Critical power in adolescents: physiological bases and assessment using all-out exercise

Barker, Alan R.; Bond, Bert; Toman, Cali; Williams, Craig A.; Armstrong, Neil

doi:10.1007/s00421-011-2088-8

Cited by 20 publications

(13 citation statements)

References 34 publications

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“…Williams et al [6] reported non steady-state responses in O2 and blood lactate during cycling at CP and 10% above CP and concluded, that CP does not represent a sustainable exercise intensity in adolescents. In accordance, Barker et al [10] showed increases in O2 and blood lactate over time, accompanied by reduced time to exhaustion during cycling 10% above CP. At an intensity 10% below CP, all participants completed 30 min of exercise and a steady-state in O2 and blood lactate profile was identified [10].…”

Section: Introductionsupporting

confidence: 70%

“…In accordance, Barker et al [10] showed increases in O2 and blood lactate over time, accompanied by reduced time to exhaustion during cycling 10% above CP. At an intensity 10% below CP, all participants completed 30 min of exercise and a steady-state in O2 and blood lactate profile was identified [10].…”

Section: Introductionsupporting

confidence: 70%

“…CP or CS is strongly associated with O2max [5,6] and endurance performance [7,8] indicating the validity to measure aerobic function. In comparison with adults, where CP has been identified as the highest sustainable exercise intensity above which a loss of intramuscular metabolic (e.g., phosphocreatine, pH) and systemic (e.g., O2, blood lactate) homeostasis occurs [9], physiological responses during exercise at CP in young people are limited [6,10]. Williams et al [6] reported non steady-state responses in O2 and blood lactate during cycling at CP and 10% above CP and concluded, that CP does not represent a sustainable exercise intensity in adolescents.…”

Section: Introductionmentioning

confidence: 99%

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Reliability of the Single-Visit Field Test of Critical Speed in Trained and Untrained Adolescents

Nimmerichter

Steindl

Williams

2015

Sports

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Recent studies in adults have shown that the critical intensity during running and cycling estimated from three prediction trials interspersed by 30 min is valid and reliable. To establish the reliability of the single-visit field test to determine critical speed (CS) and the distance above critical speed (D′) in adolescents, 29 trained and 14 untrained participants (mean ± SD age: 17.5 ± 0.5 years) performed three tests on a 400-m outdoor track separated by 48 h. Each test consisted of three distances selected to result in finishing times between 2 and 15 min that must be completed as fast as possible. CS and D′ were modeled using the linear 1/time model (Speed = D′(1/t) + CS). While the coefficient of variation (CV) of CS was between 2.4% and 4.3%, the CV of D′ was 9.3% to 13.6%. Also the intraclass correlation coefficient ranged from 0.919 to 0.983 for CS and from 0.325 to 0.828 for D′. The results show that the single-visit field test provides reliable estimates of CS but not D′ in trained and untrained adolescents.

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Section: Introductionsupporting

confidence: 70%

Section: Introductionsupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

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Reliability of the Single-Visit Field Test of Critical Speed in Trained and Untrained Adolescents

Nimmerichter

Steindl

Williams

2015

Sports

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“…Whereas in adults all work rates in the severe exercise intensity domain may elicit VO 2 max when exercise is continued to fatigue (30)(31)(32), this may not be the case for children (5,6,48). However, we reasoned that this procedure would permit identification of VO 2 max thereby making the issue of secondary criteria redundant.…”

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confidence: 99%

Maximal Oxygen Uptake Validation in Children With Expiratory Flow Limitation

Robben

Poole²,

Harms³

2013

Pediatric Exercise Science

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A two-test protocol (incremental/ramp (IWT) + supramaximal constant-load (CWR)) to affirm max and obviate reliance on secondary criteria has only been validated in highly fit children. In girls (n = 15) and boys (n = 12) with a wide range of VO 2 max (17-47 ml/kg/min), we hypothesized that this procedure would evince a VO 2 -WR plateau and unambiguous VO 2 max even in the presence of expiratory flow limitation (EFL). A plateau in the VO 2 -work rate relationship occurred in 75% of subjects irrespective of EFL There was a range in RER at max exercise for girls (0.97-1.14; mean 1.06 ± 0.04) and boys (0.98-1.09; mean 1.03 ± 0.03) such that 3/15 girls and 2/12 boys did not achieve the criterion RER. Moreover, in girls with RER > 1.0 it would have been possible to achieve this criterion at 78% VO 2 max. Boys achieved 92% VO 2 max at RER = 1.0. This was true also for HRmax where 8/15 girls' and 6/12 boys' VO 2 max would have been rejected based on HRmax being < 90% of age-predicted HRmax. In those who achieved the HRmax criterion, it represented a VO 2 of 86% (girls) and 87% (boys) VO 2 max. We conclude that this two-test protocol confirms VO 2 max in children across a threefold range of VO 2 max irrespective of EFL and circumvents reliance on secondary criteria.El protocolo que comprende dos test (incremental en rampa (TTI) + carga constante supramaximal) (CCS) aplicado para confirmar el consumo máximo de oxigeno y obviar la dependencia de los criterios secundarios ha sido solamente validado en niñas (n=15) y niños (n=12) bien entrenados, que poseían amplios rangos de VO 2 max (17-47 ml/kg/min). Nosotros hipnotizamos que este procedimiento podría evidenciar una meseta en la relación VO 2 -tasa de trabajo y por lo tanto indicar valores ambiguos de VO 2 max incluso en niños que presentan limitaciones del flujo espiratorio (LFE). La meseta en la relación entre el VO 2 -tasa de trabajo ocurre en el 75% de los sujetos, independientemente de que presenten LFE. El rango de valores en la relación de intercambio respiratorio (RER) se extendió entre 0.97 a 1.14 en niñas (M=1.06±0.04) y entre 0.98 a 1.09 en niños (M=1.03±0.03). De esta forma, 3/15 niñas y 2/12 niños no alcanzaron el criterio de RER para estimar el VO 2 max. Por otra parte, en las niñas que mostraron un RER>1.0 hubiera sido posible alcanzar este criterio con un valor del 78% VO 2 max. Los niños alcanzaron el 92% del VO 2 max con un RER=1.0. Esta respuesta, fue observada también

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“…44 In adults, at exercise intensities above the MLSS or CP the slow component of p _ VO 2 rises rapidly over time and eventually reaches peak _ VO 2 but this phenomenon has not been observed in children. 37,45 The mechanisms underlying the p _ VO 2 slow component remain speculative but it has been established that w86% have been accounted for at the contracting muscles. 46 During exercise above the T LAC the p _ VO 2 slow component is associated with a progressive recruitment of additional type II muscle fibres with the low efficiency contributing to the increased oxygen cost of exercise.…”

Section: Pulmonary Oxygen Uptake Kineticsmentioning

confidence: 99%

New insights in paediatric exercise metabolism

Armstrong

Barker

2012

Journal of Sport and Health Science

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Research in paediatric exercise metabolism has been constrained by being unable to interrogate muscle in vivo. Conventionally, research has been limited to the estimation of muscle metabolism from observations of blood and respiratory gases during maximal or steady state exercise and the analysis of a few muscle biopsies taken at rest or post-exercise. The purpose of this paper is to review how the introduction of 31 P-magnetic resonance spectroscopy and breath-by-breath oxygen uptake kinetics studies has contributed to current understanding of exercise metabolism during growth and maturation. Methodologically robust studies using 31 P-magnetic resonance spectroscopy and oxygen uptake kinetics with children are sparse and some data are in conflict. However, it can be concluded that children respond to exercise with enhanced oxygen utilization within the myocyte compared with adults and that their responses are consistent with a greater recruitment of type I muscle fibres. Changes in muscle metabolism are age, maturation-and sex-related and dependent on the intensity of the exercise challenge. The introduction of experimental models such as "priming exercise" and "work-to-work" transitions provide intriguing avenues of research into the mechanisms underpinning exercise metabolism during growth and maturation.

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Critical power in adolescents: physiological bases and assessment using all-out exercise

Cited by 20 publications

References 34 publications

Reliability of the Single-Visit Field Test of Critical Speed in Trained and Untrained Adolescents

Reliability of the Single-Visit Field Test of Critical Speed in Trained and Untrained Adolescents

Maximal Oxygen Uptake Validation in Children With Expiratory Flow Limitation

New insights in paediatric exercise metabolism

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