No functional reserve at exhaustion in endurance-trained men?
2016; American Physiological Society; Volume: 120; Issue: 4 Linguagem: Inglês
10.1152/japplphysiol.01006.2015
ISSN8750-7587
AutoresDavid Morales‐Álamo, Marcos Martín-Rincón, Mario Perez‐Valera, Samuele Marcora, José A. L. Calbet,
Tópico(s)Sports Performance and Training
ResumoLetters to the EditorNo functional reserve at exhaustion in endurance-trained men?David Morales-Alamo, Marcos Martin-Rincon, Mario Perez-Valera, Samuele Marcora, and José A. L. CalbetDavid Morales-AlamoDepartment of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), Las Palmas de Gran Canaria, Canary Islands, Spain; , Marcos Martin-RinconDepartment of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, Spain; Department of Sports and Informatics, Pablo de Olavide University, Seville, Spain; and , Mario Perez-ValeraDepartment of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), Las Palmas de Gran Canaria, Canary Islands, Spain; , Samuele MarcoraEndurance Research Group, School of Sport and Exercise Sciences, University of Kent, United Kingdom, and José A. L. CalbetDepartment of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), Las Palmas de Gran Canaria, Canary Islands, Spain; Published Online:15 Feb 2016https://doi.org/10.1152/japplphysiol.01006.2015MoreSectionsPDF (43 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat to the editor: We read with great interest the study by Ferguson et al. (2). The authors remark that the main factor limiting V̇o2 max in sedentary people is O2 extraction capacity. However, Saltin's studies clearly demonstrated that training in deconditioned subjects increases V̇o2 max by increasing both components: peripheral extraction and cardiac output. The subjects studied in Ferguson et al. had a V̇o2 max of 4.2 ± 1.0 l/min (22 years old), meaning that about one-third of them could hardly be considered endurance-trained athletes. Then, it is mentioned that energy provision or metabolite accumulation determines the limit of exercise tolerance (LoT). This neglects our recent study showing that neither energy provision nor metabolite accumulation established the LoT during an incremental exercise to exhaustion in normoxia or severe acute hypoxia in healthy physically active subjects (4). Ferguson et al. claim that there is no functional reserve for power generation at LoT, because the power measured at the flywheel was 352 ± 58 W, whereas that measured at the crank during the isokinetic (80 rpm) maximal effort at LoT was 391 ± 72 W (i.e., 12% higher, but P = 0.12). If the comparison were made correctly using the same measurement mode, that is the power measured at the crank, the corresponding values would have been 310 ± 58 vs. 391 ± 72 W (i.e., 26% higher with the isokinetic mode at LoT) and the main conclusion should have been changed to the contrary. In agreement with our findings, in Fig. 3 of Ferguson et al., all subjects increased crank power output from the hyperbolic to the isokinetic mode at LoT: how can this not be statistically significant? Moreover, our data (4) demonstrated that metabolic factors related to lactate accumulation or muscle acidification do not explain task failure, in contrast to the conjecture of Ferguson et al. Furthermore, it seems that verbal encouragement was provided only during the incremental exercise test. Therefore, some subjects may not have given a true maximal effort during the isokinetic sprints as reflected by reduced muscle activation in 6 participants.To finalize, when Marcora et al. (3) subjects were requested to sprint, 3 s after exhaustion, they achieved much higher pedaling rates and developed much more power output than at task failure. A higher pedaling rate during the final sprint than during exhaustion is of minor relevance for the matter because higher shortening speed requires more ATP. Therefore, Marcora et al. (3) experiment, in agreement with ours, clearly shows that a marked functional reserve exists at exhaustion and that the myosin ATPase can hydrolyze ATP at a much higher rate than at task failure, also implying that ATP was made available at this high rate. The latter necessarily requires that a metabolic reserve exists at exhaustion, as we recently showed by performing muscle biopsies combined with measurement of leg VO2 by the direct Fick method (1, 4). Thus Ferguson et al. do not have convincing data as to state that, in endurance-trained humans, task failure during incremental exercise occurs because maximal voluntary power cannot be increased above the task requirement.DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the author(s).AUTHOR CONTRIBUTIONSAuthor contributions: D.M.-A., S.M.M., and J.A.C. conception and design of research; D.M.-A., M.M.-R., M.P.-V., S.M.M., and J.A.C. drafted manuscript; D.M.-A., M.M.-R., M.P.-V., S.M.M., and J.A.C. edited and revised manuscript; D.M.-A., M.M.-R., M.P.-V., S.M.M., and J.A.C. approved final version of manuscript.REFERENCES1. Calbet JA, Losa-Reyna J, Torres-Peralta R, Rasmussen P, Ponce-Gonzalez JG, Sheel AW, de la Calle-Herrero J, Guadalupe-Grau A, Morales-Alamo D, Fuentes T, Rodriguez-Garcia L, Siebenmann C, Boushel R, and Lundby C. Limitations to oxygen transport and utilization during sprint exercise in humans: evidence for a functional reserve in muscle O2 diffusing capacity. J Physiol 593: 4649–4664, 2015.Crossref | PubMed | ISI | Google Scholar2. Ferguson C, Wylde LA, Benson AP, Cannon DT, and Rossiter HB. No reserve in isokinetic cycling power at intolerance during ramp incremental exercise in endurance-trained men. J Appl Physiol (1985) 120: 70–77, 2016.Link | ISI | Google Scholar3. Marcora SM, and Staiano W. The limit to exercise tolerance in humans: mind over muscle? Eur J Appl Physiol 109: 763–770, 2010.Crossref | PubMed | ISI | Google Scholar4. Morales-Alamo D, Losa-Reyna J, Torres-Peralta R, Martin-Rincon M, Perez-Valera M, Curtelin D, Ponce-Gonzalez JG, Santana A, and Calbet JA. What limits performance during whole-body incremental exercise to exhaustion in humans? J Physiol 593: 4631–4648, 2015.Crossref | PubMed | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: J. A. L. Calbet, Departamento de Educación Física, Campus Universitario de Tafira, 35017 Las Palmas de Gran Canaria, Canary Island, Spain (e-mail: lopezcalbet@gmail.com). Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Cited ByPower reserve following ramp-incremental cycling to exhaustion: implications for muscle fatigue and functionMichael D. Hodgson, Daniel A. Keir, David B. Copithorne, Charles L. Rice, and John M. Kowalchuk1 August 2018 | Journal of Applied Physiology, Vol. 125, No. 2Exercise tolerance during VO 2max testing is a multifactorial psychobiological phenomenon21 August 2017 | Research in Sports Medicine, Vol. 25, No. 4Power-Velocity and Power-Efficiency Implications in the Limitation of Ramp Incremental Cycle Ergometry: Reply to Morales-Alamo et al.Carrie Ferguson, Daniel T. Cannon, Lindsey A. Wylde, Alan P. Benson, and Harry B. Rossiter15 February 2016 | Journal of Applied Physiology, Vol. 120, No. 4 More from this issue > Volume 120Issue 4February 2016Pages 476-476 Copyright & PermissionsCopyright © 2016 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.01006.2015PubMed26879661History Published online 15 February 2016 Published in print 15 February 2016 Metrics
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