This study aimed to compare gait properties during level walking and during stair ascent and descent with varying loads. Fifteen healthy young men (mean age: 22.1 ± 1.6 years) walked while holding four different ...This study aimed to compare gait properties during level walking and during stair ascent and descent with varying loads. Fifteen healthy young men (mean age: 22.1 ± 1.6 years) walked while holding four different loads relative to each subject’s body mass (0, 20, 40 and 60% of body mass: BM) on their backs. Stance time, swing time, and double support times were selected as gait parameters. All parameters showed a maximal value during stair ascent and a minimum value during level walking. Stance and double support times increased significan- tly with each load during level walking and during stair ascent and descent. In conclusion, st- air ascent and descent creates more unstable movement than level walking regardless of the weight of the load. The effect of loads on gait increases with the weight of the load and becomes obvious once the load exceeds 60% of BM.展开更多
目的对比分析偏瘫患者以不同方式下台阶过程中下肢生物力学特征,为降低患者下台阶过程中的跌倒风险提供理论依据。方法选取10名正常人和20名符合要求的偏瘫患者,使用Qualisys动作捕捉系统和Kistler三维测力台对受试者下台阶过程中的运...目的对比分析偏瘫患者以不同方式下台阶过程中下肢生物力学特征,为降低患者下台阶过程中的跌倒风险提供理论依据。方法选取10名正常人和20名符合要求的偏瘫患者,使用Qualisys动作捕捉系统和Kistler三维测力台对受试者下台阶过程中的运动学和动力学数据进行收集,分析其在下台阶过程中的生物力学特征和跌倒风险。结果相较于正常人和先用健足下台阶(steps on the healthy side,SHS),先用患足下台阶(steps on the affected side,SAS)时,患侧下肢各关节屈伸活动幅度较小;SHS降低了健侧膝关节屈伸活动幅度,患侧下肢各关节屈伸活动幅度较SAS大;SAS下台阶左右方向地面反作用力(ground reaction force,GRF)曲线变化与正常人较为一致,患侧落地瞬间垂直GRF最大为1.05倍体重,健侧为1.25倍体重,低于正常人(1.5倍体重);SHS下台阶健侧落地瞬间最大垂直GRF为1.85倍体重,高于SAS和正常人。结论相较于SAS,患者使用SHS下台阶患侧关节活动幅度和落地瞬间垂直GRF较大,更难掌握。SAS更符合偏瘫患者下台阶的生物力学特征。展开更多
Aim: Evaluating climbing stairs for prescription and implementation of physical activity regimes. Methods: Healthy females (F, n = 14), and males (M, n = 15) participated. By climbing 100 steps of stairs with 0.173 m ...Aim: Evaluating climbing stairs for prescription and implementation of physical activity regimes. Methods: Healthy females (F, n = 14), and males (M, n = 15) participated. By climbing 100 steps of stairs with 0.173 m height, Heart rate (HR) and oxygen uptake were measured throughout the floors;Blood pressure (BP) was measured at ground and the 5th floors only. Results: Energy increased from 2 to 7.6 was metabolic equivalents (METs = 3.5 ml O<sub>2</sub>/min.kg) at 17.3 m elevation in 2 min. at the 5th floor, and percent Heart Rate Reserve (%HRR) was 66.17% in F and 48.7% in M, proportional to their aerobic efforts. Average climbing efficiency was 15.8 ± 2.3% (n = 29). Aerobic capacity estimated dividing the highest work rate (17.3 Kg.m/2min.Kg × 0.00239 = 0.0207 Kcal/min.Kg), by fractional effort (F = 0.6617, M = 0.487) and fractional efficiency (0.158), at 5 Kcal/L O2 was 0.040 in F and 0.054 L O2/Kg.min in M. Minimum training intensity reached at the 3rd floor by F. In M the highest %HRR reached was 48.7% at the 5th floor, insufficient for training. Conclusions: Stairs used for submaximal evaluation of aerobic capacity and for target intensity prescription. Training, levels climbed, repetitions per day (if 5, 100 Kcal per day, ascending) and number of days/week are adjusted. Full regime requires up to 7.6 METs, a total of 532 and 140 MET.min/week ascending and descending, respectively. Intensities >7.6 MET, climbing rate should be >8.65 m/min. Limiting ascent to 1 (3.5 METs) or 2 (5.5 METs) floors or only descents (2 - 3 METs) may be used for unfit subjects. This method is useful for those with no access to sophisticated facilities.展开更多
Purpose Understanding the femur load environment during daily activity is necessary for the understanding of risk of femoral pain,pain related falls,and femoral fractures,which could help the design of osteogenic exer...Purpose Understanding the femur load environment during daily activity is necessary for the understanding of risk of femoral pain,pain related falls,and femoral fractures,which could help the design of osteogenic exercises or the preventa-tive methods for older adults.Methods Using the finite element femur analysis,this study was to estimate the femoral strains at 9 cross-sections along the long axis of femur for stair ascent and descent(n=17;age:50-65 years).Motion analysis and inverse dynamics were com-bined with musculoskeletal modelling and optimization,then were used as input to a 3-D femur model to estimate femoral strains.Strains at the hip contact force peaks were calculated.Results The compressive and tensile strains during stair descent were greater than ascent for all or most cross-sections,especially for the proximal cross-sections of the femur:stair ascent produced−324.0±103.8 to−483.7±191.0μεcompressive strains and descent produced−608.8±288.4 to 1016.0±444.1με;stair ascent produced 336.2±105.4 to 391.8±136.9μεtensile strains and descent produced 546.9±252.8 to 741.7±333.6με.Conclusion Strains represent the material deformation effect on the bone due to the sum of all the bone external loads.Using bone strains could help future studies analyze load conditions in a more comprehensive way for other physical activities,which predicts the risk of stress fractures and tests if alternative methods(gait type change)could reduce stress and strain effectively.展开更多
文摘This study aimed to compare gait properties during level walking and during stair ascent and descent with varying loads. Fifteen healthy young men (mean age: 22.1 ± 1.6 years) walked while holding four different loads relative to each subject’s body mass (0, 20, 40 and 60% of body mass: BM) on their backs. Stance time, swing time, and double support times were selected as gait parameters. All parameters showed a maximal value during stair ascent and a minimum value during level walking. Stance and double support times increased significan- tly with each load during level walking and during stair ascent and descent. In conclusion, st- air ascent and descent creates more unstable movement than level walking regardless of the weight of the load. The effect of loads on gait increases with the weight of the load and becomes obvious once the load exceeds 60% of BM.
文摘目的对比分析偏瘫患者以不同方式下台阶过程中下肢生物力学特征,为降低患者下台阶过程中的跌倒风险提供理论依据。方法选取10名正常人和20名符合要求的偏瘫患者,使用Qualisys动作捕捉系统和Kistler三维测力台对受试者下台阶过程中的运动学和动力学数据进行收集,分析其在下台阶过程中的生物力学特征和跌倒风险。结果相较于正常人和先用健足下台阶(steps on the healthy side,SHS),先用患足下台阶(steps on the affected side,SAS)时,患侧下肢各关节屈伸活动幅度较小;SHS降低了健侧膝关节屈伸活动幅度,患侧下肢各关节屈伸活动幅度较SAS大;SAS下台阶左右方向地面反作用力(ground reaction force,GRF)曲线变化与正常人较为一致,患侧落地瞬间垂直GRF最大为1.05倍体重,健侧为1.25倍体重,低于正常人(1.5倍体重);SHS下台阶健侧落地瞬间最大垂直GRF为1.85倍体重,高于SAS和正常人。结论相较于SAS,患者使用SHS下台阶患侧关节活动幅度和落地瞬间垂直GRF较大,更难掌握。SAS更符合偏瘫患者下台阶的生物力学特征。
文摘Aim: Evaluating climbing stairs for prescription and implementation of physical activity regimes. Methods: Healthy females (F, n = 14), and males (M, n = 15) participated. By climbing 100 steps of stairs with 0.173 m height, Heart rate (HR) and oxygen uptake were measured throughout the floors;Blood pressure (BP) was measured at ground and the 5th floors only. Results: Energy increased from 2 to 7.6 was metabolic equivalents (METs = 3.5 ml O<sub>2</sub>/min.kg) at 17.3 m elevation in 2 min. at the 5th floor, and percent Heart Rate Reserve (%HRR) was 66.17% in F and 48.7% in M, proportional to their aerobic efforts. Average climbing efficiency was 15.8 ± 2.3% (n = 29). Aerobic capacity estimated dividing the highest work rate (17.3 Kg.m/2min.Kg × 0.00239 = 0.0207 Kcal/min.Kg), by fractional effort (F = 0.6617, M = 0.487) and fractional efficiency (0.158), at 5 Kcal/L O2 was 0.040 in F and 0.054 L O2/Kg.min in M. Minimum training intensity reached at the 3rd floor by F. In M the highest %HRR reached was 48.7% at the 5th floor, insufficient for training. Conclusions: Stairs used for submaximal evaluation of aerobic capacity and for target intensity prescription. Training, levels climbed, repetitions per day (if 5, 100 Kcal per day, ascending) and number of days/week are adjusted. Full regime requires up to 7.6 METs, a total of 532 and 140 MET.min/week ascending and descending, respectively. Intensities >7.6 MET, climbing rate should be >8.65 m/min. Limiting ascent to 1 (3.5 METs) or 2 (5.5 METs) floors or only descents (2 - 3 METs) may be used for unfit subjects. This method is useful for those with no access to sophisticated facilities.
基金was provided by Chinese Universities Scientific Fund(Grant No.2020063).
文摘Purpose Understanding the femur load environment during daily activity is necessary for the understanding of risk of femoral pain,pain related falls,and femoral fractures,which could help the design of osteogenic exercises or the preventa-tive methods for older adults.Methods Using the finite element femur analysis,this study was to estimate the femoral strains at 9 cross-sections along the long axis of femur for stair ascent and descent(n=17;age:50-65 years).Motion analysis and inverse dynamics were com-bined with musculoskeletal modelling and optimization,then were used as input to a 3-D femur model to estimate femoral strains.Strains at the hip contact force peaks were calculated.Results The compressive and tensile strains during stair descent were greater than ascent for all or most cross-sections,especially for the proximal cross-sections of the femur:stair ascent produced−324.0±103.8 to−483.7±191.0μεcompressive strains and descent produced−608.8±288.4 to 1016.0±444.1με;stair ascent produced 336.2±105.4 to 391.8±136.9μεtensile strains and descent produced 546.9±252.8 to 741.7±333.6με.Conclusion Strains represent the material deformation effect on the bone due to the sum of all the bone external loads.Using bone strains could help future studies analyze load conditions in a more comprehensive way for other physical activities,which predicts the risk of stress fractures and tests if alternative methods(gait type change)could reduce stress and strain effectively.
