溴阻燃剂(Brominated fire retardants,BFRs)的生产和使用对人类自身健康及其居住环境的影响问题,特别是“二恶英”(Dioxins)的问题,已引起全球范围广泛的重视。欧盟“限制电子电器产品中有害物质”的指令(RoHS)明确规定限制某些溴阻燃...溴阻燃剂(Brominated fire retardants,BFRs)的生产和使用对人类自身健康及其居住环境的影响问题,特别是“二恶英”(Dioxins)的问题,已引起全球范围广泛的重视。欧盟“限制电子电器产品中有害物质”的指令(RoHS)明确规定限制某些溴阻燃剂的使用。笔者就溴阻燃剂近十年来在空气、下水道淤泥和沉积物等非生命环境体系以及动物和人等生命体系的分布情况进行了综合分析,结果发现溴阻燃剂在非生命和生命环境体系中均有增加的趋势。对溴阻燃剂在生物体内的富集和放大作用研究发现,部分溴阻燃剂会在生物体内富集并表现出一定的放大作用。笔者对我国阻燃剂的发展方向提出了见解和建议。展开更多
bjectives:Whether low-load resistance training(RT)without muscle failure,with or without bloodflow restriction(BFR),is suffcient to increase strength and muscle growth of calf musclesin trained individualsisstill uncle...bjectives:Whether low-load resistance training(RT)without muscle failure,with or without bloodflow restriction(BFR),is suffcient to increase strength and muscle growth of calf musclesin trained individualsisstill unclear.This study aimed to compare the effects of low-intensity BFR RT vs.traditional low-intensity RT(noBFR)with moderate training volume on strength and circumference.Methods:We designed a parallel,randomized controlled trial including 36 RT-trained participants(BFR:7 females,32.9±8.8 years,11 males,28.4±3.6 years;noBFR;8 females,29.6±3.4 years;10 males,28.6±4.9 years)who underwent eight weeks of twice-weekly low-load RT with a total of 16 RT sets(30%of one-repetition maximum[1RM]).RT consisted of bilateral calf raises and seated unilateral calf raises,each conducted with 4 sets(30,15,15,15 repetitions not to failure)of either BFR or noBFR.Outcome measures included calf circumference(CC),leg stiffness(LS),and various strength tests(seated and standing calf raise 1RM,isokinetic strength of plantar-and dorsiflexion).Results:There were no significant interactions or group effects for most measures.Both groups showed significant improvementsin seated calf raise strength(p=0.046,η^(2)p=0.17).Pairwise comparisons indicated moderate to large effect sizes for strength improvements(standardized mean differences:0.35–1.11),but no changes in calf circumference were observed in either group.Conclusions:Low-load RT with and without BFR are useful to increase strength without necessarily affecting hypertrophy.Low-intensity BFR training did not confer additional benefits over traditional low-intensity RT for calf muscle strength or circumference,questioning its general advantage under such conditions.展开更多
文摘溴阻燃剂(Brominated fire retardants,BFRs)的生产和使用对人类自身健康及其居住环境的影响问题,特别是“二恶英”(Dioxins)的问题,已引起全球范围广泛的重视。欧盟“限制电子电器产品中有害物质”的指令(RoHS)明确规定限制某些溴阻燃剂的使用。笔者就溴阻燃剂近十年来在空气、下水道淤泥和沉积物等非生命环境体系以及动物和人等生命体系的分布情况进行了综合分析,结果发现溴阻燃剂在非生命和生命环境体系中均有增加的趋势。对溴阻燃剂在生物体内的富集和放大作用研究发现,部分溴阻燃剂会在生物体内富集并表现出一定的放大作用。笔者对我国阻燃剂的发展方向提出了见解和建议。
文摘bjectives:Whether low-load resistance training(RT)without muscle failure,with or without bloodflow restriction(BFR),is suffcient to increase strength and muscle growth of calf musclesin trained individualsisstill unclear.This study aimed to compare the effects of low-intensity BFR RT vs.traditional low-intensity RT(noBFR)with moderate training volume on strength and circumference.Methods:We designed a parallel,randomized controlled trial including 36 RT-trained participants(BFR:7 females,32.9±8.8 years,11 males,28.4±3.6 years;noBFR;8 females,29.6±3.4 years;10 males,28.6±4.9 years)who underwent eight weeks of twice-weekly low-load RT with a total of 16 RT sets(30%of one-repetition maximum[1RM]).RT consisted of bilateral calf raises and seated unilateral calf raises,each conducted with 4 sets(30,15,15,15 repetitions not to failure)of either BFR or noBFR.Outcome measures included calf circumference(CC),leg stiffness(LS),and various strength tests(seated and standing calf raise 1RM,isokinetic strength of plantar-and dorsiflexion).Results:There were no significant interactions or group effects for most measures.Both groups showed significant improvementsin seated calf raise strength(p=0.046,η^(2)p=0.17).Pairwise comparisons indicated moderate to large effect sizes for strength improvements(standardized mean differences:0.35–1.11),but no changes in calf circumference were observed in either group.Conclusions:Low-load RT with and without BFR are useful to increase strength without necessarily affecting hypertrophy.Low-intensity BFR training did not confer additional benefits over traditional low-intensity RT for calf muscle strength or circumference,questioning its general advantage under such conditions.
