为了快速、准确地建立4种不同滚子类型的弧面凸轮三维模型,采用UG Open Grip二次开发工具,根据不同弧面凸轮廓面方程生成一系列离散点,再由点生成线,由线生成面,由面生成体,逐步完成不同滚子类型弧面凸轮的三维建模。该方法为快速、准...为了快速、准确地建立4种不同滚子类型的弧面凸轮三维模型,采用UG Open Grip二次开发工具,根据不同弧面凸轮廓面方程生成一系列离散点,再由点生成线,由线生成面,由面生成体,逐步完成不同滚子类型弧面凸轮的三维建模。该方法为快速、准确地建立弧面凸轮三维模型提供了一种方法。展开更多
Objective This study aims to evaluate the association between lower grip strength and mortality hazard.Methods We selected 10,280 adults aged 45 to 96 years old from the China Health and Retirement Longitudinal Study ...Objective This study aims to evaluate the association between lower grip strength and mortality hazard.Methods We selected 10,280 adults aged 45 to 96 years old from the China Health and Retirement Longitudinal Study and used multivariate Cox proportional hazard models to assess the association of grip strength with mortality hazard.In addition,we explored the possibility of a nonlinear relationship using a 4-knot restricted spline regression.Results We found that elevated grip strength was associated with lower mortality up to a certain threshold.The baseline quartile values of grip strength were 30,37,and 44 kg for males and 25,30,and35 kg for females.After adjusting for confounders,with category 1 as the reference group,the adjusted HRs were 0.58(0.42-0.79)in males and 0.70(0.48-0.99)in females(category 4).We also found a linear association between grip strength values and all-cause death risk(males,P=0.274;females,P=0.883)using restricted spline regression.For males with a grip strength<37 kg and females with a grip strength<30 kg,grip strength and death were negatively associated.Conclusion Grip strength below a sex-specific threshold is inversely associated with mortality hazard among middle-aged and older Chinese adults with chronic diseases.展开更多
Background: Although handgrip strength is a biomarker for morbidity/mor-tality, there is lack of evidence on the effects of resistance training on handgrip strength in healthy adults of all ages. Objective: The aim of...Background: Although handgrip strength is a biomarker for morbidity/mor-tality, there is lack of evidence on the effects of resistance training on handgrip strength in healthy adults of all ages. Objective: The aim of this systematic review was to assess the impact of resistance training on handgrip strength in healthy adults. Methods: Five databases/search engines were searched. Studies comparing different types of resistance exercise interventions versus a non-exercised control group on handgrip strength were included. The available data did not allow us to conduct the pre-planned meta-analyses;therefore, only descriptive statistics were performed to summarize the data. Results: Twenty studies (17 randomized and three non-randomized controlled trials) were included, most of which were conducted in older adults. Twelve studies reported no significant difference in the change in handgrip strength between the resistance training and control groups. Two studies showed increases in handgrip strength in the resistance training group compared with the control group. Other studies included results for multi-training groups or left/right hands and found increasing handgrip strength compared to controls, but only in one training group or one hand. Overall, the randomized and non-ran-domized clinical trials presented moderate risk of bias. Conclusions: Due to the lack of low risk-of-bias randomized controlled trials of young and middle-aged adults, different training protocols, and small sample sizes, the existing evidence appears insufficient to support resistance training for increasing handgrip strength in healthy adults. Future studies may seek to discern the optimal way to develop and employ resistance training to improve hand-grip strength.展开更多
基金supported by the Ministry of Education of Humanities and Social Science Project[Grant No.Y202145935]。
文摘Objective This study aims to evaluate the association between lower grip strength and mortality hazard.Methods We selected 10,280 adults aged 45 to 96 years old from the China Health and Retirement Longitudinal Study and used multivariate Cox proportional hazard models to assess the association of grip strength with mortality hazard.In addition,we explored the possibility of a nonlinear relationship using a 4-knot restricted spline regression.Results We found that elevated grip strength was associated with lower mortality up to a certain threshold.The baseline quartile values of grip strength were 30,37,and 44 kg for males and 25,30,and35 kg for females.After adjusting for confounders,with category 1 as the reference group,the adjusted HRs were 0.58(0.42-0.79)in males and 0.70(0.48-0.99)in females(category 4).We also found a linear association between grip strength values and all-cause death risk(males,P=0.274;females,P=0.883)using restricted spline regression.For males with a grip strength<37 kg and females with a grip strength<30 kg,grip strength and death were negatively associated.Conclusion Grip strength below a sex-specific threshold is inversely associated with mortality hazard among middle-aged and older Chinese adults with chronic diseases.
文摘Background: Although handgrip strength is a biomarker for morbidity/mor-tality, there is lack of evidence on the effects of resistance training on handgrip strength in healthy adults of all ages. Objective: The aim of this systematic review was to assess the impact of resistance training on handgrip strength in healthy adults. Methods: Five databases/search engines were searched. Studies comparing different types of resistance exercise interventions versus a non-exercised control group on handgrip strength were included. The available data did not allow us to conduct the pre-planned meta-analyses;therefore, only descriptive statistics were performed to summarize the data. Results: Twenty studies (17 randomized and three non-randomized controlled trials) were included, most of which were conducted in older adults. Twelve studies reported no significant difference in the change in handgrip strength between the resistance training and control groups. Two studies showed increases in handgrip strength in the resistance training group compared with the control group. Other studies included results for multi-training groups or left/right hands and found increasing handgrip strength compared to controls, but only in one training group or one hand. Overall, the randomized and non-ran-domized clinical trials presented moderate risk of bias. Conclusions: Due to the lack of low risk-of-bias randomized controlled trials of young and middle-aged adults, different training protocols, and small sample sizes, the existing evidence appears insufficient to support resistance training for increasing handgrip strength in healthy adults. Future studies may seek to discern the optimal way to develop and employ resistance training to improve hand-grip strength.
