Objectives: This study investigated the associations between gait velocity and kinematic variables in the first half of the gait cycle according to stroke severity. We performed gait analysis in individuals with stroke, focusing on changes in the center-of-gravity (COG) position on the paretic side in the first half of stance phase.Methods: Gait data of 80 individuals (20 each in Brunnstrom recovery stage: III, IV, V and VI) with stroke acquired using a 3D motion analysis system was retrospectively analyzed. Associations of gait velocity with the COG positions in the anteroposterior directions and vertical increases in the first half of stance phase on the paretic side were compared according to stroke severity, using correlation analysis.Results: Gait velocity showed strong positive correlations with step length on the paretic side at initial contact, the rate of vertical increase in the COG during single-leg stance, and the proportion of single-leg stance time in the gait cycle. The associations between velocity and each kinematic variable differed according to stroke severity. Gait velocity was strongly correlated with the rate of vertical increase in the COG during single-leg stance and the proportion of single-leg stance in severe hemiplegia, while a strong correlation was observed with step length on the paretic side in mild hemiplegia.Conclusion: An upward shift of the COG during single-leg stance was an important factor in gait velocity, and the correlation between gait velocity and the rate of vertical increase in the COG during single-leg stance was stronger when hemiplegia was more severe.

Objects：Sit-to-stand (STS) interventions are frequently used as part of stroke rehabilitation. This study aimed to clarify the kinematic and kinetic characteristics of patients recovering from stroke, who have difficulties with STS movement.Method：The participants included 26 stroke patients who struggled to complete the STS maneuver. Using a 3D motion analysis system, the kinematic and kinetic parameters during STS were retrospectively analyzed and compared between failed and successful trials. The kinematic parameters of the trunk and lower limbs were obtained within the seat-off phases, and the kinetic indices of the lower limbs were obtained from measurements taken before and after the seat-off phase. The weight-bearing ratio on the unaffected side was calculated from the vertical ground reaction forces.Results：In the successful trials, analyses of the parameters revealed more forward tilting of the pelvic and thoracic regions, a further forward and downward shift of the center of mass, and larger hip and knee extension moments than those of the failed trials. However, there was no difference in the weight-bearing ratio on the non-paralyzed side.Conclusion：This study revealed that the kinematic and kinetic properties of the STS maneuver differed between successful and failed trials among patients with stroke. The study therefore provides useful information for clinical evaluation and rehabilitation.

Objects：Sit-to-stand (STS) interventions are frequently used as part of stroke rehabilitation. This study aimed to clarify the kinematic and kinetic characteristics of patients recovering from stroke, who have difficulties with STS movement.Method：The participants included 26 stroke patients who struggled to complete the STS maneuver. Using a 3D motion analysis system, the kinematic and kinetic parameters during STS were retrospectively analyzed and compared between failed and successful trials. The kinematic parameters of the trunk and lower limbs were obtained within the seat-off phases, and the kinetic indices of the lower limbs were obtained from measurements taken before and after the seat-off phase. The weight-bearing ratio on the unaffected side was calculated from the vertical ground reaction forces.Results：In the successful trials, analyses of the parameters revealed more forward tilting of the pelvic and thoracic regions, a further forward and downward shift of the center of mass, and larger hip and knee extension moments than those of the failed trials. However, there was no difference in the weight-bearing ratio on the non-paralyzed side.Conclusion：This study revealed that the kinematic and kinetic properties of the STS maneuver differed between successful and failed trials among patients with stroke. The study therefore provides useful information for clinical evaluation and rehabilitation.

Objective：The knee joint in patients using a knee-ankle-foot orthosis (KAFO) is locked, and the lack of knee flexion can cause some problems in the gait, such as circumduction and excessive pelvic obliquity. Hence, a KAFO with knee flexion control was developed. This study aimed to compare the gait in stroke patients using KAFOs with a locked knee joint and a controlled knee joint.Methods：A newly developed electro-attractive-material (EAM) was used for the knee joint in the KAFO. The knee joint is locked in the stance phase, and released immediately after the manual switch is pushed by a physical therapist.The gait of seven stroke patients in the recovery phase was measured for KAFO with a locked knee joint (locked knee) and a controlled knee joint (EAM knee) . For gait measurement, an inertial sensor, a foot switch, and an EMG sensor were used.Results：The velocity increased and the swing time decreased in the EAM-knee as compared to the locked knee. The abduction, external rotation, and extension of the hip joint decreased in the EAM knee. Increased activity of the rectus femoris muscle in the loading response, and decreased activity of the longissimus doris in the swing phase were observed in the EAM knee.Conclusions：It was suggested that EAM KAFO could improve the gait parameter and reduce the movement on the paretic side by compensatory motions in the swing phase, thereby reducing the muscle activity of the longissimus doris muscle.

Objectives:To investigate the effects of different plantarflexion resistance of an ankle foot orthosis (AFO) on the motion of the thorax and pelvis during the gait of stroke patients. Methods:From June, 2020 to January, 2021, 26 stroke inpatients in Beijing Bo'ai Hospital wore AFO with oil damper (OD) ankle hinge, and measured thorax and pelvis during stroke gait under three plantarflexion resistance (OD1, OD2.5, OD4) of the AFO with a three-dimensional motion capture system. The main parameters were pelvic (P) and thoracic (T) angles at the following time or phases: initial contact (IC), contralateral foot off (CFO), contralateral initial contact (CIC), foot off (FO); the change of thoracic angle in gait cycle (T_cyclex), the change of thoracic angle in stance phase (T_STx) and the change of thoracic angle in single stance phase (T_SSx). Thoracic and pelvic motions were defined on three coordinate axes: forward/backward tilt (x), oblique (y) and rotation (z). Results:The loading response times were significant different among different plantarflexion resistance conditions (χ² = 7.923, P = 0.019), as well as between OD2.5 and in OD4 (P = 0.017). P_CFOx, P_CFOz, P_CICx and P_Fox; T_CFOx, T_CFOy, T_CFOz and T_FOx; relative angle of thorax to pelvis TP_ICx, TP_CFOx and TP_CICx; and T_SSx were significant different among three resistance conditions (χ² > 6.077, P < 0.05). Forward tilt of pelvis decreased in condition OD2.5 and increased in condition OD4 during each timing. When CFO, the thoracic forward/backward tilt angle was less in OD2.5 than in OD4 (P < 0.05), the thoracic rotation angle was less in OD1 than in OD4 (P < 0.05). Conclusion:Plantarflexion resistance has a significant effect on the motion of the thorax and pelvis in the gait of stroke patients. Under the middle magnitude of resistance, the pelvic and thoracic posture becomes more upright, the oblique angle is reduced, showing the improvement of the upright posture. On the contrary, the pelvic forward tilt and thoracic oblique are increased when resistance become low or high, compensation of rotational motion appeared in high resistance, posture getting worse.

Objective：The knee joint in patients using a knee-ankle-foot orthosis (KAFO) is locked, and the lack of knee flexion can cause some problems in the gait, such as circumduction and excessive pelvic obliquity. Hence, a KAFO with knee flexion control was developed. This study aimed to compare the gait in stroke patients using KAFOs with a locked knee joint and a controlled knee joint.Methods：A newly developed electro-attractive-material (EAM) was used for the knee joint in the KAFO. The knee joint is locked in the stance phase, and released immediately after the manual switch is pushed by a physical therapist.The gait of seven stroke patients in the recovery phase was measured for KAFO with a locked knee joint (locked knee) and a controlled knee joint (EAM knee). For gait measurement, an inertial sensor, a foot switch, and an EMG sensor were used.Results：The velocity increased and the swing time decreased in the EAM-knee as compared to the locked knee. The abduction, external rotation, and extension of the hip joint decreased in the EAM knee. Increased activity of the rectus femoris muscle in the loading response, and decreased activity of the longissimus doris in the swing phase were observed in the EAM knee.Conclusions：It was suggested that EAM KAFO could improve the gait parameter and reduce the movement on the paretic side by compensatory motions in the swing phase, thereby reducing the muscle activity of the longissimus doris muscle.