Experimental Study of an Active Body-Weight Support System for Low Limbs Rehabilitation Training

An experimental study of an active body-weight support（BWS） system for improving treadmill-based locomotion training is performed.The dynamical foundation of the proposed system is developed based on a simplified cable suspended mass-spring-damping system which is used to mimic the vertical gait of a walking human.A specifically designed cable pulley suspended cam-slider system is used to mimic the walking gait of a human in vertical direction.A load cell is installed to connect the slider and the cable which is driven by a winch based on the acceleration feedback.The contact force between the slider and the cam is measured to evaluate the walking load of the system.The experimental results demonstrate that the proposed active BWS system can simultaneously reduce both gravitational and inertial load of the walking body,which implies that the walking body suspended in such a BWS system will dynamically behave as if certain amount of body mass had been removed.

Maternal weight and its association with risk of overweight in offspring:a trajectory analysis from a birth cohort in China

Background Most studies on the association of maternal pregnancy weight with offspring weight trajectory have a short follow-up time.This study aimed to explore the associations of maternal prepregnancy body mass index(BMI)and gestational weight gain(GWG)with childhood weight trajectories in a 7-year birth cohort.Methods A total of 946 mother–child pairs(467 boys and 479 girls)from a longitudinal birth cohort in Tianjin City,China,were included in this study,ranging from pregnancy to offspring at 7 years.The outcome variable was defined as overweight or not overweight in offspring at the last round.A group-based trajectory model was applied to identify childhood BMI trajectory groups.Results Five discrete BMI trajectory groups were identified and characterized as constant underweight(25.2%),constant normal weight(42.8%),and high or increasing trajectory[at risk of overweight(16.9%),progressive overweight(11.0%)and progressive obesity(4.1%)].Maternal prepregnancy overweight was associated with 1.72(95%CI 1.14–2.60,P=0.01)to 4.02(95%CI 1.94–8.36,P<0.001)times the risk of all high or increasing trajectory groups,and excessive GWG was related to groups at risk of overweight[relative risk ratio(RRR)2.09,95%CI 1.27–3.46,P=0.004]and progressive obesity(RRR 3.33,95%CI 1.13–9.79,P=0.029).Children in all high or increasing trajectory groups were associated with greater overweight risk at the last round[risk ratios(RRs)ranged from 3.54(95%CI 2.53–4.95,P<0.001)to 6.18(95%CI 4.05–9.42,P<0.001)].Conclusion Maternal prepregnancy overweight and excessive gestational weight gain were associated with increasing or high-level childhood body mass index trajectories as well as a greater risk of overweight at 7 years.