Objective To explore the peak moment characteristics of lower limb joints,as well as the contribution rate and compensation mechanism of lower limb joints when older adults with a history of falls cross obstacles at different paces.Methods Thirty healthy older adults and 30 eldely fallers were recruited.The Qualisys infrared high-speed motion capture system and the Kistler three-dimensional force platform were used to collect the biomechanical data of the older adults when they crossed an obstacle with a height of 15％of their height at three walking speeds(1.05,1.41,1.74 m/s).The data were then modeled and analyzed using Visual 3D software.Results As walking speed increased,the peak knee extension moment,peak ankle plantar flexion moment,and double peak value of hip flexion moment in healthy group all increased significantly(P＜0.05).Compared with healthy group,the double peak values of hip flexion moment in faller group were significantly smaller than those in healthy group(P＜0.05).During walking at moderate speed,the contribution rate of the left hip joint in faller group was significantly higher than that of healthy group(P=0.025),while the contribution rate of the ankle joint was significantly lower(P=0.044).The margin of stability in the anterior-posterior direction at the moment of ground contact of the stance leg and the stride leg increased with walking speed(P=0.007,P=0.002).Conclusions Compared with healthy older adults,the elderly fallers have lower peak torque,peak ground reaction force,and dynamic stability in the anterior-posterior direction.As the walking speed increases,the mechanical parameters and the margin of stability of older adults increase significantly,and walking stability is improved.Compared with healthy older adults,elderly fallers usually rely more on the contribution of hip joint movements and reduce the involvement of ankle joints.It is recommended to incorporate fast walking exercises into the daily fall prevention exercise program for older adults,with combination of coordinated training of the hip,knee,and ankle joints.

Objective To explore the peak moment characteristics of lower limb joints,as well as the contribution rate and compensation mechanism of lower limb joints when older adults with a history of falls cross obstacles at different paces.Methods Thirty healthy older adults and 30 eldely fallers were recruited.The Qualisys infrared high-speed motion capture system and the Kistler three-dimensional force platform were used to collect the biomechanical data of the older adults when they crossed an obstacle with a height of 15％of their height at three walking speeds(1.05,1.41,1.74 m/s).The data were then modeled and analyzed using Visual 3D software.Results As walking speed increased,the peak knee extension moment,peak ankle plantar flexion moment,and double peak value of hip flexion moment in healthy group all increased significantly(P＜0.05).Compared with healthy group,the double peak values of hip flexion moment in faller group were significantly smaller than those in healthy group(P＜0.05).During walking at moderate speed,the contribution rate of the left hip joint in faller group was significantly higher than that of healthy group(P=0.025),while the contribution rate of the ankle joint was significantly lower(P=0.044).The margin of stability in the anterior-posterior direction at the moment of ground contact of the stance leg and the stride leg increased with walking speed(P=0.007,P=0.002).Conclusions Compared with healthy older adults,the elderly fallers have lower peak torque,peak ground reaction force,and dynamic stability in the anterior-posterior direction.As the walking speed increases,the mechanical parameters and the margin of stability of older adults increase significantly,and walking stability is improved.Compared with healthy older adults,elderly fallers usually rely more on the contribution of hip joint movements and reduce the involvement of ankle joints.It is recommended to incorporate fast walking exercises into the daily fall prevention exercise program for older adults,with combination of coordinated training of the hip,knee,and ankle joints.

Objective To explore dynamic characteristics of the gait for the elderly with different fall risks before and after obstacle crossing. Methods Twenty-seven elderly people in community were graded as fall risk by using the time up and go test and five-time sit to stand test. The plantar pressure parameters of the elderly before and after obstacle crossing were measured and analyzed by foot pressure measurement system. Results There was no significant difference in the characteristic value of bimodal curve of overall plantar pressure between the high and low fall risk groups before and after obstacle crossing(P>0.05). The center of pressure (COP) trajectory in X direction of high fall risk group after obstacle crossing was significantly greater than that of low fall risk group (P<0.05). Before obstacle crossing, the peak pressure of the 3rd metatarsal of supporting foot was higher in high fall risk group than that in low fall risk group (P<0.05). After obstacle crossing, the peak pressure of the 1st phalanx of supporting foot was significantly lower than that in high fall risk group (P<0.05), while the lateral heel impulse in high fall risk group was significantly larger than that in low fall risk group (P<0.05).The distribution patterns of contact area of the foot for the elderly in two groups before and after obstacle crossing were basically the same, and there was no significant difference in contact area of each plantar region (P>0.05). Conclusions The support time of the elderly with high fall risk is longer than that of the elderly with low fall risk during obstacle crossing, the peak pressure of plantar metatarsal region of the crossing leg increases, and the plantar COP curve shows asymmetry, with an increase in transverse range of the coronal plane. In clinical evaluation, plantar pressure characteristics of people with fall risks during obstacle crossing should be focused on.

Abstract: To explore the effect of eriodictyol(Eri) on the proliferation and apoptosis of triple-negative breast cancer MDA-MB-231 cells and its possible mechanism. Methods: MDA-MB-231 cells were treated with different concentrations of Eri. MTT method was used to detect the level of cell proliferation. Plate clone method was used to detect the the level of cell clonality. The apoptosis level was detected by flow cytometry. Western blot was used to detect protein expression levels of Cleaved-caspase-3, Bax, Bcl-2, c-Myc and AR. MDA-MB-231 cells were transfected with si-c-Myc and then combined treatment with 50 μmol/L Eri. MTT method was used to detect the level of cell proliferation. The apoptosis level was detected by flow cytometry. Western blot was used to detect protein expression levels of c-Myc and AR. Results: Eri inhibited the proliferation activity of MDA-MB-231 cells in a dose and time-dependent manner. Treatment with different concentrations of Eri reduced cloning ability of MDA-MB-231 cells, promoted cell apoptosis, up-regulated the protein expression levels of Cleaved-caspase-3 and Bax, and down-regulated the protein expression level of Bcl-2, c-Myc and AR. Knockdown of c-Myc expression inhibited MDA-MB-231 cells growth, promoted cell apoptosis, and down-regulated the protein expression level of c-Myc and AR, while combined treatment with 50 μmol/L Eri could not enhance the situation. Conclusion Er inhibits proliferation and induces apoptosis in triple-negative breast cancer MDA-MB-231 cells, which may be achieved by inhibiting c-Myc/AR axis.