The term gait cycle is used in gait analysis. It is a criterion used to objectively describe the gait pattern.
What is the gait cycle?
The term gait cycle is used in gait analysis. It is a criterion used to describe the gait pattern in an objectified manner. Gait analysis involves the observation, examination, and documentation of human gait. It can be performed either with instrumental measuring devices that provide objectifiable data or by experienced observers using specific observation criteria. The gait cycle is one such criterion that describes the period of time that a leg passes through in a complete stance and swing leg phase. It begins with the touchdown of the heel at the start of the stance leg phase, progresses through it until the foot is lifted, which is followed by the swing leg phase. It ends when the heel touches down again. The same movement of the other leg is delayed by half a phase. A step comprises half a gait cycle and begins with the lifting of the foot at the start of the swing leg phase and ends when the heel makes contact with the ground again at the end. In terms of the overall gait pattern, 2 steps are taken during a gait cycle. In order to better and more accurately analyze and describe the very complex movement sequence, it is divided into further subphases, each of which is assigned to the stance or swing leg phase.
Function and task
The gait cycle serves as a descriptive tool in gait analysis, particularly as an aid for observing temporal and spatial extension in lateral comparison. In unilateral disorders, the affected leg, called the reference leg, is usually assessed in comparison with the other side. Various criteria are available to analyze quantitative and qualitative processes. Gait rhythm is one such characteristic that affects the entire gait cycle. It compares the periods of time during which the gait cycles of both legs or the associated subphases occur. In a physiological gait pattern, the respective movement cycles on the left and right are of equal length. Stride length measures the spatial distance from the tip of one foot to the heel of the other when walking. For this criterion, standard measurements can be used for comparison, on the basis of which the classification as too short or too long is made. Together with the step frequency, statements can be made about the walking speed and mobility of the observed person. A qualitative criterion for the correct description of the gait cycle is the observation of the coordinative sequence of the movement process. This means the purposeful movement taking place in the physiological trajectories, without temporal and spatial deviations. The documentation of the observation and assessment results is an important consideration for the usefulness of a gait analysis, regardless of whether it is created with computer-assisted programs or manually using documentation sheets. The knowledge gained can be used for therapy planning and at a later time for comparing the results after a therapy sequence has been completed. Success or non-success of the treatment then determines whether it is continued as before or modified or terminated. During the gait cycle, there are three main functional tasks to be performed. At the beginning, coming from the swing leg phase, the weight transfer must take place. Then, weight must be maintained on one leg while simultaneously pushing forward. Finally, in the swing leg phase, the free leg must be moved forward. In addition to an intact musculoskeletal system, a prerequisite for these tasks to occur correctly and without interference is a functioning control system through the neural network.
Diseases and ailments
Disruption of gait rhythm usually occurs when the timing is normal on one side, while it is shortened on the other due to disease or injury. Various causes can reduce the periods during which the stance leg or swing leg phases occur. These include pain, limited range of motion, loss of strength, and coordination problems. The stance leg phase is often affected when pain is created or exacerbated by the pressure that occurs. This can occur as a result of injuries affecting the muscles that must hold against gravity and accomplish forward thrust.Strains and muscle fiber tears in the anterior and posterior thigh muscles, the adductors of the hip joint, and the calf muscles are common injuries of this type. Damage in and around the joint that causes pain directly or indirectly by increasing pressure on the bone also modifies the execution of the stance leg phase. Meniscal lesions or knee and hip arthroses are such conditions. In all cases, changes in gait rhythm and stride length are the result, manifesting in a limping gait pattern, as the stance leg phase is shortened in time and space on the affected side to escape the pain as quickly as possible. The same applies to the swing leg phase, but it affects more the muscles that move against gravity, especially the hip flexors. A symmetrical change in step length and gait cycles occurs in Parkinson’s disease. It is known for the typical small-stepped and tripping gait pattern. Other neurological diseases of the central nervous system may affect the coordinative execution of gait. Hemiplegia following a stroke usually leads to extensor spasticity in the affected leg. In addition to the coordinative components, all other gait criteria are altered. The leg is moved forward in a circular motion and with difficulty in finding the target, and is touched down with the forefoot only. The contact phase and stride length are shortened to bring the other leg forward as quickly as possible. A hallmark of multiple sclerosis and other ataxic disorders is an unsteady and uncoordinated gait, which is a combination of coordination problems and a symmetrical change in stride length and track width. The result is a wide-legged gait pattern characterized by unsteadiness and wobbly uncoordinated steps. This gait pattern change is also occasionally seen after too much alcohol consumption.
