Exceeding a “critical” muscle Pi: implications for  $$\dot{\text{V}}\text{O}_{2}$$ and metabolite slow components, muscle fatigue and the power–duration relationship

Korzeniewski, Bernard; Rossiter, Harry B.

doi:10.1007/s00421-020-04388-4

Cited by 26 publications

(65 citation statements)

References 49 publications

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“…While the power-duration relationship in the severe exercise intensity domain has been well investigated based on the CP concept (Jones et al 2010 ; Poole et al 2016 ), limited research exists on deriving the power-duration relationship in the moderate and heavy exercise intensity domains (Black et al 2017 ). Hence Puchowicz et al ( 2020 ) and Peronnet and Thibault ( 1989 ) proposed mathematical models with an aerobic decay term, but limited research exists to assess if these concepts have a high predictive ability for the power-duration relationship in the moderate and heavy exercise intensity domains in relation to the muscle bioenergetic system (Korzeniewski 2019 ; Korzeniewski and Rossiter 2020 , 2021 ; Vanhatalo et al 2016 ).…”

Section: Future Directionsmentioning

confidence: 99%

Power profiling and the power-duration relationship in cycling: a narrative review

et al. 2021

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Emerging trends in technological innovations, data analysis and practical applications have facilitated the measurement of cycling power output in the field, leading to improvements in training prescription, performance testing and race analysis. This review aimed to critically reflect on power profiling strategies in association with the power-duration relationship in cycling, to provide an updated view for applied researchers and practitioners. The authors elaborate on measuring power output followed by an outline of the methodological approaches to power profiling. Moreover, the deriving a power-duration relationship section presents existing concepts of power-duration models alongside exercise intensity domains. Combining laboratory and field testing discusses how traditional laboratory and field testing can be combined to inform and individualize the power profiling approach. Deriving the parameters of power-duration modelling suggests how these measures can be obtained from laboratory and field testing, including criteria for ensuring a high ecological validity (e.g. rider specialization, race demands). It is recommended that field testing should always be conducted in accordance with pre-established guidelines from the existing literature (e.g. set number of prediction trials, inter-trial recovery, road gradient and data analysis). It is also recommended to avoid single effort prediction trials, such as functional threshold power. Power-duration parameter estimates can be derived from the 2 parameter linear or non-linear critical power model: P(t) = W′/t + CP (W′—work capacity above CP; t—time). Structured field testing should be included to obtain an accurate fingerprint of a cyclist’s power profile.

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Section: Future Directionsmentioning

confidence: 99%

Power profiling and the power-duration relationship in cycling: a narrative review

et al. 2021

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“…Regardless of the relative importance of either of these mechanisms, the key attribute to both is an increase in the [P i ] and [H + ] in the working muscles. Indeed, it has been shown that the slow component is preceded by muscular fatigue, 68 and recent modeling studies have implicated elevated [P i ] per se on the apparent reduction in muscle efficiency and development of the slow component, whereby the slow component occurs only after a critical threshold of [P i ] in the muscle is reached 69 . While this notion would explain the assumed delay in the onset of the slow component, it should be pointed out that the apparent time delay of the slow component has also been suggested to be an artifact of common mathematical modeling procedures to V̇O 2 data, without a true physiological basis 70 .…”

Section: The Effect Of Fatigue On Cycling Efficiencymentioning

confidence: 99%

Efficiency of cycling exercise: Quantification, mechanisms, and misunderstandings

MacDougall

Falconer

MacIntosh

2022

Scandinavian Med Sci Sports

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The energetics of cycling represents a well‐studied area of exercise science, yet there are still many questions that remain. Efficiency, broadly defined as the ratio of energy output to energy input, is one key metric that, despite its importance from both a scientific as well as performance perspective, is commonly misunderstood. There are many factors that may affect cycling efficiency, both intrinsic (e.g., muscle fiber type composition) and extrinsic (e.g., cycling cadence, prior exercise, and training), creating a complex interplay of many components. Due to its relative simplicity, the measurement of oxygen uptake continues to be the most common means of measuring the energy cost of exercise (and thus efficiency); however, it is limited to only a small proportion of the range of outputs humans are capable of, further limiting our understanding of the energetics of high‐intensity exercise and any mechanistic bases therein. This review presents evidence that delta efficiency does not represent muscular efficiency and challenges the notion that the slow component of oxygen uptake represents decreasing efficiency. It is noted that gross efficiency increases as intensity of exercise increases in spite of the fact that fast‐twitch fibers are recruited to achieve this high power output. Understanding the energetics of high‐intensity exercise will require critical evaluation of the available data.

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“…The concentration of Mg 2+ , which was released from MgATP also increased with the consumption of ATP [ 106 ]. However, normal exercise does not substantially reduce the ATP concentration in muscles [ 25 , 107 , 108 ], but rather a large amount of ADP is generated as a by-product [ 108 ]. ADP does not maintain RyR activity as efficiently as ATP [ 24 ].…”

Section: Ryr Regulation Under Different Muscle Conditionsmentioning

confidence: 99%

The Ryanodine Receptor as a Sensor for Intracellular Environments in Muscles

Kobayashi

Kurebayashi

Murayama

2021

IJMS

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The ryanodine receptor (RyR) is a Ca2+ release channel in the sarcoplasmic reticulum of skeletal and cardiac muscles and plays a key role in excitation–contraction coupling. The activity of the RyR is regulated by the changes in the level of many intracellular factors, such as divalent cations (Ca2+ and Mg2+), nucleotides, associated proteins, and reactive oxygen species. Since these intracellular factors change depending on the condition of the muscle, e.g., exercise, fatigue, or disease states, the RyR channel activity will be altered accordingly. In this review, we describe how the RyR channel is regulated under various conditions and discuss the possibility that the RyR acts as a sensor for changes in the intracellular environments in muscles.

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Exceeding a “critical” muscle Pi: implications for $$\dot{\text{V}}\text{O}_{2}$$ and metabolite slow components, muscle fatigue and the power–duration relationship

Abstract: This is a repository copy of Exceeding a "critical" muscle Pi: implications for V˙O2 and metabolite slow components, muscle fatigue and the power-duration relationship.

Cited by 26 publications

References 49 publications

Power profiling and the power-duration relationship in cycling: a narrative review

Power profiling and the power-duration relationship in cycling: a narrative review

Efficiency of cycling exercise: Quantification, mechanisms, and misunderstandings

The Ryanodine Receptor as a Sensor for Intracellular Environments in Muscles

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