No reserve in isokinetic cycling power at intolerance during ramp incremental exercise in endurance-trained men

Ferguson, Carrie; Wylde, Lindsey A.; Benson, Alan P.; Cannon, Daniel T.; Rossiter, Harry B.

doi:10.1152/japplphysiol.00662.2015

Cited by 15 publications

(23 citation statements)

References 56 publications

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“…3). This finding is unique because previous work has reported either the presence (25,26) or absence (11,17) of a power reserve at the LoT. The difference in findings among publications may lie in the interpretation of ⌬P at the LoT.…”

Section: Discussionmentioning

confidence: 62%

“…During RI exercise, the LoT and an inability to continue exercise have been attributed to an inability of muscle to meet the torque or power requirements of the task, despite maximal effort by the participant (11,17). It has been reported that at the LoT following an exhaustive RI exercise test, some individuals still are capable of volitionally producing power far greater than the PO associated with the termination of the RI test (i.e., evidence of a power reserve), whereas others are unable to voluntarily generate additional power beyond that required of the RI PO peak (i.e., no power reserve).…”

Section: Discussionmentioning

confidence: 99%

“…A prevailing theory is that LoT coincides with the development of a specific level of neuromuscular fatigue ("critical fatigue threshold") (3-6) that reflexively prevents the neuromuscular system from producing greater power outputs. Ferguson et al (17) recently demonstrated, in a homogeneous group of young, highly-trained endurance cyclists (age, 22 yr; V O 2peak , 4.2 l/min), that the instantaneous isokinetic maximal power-generating capacity of the muscles during cycling at the LoT in an RI protocol was not different from the task-specific power requirement, i.e., there was no "power reserve" at the LoT. In this study, the authors suggested that the LoT was related to both a reduced central drive for muscle activation and to peripheral, metabolically induced muscle fatigue (17), and was not related to a peripheral fatigue threshold or to differences among participants in their physiological and perceptual limits to the exercise task.…”

Section: Introductionmentioning

confidence: 99%

“…Ferguson et al (17) recently demonstrated, in a homogeneous group of young, highly-trained endurance cyclists (age, 22 yr; V O 2peak , 4.2 l/min), that the instantaneous isokinetic maximal power-generating capacity of the muscles during cycling at the LoT in an RI protocol was not different from the task-specific power requirement, i.e., there was no "power reserve" at the LoT. In this study, the authors suggested that the LoT was related to both a reduced central drive for muscle activation and to peripheral, metabolically induced muscle fatigue (17), and was not related to a peripheral fatigue threshold or to differences among participants in their physiological and perceptual limits to the exercise task. Alternatively, Coelho et al (11), using an exercise protocol similar to that used by Ferguson et al (17), although with a more heterogeneous group of heathy, active, older participants [age 42 yr (range, 29 -72 yr); V O 2peak 3.2 l/min], observed a small (~18%) but significant power reserve at the LoT following RI exercise.…”

Section: Introductionmentioning

confidence: 99%

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Power reserve following ramp-incremental cycling to exhaustion: implications for muscle fatigue and function

Hodgson

Keir

Copithorne

et al. 2018

Journal of Applied Physiology

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In ramp-incremental cycling exercise, some individuals are capable of producing power output (PO) in excess of that produced at their limit of tolerance (LoT) whereas others cannot. This study sought to describe the 1) prevalence of a "power reserve" within a group of young men ( n = 21; mean ± SD: age 25 ± 4 yr; V̇o 45 ± 8 ml·kg·min); and 2) muscle fatigue characteristics of those with and without a power reserve. "Power reserve" (ΔPReserve) was determined as the difference between peak PO achieved during a ramp-incremental test to exhaustion and maximal, single-leg isokinetic dynamometer power determined within 45 s of completing the ramp-incremental test. Between-group differences in pre- vs. postexercise changes in voluntary and electrically stimulated single-leg muscle force production measures (maximal voluntary contraction torque, voluntary activation, maximal isotonic velocity and isokinetic power; 1-, 10-, 50-Hz torque; and 10/50-Hz ratio), V̇o, and constant-PO cycling time-to-exhaustion also were assessed. Frequency distribution analysis revealed a dichotomy in the prevalence of a power reserve within the sample resulting in two groups: 1) "No Reserve" (NRES: power reserve <5%; n = 10) and 2) "Reserve" (RES: power reserve >15%; n = 11). At the LoT, all participants had achieved V̇o. Muscle fatigue was evident in both groups, although the NRES group had greater reductions ( P < 0.05) in 10-Hz peak torque (PT), 10/50 Hz ratio, and maximal velocity. Time to the LoT during the constant PO test was 22 ± 16% greater ( P < 0.05) in RES (116 ± 19 s; PO = 317 ± 52 W) than in NRES (90 ± 23 s; PO = 337 ± 71 W), despite similar ramp-incremental exercise durations and V̇o between groups. Compared with the RES group, the NRES group accrued greater peripheral muscle fatigue at the LoT, suggesting that the mechanisms contributing to exhaustion in a ramp-incremental protocol are not uniform. NEW & NOTEWORTHY This study demonstrates that the mechanisms associated with the limit of tolerance during ramp-incremental cycling exercise differ between those who are capable of generating power output in excess of that at exercise termination vs. those who are not. Those without a "power reserve" exhibit greater peripheral muscle fatigue and reduced muscle endurance, supporting the hypothesis that exhaustion occurs at a specific level of neuromuscular fatigue. In contrast, those with a power reserve likely are limited by other mechanisms.

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Section: Discussionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Power reserve following ramp-incremental cycling to exhaustion: implications for muscle fatigue and function

Hodgson

Keir

Copithorne

et al. 2018

Journal of Applied Physiology

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“…Maximal RPE was not reported so it is difficult to interpret these findings; however, it is plausible that other factors help explain the mechanistic basis for the effects of verbal encouragement on exercise tolerance and that these mechanisms are different for trained versus untrained individuals. Other potential mechanisms include improvements in affect (Hall et al, 2002) and alterations in motor unit activation (Ferguson et al, 2016).…”

Section: Psychological Basismentioning

confidence: 99%

A call to action towards an evidence‐based approach to using verbal encouragement during maximal exercise testing

Midgley

Marchant

Levy

2017

Clin Physio Funct Imaging

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By definition, maximal exercise testing inherently requires participants to give a maximal effort. This is an important practical issue as submaximal efforts can produce invalid test results. Verbal encouragement is commonly used to motivate participants to maintain or increase effort investment during maximal exercise testing. Accordingly, studies have reported significant increases in time to exhaustion of between 8% and 18% during VO and multistage shuttle run tests, and a significant 30·5 m mean increase in 6-min walk test distance. Significant improvements during shorter tests, such as the Wingate and 2-min walk tests, have not been observed however. Although participants typically perceive verbal encouragement positively during maximal exercise testing, around one-third have neutral or negative perceptions. Despite the ubiquity and importance of verbal encouragement during maximal exercise testing, surprisingly little research has investigated the characteristics of effective encouragement with respect to its content, timing and frequency. The only randomized controlled trial to investigate one of these issues observed that verbal encouragement delivered every 20 s increased time to exhaustion during VO testing, but not every 60 or 180 s. Of particular concern is that several exercise testing guidelines have incorporated specific guidelines for the use of verbal encouragement, but not provided any theoretical or empirical justification, presumably because of the limited research to inform practice. Recent empirical research does provide some important insight into participant preference for the content and timing of verbal encouragement during maximal exercise testing; however, much more research is clearly required to establish comprehensive evidence-based guidelines.

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The Oxygen Uptake Plateau—A Critical Review of the Frequently Misunderstood Phenomenon

2021

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A flattening of the oxygen uptake–work rate relationship at severe exercise indicates the achievement of maximum oxygen uptake $$\left({\text{VO}}_{2\max } \right)$$ VO 2 max . Unfortunately, a distinct plateau $$\left( {{{\text{VO}}}_{2} {\text{pl}}} \right)$$ VO 2 pl at $${{\text{VO}}}_{2\max }$$ VO 2 max is not found in all participants. The aim of this investigation was to critically review the influence of research methods and physiological factors on the $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl incidence. It is shown that many studies used inappropriate definitions or methodical approaches to check for the occurrence of a $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl . In contrast to the widespread assumptions it is unclear whether there is higher $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl incidence in (uphill) running compared to cycling exercise or in discontinuous compared to continuous incremental exercise tests. Furthermore, most studies that evaluated the validity of supramaximal verification phases, reported verification bout durations, which are too short to ensure that $${{\text{VO}}}_{2\max }$$ VO 2 max have been achieved by all participants. As a result, there is little evidence for a higher $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl incidence and a corresponding advantage for the diagnoses of $${{\text{VO}}}_{2\max }$$ VO 2 max when incremental tests are supplemented by supramaximal verification bouts. Preliminary evidence suggests that the occurrence of a $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl in continuous incremental tests is determined by physiological factors like anaerobic capacity, $${{\text{VO}}}_{2}$$ VO 2 -kinetics and accumulation of metabolites in the submaximal intensity domain. Subsequent studies should take more attention to the use of valid $${{\text{VO}}}_{2} {\text{pl}}$$ VO 2 pl definitions, which require a cut-off at ~ 50% of the submaximal $${{\text{VO}}}_{2}$$ VO 2 increase and rather large sampling intervals. Furthermore, if verification bouts are used to verify the achievement of $${{\text{VO}}}_{{2{\text{peak}}}}$$ VO 2 peak /$${{\text{VO}}}_{2\max }$$ VO 2 max , it should be ensured that they can be sustained for sufficient durations.

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No reserve in isokinetic cycling power at intolerance during ramp incremental exercise in endurance-trained men

Cited by 15 publications

References 56 publications

Power reserve following ramp-incremental cycling to exhaustion: implications for muscle fatigue and function

Power reserve following ramp-incremental cycling to exhaustion: implications for muscle fatigue and function

A call to action towards an evidence‐based approach to using verbal encouragement during maximal exercise testing

The Oxygen Uptake Plateau—A Critical Review of the Frequently Misunderstood Phenomenon

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