or not. CPGs do not require sensory input to be sustained. However, studies have identified that gait patterns in deafferented or immobilized animals are more simplistic than in neurologically intact animals. (Deafferentation and immobilization are experimental preparations of animals to study neural control. ''Deafferentation'' involves transecting the dorsal roots of the spinal cord that innervate the animal's limbs, which impedes transmission of sensory information while keeping motor innervation of muscles intact. In contrast, ''immobilization'' involves injecting an
acetylcholine Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Pa ...
inhibitor, which impedes the transmission of motor signals while sensory input is unaffected.) The complexity of gait arises from the need to adapt to expected and unexpected changes in the environment (e.g., changes in walking surface or obstacles).
Visual The visual system comprises the sensory organ (the eye) and parts of the central nervous system (the retina containing photoreceptor cells, the optic nerve, the optic tract and the visual cortex) which gives organisms the sense of sight (the a ...
,
vestibular The Vestibular (from pt, vestíbulo, "entrance hall") is a competitive examination and is the primary and widespread entrance system used by Brazilian universities to select the students admitted. The Vestibular usually takes place from Nov ...
,
proprioceptive Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons ...
, and tactile sensory information provides important feedback related to gait and permits the adjustment of a person's posture or foot placement depending on situational requirements. When approaching an obstacle, visual information about the size and location of the object is used to adapt the stepping pattern. These adjustments involve change in the
trajectory A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete traje ...
of leg movement and the associated postural adjustments required to maintain their balance. Vestibular information provides information about position and movement of the head as the person moves through their environment. Proprioceptors in the joints and muscles provide information about joint position and changes in muscle length. Skin receptors, referred to as exteroceptors, provide additional tactile information about
stimuli A stimulus is something that causes a physiological response. It may refer to: *Stimulation **Stimulus (physiology), something external that influences an activity **Stimulus (psychology), a concept in behaviorism and perception *Stimulus (economi ...
that a limb encounters. Gait in humans is difficult to study due to
ethical Ethics or moral philosophy is a branch of philosophy that "involves systematizing, defending, and recommending concepts of right and wrong behavior".''Internet Encyclopedia of Philosophy'' The field of ethics, along with aesthetics, concerns ma ...
concerns. Therefore, the majority of what is known about gait regulation in humans is ascertained from studies involving other animals or is demonstrated in humans using
functional magnetic resonance imaging Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area ...
during the mental imagery of gait. These studies have provided the field with several important discoveries.


Locomotor centers

There are three specific centers within the brain that regulate gait: *
Mesencephalic Locomotor Region The mesencephalic locomotor region (MLR) is a functionally defined area of the midbrain that is associated with the initiation and control of locomotor movements in vertebrate species. Neuroanatomical organization The MLR was first described by S ...
(MLR)- Within the midbrain, the MLR receives input from the premotor cortex, the limbic system, cerebellum, hypothalamus, and other parts of the brainstem. These neurons connect to other neurons within the mesencephalic reticular formation which then descend to the via the ventrolateral funiculus to the spinal locomotor networks. Studies where the MLR of
decerebrate Decerebration is the elimination of cerebral brain function in an animal by removing the cerebrum, cutting across the brain stem, or severing certain arteries in the brain stem. As a result, the animal loses certain reflexes that are integrat ...
cats have been stimulated either electrically or chemically have shown that increased intensity of stimulation has led to increased speed of stepping. Deep brain stimulation of the MLR in individuals with Parkinson's has also led to improvements in gait and posture. * Sub thalamic Locomotor Region (SLR)- The SLR is part of hypothalamus. It activates the spinal locomotor networks both directly and indirectly via the MLR. *
Cerebellar The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebel ...
Locomotor Region (CLR)- Similar to the SLR, the CLR activates the reticulo-spinal locomotor pathway via direct and indirect projections. These centers are coordinated with the posture control systems within the cerebral hemispheres and the cerebellum. With each behavioral movement, the sensory systems responsible for posture control respond. These signals act on the cerebral cortex, the cerebellum, and the brainstem. Many of these pathways are currently under investigation, but some aspects of this control are fairly well understood.


Regulation by the cerebral cortex

Sensory input from multiple areas of the cerebral cortex, such as the visual cortex, vestibular cortex, and the primary sensory cortex, is required for skilled locomotor tasks. This information is integrated and transmitted to the
supplementary motor area The supplementary motor area (SMA) is a part of the motor cortex of primates that contributes to the control of movement. It is located on the midline surface of the hemisphere just in front of (anterior to) the primary motor cortex leg representa ...
(SMA) and premotor area of the cerebral cortex where motor programs are created for intentional limb movement and anticipatory postural adjustments. For example, the motor cortex uses visual information to increase the precision of stepping movements. When approaching an obstacle, an individual will make adjustments to their stepping pattern based on visual input regarding the size and location of the obstacle. The primary motor cortex is responsible for the voluntary control for the contralateral leg while the SMA is linked to postural control.


Regulation by the cerebellum

The cerebellum plays a major role in
motor coordination Motor coordination is the orchestrated movement of multiple body parts as required to accomplish intended actions, like walking. This coordination is achieved by adjusting kinematic and kinetic parameters associated with each body part involved i ...
, regulating voluntary and involuntary processes. Regulation of gait by the cerebellum is referred to as “ error/correction,” because the cerebellum responds to abnormalities in posture in order to coordinate proper movement. The cerebellum is thought to receive sensory information (e.g. visual, vestibular) about actual stepping patterns as they occur and compare them to the intended stepping pattern. When there is a discrepancy between these two signals, the cerebellum determines the appropriate correction and relays this information to the brainstem and motor cortex. Cerebellar output to the brainstem is thought to be specifically related to postural muscle tone while output to the motor cortex is related to cognitive and motor programming processes. The cerebellum sends signals to the cerebral cortex and the brain stem in response to sensory signals received from the spinal cord. Efferent signals from these regions go to the spinal cord where motor neurons are activated to regulate gait. This information is used to regulate balance during stepping and integrates information about limb movement in space, as well as head position and movement.


Regulation by the spinal cord

Spinal reflexes not only generate the rhythm of locomotion through CPGs but also ensure postural stability during gait. There are multiple pathways within the spinal cord which play a role in regulating gait, including the role of
reciprocal inhibition Reciprocal inhibition describes the relaxation of muscles on one side of a joint to accommodate contraction on the other side. In some allied health disciplines, this is known as reflexive antagonism. The central nervous system sends a message to ...
and
stretch reflex The stretch reflex (myotatic reflex), or more accurately "muscle stretch reflex", is a muscle contraction in response to stretching within the muscle. The reflex functions to maintain the muscle at a constant length. The term deep tendon reflex is ...
es to produce alternating stepping patterns. A stretch reflex occurs when a muscle is stretched and then contracts protectively while opposing muscle groups relax. An example of this during gait occurs when the weight-bearing leg nears the end of the stance phase. At this point the hip extends and the hip flexors are elongated.
Muscle spindles Muscle spindles are stretch receptors within the body of a skeletal muscle that primarily detect changes in the length of the muscle. They convey length information to the central nervous system via afferent nerve fibers. This information can be ...
within the hip flexors detect this stretch and trigger muscle contraction of the hip flexors required for the initiation of the swing phase of gait. However,
Golgi tendon organs The Golgi tendon organ (GTO) (also called Golgi organ, tendon organ, neurotendinous organ or neurotendinous spindle) is a proprioceptor – a type of sensory receptor that senses changes in muscle tension. It lies at the interface between a musc ...
in the extensor muscles also send signals related to the amount of weight being supported through the stance leg to ensure that limb flexion does not occur until the leg is adequately unweighted and the majority of weight has been transferred to the opposite leg. Information from the spinal cord is transmitted for higher order processing to supraspinal structures via spinothalamic, spinoreticular, and spinocerebellar tracts.


Natural gaits

The so-called natural gaits, in increasing order of speed, are the
walk Walking (also known as ambulation) is one of the main gaits of terrestrial locomotion among legged animals. Walking is typically slower than running and other gaits. Walking is defined by an 'inverted pendulum' gait in which the body vaults ov ...
, jog,
skip Skip or Skips may refer to: Acronyms * SKIP (Skeletal muscle and kidney enriched inositol phosphatase), a human gene * Simple Key-Management for Internet Protocol * SKIP of New York (Sick Kids need Involved People), a non-profit agency aiding ...
, run, and sprint. While other intermediate speed gaits may occur naturally to some people, these five basic gaits occur naturally across almost all cultures. All natural gaits are designed to propel a person forward, but can also be adapted for lateral movement. As natural gaits all have the same purpose, they are mostly distinguished by when the leg muscles are used during the gait cycle.


Walk

Walking Walking (also known as ambulation) is one of the main gaits of terrestrial locomotion among legged animals. Walking is typically slower than running and other gaits. Walking is defined by an ' inverted pendulum' gait in which the body vaults o ...
involves having at least one foot in contact with the ground at all times. There is also a period of time within the gait cycle where both feet are simultaneously in contact with the ground. When a foot is lifted off the ground, that limb is in the "swing phase" of gait. When a foot is in contact with the ground, that limb is in the "stance phase" of gait. A mature walking pattern is characterized by the gait cycle being approximately 60% stance phase, 40% swing phase. Initiation of gait is a voluntary process that involves a preparatory postural adjustment where the
center of mass In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
is moved forward and laterally prior to unweighting one leg. The center of mass is only within a person's base of support when both feet are in contact with the ground (known as double limb stance). When only one foot is in contact with the ground (single limb stance), the center of mass is in front of that foot and moving towards the leg that is in the swing phase.


Skip

Skipping is a gait children display when they are about four to five years old. While a jog is similar to a horse's
trot The trot is a ten-beat diagonal horse gait where the diagonal pairs of legs move forward at the same time with a moment of suspension between each beat. It has a wide variation in possible speeds, but averages about . A very slow trot is someti ...
, the skip is closer to the bipedal equivalent of a horse's
canter The canter and gallop are variations on the fastest gait that can be performed by a horse or other equine. The canter is a controlled three-beat gait, while the gallop is a faster, four-beat variation of the same gait. It is a natural gait pos ...
. In order to investigate the gait strategies likely to be favored at low gravity, a study by Ackermann and Van Den Bogert ran a series of predictive, computational simulations of gait using a physiological model of the musculoskeletal system, without assuming any particular type of gait. They used a computationally efficient optimization strategy, allowing for multiple simulations. Their results reveal skipping as more efficient and less fatiguing than walking or running and suggest the existence of a walk-skip rather than a walk-run transition at low gravity.


Gait patterns in children

Time and distance parameters of gait patterns are dependent on a child's
age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...
. Different age leads to different step speed and timing. Arm swinging slows when the speed of walking is increased. Height of a child plays a significant role in stride distance and speed. The taller the child is the longer the stride will be and the further the step will be. Gait patterns are
velocity Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity ...
and age dependent. For example, as age increased so did velocity. Meanwhile, as age increases, cadence (rate at which someone walks that is measured in steps per minute) of the gait pattern decreased. Physical attributes such as height, weight, and even head circumference can also play a role in gait patterns in children. Environmental and emotional status also play a role in with speed, velocity, and gait patterns that a child uses. Besides, children of different genders will have different rates of gait development. Significant developmental changes in gait parameters such as stride time, swing time, and cadence occur in a child's gait two months after the onset of independent walking, possibly due to an increase in postural control at this point of development. By the age of three, most children have mastered the basic principles of walking, consistent with that of adults. Age is not the only deciding factor in gait development. Gender differences have been seen in young children as early as three years old. Girls tend to have a more stable gait than boys between the ages of 3–6 years old. Another difference includes the plantar contact area. Girls showed a smaller contact area in plantar loading patterns than boys in children with healthy feet.


Sex differences

There are sex differences in human gait patterns: female-assigned people tend to walk with smaller step width and more pelvic movement.
Gait analysis Gait analysis is the systematic study of animal locomotion, more specifically the study of human motion, using the eye and the brain of observers, augmented by instrumentation for measuring body movements, body mechanics, and the activity of the ...
generally takes biological sex into consideration. Sex differences in human gait can be explored using a demonstration created by the BioMotion Laboratory at
York University York University (french: Université York), also known as YorkU or simply YU, is a public research university in Toronto, Ontario, Canada. It is Canada's fourth-largest university, and it has approximately 55,700 students, 7,000 faculty and sta ...
in Toronto.


Efficiency and evolutionary implications

Even though plantigrade locomotion usually distributes more weight toward the end of the limb than digitigrade locomotion, which increases energy expenditure in most systems, studies have shown that humans are economical walkers, but not economical runners, which is said to be consistent with evolutionary specialization for both economical walking and endurance running. For the same distance, walking with a natural heel-first gait burns roughly 70% less energy than running. Differences of this magnitude are unusual in mammals. Kathyrn Knight of the ''
Journal of Experimental Biology ''Journal of Experimental Biology'' (formerly ''The British Journal of Experimental Biology)'' is a peer-reviewed scientific journal in the field of comparative physiology and integrative biology. It is published by The Company of Biologists. Th ...
'' summarizes the findings of one study: "Landing heel first also allows us to transfer more energy from one step to the next to improve our efficiency, while placing the foot flat on the ground reduces the forces around the ankle (generated by the ground pushing against us), which our muscles have to counteract." According to David Carrier of the
University of Utah The University of Utah (U of U, UofU, or simply The U) is a public research university in Salt Lake City, Utah. It is the flagship institution of the Utah System of Higher Education. The university was established in 1850 as the University ...
, who helped perform the study, "Given the great distances hunter-gatherers travel, it is not surprising that humans are economical walkers."


Key determinants of gait

A normal gait pattern depends on a range of biomechanical features, controlled by the nervous system for increased energy conservation and
balance Balance or balancing may refer to: Common meanings * Balance (ability) in biomechanics * Balance (accounting) * Balance or weighing scale * Balance as in equality or equilibrium Arts and entertainment Film * ''Balance'' (1983 film), a Bulgaria ...
.Kuo, A. D.; Donelan, J. M. (2010). "Dynamic principles of gait and their clinical implications". ''Physical Therapy'', 90(2), 157. These biomechanical features of normal gait have been defined as key determinants of gait. It is therefore necessary for the refined neurological control and integration of these gait features for accuracy and precision with less energy expenditure. As a result, any abnormality of the neuro-musculo-skeletal system may lead to abnormality in gait and increased energy expenditure. The six
kinematics Kinematics is a subfield of physics, developed in classical mechanics, that describes the motion of points, bodies (objects), and systems of bodies (groups of objects) without considering the forces that cause them to move. Kinematics, as a fi ...
or determinants of gait, described below, were introduced by Saunders et al. in 1953,Saunders, J.; Inman, V.; Eberhart, H. (1953). "The major determinants in normal and pathological gait". ''American Journal of Bone and Joint Surgery'', 35, 543–558. and have been widely embraced with various refinements. Recent studies have suggested that the first three determinants might contribute less to reducing the vertical displacement of the
center of mass In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
(COM). These determinants of gait are known to ensure economical locomotion, by the reduction in vertical
center of mass In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
(COM) excursion leading to reduction in metabolic energy. It is therefore suggested that the precise control of these determinants of gait leads to increased energy conservation. These kinematic features of gait are integrated or coordinated in order to ensure a circular arc trajectory of the COM, as theory proposed as the 'compass gait (straight knee)'. The theory underlying the determinants run contrary to that of the 'inverted pendulum' theory with a static stance leg acting as a pendulum that prescribes an arc. The six determinants of gaits and their effects on COM displacement and energy conservation are described below in chronological order: #Pelvic rotation: This kinematic feature of gait operates under the theory of compass gait model.Della Croce, U.; Riley, P. O.; Lelas, J. L.; Kerrigan, D. C. (2001). "A refined view of the determinants of gait". ''Gait & Posture'', 14(2), 79–84. In this model, the
pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...
rotates side to side during normal gait. In effect, it aids in the progression of the contralateral side through reduced hip flexion and extension. Its effect on the reduction of metabolic energy and the increased energy conservation is through the reduction of vertical COM displacement. This notion of reduction of metabolic cost may be disputed by a study done by Gard and Childress (1997),Gard, S. A.; Childress, D. S. (1997). "The effect of pelvic list on the vertical displacement of the trunk during normal walking". ''Gait & Posture'', 5(3), 233–238. who stated that there may be minimal effect of pelvic rotation on vertical COM displacement. Furthermore, other studies have found pelvic rotation to have little effect on the smoothing of COM trajectory. Pelvic rotation has been shown to account for about 12% reduction in the total COM vertical displacement. #Pelvic tilt/Obliquity: Normal gait results in tilting of the swing phase side, in relation to the control by the stance side hip abductors. As a consequence, there is the neutralization of raising of COM during the transition from hip flexion to extension. Its effect on the reduction of
metabolic Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run ...
energy and the increased energy conservation is via the reduction of vertical COM trajectory or peak form compass gait model. Pelvic obliquity's effects on reduction of vertical displacement of COM has been examined and been shown to only reduce vertical displacement of COM by at most, only 2–4 mm. #Knee flexion at stance phase: The knee usually supports the body weight in flexed position during walking. The knee is usually fully extended at heel strike and then begins to flex (average magnitude of 15 degrees) when foot is completely flat on the ground. The effects of the stance-phase knee flexion is to lower the apex of vertical trajectory of the COM via shortening of the leg resulting in some energy conservation. But recent studies testing this third determinant of gait have reported varied results. It was found out that stance-phase knee flexion did not contribute to the reduction in vertical trajectory of COM. Furthermore, Gard and Childress (1997) indicated that maximum COM is reached at mid-stance when knee is slightly flexed, depicting minor reduction of the maximum height of the COM by a few millimeters. #Foot and ankle motions: Saunders et al. showed relationship between angular displacement and motions of foot, ankle and knee. This results in two intersecting arcs of rotation at the foot during stance phase at heel contact and heel rise. At heel contact the COM reaches its lowest point of downward displacement when the foot is dorsiflexed and the knee joint fully extended in order for the extremity to be at its maximum length. The ankle rockers at heel strike and mid-stance leads to decrease COM displacement through the shortening of the leg. Studies by Kerrigan et al. (2001) and Gard & Childress (1997) have showed the major role played by heel rise in reducing the COM vertical displacement. #Knee motion: The motion of the knee are related to those of the ankle and foot motions and results in the reduction of COM vertical displacement. Therefore, an immobile knee or ankle could lead to increases in COM displacement and energy cost. #Lateral pelvic displacement: In this key gait feature, the displacement of the COM is realized by the lateral shift of the pelvis or by relative
adduction Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...
of the hip. Correction of disproportionate lateral displacement of the pelvis is mediated by the effect of tibiofemoral angle, and relative adduction of the hip, which results in reduction in vertical COM displacement. It is clear that these kinematic features play a critical role in ensuring efficiency in normal gait. But there may be the need for further extensive testing or validation of each of the key determinants of gait.


Abnormal gaits

Abnormal gait is a result of one or more of these tracts being disturbed. This can happen developmentally or as the result of
neurodegeneration A neurodegenerative disease is caused by the progressive loss of structure or function of neurons, in the process known as neurodegeneration. Such neuronal damage may ultimately involve cell death. Neurodegenerative diseases include amyotrophic ...
. The most prominent example of gait irregularities due to developmental problems comes from studies of children on the
autism spectrum The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition (or conditions) characterized by difficulti ...
. They have decreased muscle coordination, thus resulting in abnormalities in gait. Some of this is associated with decreased muscle tone, also known as
hypotonia Hypotonia is a state of low muscle tone (the amount of tension or resistance to stretch in a muscle), often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases a ...
, which is also common in ASD. The most prominent example of abnormal gait as a result of neurodegeneration is Parkinson's. Although these are the best understood examples of abnormal gait, there are other phenomena that are described in the medical field. *
Antalgic gait An antalgic gait is a gait that develops as a way to avoid pain while walking ('' antalgic'' = ''anti-'' + '' alge'', "against pain"). It is a form of gait abnormality where the stance phase of gait is abnormally shortened relative to the swing ph ...
: limping caused by pain that appears or worsens when bearing weight on one limb, due to injury, disease, or other painful conditions * Charlie Chaplin gait: occurs in
tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...
l torsion. * Circumduction gait: occurs in
hemiplegia Hemiparesis, or unilateral paresis, is weakness of one entire side of the body ('' hemi-'' means "half"). Hemiplegia is, in its most severe form, complete paralysis of half of the body. Hemiparesis and hemiplegia can be caused by different medi ...
* Waddling gait: occurs in bilateral congenital hip dislocation * High stepping gait: occurs in
foot drop Foot drop is a gait abnormality in which the dropping of the forefoot happens due to weakness, irritation or damage to the deep fibular nerve (deep peroneal), including the sciatic nerve, or paralysis of the muscles in the anterior portion of ...
* Scissor gait: occurs in
cerebral palsy Cerebral palsy (CP) is a group of movement disorders that appear in early childhood. Signs and symptoms vary among people and over time, but include poor coordination, stiff muscles, weak muscles, and tremors. There may be problems with sen ...
* Stiff hip gait: occurs in
ankylosis Ankylosis is a stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint, which may be the result of injury or disease. The rigidity may be complete or partial and may be due to inflammation of the tendinous or muscular ...
of the hip * Trendelenburg gait: occurs in unstable hip due to congenital dislocation of hip,
gluteus medius The gluteus medius, one of the three gluteal muscles, is a broad, thick, radiating muscle. It is situated on the outer surface of the pelvis. Its posterior third is covered by the gluteus maximus, its anterior two-thirds by the gluteal aponeur ...
muscle weakness Abnormal gait can also be a result of a stroke. However, by using treadmill therapy to activate the cerebellum, abnormalities in gait can be improved.


See also

* Astasia abasia *
Contrapposto ''Contrapposto'' () is an Italian term that means "counterpoise". It is used in the visual arts to describe a human figure standing with most of its weight on one foot, so that its shoulders and arms twist off-axis from the hips and legs in the ...
* Gait abnormality * Gait Abnormality Rating Scale *
Gait analysis Gait analysis is the systematic study of animal locomotion, more specifically the study of human motion, using the eye and the brain of observers, augmented by instrumentation for measuring body movements, body mechanics, and the activity of the ...
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Human positions Human positions refer to the different physical configurations that the human body can take. There are several synonyms that refer to human positioning, often used interchangeably, but having specific nuances of meaning. *''Position'' is a gen ...
* Marche a petit pas * Power walking *
Soft biometrics Soft Biometrics traits are physical, behavioural or adhered human characteristics, classifiable in pre–defined human compliant categories. These categories are, unlike in the classical biometric case, established and time–proven by humans with t ...
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Terrestrial locomotion in animals 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. As viewe ...


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Further reading

{{Locomotion Terrestrial locomotion Walking Posture Biomechanics