Gait describes the motion of any animal as it moves across the land, whether walking, running, crawling, or hopping. Human gait refers to the normal patterns exhibited by humans, usually while walking or running in an upright posture. Gait patterns may be described by the duration and pattern of footfalls during locomotion, the speed of locomotion, and the energy use required by the body during the activity. Typically, gait only refers to motion over solid ground, and is not used when describing the motion of animals while they are swimming or flying.
Human gait is a complex set of coordinated activities involving both voluntary and involuntary body systems. The brain, nerves, muscles and bones all work together so that body balance and stability are maintained while the weight of the body is continually shifted between the left and right foot. The muscles must contract and lengthen in a precise sequence to maintain a smooth and steady forward motion. Visual cues are also incorporated as the body must sense and alter its gait in response to changes in the substrate, such as a curb at the edge of a street or a patch of ice on the sidewalk. Doctors and scientists study normal human gait so that they have a baseline for diagnosing and interpreting abnormal human gait patterns.
Abnormalities in human gait patterns can indicate a number of underlying medical problems; because so many body systems are involved, a skilled doctor can get a good idea of what tests to order simply by observing a patient walk. Minor injuries to the feet, legs, or hips will alter a person's gait, and an obvious limp or favoring of the injured limb will be apparent. Spinal problems such as scoliosis or herniated disk can also change the way a person walks by altering the body's alignment, as well as affecting the function of the nerves in the legs and feet. Any deformity of the bones, muscles, and joints of the lower body will also be apparent in the person's gait and how the body compensates for the deformity.
Altered gait patterns can indicate more serious conditions such as Parkinson's disease, multiple sclerosis, muscular dystrophy, brain tumor, stroke and other types of brain injuries. Specific gait abnormalities have been observed and classified according to their underlying causes. Scissor gait, when the knees and legs cross over one another during walking, may indicate cerebral palsy, while a spastic or stiff gait could point to a possible brain tumor or stroke. Propulsive gait, in which the person walks hunched forward with head down, can indicate exposure to environmental toxins, Parkinson's disease, or reactions to certain medications.
Observation of gait is rarely used as the sole diagnostic test for any condition. Gait abnormalities are usually considered in combination with a review of the patient's medical history, family history, and onset of other symptoms. A person's gait patterns, when interpreted correctly, can give the doctor subtle but valuable clues and in some cases, speed up the process of diagnosing underlying problems and beginning the treatment process.
Treatment of gait abnormalities will obviously include treatment of any underlying conditions, as in the case of diabetic neuropathy or brain injuries. Physical therapy is often prescribed to strengthen and train the muscles of the lower extremities and to help the patient re-learn the coordination and balance required for walking. Special shoes, leg braces, and other orthotic devices may be used to provide stability during walking, and canes or walkers may be helpful to patients who experience balance problems.