The purpose of this investigation was to determine whether maximal oxygen consumption (VO2max) differed between clinically obese black and white children and if a difference existed to determine whether it was related...The purpose of this investigation was to determine whether maximal oxygen consumption (VO2max) differed between clinically obese black and white children and if a difference existed to determine whether it was related to hematological profiles and/or physical activity/inactivity levels. Twenty-three black and 21 white adolescents were matched for age, BMI, and Tanner stage (II-V). Body composition was determined by DEXA and CT scan, Daily physical activity/inactivity was assessed by questionnaire. VO2max was assessed using the Bruce treadmill protocol. Black participants had significantly lower VO2max and VO2max FFM values when compared with white adolescents (26.1 ± 4.2 versus 29.9 ± 3.1 mL · kg-1 · min-1; 48.3 ± 8.8 versus 55.6 ± 5.2 mL · kg-1 FFM · min -1, respectively). Black adolescents also had significantly lower Hb concentrations ( Hb ) than white children (12.7 ± 1.3 versus 13.4 ± 0.7 g/dL). Black adolescents were more physically inactive than their white peers. VO2max correlated with Hb for the combined groups. Obese black adolescents had lower VO2max compared with white children and this difference was explained, in part, by the lower Hb observed in the black participants. Further investigations should study Hb flow rate (a function of Hb · maximal cardiac output) and physical activity/inactivity patterns in obese black and white children as it relates to VO2max.展开更多
文摘The purpose of this investigation was to determine whether maximal oxygen consumption (VO2max) differed between clinically obese black and white children and if a difference existed to determine whether it was related to hematological profiles and/or physical activity/inactivity levels. Twenty-three black and 21 white adolescents were matched for age, BMI, and Tanner stage (II-V). Body composition was determined by DEXA and CT scan, Daily physical activity/inactivity was assessed by questionnaire. VO2max was assessed using the Bruce treadmill protocol. Black participants had significantly lower VO2max and VO2max FFM values when compared with white adolescents (26.1 ± 4.2 versus 29.9 ± 3.1 mL · kg-1 · min-1; 48.3 ± 8.8 versus 55.6 ± 5.2 mL · kg-1 FFM · min -1, respectively). Black adolescents also had significantly lower Hb concentrations ( Hb ) than white children (12.7 ± 1.3 versus 13.4 ± 0.7 g/dL). Black adolescents were more physically inactive than their white peers. VO2max correlated with Hb for the combined groups. Obese black adolescents had lower VO2max compared with white children and this difference was explained, in part, by the lower Hb observed in the black participants. Further investigations should study Hb flow rate (a function of Hb · maximal cardiac output) and physical activity/inactivity patterns in obese black and white children as it relates to VO2max.
文摘目的:比较大强度间歇训练(High-intensity Interval Training,HIT)和中等强度持续训练(Moderate-intensity Continuous Training,MCT)对斜坡测试(Ramp)、中等强度及高强度持续运动中耗氧量动力学(OUK,Oxygen Uptake Kinetics)等参数的影响。方法:36名青年男性受试者分为高强度间歇训练组(HIT)、中等强度持续训练组(MCT,)和对照组(NOT),MCT和HIT两干预组分别进行6周、每周3次强度不同而训练量相同的运动干预;各组干预前(Pre)、中(Mid)、后(Post)分别进行Ramp力竭测试及中、高强度持续运动的OUK测试。结果:6周干预后,HIT与MCT两干预组VO_2max/kg(最大耗氧量)、VO_2-VAT(通气无氧阈耗氧量)、VO_2/kg-VAT(通气无氧阈耗氧量相对值)、Waat-VAT(通气无氧阈功率)均表现为干预后值高于干预前(P<0.05)、干预中值(P<0.01);3组受试者之间上述参数组间差异显著(P<0.05),但仅表现HIT、MCT组与NOT组之间差异显著,HIT与MCT两组之间差异不显著(P>0.05);A_(slop)(Delta效率)、A_(OUES)(耗氧效率坡度)组间效应不显著(P>0.05)。中等强度下OUK各参数仅有τ(Tau,OUK时间常数)值组间效应显著(F=3.652,P=0.04<0.05),HIT与MCT两干预组分别与NOT之间组间效应显著(HIT vs NOT,P=0.027<0.05;MCT vs NOT,P=0.027<0.05),但HIT、MCT两干预组Mid、Post阶段,组间差异不显著(P>0.05),各组各时间点TD值、A值组间差异不显著(P>0.05)。大强度运动时A1(A,耗氧幅度)值组间效应显著(F=4.439,P=0.011<0.05),除了MCT及HIT分别与NOT组组间差异显著外,HIT与MCT之间差异显著(P<0.05),6周后HIT组A1值显著高于同阶段MCT组(1 893.9±132.1vs 1 632.3±340.0,P<0.05);而对于观测值τ_1,3组受试者之间组间效应显著(F=9.083,P<0.01),MIT及HIT组和NOT组相比,τ_1显著降低,并且MIT和HIT组间差异显著(P<0.05);3周后HIT组τ_1值已经显著高于NOT组(Mid:42.5±3.8 vs 53.7±4.3,P<0.01),而MCT在6周后出现(Post:43.1±4.6 vs 53.4±6.0,P<0.01)。3周后HIT组A2值比NOT组显著减低(P<0.05),6周后Post值显著低于MCT组及NOT组同阶段值(P<0.01),而MCT组在各阶段与NOT组之间差异不显著(P>0.05)。τ_2虽有所升高,但并无显著意义(P>0.05)。结论:大强度间歇训练和中等强度持续训练均可提高VO_2max、VAT等心肺耐力评定参数,但两种训练模式对上述参数改善并无显著区别;两训练模式对中等强度下耗氧动力参数影响无显著区别,但大强度间歇训练在提高大强度运动过程中氧耗应答速率及减少耗氧量慢成分方面有着更明显的优势。
