Biomechanical Analysis Of The Contribution Of Lower Limb Joint Muscle Groups During Walking In Stroke Patients With Hemiplegia

Objective: This study discusses the specific work contribution,main advantages and functions of joint muscle groups in the unaffected and affected side with lower limbs during hemiplegic patients walking,so as to provide a theoretical basis for improving the rehabilitation training program of walking function in hemiplegic patients,clarifying the targeted training of joint muscle groups in the unaffected and affected side with lower limbs and optimizing walking efficiency.Methods: Fifteen stroke patients with hemiplegia in convalescence were recruited as the test group,the three-dimensional kinematics data and ground reaction force data of lower limbs in complete gait cycles were collected,joint moment and power of the affected and unaffected lower limbs in the test group were obtained by inverse dynamics algorithm,angular impulse of each joint during support period and work done by each joint in gait cycle were obtained by integral derivation;calculate the average power with each joint in gait cycle and the sum of the relevant data of three joints with lower limb: support moment(sum of extensor moment),total support angular impulse(sum of extensor angular impulse),total positive(negative)work and total positive(negative)average power;then calculate contributions of extensor moment and angular impulse of each joint in the support period,the work and average power of each joint in gait cycle to the sum of relevant data with three joints in lower limb;compare the differences of related indexes among unaffected side,affected side and normal people(control group)during walking.Results: 1.The knee abductor angular impulse in affected side during support period was significantly higher than that of control group(P<0.05),the peak knee extensor moment and the knee extensor angular impulse in unaffected side during support period were significantly higher than that of affected side and control group(P<0.05),the contribution of knee extensor angular impulse during support period,and the contribution of knee extensor moment at the peak of ground reaction force to support moment at the time in unaffected side were higher than those in affected side and control group;2.In a complete gait cycle,the accumulation of negative work in sagittal plane of hip and ankle in affected side were significantly higher than that in control group(P<0.05),the accumulation of negative work in frontal plane of hip in unaffected and affected side was significantly higher than that in control group(P<0.05),and the accumulation of positive and negative work in sagittal plane of knee in unaffected side were significantly higher than those in affected side and control group(P<0.05);3.In a complete gait cycle,the negative work accumulation in frontal plane of hip joint in unaffected side and affected side were significantly higher than those of the other two planes(P<0.05),the negative work accumulation of knee joint in sagittal plane for affected side was significantly lower than that of unaffected side and control group(P<0.05),and the average power of knee joint in affected side while doing positive work in sagittal plane was significantly lower than that of unaffected side and control group,the average power of knee joint in unaffected side while doing positive work in sagittal plane was significantly higher than that of ankle joint in unaffected side and that of knee and ankle joint in control group while doing positive work in sagittal plane(P<0.05).Conclusions: 1.The medial meniscus in affected side of knee joint for hemiplegic patients had a larger load during support period,and unaffected knee joint also bears a larger load and support contribution;2.The affected hip,ankle joint and unaffected knee joint in sagittal plane,and the unaffected hip and affected hip joint muscles in frontal plane have more passive eccentric contractions during patients walking,which are all based on controlling gait and maintaining dynamic balance,and the major contributors to do negative work,and the unaffected knee joint muscles also actively exert more concentric contractions,which are mainly promoting gait,and the main contributors to do positive work;3.The abductor muscles of the unaffected and affected hip joint are more active in doing negative work in frontal plane during patients walking,at the same time,it reflects the dynamic stability of the unaffected and affected hip joint is poor during patients walking,and the efficiency of eccentric contraction passive force generation of extensor muscles in affected knee joint is lower,its ability is defective,and its buffering ability to control gait is also significantly limited,which may reduce patient’s endurance during walking and independence of walking function,While knee extensor muscles of the unaffected knee joint has a high efficiency of centripetal contraction and active force generation,which is mainly responsible for propulsion,However,only relying on the significant advantage of centripetal contraction active force generation of the unaffected knee joint can not improve patient’s walking ability well,whose endurance will still decline during walking,and independence of walking function is still limited.Suggestion: 1.It is necessary to wear knee protectors for affected knee joint before hemiplegic patients walk,to correct the poor lower limb force line during walking,reduce the risk of chronic injury of the affected knee joint and the incidence of medial osteoarthritis in affected knee joint;it should be strengthened strength of muscle groups around the unaffected knee joint,especially the strength exercises with the combination of high-efficiency centripetal and centrifugal contraction in unaffected knee extensor muscles;2.Strengthening the strength exercises with the combination of centrifugal and centripetal contraction for unaffected and affected hip abductor muscles to improve the stability of lower limbs in frontal plane;3.Increasing the movement exercises with the combination of centrifugal and centripetal contraction for affected knee extensor muscles,to improve cushioning and control ability of the affected knee joint during walking.