Biomechanical Characteristics Of Sit-To-Stand Transfer Under Different Foot Positions In Hemiplegic Stroke Patients

Objective:The hemiplegic stroke often leaded to the dysfunction of Sit-To-Stand movement(STS)to the patients.Different foot positions might affect the STS function of the patients.This study attempted to analyze the biomechanics indicators such as the patient's lower limb weight-bearing function,joint force and joint moment of the lower limb joints at the time of the seat-off.This study explored the abnormal biomechanical movement patterns of the patients' STS task.So it can provide objective data for rehabilitation assessment of stroke patients and attempted to provide specific rehabilitation training programs of the post-stroke.Methods:Twelve patients with hemiplegia were recruited and completed STS Transfer with the foot positions,which were spontaneous position(SPO),symmetrical position(SYM),asymmetrical position(ASY),and a step of position(STP).The Qualisys three-dimensional motion analysis system(100Hz,6 cameras)and the Bertec 3D force table(1500Hz,2 blocks)were used.The data was processed and analyzed using Visual3 D analysis software.The indicators which including the STS time,the weight-bearing asymmetry of the lower extremities,the joint moment asymmetry and the joint force asymmetry were selected for analysis the biomechanical characteristics of the patients.One-way analysis of variance(ANOVA)with repeated measures was employed to test the asymmetry index.Bonferroni test was used for multiple comparisons.Results:(1)Under the four foot conditions of SPO,SYM,ASY and STP,the difference of STS time between STP and SYM was significant(P=0.014).(2)Compared with the SPO and SYM,the difference in the weight-bearing asymmetry of the lower extremities at the seat-off of the STP,was statistically significant(P< 0.01);the STP was significantly different from the ASY(P=0.041).(3)Under the STP condition,the joint force of the ankle and knee was significantly different from the other three positions(P<0.05).Compared with the SPO and SYM foot positions,the difference of the joint force of the hip which under the STP conditions was significant(P<0.05).(4)The asymmetry of the joint moments of knee under the condition of ASY and STP were significantly different from those of SPO position(P=0.003,P=0.002).Theasymmetry of the hip moment was significantly different between the SYM and the ASY positions(P=0.038).Compared with the SPO and SYM foot positions,the difference of the STP conditions of hip moment was statistically significant(P<0.05).Conclusion:Compared with the other foot positions,the STP condition increased the weight-bearing of lower extremity of the patient's affected side at the seat-off.This study suggests that under the condition of the patient's good physical function,the STS transfer training of STP should be used.The STS transfer training is beneficial to the rehabilitation of ipsilateral muscle strength and nerve function.The STS transfer of the SYM and the ASY can be used as the less difficult training method.