There is an obvious gap in sprint level at home and abroad,and there are different opinions on the reasons.According to the analysis,physical energy and its distribution in each segment are the main factors restrictin...There is an obvious gap in sprint level at home and abroad,and there are different opinions on the reasons.According to the analysis,physical energy and its distribution in each segment are the main factors restricting the sprint performance in China.Different from middle and long-distance running,we must rely on accurate sectional timing technology to master the law of speed-physical energy change in the process of sprint.Each stage is an integral part of the whole dash process,and each part restricts each other.Each stage has a relative best achievement.Simply pursuing the optimal state of segment is not only not helpful to the final result,but also counterproductive.展开更多
Affective valence is typically positive at exercise intensities below the lactate threshold,yet more aversive responses occur at supra-threshold intensities.Nevertheless,the physiological and psychological predictors ...Affective valence is typically positive at exercise intensities below the lactate threshold,yet more aversive responses occur at supra-threshold intensities.Nevertheless,the physiological and psychological predictors of affective valence during supramaximal intensities including short sprint interval training(sSIT)have not yet been elucidated.Seventeen(7 women/10 men)moderately active young adults(age=[28.2±5.6]years;VO2max[maximum oxygen consumption]=[52.9±8.1]mL·kg^(-1)·min^(-1);BMI[body mass index]=[242]kg·m^(-2))completed four low-volume running sSIT sessions(10^(-4)s efforts with 30 s of passive recovery).We recorded participants’heart rate(HR),root mean square of successive differences of normal RR intervals(RMSSD),heart rate recovery(HRR),ratings of perceived exertion(RPE),feeling scale(FS),intention and self-efficacy during,and after each session.Overall,no significant correlation(p>0.05)was found between FS and baseline clinical outcomes.No significant correlation(p>0.05)was detected between FS and any training parameter.No significant correlations were noted between FS and exercise task self-efficacy and intentions(p>0.05).The regression model was significant(F_(3,61)=5.57;p=0.002)and only three variables significantly entered the generated model:ΔHRR_(end-120s end)(p=0.002;VIF=2.58;40.8%),time≥90%HR_(peak)(p=0.001;VIF=1.26;31.6%),and RMSSD_(end)(p=0.025;VIF=2.23;27.6%).These findings suggest that HR-based measures,particularly those related to in-task stress(time≥90%HR_(peak))and acute recovery(ΔHRR_(end-120s end),and RMSSD_(end)),may predict affective valence during real-world sSIT.展开更多
Background:It remains unclear whether studies comparing _(max)imal oxygen uptake(VO_(2max))response to sprint interval training(SIT)vs.moderate-intensity continuous training(MICT)are associated with a high risk of bia...Background:It remains unclear whether studies comparing _(max)imal oxygen uptake(VO_(2max))response to sprint interval training(SIT)vs.moderate-intensity continuous training(MICT)are associated with a high risk of bias and poor reporting quality.The purpose of this study was to evaluate the risk of bias and quality of reporting in studies comparing changes in VO_(2max) between SIT and MICT.Methods:We conducted a comprehensive literature search of 4 major databases:AMED,CINAHL,EMBASE,and MEDLINE.Studies were excluded if participants were not healthy adult humans or if training protocols were unsupervised,lasted less than 2 weeks,or utilized mixed exercise modalities.We used the Cochrane Collaboration tool and the CONSORT checklist for non-pharmacological trials to evaluate the risk of bias and reporting quality,respectively.Results:Twenty-eight studies with 30 comparisons(3 studies included 2 SIT groups)were included in our meta-analysis(n=360 SIT participants:body mass index(BMI)=25.9±3.7 kg/m^(2),baseline VO_(2max)=37.9±8.0 mL/kg/min;n=359 MICT participants:BMI=25.5±3.8 kg/m^(2),baseline VO_(2max)=38.3±8.0 mL/kg/min;all mean±SD).All studies had an unclear risk of bias and poor reporting quality.Conclusion:Although we observed a lack of superiority between SIT and MICT for improving VO_(2max)(weighted Hedge’s g=0.004,95%con-fidence interval(95%CI):-0.08 to 0.07),the overall unclear risk of bias calls the validity of this conclusion into question.Future studies using robust study designs are needed to interrogate the possibility that SIT and MICT result in similar changes in VO_(2max).展开更多
High intensity interval training(HIIT)causes oxidative stress and haematological alteration.Present study was aimed to evaluate the effect of 8 weeks’supplementation of vitamin C and E on HIIT induced changes in lipi...High intensity interval training(HIIT)causes oxidative stress and haematological alteration.Present study was aimed to evaluate the effect of 8 weeks’supplementation of vitamin C and E on HIIT induced changes in lipid profile parameters and haematological variables.Hundred six male adolescent players were randomly assigned into five age-matched groups,i.e.,Control(no exercise+placebo),HIIT(placebo),HIIT+vitamin-C(1000mg/day),HIIT+vitamin-E 400 IU/day)and combined HIIT+vitamin C and E.Morning and evening sessions(90min)of HIIT included 4 phases(15min each)with 3 sets(4min each).Each 4min HIIT set consisted of 2min intense sprint workout(90%–95%of heart rate maximum[HRmax])followed by 1min active recovery(60%–70%HRmax)followed by 1min of complete rest(1:1 work-rest ratio).Lipid profile parameters,haematological variables,endurance capacity and vertical jump were evaluated by standard protocols.Significant decrease in body weight,fat%,total cholesterol,triglyceride,Total Cholesterol/High Density Lipoprotein-Cholesterol and significant increase in High Density Lipoprotein-Cholesterol,maximal oxygen consumption,vertical jump were observed for all four intervention groups.White blood cell count,red blood cell count,haemoglobin percentage and haematocrit values were significantly decreased while platelet count and platelet-to-leukocyte ratio(PLR)ratio were increased significantly only for HIIT group.Blood level of tocopherol and ascorbic acid was significantly increased(values were within the normal range)in all the respective vitamin supplemented groups.Supplementation of vitamin C and E secures health protection with suppressed haemolysis and improved inflammatory blood variables with enhanced explosive leg strength and lipid profile parameters without any concomitant change in endurance capacity.展开更多
文摘There is an obvious gap in sprint level at home and abroad,and there are different opinions on the reasons.According to the analysis,physical energy and its distribution in each segment are the main factors restricting the sprint performance in China.Different from middle and long-distance running,we must rely on accurate sectional timing technology to master the law of speed-physical energy change in the process of sprint.Each stage is an integral part of the whole dash process,and each part restricts each other.Each stage has a relative best achievement.Simply pursuing the optimal state of segment is not only not helpful to the final result,but also counterproductive.
基金founded by Proyectos I+D,Comision Sectorial de Investigacion Científica,Universidad de la República,Uruguay 2018,grant number 192supported by Grant RYC2021-031098-I funded by MCIN/AEI/10.13039/501100011033,by“European Union Next Generation EU/PRTR”by a productivity research grant PQ1-D(317126/2021-0)by CNPq(Brazil).
文摘Affective valence is typically positive at exercise intensities below the lactate threshold,yet more aversive responses occur at supra-threshold intensities.Nevertheless,the physiological and psychological predictors of affective valence during supramaximal intensities including short sprint interval training(sSIT)have not yet been elucidated.Seventeen(7 women/10 men)moderately active young adults(age=[28.2±5.6]years;VO2max[maximum oxygen consumption]=[52.9±8.1]mL·kg^(-1)·min^(-1);BMI[body mass index]=[242]kg·m^(-2))completed four low-volume running sSIT sessions(10^(-4)s efforts with 30 s of passive recovery).We recorded participants’heart rate(HR),root mean square of successive differences of normal RR intervals(RMSSD),heart rate recovery(HRR),ratings of perceived exertion(RPE),feeling scale(FS),intention and self-efficacy during,and after each session.Overall,no significant correlation(p>0.05)was found between FS and baseline clinical outcomes.No significant correlation(p>0.05)was detected between FS and any training parameter.No significant correlations were noted between FS and exercise task self-efficacy and intentions(p>0.05).The regression model was significant(F_(3,61)=5.57;p=0.002)and only three variables significantly entered the generated model:ΔHRR_(end-120s end)(p=0.002;VIF=2.58;40.8%),time≥90%HR_(peak)(p=0.001;VIF=1.26;31.6%),and RMSSD_(end)(p=0.025;VIF=2.23;27.6%).These findings suggest that HR-based measures,particularly those related to in-task stress(time≥90%HR_(peak))and acute recovery(ΔHRR_(end-120s end),and RMSSD_(end)),may predict affective valence during real-world sSIT.
基金supported by an operating grant from the Natural Science and Engineering Research Council of Canada (NSERCgrant number:402635) to BJG+2 种基金JTB was supported by a NSERC Vanier Canada Graduate ScholarshipHI was supported by NSERC PGS-DNP was supported by NSERC CGS-M。
文摘Background:It remains unclear whether studies comparing _(max)imal oxygen uptake(VO_(2max))response to sprint interval training(SIT)vs.moderate-intensity continuous training(MICT)are associated with a high risk of bias and poor reporting quality.The purpose of this study was to evaluate the risk of bias and quality of reporting in studies comparing changes in VO_(2max) between SIT and MICT.Methods:We conducted a comprehensive literature search of 4 major databases:AMED,CINAHL,EMBASE,and MEDLINE.Studies were excluded if participants were not healthy adult humans or if training protocols were unsupervised,lasted less than 2 weeks,or utilized mixed exercise modalities.We used the Cochrane Collaboration tool and the CONSORT checklist for non-pharmacological trials to evaluate the risk of bias and reporting quality,respectively.Results:Twenty-eight studies with 30 comparisons(3 studies included 2 SIT groups)were included in our meta-analysis(n=360 SIT participants:body mass index(BMI)=25.9±3.7 kg/m^(2),baseline VO_(2max)=37.9±8.0 mL/kg/min;n=359 MICT participants:BMI=25.5±3.8 kg/m^(2),baseline VO_(2max)=38.3±8.0 mL/kg/min;all mean±SD).All studies had an unclear risk of bias and poor reporting quality.Conclusion:Although we observed a lack of superiority between SIT and MICT for improving VO_(2max)(weighted Hedge’s g=0.004,95%con-fidence interval(95%CI):-0.08 to 0.07),the overall unclear risk of bias calls the validity of this conclusion into question.Future studies using robust study designs are needed to interrogate the possibility that SIT and MICT result in similar changes in VO_(2max).
文摘High intensity interval training(HIIT)causes oxidative stress and haematological alteration.Present study was aimed to evaluate the effect of 8 weeks’supplementation of vitamin C and E on HIIT induced changes in lipid profile parameters and haematological variables.Hundred six male adolescent players were randomly assigned into five age-matched groups,i.e.,Control(no exercise+placebo),HIIT(placebo),HIIT+vitamin-C(1000mg/day),HIIT+vitamin-E 400 IU/day)and combined HIIT+vitamin C and E.Morning and evening sessions(90min)of HIIT included 4 phases(15min each)with 3 sets(4min each).Each 4min HIIT set consisted of 2min intense sprint workout(90%–95%of heart rate maximum[HRmax])followed by 1min active recovery(60%–70%HRmax)followed by 1min of complete rest(1:1 work-rest ratio).Lipid profile parameters,haematological variables,endurance capacity and vertical jump were evaluated by standard protocols.Significant decrease in body weight,fat%,total cholesterol,triglyceride,Total Cholesterol/High Density Lipoprotein-Cholesterol and significant increase in High Density Lipoprotein-Cholesterol,maximal oxygen consumption,vertical jump were observed for all four intervention groups.White blood cell count,red blood cell count,haemoglobin percentage and haematocrit values were significantly decreased while platelet count and platelet-to-leukocyte ratio(PLR)ratio were increased significantly only for HIIT group.Blood level of tocopherol and ascorbic acid was significantly increased(values were within the normal range)in all the respective vitamin supplemented groups.Supplementation of vitamin C and E secures health protection with suppressed haemolysis and improved inflammatory blood variables with enhanced explosive leg strength and lipid profile parameters without any concomitant change in endurance capacity.
