On issues of confidence in determining the time constant for oxygen uptake kinetics

Markovitz, Gerald H; Sayre, James W.; Storer, Thomas W.; Cooper, C.B.

doi:10.1136/bjsm.2003.004721

Cited by 31 publications

(27 citation statements)

References 38 publications

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“…This faster V O 2 kinetics is related with a shorter time lag in the unbalance of V O 2 demand and supply, implying an augmented oxidative contribution to energy transfer (Burnley and Jones 2007). Complementarily, the reported τ values were lower than those obtained for longer swimming distances (200 m; Sousa et al 2011 and 400 m front crawl; Rodriguez et al 2003), since this parameter mathematically describes the V O 2 kinetics profile reflecting the response of cardiovascular and muscular systems at the selected intensity (Markovitz et al 2004). Hence, the very high swimming intensity of the 100 m swim (implying the sudden and exponential need of V O 2 ) justifies the observed lower τ values.…”

Section: Discussionmentioning

confidence: 52%

$$\dot{V}{\text{O}}_{ 2}$$ V ˙ O 2 kinetics and metabolic contributions during full and upper body extreme swimming intensity

et al. 2014

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Despite the short duration of the event, the aerobic energy contribution covers about 50 % of total metabolic energy liberation, highlighting that both aerobic and anaerobic energy processes should be developed to improve the 100 m swimming performance. Lower limbs action provided an important contribution in the energy availability in working muscles being advised its full use in this short duration and very high-intensity event.

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Section: Discussionmentioning

confidence: 52%

$$\dot{V}{\text{O}}_{ 2}$$ V ˙ O 2 kinetics and metabolic contributions during full and upper body extreme swimming intensity

et al. 2014

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“…In the present study, the fact the time constant is not similar between the two intensities seems to be due to the extreme intensity at which the 200 m crawl were performed. Therefore, and since the value of the time constant describes the adaptation profile of the cardiovascular and muscular systems at the intensity of the performed effort 25 , the sudden and exponential need of VO 2 to higher intensities (figure 2) will be able to explain the lower values of this parameter.…”

Section: Discussionmentioning

confidence: 99%

Cinética do consumo de oxigênio a intensidades de nado moderada e extrema

Sousa¹,

Jesus²,

Figueiredo³

et al. 2013

Rev Bras Med Esporte

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Introduction: Traditionally, studies regarding oxygen consumption kinetics are conducted at lower intensities, very different from those in which the sports performance occurs. Objective: Knowing that the magnitude of this physiological parameter depends on the intensity in which the effort occurs, it was intended with this study to compare the oxygen consumption kinetics in the 200 m front crawl at two different intensities: moderate and extreme. Methods: Ten male swimmers of international level performed two tests separated by 24h: (i) progressive and intermittent protocol of 7 x 200 m, with 30 seconds intervals and with increments of 0.05m.s -1 , to determine the anaerobic threshold correspondent step; and, (ii) 200 m at maximal velocity, in both expiratory gases were continuously collected breath-by-breath. Results: Significant differences were obtained between amplitude and time constant determined in the 200 m at extreme and moderate intensities, respectively (38.53 ± 5.30 ml. kg -1 .min -1 versus 26.32 ± 9.73 ml. kg -1 .min -1 and 13.21 ± 5.86 s versus 18.89 ± 6.53 s (p ≤ 0.05). No differences were found in time delay (9.47 ± 6.42 s versus 12.36 ± 6.62 s, at extreme and moderate intensity, respectively (p ≤ 0.05). A negative correlation between time delay and time constant at the moderate intensity was reported (r = -0.74, p ≤ 0.05). Conclusions: Both intensities were well described by double-exponential fittings and there were significant differences between them in terms of amplitude and time constant.

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“…No dia seguinte os sujeitos realizaram um teste de carga constante na vVO 2max para determinação do tempo limite (T lim ), tempo para atingir o VO 2max (TAVO 2max ), tempo mantido no VO 2max (TMVO 2max ), distância total percorrida (D max ) e constante tempo (τ), sendo realizada uma única transição (4) . Os testes de carga constante foram realizados no mesmo horário do teste incremental, com variação de ± duas horas (18) .…”

Section: Determinação Da Cinética Do Vounclassified

“…O estudo das trocas gasosas durante a transição do estado de repouso para exercício físico permite avaliar a cinética (tempo de resposta) do VO 2 . Adicionalmente, foi reportado que a cinética do VO 2 na intensidade associada ao VO 2max (vVO 2max ) apresenta característica monoexponencial (3,4) . Quando um indivíduo parte da situação de repouso para um exercí-cio de alta intensidade (i.e.…”

Section: Introductionunclassified

“…Quanto mais rápido ocorrerem os ajustes do metabolismo oxidativo, menor será o desgaste e consequentemente a fadiga será retardada (2,3) . Este índice fisiológico reflete a adaptação do sistema cardiovascular e muscular em resposta à carga de trabalho (4) . Tem sido encontrada correlação inversa entre o τ, VO 2max (7,8) e atividade da enzima citrato sintase (5) , indicando limitação periférica para o VO 2 (inércia metabólica) como sendo o principal fator limitante para o rápido ajuste do metabolismo aeróbio (6) .…”

Section: Introductionunclassified

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Cinética do consumo de oxigênio e tempo limite na vvo2max: comparação entre homens e mulheres

Azevedo

Oliveira

Simões

et al. 2010

Rev Bras Med Esporte

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RESUMOFoi investigada a influência do gênero no tempo limite (T lim ) e na cinética do VO 2 durante corrida na velocidade associada ao VO 2max (vVO 2max ) em nove homens e nove mulheres, todos adultos, jovens e sedentários, com idades entre 20 e 30 anos. Homens e mulheres realizaram dois testes em esteira rolante, sendo um teste incremental para determinar VO 2max (42,66 ± 4,50 vs. 32,92 ± 6,03mL.kg -1 .min -1 ) e vVO 2max (13.2 ± 1.5 vs. 10,3 ± 2,0km.h -1 ), respectivamente. Um segundo teste com carga constante na vVO 2max até a exaustão. O T lim e a cinética do VO 2 foram determinados. Não houve diferença significante entre homens e mulheres para constante de tempo (τ) (35,76 ± 21,03 vs. 36,5 ± 6,21s, respectivamente; P = 0,29); T lim (308 ± 84,3 vs. 282,11 ± 57,19s, respectivamente; P = 0,68), tempo para atingir o VO 2max (TAVO 2max ) (164,48 ± 96,73 vs. 167,88 ± 28,59s, respectivamente; P = 0,29), tempo para atingir o VO 2max em percentual do T lim (%T lim ) (50,24 ± 16,93 vs. 62,63 ± 16,60%, respectivamente; P = 0,19), tempo mantido no VO 2max (TMVO 2max ) (144,08 ± 42,55 vs. 114,23 ± 76,96s, respectivamente; P = 0,13). Estes resultados sugerem que a cinética do VO 2 e o T lim são similares entre homens e mulheres sedentários na vVO 2max .Palavras-chave: gênero; tempo para exaustão na vVO 2max , cinética do VO 2 . ABSTRACTThe aim of this study was to investigate the influence of gender on T thre and VO 2 response during running exercise performed at vVO 2max . Therefore, eighteen untrained individuals (9 male and 9 female) with normal weight and aged between 20 -30 years (VO 2max = 42.66 ± 4.50 vs 32.92 ± 6.03 mL.kg , for male and female, respectively) were assessed. Subjects performed two exercise tests on treadmill. First one was an incremental test to determine VO 2max , velocity at VO 2max (vVO 2max ) and second test was performed at steady velocity -vVO 2max -until exhaustion. The threshold time (T thre ) and VO 2 kinetics response was determined. No significant differences were observed between men and women for time constant (τ) (35.76 ± 21.03 vs 36.5 ± 6.21s, respectively; P = 0.29); T thre (308 ± 84.3 vs 282.11 ± 57.19s, respectively; P = 0.68), time to achieve VO 2max (TAVO 2max ) (164.48 ± 96.73 vs 167.88 ± 28.59s, respectively; P = 0.29), time to achieve VO 2max in T thre percentage (%T thre ) (50.24 ± 16.93 vs 62.63 ± 16.60%, respectively; P = 0.19); time maintained at VO 2max (TMVO 2max ) (144.08 ± 42.55 vs 114.23 ± 76.96s, respectively; P = 0.13). These results suggest that the VO 2 kinetics response and T thre is similar between untrained men and women at the vVO 2max .Keywords: gender; exhaustion time at VO 2max ; VO 2 kinetics. CIÊNCIAS DO EXERCÍCIO E DO ESPORTE Artigo originAl INTRODUÇÃOO estudo em fisiologia do exercício proporciona excelente método para aumentar nosso entendimento de como os diversos sistemas fisioló-gicos respondem e interagem frente ao exercício físico. Nesta perspectiva, o VO 2 medido por meio da ventilação pulmonar durante o exercício incremental ou de carg...

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On issues of confidence in determining the time constant for oxygen uptake kinetics

Cited by 31 publications

References 38 publications

$$\dot{V}{\text{O}}_{ 2}$$ V ˙ O 2 kinetics and metabolic contributions during full and upper body extreme swimming intensity

$$\dot{V}{\text{O}}_{ 2}$$ V ˙ O 2 kinetics and metabolic contributions during full and upper body extreme swimming intensity

Cinética do consumo de oxigênio a intensidades de nado moderada e extrema

Cinética do consumo de oxigênio e tempo limite na vvo2max: comparação entre homens e mulheres

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