Objective To investigate the effects of wearing high-heeled shoes at different heel heights on ankle joint motion control during walking in women with chronic ankle instability(CAI).Methods The Vicon infrared motion capture system and a three-dimensional force plate were used to synchronously collect kinematic and kinetic parameters within 200 ms before and after foot contact for 20 healthy females and 20 CAI females while walking on flat ground wearing high-heeled shoes at different heel heights(1,3,5,and 7 cm).Two-way repeated measures ANOVA was applied to analyze the data statistically.Results There was an interaction effect between group and heel height on the peak inversion angular velocity and peak inversion angle during foot strike.Post-hoc tests revealed that within the healthy group,compared to a 1 cm heel,the 5 cm(P=0.002)and 7 cm(P=0.002)heels had significantly greater peak inversion angular velocity within 200 ms before and after foot strike;there were significant differences in peak inversion angle between the 1 cm and 5 cm(P=0.018),7 cm(P＜0.001)heels.In the CAI group,compared to a 1 cm heel,the 5 cm(P=0.002)and 7 cm(P=0.002)heels had significantly greater peak inversion angular velocity within 200 ms before and after foot strike;there were significant differences in peak inversion angle between the 1 cm and 3 cm(P＜0.001),5 cm(P＜0.001),7 cm(P＜0.001)heels.There was a significant main effect of height on peak plantarflexion angle(P＜0.001),peak external rotation angle(P＜0.001),peak external rotation angular velocity(P＜0.001),and peak plantarflexion torque(P=0.048)within 200 ms before and after foot strike;there was a significant main effect of group on peak eversion torque(P＜0.001).Conclusions Compared to healthy individuals,women with CAI have reduced ankle joint control while walking with high-heeled shoes.As heel height increases,the ankle stability decreases.It is recomended that women with CAI should wear high-heeled shoes with a heel height of 3 cm or below.

Objective To quantify the lower limb coordination and coordination variability of children with spastic cerebral palsy(CP)during flat ground walking using vector coding technology.Methods From September to December,2023,eight children with spastic CP(patients)from Ji'nan Rehabilitation Hospi-tal and Ji'nan Special Education School,and eight healthy children(controls)from communities walked on a treadmill at a speed of 0.45 m/s.Lower limb kinematic data were collected using Vicon,a three-dimensional mo-tion capture system.Vector coding technology was used to quantify the temporal and spatial parameters of ipsilat-eral lower limb joints to calculate joint coupling angles and coupling angle variability(CAV).Results In the first and second double support phase,the hip-knee coupling angle was significantly larger in the patients than in the controls(|t|>2.317,P<0.05).In the swing phase,the hip-ankle and knee-ankle coupling angles were significantly larger in the patients(|t|>2.346,P<0.05).In the first double support phase and the single support phase,CAV of the hip-knee and hip-ankle were significantly larger in the patients(|t|>2.454,P<0.05),and they were smaller in the swing phase(t>2.560,P<0.05).In the second double support phase and the swing phase,CAV of the knee-ankle was significantly larger in the patients(|t|>2.909,P<0.05).Conclusion Coordination among hip,knee and ankle joints is poor for children with spastic CP during both the stance and swing phases of walking,and variability is more during the stance phase.

BACKGROUND:Foot position and seat height are important factors affecting "Sit-to-Stand",but most of the current research on "Sit-to-Stand" focuses on healthy people and Parkinson's disease patients. The kinematic and kinetic characteristics of the lower limbs of children with spastic cerebral palsy during the "Sit-to-Stand" task under different foot positions and seat heights are not known.OBJECTIVE:To investigate the effects of different foot positions and different seat height on lower limb kinematic and kinetic parameters during the "Sit-to-Stand" task in children with cerebral palsy. METHODS:Seven children with spastic cerebral palsy were selected as the research subjects. All subjects received the "Sit-to-Stand" test of six tasks,namely three seat heights (high,medium,and low stools) × two foot positions (front and back foot positions). The kinematic and dynamic data of children with cerebral palsy were collected under different foot positions and seat heights.RESULTS AND CONCLUSION:(1) The time characteristics results showed that the total time required for the children with cerebral palsy to perform the sit-to-stand transfer task was significantly smaller in the high stool condition compared to the low stool condition (P=0.046). (2) The kinetic results showed that at the moment of lifting,the knee flexion moment was significantly larger in the bipedal posterior condition than the bipedal anterior condition (P=0.049). The knee flexion moment was significantly smaller in the high stool condition compared to the medium stool condition (P<0.001). (3) It is concluded that raising the seat height and changing the foot position had an effect on the sit-to-stand transfer in children with spastic cerebral palsy. The children were able to perform the sit-to-stand maneuver with less motor compensation in the high-stool bipedal-rear position condition. Meanwhile,the high chair can be used as an aid to enhance the performance of sit-to-stand transfer in children with spastic cerebral palsy. The high stool bipedal hindfoot condition was the most effective in improving the sit-to-stand transfer in children with spastic cerebral palsy.

Objective To investigate how interference from motor and cognitive tasks affects the postural stability of older adults during stair descent.Methods A total of 52 elderly subjects were recruited.Using the Vicon infrared motion capture system and Kistler force plate,the kinematic and dynamic data were collected simultaneously during stair descent under three conditions:single task(ST),motor task(MT),and cognitive task(CT).The body stability during stair descent was assessed quantitatively using the margin of stability(MoS)algorithm.Repeated measures ANOVA was applied to compare differences across conditions.Results Compared to the ST condition,both step speed(P<0.001)and step frequency(P<0.001)were significantly reduced under MT and CT conditions.Step length(P=0.037)was also significantly reduced under the CT condition compared to those under the ST condition.In the aspect of anterior-posterior dynamic stability,compared to the ST condition,centroid velocity(P<0.001)and extrapolated centroid position(P<0.001)were significantly increased,while MoS(P<0.001)was significantly decreased under both MT and CT conditions.In comparison to the CT condition,centroid displacement(P=0.011)and velocity(P=0.014),as well as extrapolated centroid position(P<0.001),were significantly greater those under the MT condition.In the aspect of medial-lateral dynamic stability,compared to the ST condition,centroid displacement(P<0.001)was significantly reduced under MT and CT conditions.Additionally,the extrapolated centroid position(P=0.001)was significantly reduced,and MoS(P=0.038)was significantly increased under the MT condition compared to those under the ST condition.Conclusions Older adults adjust their gait in response to dual-task interference during stairs descent by'slowing down step speed,reducing step frequency,and shortening step length'.This adjustment helps maintain medial-lateral dynamic stability,but significantly decreases anterior-posterior dynamic stability,thereby increasing the risk of falls.

Objective To quantify the lower limb coordination and coordination variability of children with spastic cerebral palsy(CP)during flat ground walking using vector coding technology.Methods From September to December,2023,eight children with spastic CP(patients)from Ji'nan Rehabilitation Hospi-tal and Ji'nan Special Education School,and eight healthy children(controls)from communities walked on a treadmill at a speed of 0.45 m/s.Lower limb kinematic data were collected using Vicon,a three-dimensional mo-tion capture system.Vector coding technology was used to quantify the temporal and spatial parameters of ipsilat-eral lower limb joints to calculate joint coupling angles and coupling angle variability(CAV).Results In the first and second double support phase,the hip-knee coupling angle was significantly larger in the patients than in the controls(|t|>2.317,P<0.05).In the swing phase,the hip-ankle and knee-ankle coupling angles were significantly larger in the patients(|t|>2.346,P<0.05).In the first double support phase and the single support phase,CAV of the hip-knee and hip-ankle were significantly larger in the patients(|t|>2.454,P<0.05),and they were smaller in the swing phase(t>2.560,P<0.05).In the second double support phase and the swing phase,CAV of the knee-ankle was significantly larger in the patients(|t|>2.909,P<0.05).Conclusion Coordination among hip,knee and ankle joints is poor for children with spastic CP during both the stance and swing phases of walking,and variability is more during the stance phase.

Objective To investigate how interference from motor and cognitive tasks affects the postural stability of older adults during stair descent.Methods A total of 52 elderly subjects were recruited.Using the Vicon infrared motion capture system and Kistler force plate,the kinematic and dynamic data were collected simultaneously during stair descent under three conditions:single task(ST),motor task(MT),and cognitive task(CT).The body stability during stair descent was assessed quantitatively using the margin of stability(MoS)algorithm.Repeated measures ANOVA was applied to compare differences across conditions.Results Compared to the ST condition,both step speed(P<0.001)and step frequency(P<0.001)were significantly reduced under MT and CT conditions.Step length(P=0.037)was also significantly reduced under the CT condition compared to those under the ST condition.In the aspect of anterior-posterior dynamic stability,compared to the ST condition,centroid velocity(P<0.001)and extrapolated centroid position(P<0.001)were significantly increased,while MoS(P<0.001)was significantly decreased under both MT and CT conditions.In comparison to the CT condition,centroid displacement(P=0.011)and velocity(P=0.014),as well as extrapolated centroid position(P<0.001),were significantly greater those under the MT condition.In the aspect of medial-lateral dynamic stability,compared to the ST condition,centroid displacement(P<0.001)was significantly reduced under MT and CT conditions.Additionally,the extrapolated centroid position(P=0.001)was significantly reduced,and MoS(P=0.038)was significantly increased under the MT condition compared to those under the ST condition.Conclusions Older adults adjust their gait in response to dual-task interference during stairs descent by'slowing down step speed,reducing step frequency,and shortening step length'.This adjustment helps maintain medial-lateral dynamic stability,but significantly decreases anterior-posterior dynamic stability,thereby increasing the risk of falls.

BACKGROUND:Foot position and seat height are important factors affecting "Sit-to-Stand",but most of the current research on "Sit-to-Stand" focuses on healthy people and Parkinson's disease patients. The kinematic and kinetic characteristics of the lower limbs of children with spastic cerebral palsy during the "Sit-to-Stand" task under different foot positions and seat heights are not known.OBJECTIVE:To investigate the effects of different foot positions and different seat height on lower limb kinematic and kinetic parameters during the "Sit-to-Stand" task in children with cerebral palsy. METHODS:Seven children with spastic cerebral palsy were selected as the research subjects. All subjects received the "Sit-to-Stand" test of six tasks,namely three seat heights (high,medium,and low stools) × two foot positions (front and back foot positions). The kinematic and dynamic data of children with cerebral palsy were collected under different foot positions and seat heights.RESULTS AND CONCLUSION:(1) The time characteristics results showed that the total time required for the children with cerebral palsy to perform the sit-to-stand transfer task was significantly smaller in the high stool condition compared to the low stool condition (P=0.046). (2) The kinetic results showed that at the moment of lifting,the knee flexion moment was significantly larger in the bipedal posterior condition than the bipedal anterior condition (P=0.049). The knee flexion moment was significantly smaller in the high stool condition compared to the medium stool condition (P<0.001). (3) It is concluded that raising the seat height and changing the foot position had an effect on the sit-to-stand transfer in children with spastic cerebral palsy. The children were able to perform the sit-to-stand maneuver with less motor compensation in the high-stool bipedal-rear position condition. Meanwhile,the high chair can be used as an aid to enhance the performance of sit-to-stand transfer in children with spastic cerebral palsy. The high stool bipedal hindfoot condition was the most effective in improving the sit-to-stand transfer in children with spastic cerebral palsy.

Objective To investigate the effects of wearing high-heeled shoes at different heel heights on ankle joint motion control during walking in women with chronic ankle instability(CAI).Methods The Vicon infrared motion capture system and a three-dimensional force plate were used to synchronously collect kinematic and kinetic parameters within 200 ms before and after foot contact for 20 healthy females and 20 CAI females while walking on flat ground wearing high-heeled shoes at different heel heights(1,3,5,and 7 cm).Two-way repeated measures ANOVA was applied to analyze the data statistically.Results There was an interaction effect between group and heel height on the peak inversion angular velocity and peak inversion angle during foot strike.Post-hoc tests revealed that within the healthy group,compared to a 1 cm heel,the 5 cm(P=0.002)and 7 cm(P=0.002)heels had significantly greater peak inversion angular velocity within 200 ms before and after foot strike;there were significant differences in peak inversion angle between the 1 cm and 5 cm(P=0.018),7 cm(P＜0.001)heels.In the CAI group,compared to a 1 cm heel,the 5 cm(P=0.002)and 7 cm(P=0.002)heels had significantly greater peak inversion angular velocity within 200 ms before and after foot strike;there were significant differences in peak inversion angle between the 1 cm and 3 cm(P＜0.001),5 cm(P＜0.001),7 cm(P＜0.001)heels.There was a significant main effect of height on peak plantarflexion angle(P＜0.001),peak external rotation angle(P＜0.001),peak external rotation angular velocity(P＜0.001),and peak plantarflexion torque(P=0.048)within 200 ms before and after foot strike;there was a significant main effect of group on peak eversion torque(P＜0.001).Conclusions Compared to healthy individuals,women with CAI have reduced ankle joint control while walking with high-heeled shoes.As heel height increases,the ankle stability decreases.It is recomended that women with CAI should wear high-heeled shoes with a heel height of 3 cm or below.

BACKGROUND:Stability of the support surface and visual input are important factors affecting static balance,but most of the studies on the balance ability of elderly with mild cognitive impairment have focused on the stable hard support surface,and the control of static balance on the unstable support surface under different visual input conditions is not known. OBJECTIVE:To investigate the static balance ability of the elderly with mild cognitive impairment on soft and hard support surfaces under different visual input conditions. METHODS:Twenty-one elderly people with mild cognitive impairment and nineteen elderly people with normal cognition were selected for the study,and the Kistler three-dimensional dynamometer was used to conduct four tests:standing with two feet on hard support surface with eyes open,standing with two feet on soft support surface with eyes open,standing with two feet on hard support surface with eyes closed,standing with two feet on soft support surface with eyes closed,and standing with two feet on soft support surface with eyes closed,and the duration of each test was 30 seconds.The plantar center of pressure data were collected and compared between the two groups under different visual conditions on the soft and hard support surfaces. RESULTS AND CONCLUSION:(1)Under the condition of visual input,the total excursions(soft support surface:P=0.003),the total excursions-medial-lateral sides(soft support surface:P=0.001,hard support surface:P<0.001)and the 95%confidence ellipse area(soft support surface:P=0.001,hard support surface:P<0.001)of the center of pressure in the elderly with mild cognitive impairment on the soft and hard support surfaces were significantly higher than those of the elderly with normal cognition.(2)In the absence of visual input,the root mean square distance(P=0.014),the root mean square distance-medial-lateral sides(P=0.014),and the 95%confidence ellipse area(P=0.001)of center of pressure in the elderly with mild cognitive impairment on the soft support surfaces were significantly higher than those of the elderly with normal cognition,but there were no significant differences between the groups on the hard support surface(P>0.05).(3)These findings confirm that compared with the elderly with normal cognition who could make full use of visual sensory input to maintain body balance on the soft and hard support surfaces,mild cognitive impairment elderly presented a deficit in balance function.In particular,mild cognitive impairment elderly relied more on ankle proprioception to maintain balance when visual interference was present,suggesting that mild cognitive impairment elderly should focus on strengthening ankle proprioceptive training.

Objective To explore the effect of 12-week simplified Tai Chi training on rehabilitation and neuromuscular control in individuals with chronic ankle instability(CAI).Methods Thirty-four partic-ipants with CAI were randomly divided into an experimental group and a control group,each of 17.The control group received 12-week health education,while the experimental group underwent simpli-fied Tai Chi training for the same length.Before and after the intervention,both groups were evaluat-ed their self-reported instability feeling,ankle muscle strength,proprioception and dynamic postural stability.Results After intervention,a significant increase was observed in the average Cumberland An-kle Instability Tool(CAIT),the maximum extension distance in the posteromedial and posterolateral di-rections of the modified Star Excursion Balance Test(mSEBT)in,as well as the ankle peak torque in plantarflexion,inversion and eversion(P<0.05)in the experimental.Moreover,the ankle passive motion proprioceptive threshold in plantarflexion and inversion decreased significantly in the experimental group after intervention(P<0.05).Meanwhile,after intervention,the average CAIT score,maximum ex-tension distances in the posteromedial and posterolateral directions in the mSEBT,and the ankle peak torques in plantarflexion,inversion and eversion of the experimental group were significantly higher than the control group(P<0.05),while the ankle passive motion proprioceptive threshold in plantarflex-ion was significantly lower than the latter(P<0.05).Conclusion Twelve-week simplified Tai Chi train-ing can improve the clinical subjective instability of CAI participants,maybe related to the improve-ment of ankle muscle strength,proprioception and dynamic postural stability.Therefore,it is suggest-ed that simplified Tai Chi should be one of the rehabilitation methods for CAI patients.