side of the leg to be assessed. at the point in time at which the leg to be viewed is in mid-stance and the leg not to be viewed in mid-swing, the knee angle and also the contact of the foot with the ground are assessed. in gait type 1, the knee angle is normal and foot contact is complete. in gait type 2, the knee angle is hyperextended and the foot contact is complete. in gait type 3, the knee angle is hyperextended and foot contact is incomplete (only on the forefoot). in gait type 4, the knee angle is flexed and foot contact is incomplete (only on the forefoot). at gait 5, the knee angle is flexed and foot contact is complete. gait type 5 is also known as crouch gait. patients with paralysis due to cerebral palsy or traumatic brain injury are usually treated with an ankle-foot orthosis (afo). the functional elements to be used in the orthosis are the same as the functional elements of an afo to compensate for paralysis of large muscle groups. however, it is important to understand that the muscle groups are not paralyzed, but are controlled by the brain with the wrong impulses. the compensatory gait is an unconscious reaction to the lack of security when standing or walking. the gait pattern usually worsens with increasing age. if the right functional elements are integrated into the orthosis, which both maintain physiological mobility and provide security when standing and walking, the necessary motor impulses can be created to create new cerebral connections. the goal of an orthotic fitting is the best possible approximation of the physiological gait pattern. stroke the n.a.p. gait classification facilitates the assessment of the gait pattern in stroke patients and helps to determine the gait type in the case of paralysis after a stroke, rapid care with an orthosis is necessary. often areas of the brain are affected that contain "programs" for controlling the musculoskeletal system. with the help of an orthosis, physiological standing and walking can be learned again, and late health consequences caused by a wrong gait pattern can be prevented. in order to consider the correct functional elements when configuring the orthosis, it is important to understand that the muscle groups are not paralyzed, but are controlled by the brain with wrong impulses, which is why a muscle function test according to vladimir janda can lead to incorrect results when assessing the ability to stand and walk. an important basic requirement for regaining the ability to walk is that the patient trains early on to be able to stand on both legs safely and well balanced. an orthosis with functional elements to support balance and safety when standing and walking can already be integrated into the therapy concept to support the first standing exercises. this makes the work of mobilizing the patient at an early stage easier. if the right functional elements are integrated into the orthosis, which both maintain physiological mobility and provide security when standing and walking, the necessary motor impulses can be created to create new cerebral connections. clinical studies confirm the importance of orthoses in stroke rehabilitation. patients with paralysis after a stroke are often treated with an ankle-foot orthosis (afo). after a stroke, it can happen that only the dorsiflexors are supplied with incorrect impulses from the central nervous system, which can lead to the risk of stumbling due to insufficient foot lifting when walking during swing phase. in these cases, an orthosis that only has functional elements to support the dorsiflexors can be helpful. such an orthosis is also called drop foot orthosis. however, when configuring such a foot lifter orthosis, it makes sense to use adjustable functional elements for setting the resistance, which make it possible to adapt the passive lowering of the forefoot (plantar flexion) to the eccentric work of the dorsal flexors during loading response. in many cases the muscle group of the plantar flexors is supplied with wrong impulses from the central nervous system, which leads to great uncertainty when standing and walking. the compensatory gait is an unconscious reaction to the lack of security when standing or walking. when configuring an orthosis, functional elements that can restore safety when standing and walking must be used in these cases. in such cases, a foot lifter orthosis is not suitable for restoring the lack of safety, since it only has functional elements that compensate for the functional deviations in the event of weakness of the dorsiflexors. in patients with paralysis after stroke, but who are able to walk have the option of analyzing the gait pattern as part of the patient history in order to determine the optimal function of an orthosis. one way of assessing is the classification according to the "n.a.p. gait classification". n.a.p. is a physiotherapeutic treatment concept. according to this classification, four gait types are described. the gait pattern is assessed in the gait phase in which the leg to be viewed is in mid-stance phase and the leg not to be viewed is in mid-swing. to assess the gait, in the first step, the patient is viewed visually or via a video recording from the side of the leg to be assessed. in gait type 1 the knee angle is hyperextended. in gait type 2 the knee angle is flexed. the patient is then viewed from the front. if the forefoot is on the outer edge of the foot, which is accompanied by a varus position in the knee, the letter "a" is added to the gait. this foot position is called inversion. if the patient stands on the inner edge of the foot, which is associated with a valgus position in the knee, the letter "b" is added to the gait type. this foot position is called eversion. the patients can be classified according to gait types 1a, 1b, 2a or 2b. the goal of orthotic fitting for patients who are able to walk is the best possible approximation of the physiological gait pattern. multiple sclerosis (ms) determination of the strength levels of the large muscle groups, taking into account the muscular fatigue typical of ms patients using the example of the muscle group of the dorsal extensors in the case of paralysis due to multiple sclerosis, the degree of strength of the six major muscle groups of the affected leg should be determined as part of the physical examination, just as in the case of diseases or injuries to the spinal/peripheral nervous system, in order to determine the necessary functions of an orthosis. however, patients with multiple sclerosis may experience muscular or cognitive fatigue beyond the physiological level. the fatigue can be more or less pronounced and, depending on the severity, lead to considerable restrictions in everyday life. persistent stress (e.g. walking) causes a deterioration in muscle function and has a significant effect on the spatial and temporal parameters when walking, for example by significantly reducing the cadence and walking speed. fatigue can be measured as muscle weakness. as part of the patient's medical history when determining the strength levels of the six major muscle groups, fatigue can be taken into account by using a standardized walking test. the six-minute walk test is suitable for this. the muscle function test according to vladimir janda is carried out in combination with the six-minute walk test in the following steps: first muscle function test (without muscular fatigue) six-minute walk test directly followed by second muscle function test (with muscular fatigue) this sequence of muscle function test and -minute walk test is used to check whether a controlled muscular fatigue can be induced. if the test reveals that there is muscular fatigue, the strength levels should be included in the planning of an orthosis, taking into account the measured fatigue when determining the functional elements. functional deviations in the case of paralysis of large muscle groups paralysis of the dorsiflexors – weakness of the dorsiflexors results in a so-called drop foot. the patient's foot can only be insufficiently lifted when walking during the swing phase, since the necessary concentric work of the dorsiflexors can not be activated. there is a risk of stumbling. in addition, the patient cannot influence the shock absorption when walking (gait phase, loading response), as the eccentric work of the dorsiflexors is limited. after initial heel contact the forefoot slaps too quickly on the floor via the heel rocker, which creates an audible noise or the foot does touch the floor with forefoot first, which disrupts gait development.: 178–181 : 44–45, 50–54 and 126 paralysis of the plantar flexors – if the plantar flexors are weak, the muscles of the forefoot lever are only inadequately activated or not activated at all. the patient has no balance when standing and has to support himself with aids such as crutches. there is a lost of energy during walking. the forefoot lever required for energy-saving walking in the gait phases from mid-stance to pre-swing cannot be activated by the plantar flexors. this leads to excessive dorsiflexion in the ankle joint in terminal stance. the center of gravity of the body lowers towards the end of the stance phase and the knee of the contralateral leg is flexed excessively. with each step, the center of gravity must be raised above the leg with the excessively flexed knee by straightening it. since the plantar flexors have their origin above the knee joint, they also have a knee-extension effect in the stance phase.: 177–210 >: 72 paralysis of the knee extensors – if the knee extensors are weak, there is an increased risk of falling. the physiological knee flexion is only inadequately or not controlled by the knee extensors when walking between loading response to the mid-stance. to control the knee, the patient develops compensatory mechanisms that lead to an incorrect gait pattern. that leads for example in the initial contact with the forefoot and not with the heel takes place in order to prevent the knee-flexing effect of the heel rocker. another way to compensate for weak knee extensors is to exaggerate the activation of the plantar flexors, which leads into hyperextension of the knee.: 222, 226 : 132, 143, 148–149 paralysis of the knee flexors – if the knee flexors are weak, it is more difficult to flex the knee in pre-swing.: 220 : 154 paralysis of the hip flexors – if the hip flexors are weak, it is more difficult to flex the knee in pre-swing.: 221 : 154 paralysis of the hip extensors – the hip extensors support the control of the knee against unwanted flexion when walking between loading response and mid-stance.: 216–17 : 45–46 functional elements in paralysis of large muscle groups the functional elements of an orthosis ensure the flexion and extension movements of the ankle joint, the knee joint and the hip joint. they correct and control the movements and secure the joints against undesired incorrect movements, e.g. to avoid falls when standing or walking. functional elements in paralysis of the dorsiflexors – if the dorsiflexors are weak, an orthosis should lift the forefoot during the swing phase in order to reduce the risk of the patient stumbling. an orthosis that has only one functional element for lifting the forefoot in order to compensate for a weakness in the dorsiflexors is also known as a drop foot orthosis. if other muscle groups, such as the plantar flexors, are weak, additional functional elements must be taken into account. an afo of the drop foot orthosis type is therefore not suitable for the care of patients with weakness in other muscle groups. in addition, initial contact with the heel should be achieved by lifting the foot through the orthosis. if the dorsiflexors are very weak, dynamic functional elements, in which the resistance of the plantar flexion can be adjusted, should also take over the control of the rapid drop of the forefoot. they should be able to be adapted to the functional deviation of the dorsiflexors in order to correct the shock absorption via the heel rocker lever of the orthosis in loading response, without blocking the plantar flexion. static functional elements that block the plantar flexion of the ankle joint lead to excessive flexion in knee and hip and thereby to an increased energy consumption