Pulmonary O<sub>2</sub> uptake on-kinetics in sprint- and endurance-trained athletes

Berger, Nicolas; Jones, Andrew M.

doi:10.1139/h06-109

Cited by 33 publications

(17 citation statements)

References 66 publications

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“…This prediction was confirmed by Paganini et al (49), who demonstrated that increased citrate synthase activity induced by endurance training resulted in faster [PCr] kinetics in rat muscle, and also by Glancy et al (16), who recently reported that increasing the content of isolated mitochondria in an incubation medium was associated with linear reductions in the for O 2 consumption. In humans, it is well known that V O 2 kinetics are faster (5,6,36,39,50) and that the extent of PCr splitting for a given work rate is spared (23,29,70) in endurance-trained subjects.…”

Section: Discussionmentioning

confidence: 99%

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Jones¹,

Wilkerson²,

Fulford³

2009

American Journal of Physiology-Regulatory, Integrative and Comp

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Jones AM, Wilkerson DP, Fulford J. Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans. Am J Physiol Regul Integr Comp Physiol 296: R1078 -R1087, 2009. First published February 11, 2009 doi:10.1152/ajpregu.90896.2008.-We hypothesized that increasing skeletal muscle total creatine (Cr) content through dietary Cr supplementation would result in slower muscle phosphocreatine concentration ([PCr]) kinetics, as assessed using 31 P magnetic resonance spectroscopy, following the onset and offset of both moderateintensity (Mod) and heavy-intensity (Hvy) exercise. Seven healthy males (age 29 Ϯ 6 yr, mean Ϯ SD) completed a series of square-wave transitions to Mod and Hvy knee extensor exercise inside the bore of a 1.5-T superconducting magnet both before and after a 5-day period of Cr loading (4ϫ 5 g/day of creatine monohydrate). Cr supplementation resulted in an ϳ8% increase in the resting muscle oxygen uptake kinetics; respiratory control; creatine kinase; muscle energetics; 31 P magnetic resonance spectroscopy MEYER'S "ELECTRICAL ANALOG" model of respiratory control posits that the time constant () for the exponential fall in muscle phosphocreatine concentration ([PCr]) following the onset of muscle contractions is a function of the mitochondrial resistance and the metabolic capacitance (45). The model predicts that an increase in mitochondrial density will result in a shorter (that is, faster [PCr] kinetics) and that an increase in metabolic capacitance, determined predominantly by the muscle total creatine (Cr) content, will result in a longer (slower [PCr] kinetics). In keeping with this prediction, Meyer and colleagues reported that increased citrate synthase activity induced by endurance training resulted in faster [PCr] kinetics in rat muscle (49) and that depletion of the total Cr content of rat gastrocnemius muscle, achieved through 8 wk of feeding with the Cr analog ␤-guanidinopropionic acid, resulted in significantly faster [PCr] (1,9,42,47). In an important recent study, Kindig et al. (35) reported that acute CK inhibition led to a significantly faster fall in intracellular PO 2 (equivalent in this model to a faster rise in V O 2 ) following the onset of contraction in isolated Xenopus myocytes. Moreover, Glancy et al. (16) demonstrated that the for oxygen consumption in isolated mitochondria was linearly related to the total Cr content in the incubation medium.Collectively, these data provide strong support for the notion that the for both muscle [PCr] and V O 2 conforms to a simple linear model of respiratory control, at least under the conditions of the experiments performed. In humans, however, data relating [PCr] and/or V O 2 kinetics to the muscle total Cr content are sparse. Francescato et al. (15) recently reported that intersubject differences in resting muscle [PCr] were positively correlated (r ϭ 0.71) with the for the fall in [PCr] during plantar flexion exercise in humans. However, the range of resting [PCr] values ...

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Section: Discussionmentioning

confidence: 99%

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Jones¹,

Wilkerson²,

Fulford³

2009

American Journal of Physiology-Regulatory, Integrative and Comp

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“…It has also been reported that the parameters of the power–time relationship are related to other markers of cardio-respiratory fitness [37]. Of particular note is that, across subjects, CP is related to fast on-kinetics [38] and W ′ is related to the magnitude of the slow component [17, 38].…”

Section: The Cp Concept and Variable-pace Exercisementioning

confidence: 99%

The ‘Critical Power’ Concept: Applications to Sports Performance with a Focus on Intermittent High-Intensity Exercise

2017

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The curvilinear relationship between power output and the time for which it can be sustained is a fundamental and well-known feature of high-intensity exercise performance. This relationship ‘levels off’ at a ‘critical power’ (CP) that separates power outputs that can be sustained with stable values of, for example, muscle phosphocreatine, blood lactate, and pulmonary oxygen uptake (), from power outputs where these variables change continuously with time until their respective minimum and maximum values are reached and exercise intolerance occurs. The amount of work that can be done during exercise above CP (the so-called W′) is constant but may be utilized at different rates depending on the proximity of the exercise power output to CP. Traditionally, this two-parameter CP model has been employed to provide insights into physiological responses, fatigue mechanisms, and performance capacity during continuous constant power output exercise in discrete exercise intensity domains. However, many team sports (e.g., basketball, football, hockey, rugby) involve frequent changes in exercise intensity and, even in endurance sports (e.g., cycling, running), intensity may vary considerably with environmental/course conditions and pacing strategy. In recent years, the appeal of the CP concept has been broadened through its application to intermittent high-intensity exercise. With the assumptions that W′ is utilized during work intervals above CP and reconstituted during recovery intervals below CP, it can be shown that performance during intermittent exercise is related to four factors: the intensity and duration of the work intervals and the intensity and duration of the recovery intervals. However, while the utilization of W′ may be assumed to be linear, studies indicate that the reconstitution of W′ may be curvilinear with kinetics that are highly variable between individuals. This has led to the development of a new CP model for intermittent exercise in which the balance of W′ remaining () may be calculated with greater accuracy. Field trials of athletes performing stochastic exercise indicate that this model can accurately predict the time at which W′ tends to zero and exhaustion is imminent. The model potentially has important applications in the real-time monitoring of athlete fatigue progression in endurance and team sports, which may inform tactics and influence pacing strategy.

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“…This phenomenon is known as the slow component of V ・ O2 16) . However, in well-trained endurance runners, V ・ O2 attains a steady state faster and the slow component is smaller than that observed in sprinters 17,18) . This suggests that high-intensity RE could be evaluated in distance runners with superior aerobic capacity.…”

Section: Introductionmentioning

confidence: 63%

“…However, the slow component of V ・ O2 is smaller in well-trained endurance runners and their V ・ O2 reaches a steady state faster than that in sprinters 17,18) . Indeed, in the present study, the subjects' V ・ O2 reached a steady state (changing by less than 100 mLO2·min −1 ) 25) even at an intensity above the LT.…”

Section: Discussionmentioning

confidence: 89%

Relation between 1,500-m running performance and running economy during high-intensity running in well-trained distance runners

Tanji

Shirai

Tsuji

et al. 2017

JPFSM

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Running economy (RE), which is evaluated at an exercise intensity below the lactate threshold (LT), is recognized as the most important physiological variable for estimating running performance. However, middle-and long-distance athletes run above LT intensity during their competitive events. This study elucidates the relation between 1,500-m running performance and physiological variables, including RE measured at intensities below and above the LT. The study included 34 male distance runners (1,500-m velocity: 22.2 ± 0.8 km·h −1 , equivalent to race times of 4′03″2 ± 8″5). RE was calculated at four running velocities selected to provide intensities of 90%LT and 95%LT below LT (REbLT) and 105%LT and 110%LT above LT (REaLT). RE was determined from aerobic energy metabolism, calculated from oxygen uptake and the respiratory exchange ratio, combined with anaerobic energy metabolism, calculated from the change in blood lactate concentration. Results show that the 1,500-m velocity was not related to maximal oxygen uptake (V ・ O 2 max) or LT intensity (r = 0.19 and 0.10, respectively). This velocity correlated with both REaLT and REbLT, with the correlation coefficient being higher for REaLT (r = −0.65 and −0.71 vs −0.56 and −0.58). Furthermore, the coefficient of determination for 1,500-m velocity determined from V ・ O 2 max, LT intensity and REaLT was higher than that determined from V ・ O 2 max, LT intensity and REbLT (R 2 = 0.603 and 0.640 vs 0.415 and 0.543). These results suggest that RE measured at an intensity above LT intensity may be better than other physiological variables for estimating 1,500-m running performance.

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Pulmonary O₂ uptake on-kinetics in sprint- and endurance-trained athletes

Cited by 33 publications

References 66 publications

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

The ‘Critical Power’ Concept: Applications to Sports Performance with a Focus on Intermittent High-Intensity Exercise

Relation between 1,500-m running performance and running economy during high-intensity running in well-trained distance runners

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Pulmonary O2 uptake on-kinetics in sprint- and endurance-trained athletes

Cited by 33 publications

References 66 publications

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

Influence of dietary creatine supplementation on muscle phosphocreatine kinetics during knee-extensor exercise in humans

The ‘Critical Power’ Concept: Applications to Sports Performance with a Focus on Intermittent High-Intensity Exercise

Relation between 1,500-m running performance and running economy during high-intensity running in well-trained distance runners

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Pulmonary O₂ uptake on-kinetics in sprint- and endurance-trained athletes