It is unknown whether oxygen uptake(VO_(2))sampling intervals influence the efficacy of a verification stage following a graded exercise test(GXT).Fifteen females and 14 males(18-25 years)completed a maximal treadmill...It is unknown whether oxygen uptake(VO_(2))sampling intervals influence the efficacy of a verification stage following a graded exercise test(GXT).Fifteen females and 14 males(18-25 years)completed a maximal treadmill GXT.After a 5min recovery,the verification stage began at the speed and grade corresponding with the penultimate stage from the GXT.Maximal oxygen consumption(VO_(2max))from the incremental GXT(iVO_(2max))and VO_(2max)from the verification stage(verVO_(2max))were determined using 10 seconds(s),30s,and 60s from breath×breath averages.There was no main effect for VO_(2max)measure(iVO_(2max)vs.verVO_(2max))10s([47.9±8.31]ml∙kg^(−1)∙min^(−1)vs[48.85±7.97]ml∙kg^(−1)∙min^(−1)),30s([46.94±8.62]ml∙kg^(−1)∙min^(−1)vs[47.28±7.97]ml∙kg^(−1)∙min^(−1)),and 60s([46.17±8.62]ml∙kg^(−1)∙min^(−1)vs[46.00±8.00]ml∙kg^(−1)∙min^(−1)].There was a stage×sampling interval interaction as the difference between(verVO_(2max)−iVO_(2max))was greater for 10-s than 60-s sampling intervals.The verVO_(2max)was>4%higher than iVO_(2max)in 31%,31%,and 17%of the tests for the 10-s,30-s,and 60-s sampling intervals respectively.Sensitivity for the plateau was<30%for 10-s,30-s,and 60-s sampling intervals.Specificity ranged from 44%to 60%for all sampling intervals.Sensitivity for heart rate+respiratory exchange ratio was>90%for all sampling intervals;while specificity was<25%.Findings from the present study suggest that the efficacy of verification stages for eliciting a higher VO_(2max)may be influenced by the sampling interval utilized.展开更多
Anthropometric variations can affect resting energy expenditure,VO_(2) max and anaerobic capacity of young,healthy individuals.Studies have shown that body fat percentage,weight,and height can all affect the three mea...Anthropometric variations can affect resting energy expenditure,VO_(2) max and anaerobic capacity of young,healthy individuals.Studies have shown that body fat percentage,weight,and height can all affect the three measures.The study aimed to study VO_(2) max and 24-hour thermogenesis measures in predominantly sedentary individuals and weight changes afterwards.VO_(2) max-associated research shows that taller individuals tend to have higher VO_(2) max levels compared to shorter individuals.This could be because taller individuals have a larger lung capacity and greater oxygen delivery to the muscles.Weight can also affect VO_(2) max,as heavier individuals tend to have higher VO_(2) max levels than lighter individuals.Weight is also associated with resting energy expenditure,as heavier individuals tend to have a higher resting energy expenditure than lighter individuals.The purpose of this study was to conduct a systematic review of the existing literature related to resting energy expenditure and metabolic effects of VO_(2) max,and anaerobic capacity in sedentary active adults of anthropometric variations.Several studies have recently examined the possibility of improving aerobic and metabolic functions ensuring cardiorespiratory fitness within the population of anthropometric variations.Everyday physical activity and heredity ability influenced mainly the gold standard measuring tool for cardiorespiratory fitness,VO_(2) max,predicting mortality and morbidity.Weight gain has also been shown to be associated with lower cardiorespiratory fitness,regardless of physical activity levels.The VO_(2) max may have a different effect on energy balance apart from physical activity’s energy expenditure(EE),possibly by affecting the resting metabolic rate(RMR)or triggering a common mechanism associated with diet-induced thermogenesis.Weight change is predicted by sedentary energy expenditure,but directly measured VO_(2) max does not appear to be correlated with weight change.The relationship between resting energy expenditure,VO_(2) max,and anaerobic capacity in individuals is complex.Resting energy expenditure is directly related to anaerobic capacity,as it is an indicator of the body’s ability to work anaerobically.VO_(2) max is also related to anaerobic capacity,as it reflects the body’s maximal aerobic power.However,the strength of this relationship is not known.Overall,both resting energy expenditure and VO_(2) max are important determinants of anaerobic capacity in individuals and are worth considering when evaluating an individual’s anaerobic potential.展开更多
Background:Intensive exercise changes physiological need for glucose and several biochemical pathways responsible for its metabolism response.Among them are those which involve insulin,insulin-like growth factor(IGF-1...Background:Intensive exercise changes physiological need for glucose and several biochemical pathways responsible for its metabolism response.Among them are those which involve insulin,insulin-like growth factor(IGF-1),and IGF-binding proteins(IGFBPs).Different types and degrees of exercise,as well as an athlete's fitness,may induce a range of responses regarding concentrations and time needed for the alteration.The idea of the work was to find out whether and how insulin/IGF axis responds to additional physical activity in the already trained subjects and if so,is the adaptation potentially beneficial from the aspect of metabolic control.Methods:The effect of 4-week intensive training on campus(preparatory training) on the levels of insulin,IGF-1,and IGFBPs during maximal progressive exercise test(MPET) on a treadmill was compared to the results obtained during MPET conducted after a regular training season of a female elite handball team(n = 17,age:17 ± 1 years,height:171 ± 8 cm,weight:65 ± 8 kg,body mass index:22 ± 1 kg/m^2 at the beginning of the study;there were no significant changes at the end).Serum samples were obtained from players immediately before the test(basal),at the end of the test after reaching the point of maximal oxygen consumption(VO_(2max)),and after recovery.Results:The concentration of insulin decreased at VO_(2max),but remained higher in players after preparatory training(12.2 ± 2.5 m U/L vs.8.9 ± 4.4 m U/L,p = 0.049).The level of IGFBP-1 decreased in players at VO_(2max) in either case of training,but it remained much higher in tests performed after the preparatory regime than before(p = 0.029).Concentrations of IGF-1,IGFBP-2,-3,and-4 did not change significantly.Conclusion:The inverse relation between insulin and IGFBP-1 was lost during MPET,as these 2 molecules changed in the same direction.The results obtained suggest less severe stress-induced depression of insulin and IGFBP-1 after preparatory training.But another metabolic mechanism cannot be excluded,and that is potentially impaired insulin sensitivity resulting in higher level of IGFBP-1.展开更多
Background Non-exercise estimated cardiorespiratory fitness(NEE-CRF)has been shown to be associated with mortality,although its association with cancer incidence is unknown.The study aimed to assess the prospective as...Background Non-exercise estimated cardiorespiratory fitness(NEE-CRF)has been shown to be associated with mortality,although its association with cancer incidence is unknown.The study aimed to assess the prospective association between NEE-CRF and cancer incidence in a large cohort of men and women.Methods The National Institutes of Health-American Association of Retired Persons diet and health study is a prospective cohort that included 402,548 participants aged 50–71 years who were free from cancer at baseline(1995–1996)(men(n=238,835)and women(n=163,713))and were followed until December 31,2015.The exposure variable was NEE-CRF expressed in metabolic equivalents.NEE-CRF was estimated using a validated equation of self-reported predictors on demographics and lifestyle behaviors derived from baseline questionnaires.Primary outcomes were total cancer incidence and incidence of prostate,breast,lung,and colorectal cancers.Cox proportional hazards models were analyzed for the association between NEE-CRF and cancer incidence outcomes adjusted for established cancer risk factors.Results During 13.7±3.2 years of follow-up(mean±SD),64,344 men and 31,315 women developed a new cancer.For every 1-metabolic equivalent higher NEE-CRF,the hazard ratios and 95%confidence intervals(95%CIs)were 0.96(95%CI:0.94–0.97)and 0.88(95%CI:0.84–0.92)of total and colorectal cancer incidence among men,and 0.95(95%CI:0.93–0.97)and 0.94(95%CI:0.91–0.97)of total and breast cancer incidence among women,respectively(all p<0.001).NEE-CRF was not associated with incidence of prostate and lung cancers in men or colorectal and lung cancers in women.Conclusion These results suggest that higher CRF levels,as assessed by the applied non-exercise estimated method,may provide preventive benefits against the development of cancer,while low CRF could potentially serve as a modifiable cancer risk factor.Integrating NEE-CRF into screening paradigms and referring low-fit individuals to improve CRF could complement the public health prevention strategy against cancer.展开更多
<span style="font-family:Verdana;">Cardiorespiratory endurance is a determining factor in the assessment of the state of health of a person. Objective: To determine the reference values for cardiorespi...<span style="font-family:Verdana;">Cardiorespiratory endurance is a determining factor in the assessment of the state of health of a person. Objective: To determine the reference values for cardiorespiratory endurance in Beninese adults. Methods: Prospective trans</span><span style="font-family:Verdana;">versal study, with a descriptive and analytical aim. It was carried out on h</span><span style="font-family:Verdana;">ealthy adult subjects (18 to 50 years old), of Cotonou and Abomey cities, from October 2017 to May 2018, without clinically identifiable orthopedic, cardiorespiratory, osteoarticular or neuromotor impairment. These subjects performed three different cardio-respiratory endurance tests: The six-minute walk test (WT6), cycloergometer test (CT) and the step test (ST). Data processing and analysis were done using SPSS version 22 software. A linear regression model was used to establish the prediction equation of maximal oxygen uptake (VO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">max) with the WT6 data. The significance level chosen was 5%. Results: Subjects average age was 30.0 ± 9.8 years. It was especially men (54.20%), students (42.13%), with a normal corpulence (69.91%). At WT6, they walked 365 m to 798 m (557.1 ± 93.6 m) with extreme heart rates (EHR) of 67 to 189 (136.7 ± 19.0) beats per minute. At ST, the extreme powers developed were 2.7 watts/kg and 11.8 watts/kg (6.4 ± 1.8 watts/kg), with EHR of 99 to 204 (168.4 ± 15.4) beats per minute. The predictor equation of VO</span><sub><span style="font-family:Verdana;">2</span></sub></span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">max by WT6 was function of the subject’s weight, age and sex (R = 0.73). Conclusion-</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">Discussion: These normative values of cardio-respiratory endurance of Beninese subjects seem to be specific to them. An extension of the present study to a larger sample nevertheless seems desirable.</span>展开更多
Although the impact of obesity on exercise performance is multifactorial,excessive fat mass which can impose an unfavorable burden on cardiac function and working muscle,will affect the aerobic exercise capacity.Weigh...Although the impact of obesity on exercise performance is multifactorial,excessive fat mass which can impose an unfavorable burden on cardiac function and working muscle,will affect the aerobic exercise capacity.Weight loss strategies,such as bariatric surgery can obviously affect both the body composition and aerobic exercise capacity.Maximal oxygen consumption(_VO 2max)is a widely used important indicator of aerobic exercise capacity of an individual and is closely related to body weight,size and composition.An individual's aerobic exercise capacity may show different results depending on howVO_(2)is expressed.The absoluteVO_(2)and_VO 2max relative to body weight are the most commonly used indicators.TheVO_(2)relative to fat-free mass,lean body mass or skeletal muscle mass are not influenced by adipose tissue.The last two are more useful to precisely distinguish between individuals differing in muscle adaptation to maximum oxygen uptake.The_VO 2max relative to body height is used for studying growth in children.With the in-depth study of exercise capacity and body composition in obesity,the relative oxygen uptake has been increasingly reinterpreted.展开更多
The purpose of this study was to examine and evaluate the effectiveness of Super High-Intensity Continuous Training(SHCT)on elite team handball players.SHCT is a new approach of aerobic training that combines the adva...The purpose of this study was to examine and evaluate the effectiveness of Super High-Intensity Continuous Training(SHCT)on elite team handball players.SHCT is a new approach of aerobic training that combines the advantages of both continuous and interval training methods.The study included 14 professional handball players who are members of the first national handball league team.The participants were trained five times a week over eight weeks using the SHCT method.The train-ing intensity for each athlete was tailored to their individual oxygen consumption.Significant(P<0.001)improvements were obtained in all measured and evaluated indicators of aerobic abilities,including maximal oxygen uptake(VO_(2max)),maximum relative oxygen uptake(VO_(2rel)),running speed at which maximum oxygen uptake occurs(VO_(2max)),when comparing the pre-,intermediate,and post-tests,as well as a huge positive effect(η^(2)_(G) reaching from 0.19 to 0.49 and η^(2)_(p) of 0.91).These effects from short cycles of aerobic training have not been previously obtained in studies involving elite and and recreational ath-letes,whether using continuous or interval training approaches.In addition to the above,SHCT showed several other positive features.As such,we recommend further research into SHCT and encourage its integration into athletic training practices.展开更多
文摘It is unknown whether oxygen uptake(VO_(2))sampling intervals influence the efficacy of a verification stage following a graded exercise test(GXT).Fifteen females and 14 males(18-25 years)completed a maximal treadmill GXT.After a 5min recovery,the verification stage began at the speed and grade corresponding with the penultimate stage from the GXT.Maximal oxygen consumption(VO_(2max))from the incremental GXT(iVO_(2max))and VO_(2max)from the verification stage(verVO_(2max))were determined using 10 seconds(s),30s,and 60s from breath×breath averages.There was no main effect for VO_(2max)measure(iVO_(2max)vs.verVO_(2max))10s([47.9±8.31]ml∙kg^(−1)∙min^(−1)vs[48.85±7.97]ml∙kg^(−1)∙min^(−1)),30s([46.94±8.62]ml∙kg^(−1)∙min^(−1)vs[47.28±7.97]ml∙kg^(−1)∙min^(−1)),and 60s([46.17±8.62]ml∙kg^(−1)∙min^(−1)vs[46.00±8.00]ml∙kg^(−1)∙min^(−1)].There was a stage×sampling interval interaction as the difference between(verVO_(2max)−iVO_(2max))was greater for 10-s than 60-s sampling intervals.The verVO_(2max)was>4%higher than iVO_(2max)in 31%,31%,and 17%of the tests for the 10-s,30-s,and 60-s sampling intervals respectively.Sensitivity for the plateau was<30%for 10-s,30-s,and 60-s sampling intervals.Specificity ranged from 44%to 60%for all sampling intervals.Sensitivity for heart rate+respiratory exchange ratio was>90%for all sampling intervals;while specificity was<25%.Findings from the present study suggest that the efficacy of verification stages for eliciting a higher VO_(2max)may be influenced by the sampling interval utilized.
文摘Anthropometric variations can affect resting energy expenditure,VO_(2) max and anaerobic capacity of young,healthy individuals.Studies have shown that body fat percentage,weight,and height can all affect the three measures.The study aimed to study VO_(2) max and 24-hour thermogenesis measures in predominantly sedentary individuals and weight changes afterwards.VO_(2) max-associated research shows that taller individuals tend to have higher VO_(2) max levels compared to shorter individuals.This could be because taller individuals have a larger lung capacity and greater oxygen delivery to the muscles.Weight can also affect VO_(2) max,as heavier individuals tend to have higher VO_(2) max levels than lighter individuals.Weight is also associated with resting energy expenditure,as heavier individuals tend to have a higher resting energy expenditure than lighter individuals.The purpose of this study was to conduct a systematic review of the existing literature related to resting energy expenditure and metabolic effects of VO_(2) max,and anaerobic capacity in sedentary active adults of anthropometric variations.Several studies have recently examined the possibility of improving aerobic and metabolic functions ensuring cardiorespiratory fitness within the population of anthropometric variations.Everyday physical activity and heredity ability influenced mainly the gold standard measuring tool for cardiorespiratory fitness,VO_(2) max,predicting mortality and morbidity.Weight gain has also been shown to be associated with lower cardiorespiratory fitness,regardless of physical activity levels.The VO_(2) max may have a different effect on energy balance apart from physical activity’s energy expenditure(EE),possibly by affecting the resting metabolic rate(RMR)or triggering a common mechanism associated with diet-induced thermogenesis.Weight change is predicted by sedentary energy expenditure,but directly measured VO_(2) max does not appear to be correlated with weight change.The relationship between resting energy expenditure,VO_(2) max,and anaerobic capacity in individuals is complex.Resting energy expenditure is directly related to anaerobic capacity,as it is an indicator of the body’s ability to work anaerobically.VO_(2) max is also related to anaerobic capacity,as it reflects the body’s maximal aerobic power.However,the strength of this relationship is not known.Overall,both resting energy expenditure and VO_(2) max are important determinants of anaerobic capacity in individuals and are worth considering when evaluating an individual’s anaerobic potential.
基金supported by the Ministry of Education,Science and Technological Development of the Republic of Serbia(No.173042 and III41030)
文摘Background:Intensive exercise changes physiological need for glucose and several biochemical pathways responsible for its metabolism response.Among them are those which involve insulin,insulin-like growth factor(IGF-1),and IGF-binding proteins(IGFBPs).Different types and degrees of exercise,as well as an athlete's fitness,may induce a range of responses regarding concentrations and time needed for the alteration.The idea of the work was to find out whether and how insulin/IGF axis responds to additional physical activity in the already trained subjects and if so,is the adaptation potentially beneficial from the aspect of metabolic control.Methods:The effect of 4-week intensive training on campus(preparatory training) on the levels of insulin,IGF-1,and IGFBPs during maximal progressive exercise test(MPET) on a treadmill was compared to the results obtained during MPET conducted after a regular training season of a female elite handball team(n = 17,age:17 ± 1 years,height:171 ± 8 cm,weight:65 ± 8 kg,body mass index:22 ± 1 kg/m^2 at the beginning of the study;there were no significant changes at the end).Serum samples were obtained from players immediately before the test(basal),at the end of the test after reaching the point of maximal oxygen consumption(VO_(2max)),and after recovery.Results:The concentration of insulin decreased at VO_(2max),but remained higher in players after preparatory training(12.2 ± 2.5 m U/L vs.8.9 ± 4.4 m U/L,p = 0.049).The level of IGFBP-1 decreased in players at VO_(2max) in either case of training,but it remained much higher in tests performed after the preparatory regime than before(p = 0.029).Concentrations of IGF-1,IGFBP-2,-3,and-4 did not change significantly.Conclusion:The inverse relation between insulin and IGFBP-1 was lost during MPET,as these 2 molecules changed in the same direction.The results obtained suggest less severe stress-induced depression of insulin and IGFBP-1 after preparatory training.But another metabolic mechanism cannot be excluded,and that is potentially impaired insulin sensitivity resulting in higher level of IGFBP-1.
基金supported (in part) by the Intramural Research Program of the NIH,National Cancer Institute
文摘Background Non-exercise estimated cardiorespiratory fitness(NEE-CRF)has been shown to be associated with mortality,although its association with cancer incidence is unknown.The study aimed to assess the prospective association between NEE-CRF and cancer incidence in a large cohort of men and women.Methods The National Institutes of Health-American Association of Retired Persons diet and health study is a prospective cohort that included 402,548 participants aged 50–71 years who were free from cancer at baseline(1995–1996)(men(n=238,835)and women(n=163,713))and were followed until December 31,2015.The exposure variable was NEE-CRF expressed in metabolic equivalents.NEE-CRF was estimated using a validated equation of self-reported predictors on demographics and lifestyle behaviors derived from baseline questionnaires.Primary outcomes were total cancer incidence and incidence of prostate,breast,lung,and colorectal cancers.Cox proportional hazards models were analyzed for the association between NEE-CRF and cancer incidence outcomes adjusted for established cancer risk factors.Results During 13.7±3.2 years of follow-up(mean±SD),64,344 men and 31,315 women developed a new cancer.For every 1-metabolic equivalent higher NEE-CRF,the hazard ratios and 95%confidence intervals(95%CIs)were 0.96(95%CI:0.94–0.97)and 0.88(95%CI:0.84–0.92)of total and colorectal cancer incidence among men,and 0.95(95%CI:0.93–0.97)and 0.94(95%CI:0.91–0.97)of total and breast cancer incidence among women,respectively(all p<0.001).NEE-CRF was not associated with incidence of prostate and lung cancers in men or colorectal and lung cancers in women.Conclusion These results suggest that higher CRF levels,as assessed by the applied non-exercise estimated method,may provide preventive benefits against the development of cancer,while low CRF could potentially serve as a modifiable cancer risk factor.Integrating NEE-CRF into screening paradigms and referring low-fit individuals to improve CRF could complement the public health prevention strategy against cancer.
文摘<span style="font-family:Verdana;">Cardiorespiratory endurance is a determining factor in the assessment of the state of health of a person. Objective: To determine the reference values for cardiorespiratory endurance in Beninese adults. Methods: Prospective trans</span><span style="font-family:Verdana;">versal study, with a descriptive and analytical aim. It was carried out on h</span><span style="font-family:Verdana;">ealthy adult subjects (18 to 50 years old), of Cotonou and Abomey cities, from October 2017 to May 2018, without clinically identifiable orthopedic, cardiorespiratory, osteoarticular or neuromotor impairment. These subjects performed three different cardio-respiratory endurance tests: The six-minute walk test (WT6), cycloergometer test (CT) and the step test (ST). Data processing and analysis were done using SPSS version 22 software. A linear regression model was used to establish the prediction equation of maximal oxygen uptake (VO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">max) with the WT6 data. The significance level chosen was 5%. Results: Subjects average age was 30.0 ± 9.8 years. It was especially men (54.20%), students (42.13%), with a normal corpulence (69.91%). At WT6, they walked 365 m to 798 m (557.1 ± 93.6 m) with extreme heart rates (EHR) of 67 to 189 (136.7 ± 19.0) beats per minute. At ST, the extreme powers developed were 2.7 watts/kg and 11.8 watts/kg (6.4 ± 1.8 watts/kg), with EHR of 99 to 204 (168.4 ± 15.4) beats per minute. The predictor equation of VO</span><sub><span style="font-family:Verdana;">2</span></sub></span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">max by WT6 was function of the subject’s weight, age and sex (R = 0.73). Conclusion-</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">Discussion: These normative values of cardio-respiratory endurance of Beninese subjects seem to be specific to them. An extension of the present study to a larger sample nevertheless seems desirable.</span>
文摘Although the impact of obesity on exercise performance is multifactorial,excessive fat mass which can impose an unfavorable burden on cardiac function and working muscle,will affect the aerobic exercise capacity.Weight loss strategies,such as bariatric surgery can obviously affect both the body composition and aerobic exercise capacity.Maximal oxygen consumption(_VO 2max)is a widely used important indicator of aerobic exercise capacity of an individual and is closely related to body weight,size and composition.An individual's aerobic exercise capacity may show different results depending on howVO_(2)is expressed.The absoluteVO_(2)and_VO 2max relative to body weight are the most commonly used indicators.TheVO_(2)relative to fat-free mass,lean body mass or skeletal muscle mass are not influenced by adipose tissue.The last two are more useful to precisely distinguish between individuals differing in muscle adaptation to maximum oxygen uptake.The_VO 2max relative to body height is used for studying growth in children.With the in-depth study of exercise capacity and body composition in obesity,the relative oxygen uptake has been increasingly reinterpreted.
文摘The purpose of this study was to examine and evaluate the effectiveness of Super High-Intensity Continuous Training(SHCT)on elite team handball players.SHCT is a new approach of aerobic training that combines the advantages of both continuous and interval training methods.The study included 14 professional handball players who are members of the first national handball league team.The participants were trained five times a week over eight weeks using the SHCT method.The train-ing intensity for each athlete was tailored to their individual oxygen consumption.Significant(P<0.001)improvements were obtained in all measured and evaluated indicators of aerobic abilities,including maximal oxygen uptake(VO_(2max)),maximum relative oxygen uptake(VO_(2rel)),running speed at which maximum oxygen uptake occurs(VO_(2max)),when comparing the pre-,intermediate,and post-tests,as well as a huge positive effect(η^(2)_(G) reaching from 0.19 to 0.49 and η^(2)_(p) of 0.91).These effects from short cycles of aerobic training have not been previously obtained in studies involving elite and and recreational ath-letes,whether using continuous or interval training approaches.In addition to the above,SHCT showed several other positive features.As such,we recommend further research into SHCT and encourage its integration into athletic training practices.
