1.The basic situation of gait
From one side of the foot followed the ground, until the heel of this side again on the ground, for a walking cycle (gaitcycle). Each foot has experienced a period of support in contact with the ground (stancephase) and a period of vacant movement (swingphase). The support phase consists of five links, in order for the foot to follow the ground (heelstride, HS), the footflat (FF), the center of gravity moves forward to the ankle above the midstance (MSt), the body continues to move forward to the foot lift the heel off (heeloff, HO), and finally the toe off (toe-off). The swinging period starts from toe-off, and ends at mid-swing (midswing,MSw) when the lower limb is in the vertical position through the acceleration period, and ends at the foot following the ground through the deceleration period, with a single step (step) from one side of the foot following the ground to the other side of the foot following the ground, and a compound step (stride) when the heel of the same side hits the ground again.
In the walking cycle support longer than the swing period, so each walking cycle, about 15% of the time that since one side of the foot followed the ground to the opposite side of the toes off the ground, both legs are in the support period, known as bilateral support period (doublesupport). It is the characteristic of walking, such as no bilateral support, instead of double foot vacancy that is running.
Step frequency (cadence) refers to the number of steps per minute of action, about 110-120 steps/minute for adults, fast steps can be up to 140 steps/minute. The stepwidth refers to the distance of a single step, which is related to the step frequency and height, generally 70-75cm for men.
When walking, the body’s center of gravity moves forward along a complex spiral curve, the projection in the sagittal and horizontal planes are each in a sinusoidal curve, and the forward motion has alternating acceleration and deceleration into. In order to make the movement of the center of gravity in the axial position tends to be smooth, reduce the up and down shift and acceleration so as to reduce energy consumption, with the movement of the hip, knee and ankle joints, the pelvis also has front and back tilt and horizontal lateral shift.
The normal variation of the above activities during walking constitutes the gait characteristics of each person. The variation beyond a certain range due to pathological factors constitutes abnormal gait. After the examiner is familiar with the composition of normal gait and the basic characteristics of common pathological gait, he can evaluate the gait by direct observation, and if necessary, he can make separate or integrated observation by multi-dimensional continuous camera, electronic goniometer and multi-conductor electromyography, etc. to obtain the activity spectrum of muscles, joints or body center of gravity during walking, so as to compare and analyze with the normal activity spectrum. The normal joint and muscle activity profiles are shown in Figure 2-1-9. The muscles work by centripetal and distal contractions.
Flexion and extension activities of hip, knee and ankle joints during walking at normal speed
Figure 2-1-9 Flexion and extension of hip, knee and ankle joints during normal walking speed
Normal gait is very efficient, especially when walking at a speed of 4.5~5km/hour, the energy consumption per unit distance is low and the electromyographic activity is also minimal at this time. The forward movement of the body during walking is actually provided mainly by gravity and inertia rather than entirely by muscle contraction. Energy consumption increases when gait is abnormal, more so when paraplegia and amputation, thus limiting gait speed, such as walking with crutches in paraplegic patients, gait speed is generally limited to 1.6~2.4km per hour.
2.Common pathological gait
According to the pathology and performance of abnormal gait, it can be divided into the following categories.
(1) Short-legged gait, such as when one leg is shortened by more than 3.5cm, the ipsilateral pelvis and shoulder sink when the affected leg is supported, so it is also called sloping shoulder gait, and compensatory foot drop when swinging.
(2) Joint tonic gait changes when the joints of the lower limb contracture are tonic, and the joint contracture changes even more when it is in a deformed position. For example, hip flexion contracture causes compensatory anterior pelvic tilt, lumbar spine hyperextension, shortened stride length, and short-legged gait when the knee flexion contracture is more than 30°. In knee extension contracture, lower limb abduction or ipsilateral pelvic upraise is seen when swinging to prevent toes from dragging on the ground. When the ankle plantar flexion contracture, the heel cannot touch the ground, and the swing is compensated by increasing the hip and knee flexion, which is like crossing the threshold, so it is called cross-threshold gait. At this time, the affected limb support period often has knee hyperextension, which can cause knee retroflexion.
(3) Unsteady joint posture such as congenital hip dislocation when walking left and right swaying like a duck gait.
(4) Painful gait When various reasons cause pain when the affected limb is weighted with the common limb, the patient tries to shorten the support period of the affected limb, so that the opposite swing leg is jumping forward quickly and the stride length is shortened, also known as short gait.
(5) Muscle weakness gait
(1) anterior tibial muscle gait: the foot drops when the anterior tibial muscle is weak, and the swing period is used to increase hip and knee flexion to prevent the toes from dragging the ground, forming a cross-threshold gait.
②Supporting the late loyal hip sag when the calf triceps is weak, and slowing down the body’s forward propulsion.
③Quadriceps gait: in the affected leg support period cannot actively maintain stable knee extension, so the patient makes the body lean forward and let the gravity line pass in front of the knee, thus making the knee passively straight, at this time the hip slightly flexed can strengthen the tension of the gluteus and posterior femoral muscle groups, so that the lower end of the femur swings back and helps to passively extend the knee. Continuous hyperextension of the knee is utilized as a compensatory stabilization mechanism early in support often leading to knee retroversion. If hip extensor weakness is also present, the patient must often bend over and press the thigh with his or her hand to straighten the knee.
When the hip extensors are weak, the patient often tilts the trunk back so that the line of gravity passes behind the hip joint to maintain passive hip extension and control the inertia of the trunk to move forward. The posture of chest up and convex belly is formed.
⑤ Gluteus medius gait: When the hip abductor muscle is weak, it cannot maintain the lateral stability of the hip, so the patient makes the upper body change to the affected side during the support period so that the gravity line passes on the lateral side of the hip joint in order to rely on the adductor muscle to maintain stability, while preventing the contralateral hip from sinking and driving the contralateral lower limb to lift and swing. When the hip abductors on both sides are damaged, the upper body sways from side to side when walking, like a duck, also known as duck gait.
(6) Myoclonic gait is caused by high muscle tone. Such as.
(1) hemiplegic gait: often with the affected foot drooping, inversion, external or internal rotation of the lower limb, the knee can not relax flexion, in order to avoid foot dragging, swinging often make the affected limb along the arc through the lateral gyration forward, so also known as the gyratory gait. The upper arm is often flexed inward and the swinging stops. The hemiplegic gait seen clinically can have more variants.
Scissor gait: also called cross gait, mostly seen in patients with cerebral palsy or high paraplegia. Due to the spasm of the adductor muscles, the two hips are inwardly contracted when walking, the two knees rub against each other, and the gait is unstable. Severe spasm of the adductor muscle makes it difficult to separate the two legs from each other, and walking becomes impossible.
(7) Other central nervous system damage
(1) In cerebellar ataxia, walking is unstable and looks like a drunken man, so it is called Moet gait.
In Parkinson’s disease or other basal ganglia lesions, the gait is short and fast, with paroxysmal acceleration, unable to stop or turn at will, and the arm swing is narrowed or stopped, called forward gait or panic gait.
(8) Strange gait can not have known gait explanation should be considered whether it is hysterical gait, which is characterized by inconsistent movement performance, sometimes using a slower and more laborious way to complete the movement, inconsistent with the results of muscle strength examination, cogwheelresponse during muscle tone examination, etc.
3.Gait examination
For clinical gait examination, the patient should be asked to walk back and forth several times with his accustomed posture and speed to observe whether his whole body posture is coordinated, whether the posture and amplitude of the joints of the lower limbs are normal in each period, whether the speed and stride are proportional, and whether the upper limbs swing naturally. Next, the patient was asked to do fast and slow walking, and if necessary, to do casual and relaxed walking and focused walking, respectively, for observation. And try to perform such actions as standing and stopping, turning, turning, going up and down stairs or ramps, going around obstacles, going through doorways, sitting down and standing up, stepping slowly or standing on one foot, and standing with eyes closed. Sometimes walking with the patient’s eyes closed can also make mild gait abnormalities more apparent.
Walking with a cane or crutches can mask many abnormal gait patterns, so gait examinations with and without crutches or canes should be performed separately for those walking with crutches.
The gait examination is often combined with a series of basic condition tests, such as physical examination of the neurological system, muscle strength and tone examination of various muscle groups, joint mobility examination, lower limb length determination, and morphological examination of the spine and pelvis. These examinations are of great significance in determining the nature, cause and treatment of abnormal gait.
If necessary, electromyography, electronic protractor, multi-dimensional camera and other examinations are made during walking for more detailed analysis.
4, abnormal gait correction principles
(1) Correction of abnormal gait etiology
①Patients with short-legged gait must use orthopedic surgery or orthopedic shoes to balance the length of the two lower limbs.
(2) In case of joint contracture deformity, joint mobility must be improved through joint mobility exercises or orthopedic surgery to eliminate the deformity.
③If the gait is abnormal due to pain, physical therapy, local seal, massage and medication should be used to eliminate the pain. If the pain is caused by joint instability or osteoarthritis, a load-free brace should be used to reduce the local load.
④ When the muscles are weak, they can be strengthened by muscle exercises. If exercise is not effective, muscle reconstruction surgery or functional replacement with a brace should be considered.
⑤ When the muscle spasm is relieved by relaxation exercises, including myoelectric feedback exercises, massage, passive stretching, hot or cold compresses, antispasmodic drugs, nerve injections or surgical resection, etc.
(2) Gait training Gait training is usually performed in front of a mirror. The therapist will point out the points that need to be corrected from the side and provide guidance to correct them, so that they can be mastered and consolidated through repeated practice. The gait training should set an immediate goal that can be achieved. From the various movements used in the gait check, the patient can select the movements that he can barely perform but have shortcomings and difficulties as the practice movements for systematic practice, and then select the more difficult movements as the practice movements after achieving the goal. The patient should be able to concentrate properly during the exercise, but should not cause excessive tension, especially when the muscle spasm. Exercises are generally performed 1 to 2 times a day for 1 to 2 hours each time, including intervals of rest, to avoid significant fatigue.
Necessary safety measures should be taken during walking exercises, including the use of appropriate braces, crutches, walkers, parallel bars, etc. Or give artificial protection or support to prevent falls and to give the patient the necessary sense of security.
In gait training, attention should be paid to the patient’s whole body adaptability, and endurance exercises of sitting and standing, upper limb and abdominal and back muscle strength exercises and functional exercises of cardiovascular system should be carried out when necessary, i.e. endurance exercise exercises with upper limb movements or pedaling, etc., to adapt to the increased energy consumption of walking when gait is abnormal.