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Caswell AM, Tripp TR, Kontro H, Edgett BA, Wiley JP, Lun V, MacInnis MJ. The influence of sex, hemoglobin mass, and skeletal muscle characteristics on cycling critical power. J Appl Physiol (1985) 2024; 137:10-22. [PMID: 38779761 DOI: 10.1152/japplphysiol.00120.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/29/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024] Open
Abstract
Critical power (CP) represents an important threshold for exercise performance and fatiguability. We sought to determine the extent to which sex, hemoglobin mass (Hbmass), and skeletal muscle characteristics influence CP. Before CP determination (i.e., 3-5 constant work rate trials to task failure), Hbmass and skeletal muscle oxidative capacity (τ) were measured and vastus lateralis (VL) muscle biopsy samples were collected from 12 females and 12 males matched for aerobic fitness relative to fat-free mass (FFM) [means (SD); V̇o2max: 59.2 (7.7) vs. 59.5 (7.1) mL·kg·FFM-1·min-1, respectively]. Males had a significantly greater CP than females in absolute units [225 (28) vs. 170 (43) W; P = 0.001] but not relative to body mass [3.0 (0.6) vs. 2.7 (0.6) W·kg·BM-1; P = 0.267] or FFM [3.6 (0.7) vs. 3.7 (0.8) W·kg·FFM-1; P = 0.622]. Males had significantly greater W' (P ≤ 0.030) and greater Hbmass (P ≤ 0.016) than females, regardless of the normalization approach; however, there were no differences in mitochondrial protein content (P = 0.375), τ (P = 0.603), or MHC I proportionality (P = 0.574) between males and females. Whether it was expressed in absolute or relative units, CP was positively correlated with Hbmass (0.444 ≤ r ≤ 0.695; P < 0.05), mitochondrial protein content (0.413 ≤ r ≤ 0.708; P < 0.05), and MHC I proportionality (0.506 ≤ r ≤ 0.585; P < 0.05), and negatively correlated with τ when expressed in relative units only (-0.588 ≤ r ≤ -0.527; P < 0.05). Overall, CP was independent of sex, but variability in CP was related to Hbmass and skeletal muscle characteristics. The extent to which manipulations in these physiological parameters influence CP warrants further investigation to better understand the factors underpinning CP.NEW & NOTEWORTHY In males and females matched for aerobic fitness [maximal oxygen uptake normalized to fat-free mass (FFM)], absolute critical power (CP) was greater in males, but relative CP (per kilogram body mass or FFM) was similar between sexes. CP correlated with hemoglobin mass, mitochondrial protein content, myosin heavy chain type I proportion, and skeletal muscle oxidative capacity. These findings demonstrate the importance of matching sexes for aerobic fitness, but further experiments are needed to determine causality.
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Affiliation(s)
- Allison M Caswell
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Hilkka Kontro
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Brittany A Edgett
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - J Preston Wiley
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Victor Lun
- Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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Hovorka M, Prinz B, Simon D, Zöger M, Rumpl C, Nimmerichter A. Long-Term Alterations in Pulmonary V˙O2 and Muscle Deoxygenation On-Kinetics During Heavy-Intensity Exercise in Competitive Youth Cyclists: A Cohort Study. Pediatr Exerc Sci 2024:1-7. [PMID: 38714302 DOI: 10.1123/pes.2023-0110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 02/20/2024] [Accepted: 03/12/2024] [Indexed: 05/09/2024]
Abstract
PURPOSE The aim of this investigation was to assess alterations of pulmonary oxygen uptake (V˙O2) and muscle deoxygenation on-kinetics during heavy-intensity cycling in youth cyclists over a period of 15 months. METHODS Eleven cyclists (initial age, 14.3 [1.6] y; peak V˙O2, 62.2 [4.5] mL·min-1·kg-1) visited the laboratory twice on 3 occasions within 15 months. Participants performed an incremental ramp exercise test and a constant workrate test within the heavy-intensity domain during the first visit and second visit, respectively. Subsequently, parameter estimates of the V˙O2 and muscle deoxygenation on-kinetics were determined with mono-exponential models. RESULTS The V˙O2 phase II time constant decreased from occasion 1 (34 [4] s) to occasion 2 (30 [4] s, P = .005) and 3 (28 [4] s, P = .010). However, no significant alteration was observed between occasions 2 and 3 (P = .565). The V˙O2 slow component amplitude either expressed in absolute values (ie, L·min-1) or relative to end exercise V˙O2 (ie, %) showed no significant changes throughout the study (P = .972 and .996). Furthermore, the muscle deoxygenation on-kinetic mean response time showed no significant changes throughout the study (18 [8], 18 [3], and 16 [5] s for occasions 1, 2, and 3, respectively; P = .279). CONCLUSION These results indicate proportional enhancements of local muscle oxygen distribution and utilization, which both contributed to the speeding of the V˙O2 on-kinetics herein.
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Affiliation(s)
- Matthias Hovorka
- Training and Sports Sciences, University of Applied Sciences Wiener Neustadt, Wiener Neustadt,Austria
- Centre for Sport Science and University Sports, University of Vienna, Vienna,Austria
- Doctoral School of Pharmaceutical, Nutritional and Sport Sciences, University of Vienna, Vienna,Austria
| | - Bernhard Prinz
- Training and Sports Sciences, University of Applied Sciences Wiener Neustadt, Wiener Neustadt,Austria
| | - Dieter Simon
- Training and Sports Sciences, University of Applied Sciences Wiener Neustadt, Wiener Neustadt,Austria
| | - Manfred Zöger
- Training and Sports Sciences, University of Applied Sciences Wiener Neustadt, Wiener Neustadt,Austria
| | - Clemens Rumpl
- Training and Sports Sciences, University of Applied Sciences Wiener Neustadt, Wiener Neustadt,Austria
| | - Alfred Nimmerichter
- Training and Sports Sciences, University of Applied Sciences Wiener Neustadt, Wiener Neustadt,Austria
- Centre for Sport Science and University Sports, University of Vienna, Vienna,Austria
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Solleiro Pons M, Bernert L, Hume E, Hughes L, Williams ZJ, Burnley M, Ansdell P. No sex differences in oxygen uptake or extraction kinetics in the moderate or heavy exercise intensity domains. J Appl Physiol (1985) 2024; 136:472-481. [PMID: 38205552 PMCID: PMC11213575 DOI: 10.1152/japplphysiol.00429.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 01/02/2024] [Accepted: 01/04/2024] [Indexed: 01/12/2024] Open
Abstract
The integrative response to exercise differs between sexes, with oxidative energy contribution purported as a potential mechanism. The present study investigated whether this difference was evident in the kinetics of oxygen uptake (V̇o2) and extraction (HHb + Mb) during exercise. Sixteen adults (8 males, 8 females, age: 27 ± 5 yr) completed three experimental visits. Incremental exercise testing was performed to obtain lactate threshold and V̇o2peak. Subsequent visits involved three 6-min cycling bouts at 80% of lactate threshold and one 30-min bout at a work rate of 30% between the lactate threshold and power at V̇o2peak. Pulmonary gas exchange and near-infrared spectroscopy of the vastus lateralis were used to continuously sample V̇o2 and HHb + Mb, respectively. The phase II V̇o2 kinetics were quantified using monoexponential curves during moderate and heavy exercise. Slow component amplitudes were also quantified for the heavy-intensity domain. Relative V̇o2peak values were not different between sexes (P = 0.111). Males achieved ∼30% greater power outputs (P = 0.002). In the moderate- and heavy-intensity domains, the relative amplitude of the phase II transition was not different between sexes for V̇o2 (∼24 and ∼40% V̇o2peak, P ≥ 0.179) and HHb + Mb (∼20 and ∼32% ischemia, P ≥ 0.193). Similarly, there were no sex differences in the time constants for V̇o2 (∼28 s, P ≥ 0.385) or HHb + Mb (∼10 s, P ≥ 0.274). In the heavy-intensity domain, neither V̇o2 (P ≥ 0.686) or HHb + Mb (P ≥ 0.432) slow component amplitudes were different between sexes. The oxidative response to moderate- and heavy-intensity exercises did not differ between males and females, suggesting similar dynamic responses of oxidative metabolism during intensity-matched exercise.NEW & NOTEWORTHY This study demonstrated no sex differences in the oxidative response to moderate- and heavy-intensity cycling exercise. The change in oxygen uptake and deoxyhemoglobin were modeled with monoexponential curve fitting, which revealed no differences in the rate of oxidative energy provision between sexes. This provides insight into previously reported sex differences in the integrative response to exercise.
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Affiliation(s)
- Maria Solleiro Pons
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Lina Bernert
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
- Institute of Sport and Exercise Sciences, University of Münster, Münster, Germany
| | - Emily Hume
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Luke Hughes
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Zander J Williams
- Department of Respiratory Medicine, Royal Brompton Hospital, London, United Kingdom
| | - Mark Burnley
- School of Sport, Health and Exercise Sciences, Loughborough University, Loughborough, United Kingdom
| | - Paul Ansdell
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
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Lei T, Wang I, Chen Y, Liu X, Fujii N, Koga S, Perry B, Mundel T, Wang F, Cao Y, Dobashi K, Kondo N, Li H, Goulding RP. Critical power is a key threshold determining the magnitude of post-exercise hypotension in non-hypertensive young males. Exp Physiol 2023; 108:1409-1421. [PMID: 37712355 PMCID: PMC10988428 DOI: 10.1113/ep091429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 08/24/2023] [Indexed: 09/16/2023]
Abstract
The effect of different exercise intensities on the magnitude of post-exercise hypotension has not been rigorously clarified with respect to the metabolic thresholds that partition discrete exercise intensity domains (i.e., critical power and the gas exchange threshold (GET)). We hypothesized that the magnitude of post-exercise hypotension would be greater following isocaloric exercise performed above versus below critical power. Twelve non-hypertensive men completed a ramp incremental exercise test to determine maximal oxygen uptake and the GET, followed by five exhaustive constant load trials to determine critical power and W' (work available above critical power). Subsequently, criterion trials were performed at four discrete intensities matched for total work performed (i.e., isocaloric) to determine the impact of exercise intensity on post-exercise hypotension: 10% above critical power (10% > CP), 10% below critical power (10% < CP), 10% above GET (10% > GET) and 10% below GET (10% < GET). The post-exercise decrease (i.e., the minimum post-exercise values) in mean arterial (10% > CP: -12.7 ± 8.3 vs. 10% < CP: v3.5 ± 2.9 mmHg), diastolic (10% > CP: -9.6 ± 9.8 vs. 10% < CP: -1.4 ± 5.0 mmHg) and systolic (10% > CP: -23.8 ± 7.0 vs. 10% < CP: -9.9 ± 4.3 mmHg) blood pressures were greater following exercise performed 10% > CP compared to all other trials (all P < 0.01). No effects of exercise intensity on the magnitude of post-exercise hypotension were observed during exercise performed below critical power (all P > 0.05). Critical power represents a threshold above which the magnitude of post-exercise hypotension is greatly augmented. NEW FINDINGS: What is the central questions of this study? What is the influence of exercise intensity on the magnitude of post-exercise hypotension with respect to metabolic thresholds? What is the main finding and its importance? The magnitude of post-exercise hypotension is greatly increased following exercise performed above critical power. However, below critical power, there was no clear effect of exercise intensity on the magnitude of post-exercise hypotension.
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Affiliation(s)
- Tze‐Huan Lei
- College of Physical EducationHubei Normal UniversityHuangshiChina
| | - I‐Lin Wang
- College of Physical EducationHubei Normal UniversityHuangshiChina
| | - Yi‐Ming Chen
- Department of Food ScienceFu Jen Catholic UniversityNew Taipei CityTaiwan
| | - Xin‐Hao Liu
- College of Physical EducationHubei Normal UniversityHuangshiChina
| | - Naoto Fujii
- Faculty of Health and Sport SciencesUniversity of TsukubaTsukubaJapan
| | - Shunsaku Koga
- Applied Physiology LaboratoryKobe Design UniversityKobeJapan
| | - Blake Perry
- School of Health SciencesMassey UniversityWellingtonNew Zealand
| | - Toby Mundel
- Department of KinesiologyBrock UniversitySt CatharinesCanada
| | - Faming Wang
- Division Animal and Human Health Engineering, Department of Biosystems (BIOSYST)KU LeuvenLeuvenBelgium
| | - Yinhang Cao
- School of Athletic PerformanceShanghai Sport UniversityShanghaiChina
| | - Kohei Dobashi
- Faculty of EducationHokkaido University of EducationAsahikawaJapan
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human Development and EnvironmentKobe UniversityKobeJapan
| | - Hao‐Yu Li
- College of Physical EducationHubei Normal UniversityHuangshiChina
| | - Richie P. Goulding
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioral and Human Movement Sciences, Vrije Universiteit AmsterdamAmsterdam Movement SciencesAmsterdamthe Netherlands
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Korzeniewski B. Training-Induced Increase in V·O 2max and Critical Power, and Acceleration of V·O 2 on-Kinetics Result from Attenuated P i Increase Caused by Elevated OXPHOS Activity. Metabolites 2023; 13:1111. [PMID: 37999207 PMCID: PMC10673597 DOI: 10.3390/metabo13111111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/16/2023] [Accepted: 09/21/2023] [Indexed: 11/25/2023] Open
Abstract
Computer simulations using a dynamic model of the skeletal muscle bioenergetic system, involving the Pi-double-threshold mechanism of muscle fatigue, demonstrate that the training-induced increase in V·O2max, increase in critical power (CP) and acceleration of primary phase II of the V·O2 on kinetics (decrease in t0.63) is caused by elevated OXPHOS activity acting through a decrease in and slowing of the Pi (inorganic phosphate) rise during the rest-to-work transition. This change leads to attenuation of the reaching by Pi of Pipeak, peak Pi at which exercise is terminated because of fatigue. The delayed (in time and in relation to V·O2 increase) Pi rise for a given power output (PO) in trained muscle causes Pi to reach Pipeak (in very heavy exercise) after a longer time and at a higher V·O2; thus, exercise duration is lengthened, and V·O2max is elevated compared to untrained muscle. The diminished Pi increase during exercise with a given PO can cause Pi to stabilize at a steady state less than Pipeak, and exercise can continue potentially ad infinitum (heavy exercise), instead of rising unceasingly and ultimately reaching Pipeak and causing exercise termination (very heavy exercise). This outcome means that CP rises, as the given PO is now less than, and not greater than CP. Finally, the diminished Pi increase (and other metabolite changes) results in, at a given PO (moderate exercise), the steady state of fluxes (including V·O2) and metabolites being reached faster; thus, t0.63 is shortened. This effect of elevated OXPHOS activity is possibly somewhat diminished by the training-induced decrease in Pipeak.
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Vinetti G, Rossi H, Bruseghini P, Corti M, Ferretti G, Piva S, Taboni A, Fagoni N. Functional Threshold Power Field Test Exceeds Laboratory Performance in Junior Road Cyclists. J Strength Cond Res 2023; 37:1815-1820. [PMID: 36692223 PMCID: PMC10448799 DOI: 10.1519/jsc.0000000000004471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Vinetti, G, Rossi, H, Bruseghini, P, Corti, M, Ferretti, G, Piva, S, Taboni, A, and Fagoni, N. The functional threshold power field test exceeds laboratory performance in junior road cyclists. J Strength Cond Res 37(9): 1815–1820, 2023—The functional threshold power (FTP) field test is appealing for junior cyclists, but it was never investigated in this age category, and even in adults, there are few data on FTP collected in field conditions. Nine male junior road cyclists (16.9 ± 0.8 years) performed laboratory determination of maximal aerobic power (MAP), 4-mM lactate threshold (P4mM), critical power (CP), and the curvature constant (W ′), plus a field determination of FTP as 95% of the average power output during a 20-minute time trial in an uphill road. The level of significance was set at p < 0.05. Outdoor FTP (269 ± 34 W) was significantly higher than CP (236 ± 24 W) and P4mM (233 ± 23 W). The V ˙ O 2 peak of the field FTP test (66.9 ± 4.4 ml·kg−1·min−1) was significantly higher than the V ˙ O 2 peak assessed in the laboratory (62.7 ± 3.7 ml·kg−1·min−1). Functional threshold power was correlated, in descending order, with MAP (r = 0.95), P4mM (r = 0.94), outdoor and indoor V ˙ O 2 peak (r = 0.93 and 0.93, respectively), CP (r = 0.84), and W ′ (r = 0.66). It follows that in junior road cyclists, the FTP field test was feasible and related primarily to aerobic endurance parameters and secondarily, but notably, to W ′. However, the FTP field test significantly exceeded all laboratory performance tests. When translating laboratory results to outdoor uphill conditions, coaches and sport scientists should consider this discrepancy, which may be particularly enhanced in this cycling age category.
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Affiliation(s)
- Giovanni Vinetti
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Huber Rossi
- Marathon Sport Medical Center, Brescia, Italy
| | - Paolo Bruseghini
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Marco Corti
- Department of Human Sciences and Promotion of the Quality of Life, University San Raffaele Roma, Rome, Italy; and
| | - Guido Ferretti
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Simone Piva
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Anna Taboni
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Nazzareno Fagoni
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
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7
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Jones AM. The fourth dimension: physiological resilience as an independent determinant of endurance exercise performance. J Physiol 2023. [PMID: 37606604 DOI: 10.1113/jp284205] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/28/2023] [Indexed: 08/23/2023] Open
Abstract
Endurance exercise performance is known to be closely associated with the three physiological pillars of maximal O2 uptake (V ̇ O 2 max $\dot{V}_{{\rm O}_{2}{\rm max}}$ ), economy or efficiency during submaximal exercise, and the fractional utilisation ofV ̇ O 2 max $\dot{V}_{{\rm O}_{2}{\rm max}}$ (linked to metabolic/lactate threshold phenomena). However, while 'start line' values of these variables are collectively useful in predicting performance in endurance events such as the marathon, it is not widely appreciated that these variables are not static but are prone to significant deterioration as fatiguing endurance exercise proceeds. For example, the 'critical power' (CP), which is a composite of the highest achievable steady-state oxidative metabolic rate and efficiency (O2 cost per watt), may fall by an average of 10% following 2 h of heavy intensity cycle exercise. Even more striking is that the extent of this deterioration displays appreciable inter-individual variability, with changes in CP ranging from <1% to ∼32%. The mechanistic basis for such differences in fatigue resistance or 'physiological resilience' are not resolved. However, resilience may be important in explaining superlative endurance performance and it has implications for the physiological evaluation of athletes and the design of interventions to enhance performance. This article presents new information concerning the dynamic plasticity of the three 'traditional' physiological variables and argues that physiological resilience should be considered as an additional component, or fourth dimension, in models of endurance exercise performance.
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Affiliation(s)
- Andrew M Jones
- Department of Public Health and Sport Sciences, University of Exeter Medical School, St Luke's Campus, Exeter, UK
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8
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Goulding RP, Burnley M, Wüst RCI. How Priming Exercise Affects Oxygen Uptake Kinetics: From Underpinning Mechanisms to Endurance Performance. Sports Med 2023; 53:959-976. [PMID: 37010782 PMCID: PMC10115720 DOI: 10.1007/s40279-023-01832-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2023] [Indexed: 04/04/2023]
Abstract
The observation that prior heavy or severe-intensity exercise speeds overall oxygen uptake ([Formula: see text]O2) kinetics, termed the "priming effect", has garnered significant research attention and its underpinning mechanisms have been hotly debated. In the first part of this review, the evidence for and against (1) lactic acidosis, (2) increased muscle temperature, (3) O2 delivery, (4) altered motor unit recruitment patterns and (5) enhanced intracellular O2 utilisation in underpinning the priming effect is discussed. Lactic acidosis and increased muscle temperature are most likely not key determinants of the priming effect. Whilst priming increases muscle O2 delivery, many studies have demonstrated that an increased muscle O2 delivery is not a prerequisite for the priming effect. Motor unit recruitment patterns are altered by prior exercise, and these alterations are consistent with some of the observed changes in [Formula: see text]O2 kinetics in humans. Enhancements in intracellular O2 utilisation likely play a central role in mediating the priming effect, probably related to elevated mitochondrial calcium levels and parallel activation of mitochondrial enzymes at the onset of the second bout. In the latter portion of the review, the implications of priming on the parameters of the power-duration relationship are discussed. The effect of priming on subsequent endurance performance depends critically upon which phases of the [Formula: see text]O2 response are altered. A reduced [Formula: see text]O2 slow component or increased fundamental phase amplitude tend to increase the work performable above critical power (i.e. W´), whereas a reduction in the fundamental phase time constant following priming results in an increased critical power.
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Affiliation(s)
- Richie P Goulding
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
| | - Mark Burnley
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Rob C I Wüst
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
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9
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Pechstein AE, Gollie JM, Keyser RE, Guccione AA. Walking Endurance and Oxygen Uptake On-Kinetics in Individuals With Parkinson Disease Following Overground Locomotor Training. J Neurol Phys Ther 2023; 47:99-111. [PMID: 36538418 DOI: 10.1097/npt.0000000000000423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND PURPOSE Poor walking endurance in Parkinson disease (PD) may be attributable to both bioenergetic and biomechanical factors, but locomotor training methods addressing both these factors simultaneously are understudied. Our objective was to examine the effects of overground locomotor training (OLT) on walking endurance in individuals with mild-to-moderate PD, and to further explore potential cardiorespiratory contributions. METHODS A single-arm, longitudinal design was used to examine the effects of 24 biweekly sessions of OLT in people with mild-to-moderate PD (n = 12). Walking endurance was measured as total distance walked during a 10-minute walk test (10minWT). Oxygen uptake (V˙ o2 ) on-kinetic profiles were determined using a monoexponential function. Perceived fatigability was assessed following the 10minWT using a self-report scale. Magnitude of change in primary outcomes was assessed using Cohen's d and adjusted for sample size (Cohen's d(unbiased) ). RESULTS Participants executed 3036 (297) steps and maintained 65.5% (8%) age-predicted heart rate maximum in a typical session lasting 56.9 (2.5) minutes. Medium effects in total distance walked-885.9 (157.2) versus 969.5 (140.9); Cohen's d(unbiased) = 0.54-and phase II time constant of the V˙ o2 on-kinetic profile-33.7 (12.3) versus 25.9 (15.3); Cohen's d(unbiased) = 0.54-were observed alongside trivial effects for perceived fatigability-4.7 (1.4) versus 4.8 (1.5); Cohen's d(unbiased) = 0.11-following OLT. DISCUSSION AND CONCLUSIONS These preliminary findings may demonstrate the potential for moderate-intensity OLT to improve walking endurance and enhance cardiorespiratory adjustments to walking activity in adults with mild-to-moderate PD.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A407 ).
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Affiliation(s)
- Andrew E Pechstein
- Department of Rehabilitation Science, George Mason University, Fairfax, Virginia (A.E.P., J.M.G., R.E.K., A.A.G.); Department of Physical Therapy, University of Delaware, Newark (A.E.P.); and Research Service, Veterans Affairs Medical Center, Washington, District of Columbia (J.M.G.)
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10
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Festa RR, Monsalves-Álvarez M, Cancino J, Jannas-Vela S. Prescription of High-intensity Aerobic Interval Training Based on Oxygen Uptake Kinetics. Int J Sports Med 2023; 44:159-168. [PMID: 35995143 DOI: 10.1055/a-1929-0295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Endurance training results in diverse adaptations that lead to increased performance and health benefits. A commonly measured training response is the analysis of oxygen uptake kinetics, representing the demand of a determined load (speed/work) on the cardiovascular, respiratory, and metabolic systems, providing useful information for the prescription of constant load or interval-type aerobic exercise. There is evidence that during high-intensity aerobic exercise some interventions prescribe brief interval times (<1-min), which may lead to a dissociation between the load prescribed and the oxygen uptake demanded, potentially affecting training outcomes. Therefore, this review explored the time to achieve a close association between the speed/work prescribed and the oxygen uptake demanded after the onset of high-intensity aerobic exercise. The evidence assessed revealed that at least 80% of the oxygen uptake amplitude is reached when phase II of oxygen uptake kinetics is completed (1 to 2 minutes after the onset of exercise, depending on the training status). We propose that the minimum work-time during high-intensity aerobic interval training sessions should be at least 1 minute for athletes and 2 minutes for non-athletes. This suggestion could be used by coaches, physical trainers, clinicians and sports or health scientists for the prescription of high-intensity aerobic interval training.
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Affiliation(s)
- Raúl Ricardo Festa
- Laboratorio de Fisiología del Ejercicio y Metabolismo, Escuela de Kinesiología, Universidad Finis Terrae, Santiago, Chile
| | | | - Jorge Cancino
- Laboratorio de Fisiología del Ejercicio y Metabolismo, Escuela de Kinesiología, Universidad Finis Terrae, Santiago, Chile
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11
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Spragg J, Leo P, Swart J. The Relationship between Physiological Characteristics and Durability in Male Professional Cyclists. Med Sci Sports Exerc 2023; 55:133-140. [PMID: 35977108 DOI: 10.1249/mss.0000000000003024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study aimed to determine if durability can be predicted from laboratory measures in a professional cycling population. METHODS Data were collected from 10 professional cyclists (age = 19.2 ± 0.8 yr, body mass = 70.4 ± 5.5 kg, height = 182.9 ± 4.0 cm, body mass index = 21.0 ± 1.3 kg·m -2 , V̇O 2max = 74.4 ± 4.8 mL·kg -1 ·min -1 , critical power [CP] = 5.6 ± 0.6 W·kg -1 , W' = 23.7 ± 5.4 kJ). Participants completed a laboratory test and a CP test on two occasions. The second occasion was preceded by a novel fatiguing protocol, which consisted of five bouts of 8-min of exercise at 105%-110% of CP. CP in a fatigued state was expressed as a percentage of the fresh CP and coined delta CP (∆CP). The Pearson product correlation analysis was conducted to determine the relationship between laboratory-based measures and ∆CP. RESULTS Significant positive relationships were found between ∆CP and relative peak power output ( r = 0.891, P < 0.001), relative maximum oxygen uptake ( r = 0.835, P = 0.003), relative power output at the second ventilatory threshold ( r = 0.738, P = 0.015), power output at the first ventilatory threshold ( r = 0.748, P = 0.013) and relative power output at the first ventilatory threshold ( r = 0.826, P = 0.003), gross efficiency at 300 W ( r = 0.869, P = 0.001), and at 200 W ( r = 0.792, P = 0.006). Significant negative relationships were found between ∆CP and carbohydrate oxidation at 200 W ( r = -0.702, P = 0.024). A multiple linear regression demonstrated that ∆CP can be predicted from laboratory measures ( R2 = 0.96-0.98, P < 0.001). CONCLUSIONS These findings demonstrate the physiological determinants of durability in a professional cycling population.
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Affiliation(s)
- James Spragg
- HPALS, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, SOUTH AFRICA
| | - Peter Leo
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, AUSTRIA
| | - Jeroen Swart
- HPALS, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, SOUTH AFRICA
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12
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Korzeniewski B. Sensitivity of V̇O2max, critical power and V̇O2 on-kinetics to O2 concentration/delivery and other factors in skeletal muscle. Respir Physiol Neurobiol 2023; 307:103977. [DOI: 10.1016/j.resp.2022.103977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/29/2022] [Accepted: 10/03/2022] [Indexed: 11/07/2022]
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13
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Rocha J, Gildea N, O’Shea D, Green S, Egaña M. Priming exercise accelerates oxygen uptake kinetics during high-intensity cycle exercise in middle-aged individuals with type 2 diabetes. Front Physiol 2022; 13:1006993. [PMID: 36505082 PMCID: PMC9727537 DOI: 10.3389/fphys.2022.1006993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/31/2022] [Indexed: 11/19/2022] Open
Abstract
Background: The primary phase time constant of pulmonary oxygen uptake kinetics (V · O 2 τ p) during submaximal efforts is longer in middle-aged people with type 2 diabetes (T2D), partly due to limitations in oxygen supply to active muscles. This study examined if a high-intensity "priming" exercise (PE) would speedV · O 2 τ p during a subsequent high-intensity cycling exercise in T2D due to enhanced oxygen delivery. Methods: Eleven (4 women) middle-aged individuals with type 2 diabetes and 11 (4 women) non-diabetic controls completed four separate cycling bouts each starting at an 'unloaded' baseline of 10 W and transitioning to a high-intensity constant-load. Two of the four cycling bouts were preceded by priming exercise. The dynamics of pulmonaryV · O 2 and muscle deoxygenation (i.e. deoxygenated haemoglobin and myoglobin concentration [HHb + Mb]), were calculated from breath-by-breath and near-infrared spectroscopy data at the vastus lateralis, respectively. Results: At baselineV · O 2 τ p, was slower (p < 0.001) in the type 2 diabetes group (48 ± 6 s) compared to the control group (34 ± 2 s) but priming exercise significantly reducedV · O 2 τ p (p < 0.001) in type 2 diabetes (32 ± 6 s) so that post priming exercise it was not different compared with controls (34 ± 3 s). Priming exercise reduced the amplitude of theV · O 2 slow component (As) in both groups (type 2 diabetes: 0.26 ± 0.11 to 0.16 ± 0.07 L/min; control: 0.33 ± 0.13 to 0.25 ± 0.14 L/min, p < 0.001), while [HHb + Mb] kinetics remained unchanged. Conclusion: These results suggest that in middle-aged men and women with T2D, PE speedsV · O 2 τ p likely by a better matching of O2 delivery to utilisation and reduces theV · O 2 As during a subsequent high-intensity exercise.
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Affiliation(s)
- Joel Rocha
- Division of Sport and Exercise Sciences, Abertay University, Dundee, United Kingdom
| | - Norita Gildea
- Department of Physiology, School of Medicine, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Donal O’Shea
- Endocrinology, St Columcille’s and St Vincent’s Hospitals, Dublin, Ireland
| | - Simon Green
- School of Science and Health, Western Sydney University, Sydney, AU-NSW, Australia
| | - Mikel Egaña
- Department of Physiology, School of Medicine, Trinity College Dublin, The University of Dublin, Dublin, Ireland
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14
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Spaas J, Goulding RP, Keytsman C, Fonteyn L, van Horssen J, Jaspers RT, Eijnde BO, Wüst RCI. Altered muscle oxidative phenotype impairs exercise tolerance but does not improve after exercise training in multiple sclerosis. J Cachexia Sarcopenia Muscle 2022; 13:2537-2550. [PMID: 35929063 PMCID: PMC9530506 DOI: 10.1002/jcsm.13050] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 06/05/2022] [Accepted: 06/13/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Patients with multiple sclerosis (MS) experience reduced exercise tolerance that substantially reduces quality of life. The mechanisms underpinning exercise intolerance in MS are not fully clear. This study aimed to determine the contributions of the cardiopulmonary system and peripheral muscle in MS-induced exercise intolerance before and after exercise training. METHODS Twenty-three patients with MS (13 women) and 20 age-matched and sex-matched healthy controls (13 women) performed a cardiopulmonary exercise test. Muscle fibre type composition, size, succinate dehydrogenase (SDH) activity, capillarity, and gene expression and proteins related to mitochondrial density were determined in vastus lateralis muscle biopsies. Nine MS patients (five women) were re-examined following a 12 week exercise training programme consisting of high-intensity cycling interval and resistance training. RESULTS Patients with MS had lower maximal oxygen uptake compared with healthy controls (V̇O2peak , 25.0 ± 8.5 vs. 35.7 ± 6.4 mL/kg/min, P < 0.001). The lower gas exchange threshold (MS: 14.5 ± 5.5 vs. controls: 19.7 ± 2.9 mL/kg/min, P = 0.01) and slope of V̇O2 versus work rate (MS: 9.5 ± 1.7 vs. controls: 10.8 ± 1.1 mL/min/W, P = 0.01) suggested an intramuscular contribution to exercise intolerance in patients with MS. Muscle SDH activity was 22% lower in MS (P = 0.004), and strongly correlated with several indices of whole-body exercise capacity in MS patients (e.g. V̇O2peak , Spearman's ρ = 0.81, P = 0.002), but not healthy controls (ρ = 0.24, P = 0.38). In addition, protein levels of mitochondrial OXPHOS complexes I (-40%, P = 0.047) and II (-45%, P = 0.026) were lower in MS patients versus controls. Muscle capillary/fibre ratio correlated with V̇O2peak in healthy controls (ρ = 0.86, P < 0.001) but not in MS (ρ = 0.35, P = 0.22), and did not differ between groups (1.41 ± 0.30 vs. 1.47 ± 0.38, P = 0.65). Expression of genes involved in mitochondrial function, such as PPARA, PPARG, and TFAM, was markedly reduced in muscle tissue samples of MS patients (all P < 0.05). No differences in muscle fibre type composition or size were observed between groups (all P > 0.05). V̇O2peak increased by 23% following exercise training in MS (P < 0.001); however, no changes in muscle capillarity, SDH activity, gene or protein expression were observed (all P > 0.05). CONCLUSIONS Skeletal muscle oxidative phenotype (mitochondrial complex I and II content, SDH activity) is lower in patients with MS, contributing to reduced exercise tolerance. However, skeletal muscle mitochondria appeared resistant to the beneficial effects of exercise training, suggesting that other physiological systems, at least in part, drive the improvements in exercise capacity following exercise training in MS.
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Affiliation(s)
- Jan Spaas
- University MS Center (UMSC) Hasselt - Pelt, Hasselt, Belgium.,SMRC Sports Medical Research Center, BIOMED Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt, Belgium.,Department of Movement and Sports Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Richie P Goulding
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Charly Keytsman
- University MS Center (UMSC) Hasselt - Pelt, Hasselt, Belgium.,SMRC Sports Medical Research Center, BIOMED Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt, Belgium
| | - Lena Fonteyn
- University MS Center (UMSC) Hasselt - Pelt, Hasselt, Belgium.,SMRC Sports Medical Research Center, BIOMED Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt, Belgium
| | - Jack van Horssen
- University MS Center (UMSC) Hasselt - Pelt, Hasselt, Belgium.,Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, MS Center Amsterdam, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Richard T Jaspers
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Bert O Eijnde
- University MS Center (UMSC) Hasselt - Pelt, Hasselt, Belgium.,SMRC Sports Medical Research Center, BIOMED Biomedical Research Institute, Faculty of Medicine and Life Sciences, Hasselt University, Hasselt, Belgium
| | - Rob C I Wüst
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
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15
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Longobardi I, Prado DMLD, Goessler KF, Meletti MM, de Oliveira Júnior GN, de Andrade DCO, Gualano B, Roschel H. Oxygen uptake kinetics and chronotropic responses to exercise are impaired in survivors of severe COVID-19. Am J Physiol Heart Circ Physiol 2022; 323:H569-H576. [PMID: 35984763 PMCID: PMC9448283 DOI: 10.1152/ajpheart.00291.2022] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The post-acute phase of coronavirus disease 2019 (COVID-19) is often marked by several persistent symptoms and exertional intolerance, which compromise survivors’ exercise capacity. This was a cross-sectional study aiming to investigate the impact of COVID-19 on oxygen uptake (V̇o2) kinetics and cardiopulmonary function in survivors of severe COVID-19 about 3–6 mo after intensive care unit (ICU) hospitalization. Thirty-five COVID-19 survivors previously admitted to ICU (5 ± 1 mo after hospital discharge) and 18 controls matched for sex, age, comorbidities, and physical activity level with no prior history of SARS-CoV-2 infection were recruited. Subjects were submitted to a maximum-graded cardiopulmonary exercise test (CPX) with an initial 3-min period of a constant, moderate-intensity walk (i.e., below ventilatory threshold, VT). V̇o2 kinetics was remarkably impaired in COVID-19 survivors as evidenced at the on-transient by an 85% (P = 0.008) and 28% (P = 0.001) greater oxygen deficit and mean response time (MRT), respectively. Furthermore, COVID-19 survivors showed an 11% longer (P = 0.046) half-time of recovery of V̇o2 (T1/2V̇o2) at the off-transient. CPX also revealed cardiopulmonary impairments following COVID-19. Peak oxygen uptake (V̇o2peak), percent-predicted V̇o2peak, and V̇o2 at the ventilatory threshold (V̇o2VT) were reduced by 17%, 17%, and 12% in COVID-19 survivors, respectively (all P < 0.05). None of the ventilatory parameters differed between groups (all P > 0.05). In addition, COVID-19 survivors also presented with blunted chronotropic responses (i.e., chronotropic index, maximum heart rate, and heart rate recovery; all P < 0.05). These findings suggest that COVID-19 negatively affects central (chronotropic) and peripheral (metabolic) factors that impair the rate at which V̇o2 is adjusted to changes in energy demands. NEW & NOTEWORTHY Our findings provide novel data regarding the impact of COVID-19 on submaximal and maximal cardiopulmonary responses to exercise. We showed that V̇o2 kinetics is significantly impaired at both the onset (on-transient) and the recovery phase (off-transient) of exercise in these patients. Furthermore, our results suggest that survivors of severe COVID-19 may have a higher metabolic demand at a walking pace. These findings may partly explain the exertional intolerance frequently observed following COVID-19.
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Affiliation(s)
- Igor Longobardi
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, School of Medicine, University of Sao Paulo, São Paulo, Brazil
| | - Danilo Marcelo Leite do Prado
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, School of Medicine, University of Sao Paulo, São Paulo, Brazil
| | - Karla Fabiana Goessler
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, School of Medicine, University of Sao Paulo, São Paulo, Brazil
| | - Matheus Molina Meletti
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, School of Medicine, University of Sao Paulo, São Paulo, Brazil
| | - Gersiel Nascimento de Oliveira Júnior
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, School of Medicine, University of Sao Paulo, São Paulo, Brazil
| | | | - Bruno Gualano
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, School of Medicine, University of Sao Paulo, São Paulo, Brazil.,Rheumatology Division, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, University of Sao Paulo, São Paulo, Brazil
| | - Hamilton Roschel
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, School of Medicine, University of Sao Paulo, São Paulo, Brazil.,Rheumatology Division, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, University of Sao Paulo, São Paulo, Brazil
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16
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Skeletal Muscle Biochemical Origin of Exercise Intensity Domains and their Relation to Whole-Body V̇O2 Kinetics. Biosci Rep 2022; 42:231600. [PMID: 35880531 PMCID: PMC9366749 DOI: 10.1042/bsr20220798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/16/2022] [Accepted: 06/29/2022] [Indexed: 11/17/2022] Open
Abstract
This article presents the biochemical intra-skeletal-muscle basis of exercise intensity domains: moderate (M), heavy (H), very heavy (VH) and severe (S). Threshold origins are mediated by a "Pi double-threshold" mechanism of muscle fatigue, which assumes: (1) additional ATP usage, underlying muscle V̇O2 and metabolite slow components, is initiated when inorganic phosphate (Pi) exceeds a critical value (Picrit); (2) exercise is terminated because of fatigue, when Pi reaches a peak value (Pipeak); (3) the Pi increase and additional ATP usage increase mutually stimulate each other forming a positive feedback. M/H and H/VH borders are defined by Pi on-kinetics in relation to Picrit and Pipeak. The values of the ATP usage activity, proportional to power output (PO), for the M/H, H/VH and VH/S borders are lowest in untrained muscle and highest in well-trained muscle. The metabolic range between the M/H and H/VH border (or "H space") decreases with muscle training, while the difference between the H/VH and VH/S border (or "VH space") is only weakly dependent on training status. The absolute magnitude of the muscle V̇O2 slow-component, absent in M exercise, rises gradually with PO to a maximal value in H exercise, and then decreases with PO in VH and S exercise. Simulations of untrained, physically-active and well-trained muscle demonstrate that the muscle M/H border need not be identical to the whole-body M/H border determined from pulmonary V̇O2 on-kinetics and blood lactate, while suggesting that the biochemical origins of the H/VH border reside within skeletal muscle and correspond to whole-body critical power.
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17
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Marwood S, Goulding RP. Over 55 years of critical power: Fact. Scand J Med Sci Sports 2022; 32:1064-1065. [PMID: 35567403 DOI: 10.1111/sms.14153] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/04/2022] [Accepted: 01/06/2022] [Indexed: 01/03/2023]
Affiliation(s)
- Simon Marwood
- School of Health & Sport Sciences, Liverpool Hope University, Liverpool, UK
| | - Richie P Goulding
- Laboratory for Myology, Vrije Universiteit, Amsterdam, The Netherlands
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18
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Baldassarre G, Zuccarelli L, Manferdelli G, Manfredini V, Marzorati M, Pilotto A, Porcelli S, Rasica L, Šimunič B, Pišot R, Narici M, Grassi B. Decrease in work rate in order to keep a constant heart rate: biomarker of exercise intolerance following a 10-day bed rest. J Appl Physiol (1985) 2022; 132:1569-1579. [PMID: 35511721 DOI: 10.1152/japplphysiol.00052.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aerobic exercise prescription is often set at specific heart rate (HR) values. Previous studies demonstrated that during exercise carried out at a HR slightly above that corresponding to the gas exchange threshold (GET), work rate (WR) has to decrease in order to maintain HR constant. We hypothesized a greater WR decrease at a fixed HR following simulated microgravity/inactivity (bed rest, BR). Ten male volunteers (23±5 yr) were tested before (PRE) and after (POST) a 10-day horizontal BR, and performed on a cycle ergometer: a) incremental exercise; b) 15-min HRCLAMPED exercise, in which WR was continuously adjusted to maintain a constant HR, corresponding to that at 120% of GET determined in PRE; c) two moderate-intensity constant WR (MOD) exercises. Breath-by-breath VO2, HR and other variables were determined. After BR, VO2peak and GET significantly decreased, by about 10%. During HRCLAMPED (145±11 b∙min-1), the decrease in WR needed to maintain a constant HR was greater in POST vs. PRE (-39±10 vs. -29±14%, p<0.01). In 6 subjects the decreased WR switched from the heavy- to the moderate-intensity domain. The decrease in WR during HRCLAMPED, in PRE vs. POST, was significantly correlated with the VO2peak decrease (R2=0.52; p=0.02). A greater amplitude of the slow component of the HR kinetics was observed during MOD following BR. Exercise at a fixed HR is not associated with a specific WR or WR domain; the problem, affecting exercise evaluation and prescription, is greater following BR. The WR decrease during HRCLAMPED is a biomarker of exercise intolerance following BR.
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Affiliation(s)
| | | | - Giorgio Manferdelli
- Institute of Biomedical Technologies, National Research Council, Segrate, Italy
| | | | - Mauro Marzorati
- Institute of Biomedical Technologies, National Research Council, Segrate, Italy
| | - Andrea Pilotto
- Department of Medicine, University of Udine, Udine, Italy.,Institute of Biomedical Technologies, National Research Council, Segrate, Italy
| | - Simone Porcelli
- Institute of Biomedical Technologies, National Research Council, Segrate, Italy.,Department of Molecular Medicine, University of Pavia, Italy
| | - Letizia Rasica
- Institute of Biomedical Technologies, National Research Council, Segrate, Italy
| | - Boštjan Šimunič
- Institute for Kinesiology Research, Science and Research Center, Koper, Slovenia
| | - Rado Pišot
- Institute for Kinesiology Research, Science and Research Center, Koper, Slovenia
| | - Marco Narici
- Department of Biomedical Sciences, University of Padova, Italy
| | - Bruno Grassi
- Department of Medicine, University of Udine, Udine, Italy
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19
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Zubac D, Ivančev V, Martin V, Dello Iacono A, Meulenberg CJ, McDonnell AC. Determination of exercise intensity domains during upright versus supine cycling: a methodological study. PeerJ 2022; 10:e13199. [PMID: 35437475 PMCID: PMC9013233 DOI: 10.7717/peerj.13199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/09/2022] [Indexed: 01/12/2023] Open
Abstract
Background There is a growing interest among the research community and clinical practitioners to investigate cardiopulmonary exercise test (CPET) procedures and protocols utilized in supine cycling. Materials and Methods The current study investigated the effects of posture on indicators of exercise intensity including gas exchange threshold (GET), respiratory compensation point (RCP), and the rate of peak oxygen uptake (V̇O2 peak), as well as the role of V̇O2 mean response time (MRT) in determining exercise intensity domains in nineteen healthy men (age: 22 ± 3 years). Two moderate-intensity step-transitions from 20 to 100 Watt (W) were completed, followed by a maximal CPET. After completing the ramp test, participants performed a constant-load at 90% of their attained peak power output (PPO). Results No differences were observed in the V̇O2 MRT between the two positions, although the phase II-time constant (τV̇O2p) was 7 s slower in supine position compared to upright (p = 0.001). The rate of O2 uptake in the supine position at GET and RCP were lower compared to the upright position (208 ± 200 mL·min-1 (p = 0.007) and 265 ± 235 mL·min-1 (p = 0.012) respectively). Besides, V̇O2 peak was significantly decreased (by 6%, p = 0.002) during supine position. These findings were confirmed by the wide limits of agreement between the measures of V̇O2 in different postures (V̇O2 peak: -341 to 859; constant-load test: -528 to 783; GET: -375 to 789; RCP: -520 to 1021 all in mL·min-1). Conclusion Since an accurate identification of an appropriate power output (PO) from a single-visit CPET remains a matter of debate, especially for supine cycling, we propose that moderate-intensity step-transitions preceding a ramp CPET could be a viable addition to ensure appropriate exercise-intensity domain determination, in particular upon GET-based prescription.
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Affiliation(s)
- Damir Zubac
- Kinesiology, University of Split, Split, Croatia,Institute for Kinesiology Research, Science and Research Center Koper, Koper, Slovenia
| | | | - Vincent Martin
- AME2P, Université d’Auvergne (Clermont-Ferrand I), Clermont-Ferrand, France,Institut Universitaire de France, Paris, France
| | - Antonio Dello Iacono
- Institute for Clinical Exercise and Health Science, School of Health and Life Sciences, University of the West of Scotland, Hamilton, United Kingdom
| | - Cécil J.W. Meulenberg
- Institute for Kinesiology Research, Science and Research Center Koper, Koper, Slovenia
| | - Adam C. McDonnell
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
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20
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Korzeniewski B. V˙O2 On-Kinetics-Critical Power Relationship: Correlation But Not Direct Causal Link. Exerc Sport Sci Rev 2022; 50:104. [PMID: 35275896 DOI: 10.1249/jes.0000000000000286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Goulding RP, Rossiter HB, Marwood S, Ferguson C. Response. Exerc Sport Sci Rev 2022; 50:105-106. [PMID: 35275897 PMCID: PMC9113404 DOI: 10.1249/jes.0000000000000285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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