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
Purpose The purpose of this study was to examine the response of myokines to blood-flow restricted resistance-exercise(BFR-RE)in younger and older males before and after completing a 12-week resistance-training progra...Purpose The purpose of this study was to examine the response of myokines to blood-flow restricted resistance-exercise(BFR-RE)in younger and older males before and after completing a 12-week resistance-training program.Methods There were 8 younger(24.8±3.9 yrs)and 7 older(68.3±5.0 yrs)untrained male participants completed this study.Anthropometric and maximal strength(1RM)measurements were collected before and after a 12-week,supervised,progres-sive full-body resistance-training program.As well,an acute bout of full-body BFR-RE was performed with venipuncture blood samples collected before and immediately following the BFR-RE,followed by sampling at 3,6,24 and 48 h.Results The 12-week training program stimulated a 32.2%increase in average strength and 30%increase in strength per kg of fat free mass.The response of particular myokines to the acute bout of BFR-RE was influenced training status(IL-4,untrained=78.1±133.2 pg/mL vs.trained=59.8±121.6 pg/mL,P=0.019;IL-7,untrained=3.46±1.8 pg/mL vs.trained=2.66±1.3 pg/mL,P=0.047)or both training and age(irisin,P=0.04;leukemia inhibitory factor,P<0.001).As well,changes in strength per kg of fat free mass were correlated with area under the curve for IL-4(r=0.537;P=0.039),IL-6(r=0.525;P=0.044)and LIF(r=−0.548;P=0.035)in the untrained condition.Conclusion This study identified that both age and training status influence the myokine response to an acute bout of BFR-RE with the release of IL-4,IL-6 and LIF in the untrained state being associated with changes in strength per kg of fat free mass.展开更多
Age-related sarcopenia places a tremendous burden on healthcare providers and patients'families.Blood flow restriction(BFR)training may be a promising treatment to bring sarcopenia down,and it offers numerous adva...Age-related sarcopenia places a tremendous burden on healthcare providers and patients'families.Blood flow restriction(BFR)training may be a promising treatment to bring sarcopenia down,and it offers numerous advantages over traditional resistance training.The purpose of this review was to compare the effects of BFR training and conventional resistance training on clinically delayed sarcopenia in the elderly.Databases such as PubMed,Web of Science,Embase,and Science Direct were searched to identify eligible studies;blinded data extraction was performed to assess study quality,and conflicts were submitted to third parties.Someone made the decision.One author used Review Manager(RevMan)5.4 and compared it with data obtained by another author for this purpose.A total of 14 studies met the inclusion criteria for this review.The funnel plots of the studies did not show any substantial publication bias.Low-load blood flow restriction(LL-BFR)had no significant effect on muscle mass compared with high-load resistance training(HL-RT)(p=0.74,SMD=0.07,95%CI:0.33 to 0.46)and LL-BFR had a significant effect on muscle strength compared with HL-RT(p=0.03,Z=2.16,SMD=-0.34,95%CI:0.65 to-0.03).LL-BFR showed a slight effect on mass compared to LL-RT(p=0.26,SMD=0.25,95%CI:0.19 to 0.69).Sensitivity analysis produced a nonsignificant change,suggesting that the results of this study are reasonable.In conclusion,the data suggest the possibility that BFR training improves age-related sarcopenia.展开更多
One active and two passive air sampling configurations were deployed simultaneously in three offices in Beijing,China to test their comparability for sampling emerging and legacy halogenated flame retardants spanning ...One active and two passive air sampling configurations were deployed simultaneously in three offices in Beijing,China to test their comparability for sampling emerging and legacy halogenated flame retardants spanning a large range of octanoleair partition coefficients(KOA).Sampling in each office was carried out for three consecutive 28-day periods in the spring-summer of 2013.The active sampler was run for 2.5 h at different times every day for 28 days to parallel the passive samplers and sample a total volume comparable to that sampled by the passive samplers(~20 m^3).At the end of each 28-day sampling period,a separate active air sample was taken by running the sampler pump continuously for about 2.5 days.The comparability of measured concentrations varied between the air sampling configurations and for different compounds.The predominant compound measured in nearly all samples was BDE-209,a compound known to have heavy use in China.Several emerging flame retardants were also detected including DBE-DBCH,PBT,HBB,DDC-CO,and DBDPE.Very little of the tetra-hexabrominated BDEs associated with the technical PentaBDE product was observed.展开更多
【目的】验证根癌农杆菌(Agrobacterium fabrum,以前也叫Agrobacterium tumefaciens)两种储铁蛋白——饥饿细胞的DNA结合蛋白(DNA-binding protein from starved cells, Dps)和细菌铁蛋白(bacterioferritin, Bfr)的编码基因atu2477和atu...【目的】验证根癌农杆菌(Agrobacterium fabrum,以前也叫Agrobacterium tumefaciens)两种储铁蛋白——饥饿细胞的DNA结合蛋白(DNA-binding protein from starved cells, Dps)和细菌铁蛋白(bacterioferritin, Bfr)的编码基因atu2477和atu2771的功能。确定Bfr编码基因的开放阅读框。研究末端融合、血红素和个别关键氨基酸突变对Bfr功能和体外自组装的影响。探讨两种储铁蛋白的可能应用潜力。【方法】通过质粒将编码储铁蛋白的基因重新引入根癌农杆菌储铁蛋白缺失突变体中,回补储铁蛋白,验证回补的储铁蛋白编码基因是否能表达出具有储铁能力的储铁蛋白。用非变性凝胶电泳分离细胞粗提液中的蛋白质,铁特异性染色的方法鉴定电泳分离的蛋白质中是否有储铁蛋白。将不同的肽或蛋白质融合到储铁蛋白的末端,通过异源过量表达和纯化储铁蛋白的重组蛋白,用非变性凝胶电泳分析这些重组蛋白在体外的自组装。用血红素重构处理和氨基酸定点突变的方法研究血红素和个别关键氨基酸对Bfr功能和体外自组装的影响。【结果】非变性凝胶电泳和铁特异性染色结果显示,在根癌农杆菌的野生菌株、其相关突变体以及对应的回补菌株中,均仅检测到Bfr的表达,未检测到Dps的存在。当分别回补能编码161个和169个氨基酸Bfr的基因后,发现野生型菌株中的Bfr与回补编码161个氨基酸Bfr的回补菌株一样大。多肽和蛋白质的末端融合对Bfr的功能和自组装有一定影响,但不会使Bfr完全失去功能和自组装能力。结果还表明,血红素和预测可络合血红素铁的Met60的替换也只影响Bfr的功能和自组装,并未使Bfr功能完全丧失。【结论】根癌农杆菌主要通过Bfr存储铁元素。bfr基因的开放阅读框(open reading frame, ORF)以少见的UUG为起始密码子,编码产生包含161个氨基酸的蛋白质,而非169个氨基酸。根癌农杆菌的dps基因在�展开更多
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.
基金This project was supported by the University Collaborative Research Program and Faculty of Science Collaborative Grant-University of Manitoba.
文摘Purpose The purpose of this study was to examine the response of myokines to blood-flow restricted resistance-exercise(BFR-RE)in younger and older males before and after completing a 12-week resistance-training program.Methods There were 8 younger(24.8±3.9 yrs)and 7 older(68.3±5.0 yrs)untrained male participants completed this study.Anthropometric and maximal strength(1RM)measurements were collected before and after a 12-week,supervised,progres-sive full-body resistance-training program.As well,an acute bout of full-body BFR-RE was performed with venipuncture blood samples collected before and immediately following the BFR-RE,followed by sampling at 3,6,24 and 48 h.Results The 12-week training program stimulated a 32.2%increase in average strength and 30%increase in strength per kg of fat free mass.The response of particular myokines to the acute bout of BFR-RE was influenced training status(IL-4,untrained=78.1±133.2 pg/mL vs.trained=59.8±121.6 pg/mL,P=0.019;IL-7,untrained=3.46±1.8 pg/mL vs.trained=2.66±1.3 pg/mL,P=0.047)or both training and age(irisin,P=0.04;leukemia inhibitory factor,P<0.001).As well,changes in strength per kg of fat free mass were correlated with area under the curve for IL-4(r=0.537;P=0.039),IL-6(r=0.525;P=0.044)and LIF(r=−0.548;P=0.035)in the untrained condition.Conclusion This study identified that both age and training status influence the myokine response to an acute bout of BFR-RE with the release of IL-4,IL-6 and LIF in the untrained state being associated with changes in strength per kg of fat free mass.
文摘Age-related sarcopenia places a tremendous burden on healthcare providers and patients'families.Blood flow restriction(BFR)training may be a promising treatment to bring sarcopenia down,and it offers numerous advantages over traditional resistance training.The purpose of this review was to compare the effects of BFR training and conventional resistance training on clinically delayed sarcopenia in the elderly.Databases such as PubMed,Web of Science,Embase,and Science Direct were searched to identify eligible studies;blinded data extraction was performed to assess study quality,and conflicts were submitted to third parties.Someone made the decision.One author used Review Manager(RevMan)5.4 and compared it with data obtained by another author for this purpose.A total of 14 studies met the inclusion criteria for this review.The funnel plots of the studies did not show any substantial publication bias.Low-load blood flow restriction(LL-BFR)had no significant effect on muscle mass compared with high-load resistance training(HL-RT)(p=0.74,SMD=0.07,95%CI:0.33 to 0.46)and LL-BFR had a significant effect on muscle strength compared with HL-RT(p=0.03,Z=2.16,SMD=-0.34,95%CI:0.65 to-0.03).LL-BFR showed a slight effect on mass compared to LL-RT(p=0.26,SMD=0.25,95%CI:0.19 to 0.69).Sensitivity analysis produced a nonsignificant change,suggesting that the results of this study are reasonable.In conclusion,the data suggest the possibility that BFR training improves age-related sarcopenia.
基金funded by the European Commission,Seventh Framework Programme under the EU Marie Curie Initial Training Network INFLAME(GA No.264600)Funding for the participation of Ulla Sellströom,William Stubbings,Congqiao Yang,and Sandra Brommer in this study came from European Union Seventh Framework Programme International Research Staff Exchange Scheme INTERFLAME(GA No.295138).
文摘One active and two passive air sampling configurations were deployed simultaneously in three offices in Beijing,China to test their comparability for sampling emerging and legacy halogenated flame retardants spanning a large range of octanoleair partition coefficients(KOA).Sampling in each office was carried out for three consecutive 28-day periods in the spring-summer of 2013.The active sampler was run for 2.5 h at different times every day for 28 days to parallel the passive samplers and sample a total volume comparable to that sampled by the passive samplers(~20 m^3).At the end of each 28-day sampling period,a separate active air sample was taken by running the sampler pump continuously for about 2.5 days.The comparability of measured concentrations varied between the air sampling configurations and for different compounds.The predominant compound measured in nearly all samples was BDE-209,a compound known to have heavy use in China.Several emerging flame retardants were also detected including DBE-DBCH,PBT,HBB,DDC-CO,and DBDPE.Very little of the tetra-hexabrominated BDEs associated with the technical PentaBDE product was observed.
