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Lee G, Bae J, Jacobs JV, Lee S. Wearable heart rate sensing and critical power-based whole-body fatigue monitoring in the field. APPLIED ERGONOMICS 2024; 121:104358. [PMID: 39098207 DOI: 10.1016/j.apergo.2024.104358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 07/16/2024] [Accepted: 07/18/2024] [Indexed: 08/06/2024]
Abstract
Whole-body fatigue (WBF) presents a concerning risk to construction workers, which can impact function and ultimately lead to accidents and diminished productivity. This study proposes a new WBF monitoring technique by applying the Critical Power (CP) model, a bioenergetic model, with a wrist-worn heart rate sensor. The authors modified the CP model to calculate WBF from the percentage of heart rate reserve (%HRR) and generated a personalized model via WBF perception surveys. Data were collected for two days from 33 workers at four construction sites. The results showed that the proposed technique can monitor field workers' perceived WBF with a mean absolute error of 12.8% and Spearman correlation coefficient of 0.83. This study, therefore, demonstrates the viability of wearable WBF monitoring on construction sites to support programs aimed at improving workplace safety and productivity.
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Affiliation(s)
- Gaang Lee
- Hole School of Construction Engineering and Management, Dept. of Civil and Environmental Engineering, Univ. of Alberta, 9211-116 St., Donadeo Innovation Centre for Engineering, Edmonton, AB, T6G2H5, Canada.
| | - JuHyeon Bae
- Tishman Construction Management Program, Dept. of Civil and Environmental Engineering, Univ. of Michigan, 2350 Hayward St., G.G Brown Bldg., Ann Arbor, MI, 48109, USA.
| | - Jesse V Jacobs
- Risk Control Services, Liberty Mutual Insurance, 157 Berkeley St., Boston, MA, 02116, USA.
| | - SangHyun Lee
- Tishman Construction Management Program, Dept. of Civil and Environmental +Engineering, Univ. of Michigan, 2350 Hayward St., G.G Brown Bldg., Ann Arbor, MI, 48109, USA.
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Caen K, Poole DC, Vanhatalo A, Jones AM. Critical Power and Maximal Lactate Steady State in Cycling: "Watts" the Difference? Sports Med 2024; 54:2497-2513. [PMID: 39196486 DOI: 10.1007/s40279-024-02075-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2024] [Indexed: 08/29/2024]
Abstract
From a physiological perspective, the delineation between steady-state and non-steady-state exercise, also referred to as the maximal metabolic steady state, holds paramount importance for evaluating athletic performance and designing and monitoring training programs. The critical power and the maximal lactate steady state are two widely used indices to estimate this threshold, yet previous studies consistently reported significant discrepancies between their associated power outputs. These findings have fueled the debate regarding the interchangeability of critical power and the maximal lactate steady state in practice. This paper reviews the methodological intricacies intrinsic to the determination of these thresholds, and elucidates how inappropriate determination methods and methodological inconsistencies between studies have contributed to the documented differences in the literature. Through a critical examination of relevant literature and by integration of our laboratory data, we demonstrate that differences between critical power and the maximal lactate steady state may be reconciled to only a few Watts when applying appropriate and strict determination criteria, so that both indices may be used to estimate the maximal metabolic steady-state threshold in practice. To this end, we have defined a set of good practice guidelines to assist scientists and coaches in obtaining the most valid critical power and maximal lactate steady state estimates.
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Affiliation(s)
- Kevin Caen
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.
| | - David C Poole
- Departments of Kinesiology and Anatomy and Physiology, Kansas State University, Manhattan, KS, USA
| | - Anni Vanhatalo
- Department of Public Health and Sport Science, University of Exeter, Exeter, UK
| | - Andrew M Jones
- Department of Public Health and Sport Science, University of Exeter, Exeter, UK
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Lievens M, Ghijs M, Bourgois JG, Vermeire KM, Bourgois G, Colosio AL, Boone J, Caen K. Characterizing the Exponential Profile of W' Recovery Following Partial Depletion. Med Sci Sports Exerc 2024; 56:1770-1781. [PMID: 38767992 DOI: 10.1249/mss.0000000000003468] [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: 05/22/2024]
Abstract
PURPOSE The aim of this study was to characterize W' recovery kinetics in response to a partial W' depletion. We hypothesized that W' recovery following a partial depletion would be better described by a biexponential than by a monoexponential model. METHODS Nine healthy men performed a ramp incremental exercise test, three to five constant load trials to determine critical power and W', and 10 experimental trials to quantify W' depletion. Each experimental trial consisted of two constant load work bouts (WB1 and WB2) interspersed by a recovery interval. WB1 was designed to evoke a 25% or 75% W' depletion (DEP 25% and DEP 75% ). Subsequently, participants recovered for 30, 60, 120, 300, or 600 s and then performed WB2 to exhaustion to calculate the observed W' recovery (W' OBS ). W' OBS data were fitted using monoexponential and biexponential models, both with a variable and with a fixed model amplitude. Root mean square error and Akaike information criterion (AIC c ) were calculated to evaluate the models' goodness-of-fit. RESULTS The biexponential model fits were associated with overall lower root mean square error values (0.4% to 5.0%) when compared with the monoexponential models (2.9% to 8.0%). However, ΔAIC c resulted in negative values (-15.5 and -23.3) for the model fits where the amplitude was kept free, thereby favoring the use of a monoexponential model for both depletion conditions. For the model fits where the amplitude was fixed at 100%, ΔAIC c was negative for DEP 25% (-15.0) but positive for DEP 75% (11.2). W' OBS values were strongly correlated between both depletion conditions ( r = 0.92) and positively associated with V̇O 2peak , critical power, and gas exchange threshold ( r = 0.67 to 0.77). CONCLUSIONS The present study results did not provide evidence in favor of a biexponential modeling technique to characterize W' recovery following a partial depletion. Moreover, we demonstrated that fixed time constants were insufficient to model W' recovery across different depletion levels, and that W' recovery was positively associated with aerobic fitness. These findings underline the importance of employing variable and individualized time constants in future predictive W' models.
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Affiliation(s)
| | - Michael Ghijs
- Department of Movement and Sports Sciences, Ghent University, Ghent, BELGIUM
| | | | | | - Gil Bourgois
- Department of Movement and Sports Sciences, Ghent University, Ghent, BELGIUM
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Borrelli M, Shokohyar S, Rampichini S, Bruseghini P, Doria C, Limonta EG, Ferretti G, Esposito F. Energetics of sinusoidal exercise below and across critical power and the effects of fatigue. Eur J Appl Physiol 2024; 124:1845-1859. [PMID: 38242972 PMCID: PMC11130025 DOI: 10.1007/s00421-023-05410-1] [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: 09/27/2023] [Accepted: 12/23/2023] [Indexed: 01/21/2024]
Abstract
PURPOSE Previous studies investigating sinusoidal exercise were not devoted to an analysis of its energetics and of the effects of fatigue. We aimed to determine the contribution of aerobic and anaerobic lactic metabolism to the energy balance and investigate the fatigue effects on the cardiorespiratory and metabolic responses to sinusoidal protocols, across and below critical power (CP). METHODS Eight males (26.6 ± 6.2 years; 75.6 ± 8.7 kg; maximum oxygen uptake 52.8 ± 7.9 ml·min-1·kg-1; CP 218 ± 13 W) underwent exhausting sinusoidal cycloergometric exercises, with sinusoid midpoint (MP) at CP (CPex) and 50 W below CP (CP-50ex). Sinusoid amplitude (AMP) and period were 50 W and 4 min, respectively. MP, AMP, and time-delay (tD) between mechanical and metabolic signals of expiratory ventilation (V ˙ E ), oxygen uptake (V ˙ O 2 ), and heart rate ( f H ) were assessed sinusoid-by-sinusoid. Blood lactate ([La-]) and rate of perceived exertion (RPE) were determined at each sinusoid. RESULTS V ˙ O 2 AMP was 304 ± 11 and 488 ± 36 ml·min-1 in CPex and CP-50ex, respectively. Asymmetries between rising and declining sinusoid phases occurred in CPex (36.1 ± 7.7 vs. 41.4 ± 9.7 s forV ˙ O 2 tD up and tD down, respectively; P < 0.01), with unchanged tDs.V ˙ O 2 MP and RPE increased progressively during CPex. [La-] increased by 2.1 mM in CPex but remained stable during CP-50ex. Anaerobic contribution was larger in CPex than CP-50ex. CONCLUSION The lower aerobic component during CPex than CP-50ex associated with lactate accumulation explained lowerV ˙ O 2 AMP in CPex. The asymmetries in CPex suggest progressive decline of muscle phosphocreatine concentration, leading to fatigue, as witnessed by RPE.
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Affiliation(s)
- Marta Borrelli
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via Giuseppe Colombo 71, 20133, Milan, Italy
| | - Sheida Shokohyar
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via Giuseppe Colombo 71, 20133, Milan, Italy
| | - Susanna Rampichini
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via Giuseppe Colombo 71, 20133, Milan, Italy.
| | - Paolo Bruseghini
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Christian Doria
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via Giuseppe Colombo 71, 20133, Milan, Italy
| | - Eloisa Guglielmina Limonta
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via Giuseppe Colombo 71, 20133, Milan, Italy
- IRCCS Ospedale Galeazzi - Sant'Ambrogio, Via Cristina Belgioioso, 173, 20157, Milan, Italy
| | - Guido Ferretti
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Fabio Esposito
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Via Giuseppe Colombo 71, 20133, Milan, Italy
- IRCCS Ospedale Galeazzi - Sant'Ambrogio, Via Cristina Belgioioso, 173, 20157, Milan, Italy
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Peden DL, Rogers R, Mitchell EA, Taylor SM, Bailey SJ, Ferguson RA. Skeletal muscle mitochondrial correlates of critical power and W' in healthy active individuals. Exp Physiol 2024. [PMID: 38593224 DOI: 10.1113/ep091835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 03/25/2024] [Indexed: 04/11/2024]
Abstract
The asymptote (critical power; CP) and curvature constant (W') of the hyperbolic power-duration relationship can predict performance within the severe-intensity exercise domain. However, the extent to which these parameters relate to skeletal muscle mitochondrial content and respiratory function is not known. Fifteen males (peak O2 uptake, 52.2 ± 8.7 mL kg-1 min-1; peak work rate, 366 ± 40 W; and gas exchange threshold, 162 ± 41 W) performed three to five constant-load tests to task failure for the determination of CP (246 ± 44 W) and W' (18.6 ± 4.1 kJ). Skeletal muscle biopsies were obtained from the vastus lateralis to determine citrate synthase (CS) activity, as a marker of mitochondrial content, and the ADP-stimulated respiration (P) and maximal electron transfer (E) through mitochondrial complexes (C) I-IV. The CP was positively correlated with CS activity (absolute CP, r = 0.881, P < 0.001; relative CP, r = 0.751, P = 0.001). The W' was not correlated with CS activity (P > 0.05). Relative CP was positively correlated with mass-corrected CI + IIE (r = 0.659, P = 0.038), with absolute CP being inversely correlated with CS activity-corrected CIVE (r = -0.701, P = 0.024). Relative W' was positively correlated with CS activity-corrected CI + IIP (r = 0.713, P = 0.021) and the phosphorylation control ratio (r = 0.661, P = 0.038). There were no further correlations between CP or W' and mitochondrial respiratory variables. These findings support the assertion that skeletal muscle mitochondrial oxidative capacity is positively associated with CP and that this relationship is strongly determined by mitochondrial content.
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Affiliation(s)
- Donald L Peden
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Robert Rogers
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Emma A Mitchell
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Suzanne M Taylor
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Stephen J Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Richard A Ferguson
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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Dos Santos DFC, Wanner SP, de Paula RF, Zanetti GO, de Oliveira DCX, Orsatti FL, Teixeira-Coelho F. Acute alcohol ingestion decreases the work done above the end-test power during a 3-min all-out cycling exercise. Alcohol Alcohol 2024; 59:agae017. [PMID: 38529709 DOI: 10.1093/alcalc/agae017] [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: 01/20/2023] [Revised: 02/19/2024] [Accepted: 03/10/2024] [Indexed: 03/27/2024] Open
Abstract
INTRODUCTION Alcohol ingestion influences metabolism during a subsequent exercise session, as evidenced by increased blood lactate concentration during fixed-intensity exercise. Therefore, augmented blood concentrations of alcohol may interfere with the anaerobic metabolism during high-intensity, short-duration exercise bout, thereby leading to impaired athletic performance. OBJECTIVE This study investigated whether the acute ingestion of alcohol as ethanol modulates performance parameters derived from the power-duration relationship in a 3-min all-out cycling test that allows for identifying the power output related to heavy and severe exercise intensities. METHODS Twenty-four recreationally active cyclists (16 men and 8 women) ingested a beverage containing either 0.4 g ethanol.kg-1 body mass (EtOH) or a placebo (PLA) solution. Thirty minutes following ingestion, they completed a 3-min all-out test to measure power output and determine the end-test power (EP) and the work done above EP (WEP). RESULTS Alcohol ingestion decreased WEP by 16% (EtOH: 5.6 ± 2.5 kJ vs. PLA: 6.7 ± 2.4 kJ; P = .003) but did not change EP (EtOH: 211 ± 44 W vs. PLA: 212 ± 44 W; P = .671). The alcohol-mediated effect in WEP was not influenced when controlling for participants' sex or accuracy in identifying the beverage ingested. CONCLUSION Our data indicate that alcohol ingestion impaired the anaerobic work capacity, as evidenced by the reduction in WEP during the 3-min all-out test. Moreover, the ability to exercise at an intensity above the heavy domain may be decreased after ingestion of a moderate alcohol dose.
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Affiliation(s)
| | - Samuel Penna Wanner
- Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, MG, Brazil
| | - Rodolfo Ferreira de Paula
- Department of Sport Sciences, Health Science Institute, Universidade Federal do Triângulo Mineiro, Uberaba, 38025-440, MG, Brazil
| | - Gustavo Oliveira Zanetti
- Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901, MG, Brazil
| | | | - Fabio Lera Orsatti
- Department of Sport Sciences, Health Science Institute, Universidade Federal do Triângulo Mineiro, Uberaba, 38025-440, MG, Brazil
| | - Francisco Teixeira-Coelho
- Department of Sport Sciences, Health Science Institute, Universidade Federal do Triângulo Mineiro, Uberaba, 38025-440, MG, Brazil
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Le Hyaric A, Aftalion A, Hanley B. Modelling the optimization of world-class 400 m and 1,500 m running performances using high-resolution data. Front Sports Act Living 2024; 6:1293145. [PMID: 38504690 PMCID: PMC10948471 DOI: 10.3389/fspor.2024.1293145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 02/02/2024] [Indexed: 03/21/2024] Open
Abstract
The 400 m and 1,500 m are track events that rely on different but important contributions from both the aerobic and anaerobic energy systems. The purpose of this study is to model men's and women's 400 m and 1,500 m championship performances to gain a deeper understanding of the key mechanical and physiological factors affecting running speed and bend running using high-resolution data from live competition (10 Hz). To investigate World-class athletes' instantaneous speeds, propulsive forces and aerobic and anaerobic energy, we model and simulate the performances of the men's and women's European Athletics 400 m champions, Matthew Hudson-Smith and Femke Bol, as well as the men's European Athletics 1,500 m champion, Jakob Ingebrigtsen, and the women's European Athletics U23 1,500 m champion, Gaia Sabbatini. The simulations show that a fast start is essential in both the 400 m and 1,500 m because of the need for fast oxygen kinetics, with peak running speeds occurring within the first ∼50 m in both events. Subsequently, 400 m athletes slow continually from this maximum speed to the finish, and a total anaerobic contribution of ∼77% is found for both male and female champions. The key to faster 400 m racing is to reduce the decrease in velocity: this comes from both a high VO2 and a high anaerobic contribution. Ingebrigtsen's winning tactic in the European 1,500 m final is to adopt a very fast cruising pace from 300 m onwards that is possible because he is able to maintain a high VO2 value until the end of the race and has a large anaerobic contribution. He has fast VO2 kinetics that does not require as fast a start as his opponents, but then he speeds up in the last two laps, without a fast sprint finish. The comparison between Sabbatini's slower and quicker races (∼8 s difference) shows that it is the improvement of aerobic metabolism that has the greatest effect on 1,500 m performance. Coaches should note in particular that the all-out pacing nature of the 400 m requires the prioritization of anaerobic energy system development, and those who coach the 1,500 m should note the differing energy contributions between even-paced races and championship racing.
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Affiliation(s)
- Antoine Le Hyaric
- Laboratoire Jacques-Louis Lions (LJLL), CNRS, Inria, Sorbonne Université, Université de Paris, Paris, France
| | - Amandine Aftalion
- Centre D’Analyse et de Mathématique Sociales, CNRS UMR-8557, Ecole des Hautes Etudes en Sciences Sociales, Paris, France
| | - Brian Hanley
- Carnegie School of Sport, Leeds Beckett University, Leeds, United Kingdom
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Boillet A, Messonnier LA, Cohen C. Individualized physiology-based digital twin model for sports performance prediction: a reinterpretation of the Margaria-Morton model. Sci Rep 2024; 14:5470. [PMID: 38443504 PMCID: PMC10915161 DOI: 10.1038/s41598-024-56042-0] [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: 01/11/2024] [Accepted: 03/01/2024] [Indexed: 03/07/2024] Open
Abstract
Performance in many racing sports depends on the ability of the athletes to produce and maintain the highest possible work i.e., the highest power for the duration of the race. To model this energy production in an individualized way, an adaptation and a reinterpretation (including a physiological meaning of parameters) of the three-component Margaria-Morton model were performed. The model is applied to the muscles involved in a given task. The introduction of physiological meanings was possible thanks to the measurement of physiological characteristics for a given athlete. A method for creating a digital twin was therefore proposed and applied for national-level cyclists. The twins thus created were validated by comparison with field performance, experimental observations, and literature data. Simulations of record times and 3-minute all-out tests were consistent with experimental data. Considering the literature, the model provided good estimates of the time course of muscle metabolite concentrations (e.g., lactate and phosphocreatine). It also simulated the behavior of oxygen kinetics at exercise onset and during recovery. This methodology has a wide range of applications, including prediction and optimization of the performance of individually modeled athletes.
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Affiliation(s)
- Alice Boillet
- LadHyX, UMR 7646 du CNRS, Ecole polytechnique, 91120, Palaiseau, France.
| | - Laurent A Messonnier
- Université Savoie Mont Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, 73000, Chambéry, France
- Institut universitaire de France (IUF), 75231, Paris, France
| | - Caroline Cohen
- LadHyX, UMR 7646 du CNRS, Ecole polytechnique, 91120, Palaiseau, France
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Luciano F, Minetti AE, Pavei G. Metabolic cost and mechanical work of walking in a virtual reality emulator. Eur J Appl Physiol 2024; 124:783-792. [PMID: 37776345 PMCID: PMC10879236 DOI: 10.1007/s00421-023-05306-0] [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: 04/21/2023] [Accepted: 08/31/2023] [Indexed: 10/02/2023]
Abstract
PURPOSE The purpose of this study was to investigate the metabolic cost (C), mechanical work, and kinematics of walking on a multidirectional treadmill designed for locomotion in virtual reality. METHODS Ten participants (5 females, body mass 67.2 ± 8.1 kg, height 1.71 ± 0.07 m, age 23.6 ± 1.9 years, mean ± SD) walked on a Virtuix Omni multidirectional treadmill at four imposed stride frequencies: 0.70, 0.85, 1.00, and 1.15 Hz. A portable metabolic system measured oxygen uptake, enabling calculation of C and the metabolic equivalent of task (MET). Gait kinematics and external, internal, and total mechanical work (WTOT) were calculated by an optoelectronic system. Efficiency was calculated either as WTOT/C or by summing WTOT to the work against sliding frictions. Results were compared with normal walking, running, and skipping. RESULTS C was higher for walking on the multidirectional treadmill than for normal walking, running, and skipping, and decreased with speed (best-fit equation: C = 20.2-27.5·speed + 15.8·speed2); the average MET was 4.6 ± 1.4. Mechanical work was higher at lower speeds, but similar to that of normal walking at higher speeds, with lower pendular energy recovery and efficiency; differences in efficiency were explained by the additional work against sliding frictions. At paired speeds, participants showed a more forward-leaned trunk and higher ankle dorsiflexion, stride frequency, and duty factor than normal walking. CONCLUSION Walking on a multidirectional treadmill requires a higher metabolic cost and different mechanical work and kinematics than normal walking. This raises questions on its use for gait rehabilitation but highlights its potential for high-intensity exercise and physical activity promotion.
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Affiliation(s)
- Francesco Luciano
- Locomotion Physiomechanics Laboratory, Department of Pathophysiology and Transplantation - Division of Physiology, University of Milan, Via Mangiagalli 32, 20133, Milan, Italy.
| | - Alberto E Minetti
- Locomotion Physiomechanics Laboratory, Department of Pathophysiology and Transplantation - Division of Physiology, University of Milan, Via Mangiagalli 32, 20133, Milan, Italy
| | - Gaspare Pavei
- Locomotion Physiomechanics Laboratory, Department of Pathophysiology and Transplantation - Division of Physiology, University of Milan, Via Mangiagalli 32, 20133, Milan, Italy
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Bowen M, Samozino P, Vonderscher M, Dutykh D, Morel B. Mathematical modeling of exercise fatigability in the severe domain: A unifying integrative framework in isokinetic condition. J Theor Biol 2024; 578:111696. [PMID: 38070705 DOI: 10.1016/j.jtbi.2023.111696] [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: 04/17/2023] [Revised: 11/15/2023] [Accepted: 12/04/2023] [Indexed: 12/22/2023]
Abstract
Muscle fatigue is the decay in the ability of muscles to generate force, and results from neural and metabolic perturbations. This article presents an integrative mathematical model that describes the decrease in maximal force capacity (i.e. fatigue) over exercises performed at intensities above the critical force Fc (i.e. severe domain). The model unifies the previous Critical Power Model and All-Out Model and can be applied to any exercise described by a changing force F over time. The assumptions of the model are (i) isokinetic conditions, an intensity domain of Fc
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Affiliation(s)
- M Bowen
- Laboratoire Interuniversitaire de Biologie de la Motricité LIBM, EA 7424, Savoie Mont Blanc University, F-7300, Chambéry, France.
| | - P Samozino
- Laboratoire Interuniversitaire de Biologie de la Motricité LIBM, EA 7424, Savoie Mont Blanc University, F-7300, Chambéry, France
| | - M Vonderscher
- Laboratoire Interuniversitaire de Biologie de la Motricité LIBM, EA 7424, Savoie Mont Blanc University, F-7300, Chambéry, France
| | - D Dutykh
- Mathematics Department, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates; Causal Dynamics Pty Ltd, WA 6009, Perth, Australia
| | - B Morel
- Laboratoire Interuniversitaire de Biologie de la Motricité LIBM, EA 7424, Savoie Mont Blanc University, F-7300, Chambéry, France
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Bourgois G, Mucci P, Boone J, Colosio AL, Bourgois JG, Pogliaghi S, Caen K. Critical power, W' and W' reconstitution in women and men. Eur J Appl Physiol 2023; 123:2791-2801. [PMID: 37369796 DOI: 10.1007/s00421-023-05268-3] [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: 03/01/2023] [Accepted: 06/20/2023] [Indexed: 06/29/2023]
Abstract
PURPOSE The aim of this study was to compare critical power (CP) and work capacity W', and W' reconstitution (W'REC) following repeated maximal exercise between women and men. METHODS Twelve women ([Formula: see text]O2PEAK: 2.53 ± 0.37 L·min-1) and 12 men ([Formula: see text]O2PEAK: 4.26 ± 0.30 L·min-1) performed a minimum of 3 constant workload tests, to determine CP and W', and 1 maximal exercise repetition test with three work bouts (WB) to failure, to quantify W'REC during 2 recovery periods, i.e., W'REC1 and W'REC2. An independent samples t test was used to compare CP and W' values between women and men, and a repeated-measures ANOVA was used to compare W'REC as fraction of W' expended during the first WB, absolute W'REC, and normalized to lean body mass (LBM). RESULTS CP normalized to LBM was not different between women and men, respectively, 3.7 ± 0.5 vs. 4.1 ± 0.4 W·kgLBM-1, while W' normalized to LBM was lower in women 256 ± 29 vs. 305 ± 45 J·kgLBM-1. Fractional W'REC1 was higher in women than in men, respectively, 74.0 ± 12.0% vs. 56.8 ± 9.5%. Women reconstituted less W' than men in absolute terms (8.7 ± 1.2 vs. 10.9 ± 2.0 kJ) during W'REC1, while normalized to LBM no difference was observed between women and men (174 ± 23 vs. 167 ± 31 J·kgLBM-1). W'REC2 was lower than W'REC1 both in women and men. CONCLUSION Sex differences in W'REC (absolute women < men; fractional women > men) are eliminated when LBM is accounted for. Prediction models of W'REC might benefit from including LBM as a biological variable in the equation. This study confirms the occurrence of a slowing of W'REC during repeated maximal exercise.
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Affiliation(s)
- Gil Bourgois
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium
- Univ. Lille, Univ. Artois, Univ. Littoral Côte d'Opale, ULR 7369-URePSSS-Unité de Recherche Pluridisciplinaire Sport Santé Société, 59000, Lille, France
| | - Patrick Mucci
- Univ. Lille, Univ. Artois, Univ. Littoral Côte d'Opale, ULR 7369-URePSSS-Unité de Recherche Pluridisciplinaire Sport Santé Société, 59000, Lille, France
| | - Jan Boone
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium.
- Center of Sports Medicine, Ghent University Hospital, Ghent, Belgium.
| | - Alessandro L Colosio
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium
| | - Jan G Bourgois
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium
- Center of Sports Medicine, Ghent University Hospital, Ghent, Belgium
| | - Silvia Pogliaghi
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Kevin Caen
- Department of Movement and Sports Sciences, Ghent University, Watersportlaan 2, 9000, Ghent, Belgium
- Center of Sports Medicine, Ghent University Hospital, Ghent, Belgium
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12
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Crawford DA, Heinrich KM, Haddock CK, Poston WSC, Day RS, Kaipust C, Skola B, Wakeman AJ, Kunkel E, Bell A, Wilhite E, Young N, Whitley A, Fritts M. A Single, Multimodal Exercise Tolerance Test Can Assess Combat Readiness in Army-ROTC Cadets: A Brief Report. J Funct Morphol Kinesiol 2023; 8:152. [PMID: 37987488 PMCID: PMC10660721 DOI: 10.3390/jfmk8040152] [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: 09/15/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/22/2023] Open
Abstract
The Army Combat Fitness Test (ACFT) is a multi-event assessment battery designed to determine the combat readiness of U.S. Army personnel. However, for Reserve Officers' Training Corps (ROTC) programs the logistical demands of collegiate life make repeated administration of the ACFT challenging. The present study sought to design and evaluate a single, multimodal exercise tolerance test (METT) capable of serving as a time-efficient proxy measure of combat readiness. METHODS Using a formal instrument design process, we constructed the METT to mimic the demands of the ACFT and assessed its reliability, validity, and responsiveness. RESULTS The METT demonstrates minimal measurement error (i.e., a 2% coefficient of variation), concurrent validity with the ACFT (R2 = 0.327, F = 10.67, p < 0.001), the ability to classify cadets who may be at-risk for failing the ACFT (X2 = 8.16, p = 0.017, sensitivity = 0.878, specificity = 0.667), and appropriate change following a training intervention (5.69 ± 8.9%). CONCLUSIONS The METT has the potential to provide a means to monitor progress, identify areas for improvement, and guide informed decision-making regarding individualization of cadet combat training plans.
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Affiliation(s)
- Derek A. Crawford
- Department of Nutrition, Kinesiology, and Health, University of Central Missouri, Warrensburg, MO 64093, USA; (B.S.); (A.J.W.); (E.K.); (A.B.); (E.W.); (N.Y.); (A.W.); (M.F.)
- NDRI-USA, New York, NY 10001, USA; (C.K.H.); (W.S.C.P.); (R.S.D.); (C.K.)
| | - Katie M. Heinrich
- NDRI-USA, New York, NY 10001, USA; (C.K.H.); (W.S.C.P.); (R.S.D.); (C.K.)
- Department of Kinesiology, Kansas State University, Manhattan, KS 66506, USA
| | | | | | - R. Sue Day
- NDRI-USA, New York, NY 10001, USA; (C.K.H.); (W.S.C.P.); (R.S.D.); (C.K.)
| | | | - Blake Skola
- Department of Nutrition, Kinesiology, and Health, University of Central Missouri, Warrensburg, MO 64093, USA; (B.S.); (A.J.W.); (E.K.); (A.B.); (E.W.); (N.Y.); (A.W.); (M.F.)
- NDRI-USA, New York, NY 10001, USA; (C.K.H.); (W.S.C.P.); (R.S.D.); (C.K.)
| | - Amanda J. Wakeman
- Department of Nutrition, Kinesiology, and Health, University of Central Missouri, Warrensburg, MO 64093, USA; (B.S.); (A.J.W.); (E.K.); (A.B.); (E.W.); (N.Y.); (A.W.); (M.F.)
| | - Eric Kunkel
- Department of Nutrition, Kinesiology, and Health, University of Central Missouri, Warrensburg, MO 64093, USA; (B.S.); (A.J.W.); (E.K.); (A.B.); (E.W.); (N.Y.); (A.W.); (M.F.)
| | - Addison Bell
- Department of Nutrition, Kinesiology, and Health, University of Central Missouri, Warrensburg, MO 64093, USA; (B.S.); (A.J.W.); (E.K.); (A.B.); (E.W.); (N.Y.); (A.W.); (M.F.)
| | - Emily Wilhite
- Department of Nutrition, Kinesiology, and Health, University of Central Missouri, Warrensburg, MO 64093, USA; (B.S.); (A.J.W.); (E.K.); (A.B.); (E.W.); (N.Y.); (A.W.); (M.F.)
| | - Nathanial Young
- Department of Nutrition, Kinesiology, and Health, University of Central Missouri, Warrensburg, MO 64093, USA; (B.S.); (A.J.W.); (E.K.); (A.B.); (E.W.); (N.Y.); (A.W.); (M.F.)
| | - Allison Whitley
- Department of Nutrition, Kinesiology, and Health, University of Central Missouri, Warrensburg, MO 64093, USA; (B.S.); (A.J.W.); (E.K.); (A.B.); (E.W.); (N.Y.); (A.W.); (M.F.)
| | - Madelyn Fritts
- Department of Nutrition, Kinesiology, and Health, University of Central Missouri, Warrensburg, MO 64093, USA; (B.S.); (A.J.W.); (E.K.); (A.B.); (E.W.); (N.Y.); (A.W.); (M.F.)
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Orsi JB, Araujo LS, Scariot PPM, Polisel EEC, Cardoso LO, Gobatto CA, Manchado-Gobatto FB. Critical Velocity, Maximal Lactate Steady State, and Muscle MCT1 and MCT4 after Exhaustive Running in Mice. Int J Mol Sci 2023; 24:15753. [PMID: 37958736 PMCID: PMC10648804 DOI: 10.3390/ijms242115753] [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: 08/22/2023] [Revised: 09/30/2023] [Accepted: 10/12/2023] [Indexed: 11/15/2023] Open
Abstract
Although the critical velocity (CV) protocol has been used to determine the aerobic capacity in rodents, there is a lack of studies that compare CV with maximal lactate steady state intensity (iMLSS) in mice. As a consequence, their physiological and molecular responses after exercise until exhaustion at CV intensity remain unclear. Thus, we aimed to compare and correlate CV with iMLSS in running mice, following different mathematical models for CV estimation. We also evaluated their physiological responses and muscle MCT1 and MCT4 after running until exhaustion at CV. Thirty C57BL/6J mice were divided into two groups (exercised-E and control-C). Group E was submitted to a CV protocol (4 days), using linear (lin1 and lin2) and hyperbolic (hyp) mathematical models to determine the distance, velocity, and time to exhaustion (tlim) of each predictive CV trial, followed by an MLSS protocol. After a running effort until exhaustion at CV intensity, the mice were immediately euthanized, while group C was euthanized at rest. No differences were observed between iMLSS (21.1 ± 1.1 m.min-1) and CV estimated by lin1 (21.0 ± 0.9 m.min-1, p = 0.415), lin2 (21.3 ± 0.9 m.min-1, p = 0.209), and hyp (20.6 ± 0.9 m.min-1, p = 0.914). According to the results, CV was significantly correlated with iMLSS. After running until exhaustion at CV (tlim = 28.4 ± 8,29 min), group E showed lower concentrations of hepatic and gluteal glycogen than group C, but no difference in the content of MCT1 (p = 0.933) and MCT4 (p = 0.123) in soleus muscle. Significant correlations were not found between MCT1 and MCT4 and tlim at CV intensity. Our results reinforce that CV is a valid and non-invasive protocol to estimate the maximal aerobic capacity in mice and that the content of MCT1 and MCT4 was not decisive in determining the tlim at CV, at least when measured immediately after the running effort.
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Affiliation(s)
- Juan B Orsi
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Pedro Zaccaria Street, 1.300, Jardim Santa Luíza, Limeira 13484-350, São Paulo, Brazil
| | - Lara S Araujo
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Pedro Zaccaria Street, 1.300, Jardim Santa Luíza, Limeira 13484-350, São Paulo, Brazil
| | - Pedro P M Scariot
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Pedro Zaccaria Street, 1.300, Jardim Santa Luíza, Limeira 13484-350, São Paulo, Brazil
| | - Emanuel E C Polisel
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Pedro Zaccaria Street, 1.300, Jardim Santa Luíza, Limeira 13484-350, São Paulo, Brazil
| | - Luisa O Cardoso
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Pedro Zaccaria Street, 1.300, Jardim Santa Luíza, Limeira 13484-350, São Paulo, Brazil
| | - Claudio A Gobatto
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Pedro Zaccaria Street, 1.300, Jardim Santa Luíza, Limeira 13484-350, São Paulo, Brazil
| | - Fúlvia B Manchado-Gobatto
- Laboratory of Applied Sport Physiology, School of Applied Sciences, University of Campinas, Pedro Zaccaria Street, 1.300, Jardim Santa Luíza, Limeira 13484-350, São Paulo, Brazil
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14
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Ruiz-Alias SA, Ñancupil-Andrade AA, Pérez-Castilla A, García-Pinillos F. Can we predict long-duration running power output? A matter of selecting the appropriate predicting trials and empirical model. Eur J Appl Physiol 2023; 123:2283-2294. [PMID: 37272943 DOI: 10.1007/s00421-023-05243-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 05/26/2023] [Indexed: 06/06/2023]
Abstract
When facing a long-distance race, athletes and practitioners could develop an efficient pacing strategy and training paces if an accurate performance estimate of the target distance is achieved. Therefore, this study aims to determine the validity of different empirical models (i.e. critical power [CP], Power law and Peronnet) to predict long-duration power output (i.e. 60 min) when using two or three time trial configurations. In a 5-week training period, fifteen highly trained athletes performed nine-time trials (i.e. 1, 2, 3, 4, 5, 10, 20, 30, and 60 min) in a randomized order. Their power-duration curves were defined through the work-time (CPwork), power-1/time (CP1/time), two-parameter hyperbolic (CP2hyp), three-parameter hyperbolic (CP3hyp) CP models using different two- and three-time trial configurations. The undisclosed proprietary CP models of the Stryd (CPstryd) and Golden Cheetah training software (CPcheetah) were also computed as well as the non-asymptotic Power law and Peronnet models. These were extrapolated to the 60-min power output and compared to the actual performance. The shortest valid configuration (95% confidence interval < 12 W) for CPwork and CP1/time was 3-30 min (Bias: 8.3 [4.9 to 11.7] W), for CPstryd was 10-30 min (Bias: 4.2 [- 1.0 to 9.4] W), for CP2hyp, CP3hyp and CPcheetah was 3-5-30 min (Bias < 5.7 W), for Power law was 1-3-10 min (- 1.0 [- 11.9 to 9.9] W), and for Peronnet was 4-20 min (- 3.0 [- 10.2 to 4.3] W). All the empirical models provided valid estimates when the two or three predicting trial configurations selected attended each model fitting needs.
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Affiliation(s)
- Santiago A Ruiz-Alias
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Carretera de Alfacar 21, 18011, Granada, Spain.
- Sport and Health University Research Center (iMUDS), University of Granada, C/. Menéndez Pelayo 32, 18016, Granada, Spain.
| | - Alberto A Ñancupil-Andrade
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Carretera de Alfacar 21, 18011, Granada, Spain
- Sport and Health University Research Center (iMUDS), University of Granada, C/. Menéndez Pelayo 32, 18016, Granada, Spain
- Department of Health, Los Lagos University, Puerto Montt, Chile
| | - Alejandro Pérez-Castilla
- Department of Education, Faculty of Education Sciences, University of Almería, Almería, Spain
- SPORT Research Group (CTS-1024), CERNEP Research Center, University of Almería, Almería, Spain
| | - Felipe García-Pinillos
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Carretera de Alfacar 21, 18011, Granada, Spain
- Sport and Health University Research Center (iMUDS), University of Granada, C/. Menéndez Pelayo 32, 18016, Granada, Spain
- Department of Physical Education, Sports and Recreation, Universidad de La Frontera, Temuco, Chile
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15
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TILLER NICHOLASB, PORSZASZ JANOS, CASABURI RICHARD, ROSSITER HARRYB, FERGUSON CARRIE. Critical Power and Respiratory Compensation Point Are Not Equivalent in Patients with COPD. Med Sci Sports Exerc 2023; 55:1097-1104. [PMID: 36633582 PMCID: PMC10184810 DOI: 10.1249/mss.0000000000003124] [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] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Several studies report that pulmonary oxygen uptake (V̇O 2 ) at the respiratory compensation point (RCP) is equivalent to the V̇O 2 at critical power (CP), suggesting that the variables can be used interchangeably to demarcate the threshold between heavy and severe intensity domains. However, if RCP is a valid surrogate for CP, their values should correspond even when assessed in patients with chronic obstructive pulmonary disease (COPD) in whom the "normal" mechanisms linking CP and RCP are impeded. The aim of this study was to compare V̇O 2 at CP with V̇O 2 at RCP in patients with COPD. METHODS Twenty-two COPD patients (14 male/8 female; forced expiratory volume in 1 s, 46% ± 17% pred) performed ramp-incremental cycle ergometry to intolerance (5-10 W·min -1 ) for the determination of gas exchange threshold (GET) and RCP. CP was calculated from the asymptote of the hyperbolic power-duration relationship from 3-5 constant-power exercise tests to intolerance. CP was validated with a 20-min constant-power ride. RESULTS GET was identified in 20 of 22 patients at a V̇O 2 of 0.93 ± 0.18 L·min -1 (75% ± 13% V̇O 2peak ), whereas RCP was identified in just 3 of 22 patients at a V̇O 2 of 1.40 ± 0.39 L·min -1 (85% ± 2% V̇O 2peak ). All patients completed constant-power trials with no difference in peak physiological responses relative to ramp-incremental exercise ( P > 0.05). CP was 46 ± 22 W, which elicited a V̇O 2 of 1.04 ± 0.29 L·min -1 (90% ± 9% V̇O 2peak ) during the validation ride. The difference in V̇O 2 at 15 and 20 min of the validation ride was 0.00 ± 0.04 L, which was not different from a hypothesized mean of 0 ( P = 0.856), thereby indicating a V̇O 2 steady state. CONCLUSIONS In COPD patients, who present with cardiopulmonary and/or respiratory-mechanical dysfunction, CP can be determined in the absence of RCP. Accordingly, CP and RCP are not equivalent in this group.
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Cook C, Chen G, Hager WW, Lenhart S. Optimally controlling nutrition and propulsion force in a long distance running race. Front Nutr 2023; 10:1096194. [PMID: 37275649 PMCID: PMC10233029 DOI: 10.3389/fnut.2023.1096194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/18/2023] [Indexed: 06/07/2023] Open
Abstract
Introduction Runners competing in races are looking to optimize their performance. In this paper, a runner's performance in a race, such as a marathon, is formulated as an optimal control problem where the controls are: the nutrition intake throughout the race and the propulsion force of the runner. As nutrition is an integral part of successfully running long distance races, it needs to be included in models of running strategies. Methods We formulate a system of ordinary differential equations to represent the velocity, fat energy, glycogen energy, and nutrition for a runner competing in a long-distance race. The energy compartments represent the energy sources available in the runner's body. We allocate the energy source from which the runner draws, based on how fast the runner is moving. The food consumed during the race is a source term for the nutrition differential equation. With our model, we are investigating strategies to manage the nutrition and propulsion force in order to minimize the running time in a fixed distance race. This requires the solution of a nontrivial singular control problem. Results As the goal of an optimal control model is to determine the optimal strategy, comparing our results against real data presents a challenge; however, in comparing our results to the world record for the marathon, our results differed by 0.4%, 31 seconds. Per each additional gel consumed, the runner is able to run 0.5 to 0.7 kilometers further in the same amount of time, resulting in a 7.75% increase in taking five 100 calorie gels vs no nutrition. Discussion Our results confirm the belief that the most effective way to run a race is to run approximately the same pace the entire race without letting one's energies hit zero, by consuming in-race nutrition. While this model does not take all factors into account, we consider it a building block for future models, considering our novel energy representation, and in-race nutrition.
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Affiliation(s)
- Cameron Cook
- Research Triangle Institute (RTI) Health Solutions, Research Triangle Park, NC, United States
| | - Guoxun Chen
- Department of Nutrition, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - William W Hager
- Department of Mathematics, University of Florida, Gainsville, FL, United States
| | - Suzanne Lenhart
- Department of Mathematics, University of Tennessee, Knoxville, Knoxville, TN, United States
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Vinetti G, Pollastri L, Lanfranconi F, Bruseghini P, Taboni A, Ferretti G. Modeling the Power-Duration Relationship in Professional Cyclists During the Giro d'Italia. J Strength Cond Res 2023; 37:866-871. [PMID: 36026464 DOI: 10.1519/jsc.0000000000004350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 06/12/2022] [Indexed: 11/08/2022]
Abstract
ABSTRACT Vinetti, G, Pollastri, L, Lanfranconi, F, Bruseghini, P, Taboni, A, and Ferretti, G. Modeling the power-duration relationship in professional cyclists during the Giro d'Italia. J Strength Cond Res 37(4): 866-871, 2023-Multistage road bicycle races allow the assessment of maximal mean power output (MMP) over a wide spectrum of durations. By modeling the resulting power-duration relationship, the critical power ( CP ) and the curvature constant ( W' ) can be calculated and, in the 3-parameter (3-p) model, also the maximal instantaneous power ( P0 ). Our aim is to test the 3-p model for the first time in this context and to compare it with the 2-parameter (2-p) model. A team of 9 male professional cyclists participated in the 2014 Giro d'Italia with a crank-based power meter. The maximal mean power output between 10 seconds and 10 minutes were fitted with 3-p, whereas those between 1 and 10 minutes with the 2- model. The level of significance was set at p < 0.05. 3-p yielded CP 357 ± 29 W, W' 13.3 ± 4.2 kJ, and P0 1,330 ± 251 W with a SEE of 10 ± 5 W, 3.0 ± 1.7 kJ, and 507 ± 528 W, respectively. 2-p yielded a CP and W' slightly higher (+4 ± 2 W) and lower (-2.3 ± 1.1 kJ), respectively ( p < 0.001 for both). Model predictions were within ±10 W of the 20-minute MMP of time-trial stages. In conclusion, during a single multistage racing event, the 3-p model accurately described the power-duration relationship over a wider MMP range without physiologically relevant differences in CP with respect to 2-p, potentially offering a noninvasive tool to evaluate competitive cyclists at the peak of training.
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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
| | - Luca Pollastri
- Pentavis, Laboratory of Sport Sciences, Lecco, Italy
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy; and
| | | | - Paolo Bruseghini
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Anna Taboni
- Department of Anesthesiology, Pharmacology, Intensive Care and Emergencies, University of Geneva, Geneva, Switzerland
| | - Guido Ferretti
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
- Department of Anesthesiology, Pharmacology, Intensive Care and Emergencies, University of Geneva, Geneva, Switzerland
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Chorley A, Lamb KL. Effect of varying recovery intensities on power outputs during severe intensity intervals in trained cyclists during the Covid-19 pandemic. SPORT SCIENCES FOR HEALTH 2023; 19:1-9. [PMID: 36820074 PMCID: PMC9933020 DOI: 10.1007/s11332-023-01050-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/31/2023] [Indexed: 02/18/2023]
Abstract
Purpose The study aimed to investigate the effects of different recovery intensities on the power outputs of repeated severe intensity intervals and the implications for W' reconstitution in trained cyclists. Methods Eighteen trained cyclists (FTP 258.0 ± 42.7 W; weekly training 8.6 ± 1.7 h∙week-1) familiar with interval training, use of the Zwift® platform throughout the Covid-19 pandemic, and previously established FTP (95% of mean power output from a 20-min test), performed 5 × 3-min severe intensity efforts interspersed with 2-min recoveries. Recovery intensities were: 50 W (LOW), 50% of functional threshold power (MOD), and self-selected power output (SELF). Results Whilst power outputs declined as the session progressed, mean power outputs during the severe intervals across the conditions were not different to each other (LOW 300.1 ± 48.1 W; MOD: 296.9 ± 50.4 W; SELF: 298.8 ± 53.3 W) despite the different recovery conditions. Mean power outputs of the self-selected recovery periods were 121.7 ± 26.2 W. However, intensity varied during the self-selected recovery periods, with values in the last 15 s being greater than the first 15 s (p < 0.001) and decreasing throughout the session (128.7 ± 25.4 W to 113.9 ± 29.3 W). Conclusion Reducing recovery intensities below 50% of FTP failed to enhance subsequent severe intensity intervals, suggesting that a lower limit for optimal W' reconstitution had been reached. As self-selected recoveries were seen to adapt to maintain the severe intensity power output as the session progressed, adopting such a strategy might be preferential for interval training sessions.
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Affiliation(s)
- Alan Chorley
- Department of Sport and Exercise Sciences, University of Chester, Chester, CH1 4BJ UK
| | - Kevin L. Lamb
- Department of Sport and Exercise Sciences, University of Chester, Chester, CH1 4BJ UK
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19
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Black MI, Skiba PF, Wylie LJ, Lewis J, Jones AM, Vanhatalo A. Accounting for Dynamic Changes in the Power-Duration Relationship Improves the Accuracy of W' Balance Modeling. Med Sci Sports Exerc 2023; 55:235-244. [PMID: 36094337 DOI: 10.1249/mss.0000000000003039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
PURPOSE This study aimed 1) to examine the accuracy with which W' reconstitution (W' REC ) is estimated by the W' balance (W' BAL ) models after a 3-min all-out cycling test (3MT), 2) to determine the effects of a 3MT on the power-duration relationship, and 3) to assess whether accounting for changes in the power-duration relationship during exercise improved estimates of W' REC . METHODS The power-duration relationship and the actual and estimated W' REC were determined for 12 data sets extracted from our laboratory database where participants had completed two 3MT separated by 1-min recovery (i.e., control [C-3MT] and fatigued [F-3MT]). RESULTS Actual W' REC (6.3 ± 1.4 kJ) was significantly overestimated by the W' BAL·ODE (9.8 ± 1.3 kJ; P < 0.001) and the W' BAL·MORTON (16.9 ± 2.6 kJ; P < 0.001) models but was not significantly different to the estimate provided by the W' BAL·INT (7.5 ± 1.5 kJ; P > 0.05) model. End power (EP) was 7% lower in the F-3MT (263 ± 40 W) compared with the C-3MT (282 ± 44 W; P < 0.001), and work done above EP (WEP) was 61% lower in the F-3MT (6.3 ± 1.4 kJ) compared with the C-3MT (16.9 ± 3.2 kJ). The size of the error in the estimated W' REC was correlated with the reduction in WEP for the W' BAL·INT and W' BAL·ODE models (both r > -0.74, P < 0.01) but not the W' BAL·MORTON model ( r = -0.18, P > 0.05). Accounting for the changes in the power-duration relationship improved the accuracy of the W' BAL·ODE and W' BAL·MORTON , but they remained significantly different to actual W' REC . CONCLUSIONS These findings demonstrate that the power-duration relationship is altered after a 3MT, and accounting for these changes improves the accuracy of the W' BAL·ODE and the W' BAL·MORTON , but not W' BAL·INT models. These results have important implications for the design and use of mathematical models describing the energetics of exercise performance.
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Affiliation(s)
- Matthew I Black
- School of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UNITED KINGDOM
| | | | - Lee J Wylie
- School of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UNITED KINGDOM
| | - James Lewis
- School of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UNITED KINGDOM
| | - Andrew M Jones
- School of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UNITED KINGDOM
| | - Anni Vanhatalo
- School of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UNITED KINGDOM
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20
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Andersson EP, Bachl P, Schmuttermair A, Staunton CA, Stöggl TL. Anaerobic work capacity in cycling: the effect of computational method. Eur J Appl Physiol 2022; 122:2637-2650. [DOI: 10.1007/s00421-022-05038-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 09/06/2022] [Indexed: 11/30/2022]
Abstract
Abstract
Purpose
To compare the anaerobic work capacity (AnWC, i.e., attributable anaerobic mechanical work) assessed using four different approaches/models applied to time-trial (TT) cycle-ergometry exercise.
Methods
Fifteen male cyclists completed a 7 × 4-min submaximal protocol and a 3-min all-out TT (TTAO). Linear relationships between power output (PO) and submaximal metabolic rate were constructed to estimate TT-specific gross efficiency (GE) and AnWC, using either a measured resting metabolic rate as a Y-intercept (7 + YLIN) or no measured Y-intercept (7-YLIN). In addition, GE of the last submaximal bout (GELAST) was used to estimate AnWC, and critical power (CP) from TTAO (CP3´AO) was used to estimate mechanical work above CP (W’, i.e., “AnWC”).
Results
Average PO during TTAO was 5.43 ± 0.30 and CP was 4.48 ± 0.23 W∙kg−1. The TT-associated GE values were ~ 22.0% for both 7 + YLIN and 7-YLIN and ~ 21.1% for GELAST (both P < 0.001). The AnWC were 269 ± 60, 272 ± 55, 299 ± 61, and 196 ± 52 J∙kg−1 for the 7 + YLIN, 7-YLIN, GELAST, and CP3´AO models, respectively (7 + YLIN and 7-YLIN versus GELAST, both P < 0.001; 7 + YLIN, 7-YLIN, and GELAST versus CP3´AO, all P < 0.01). For the three pair-wise comparisons between 7 + YLIN, 7-YLIN, and GELAST, typical errors in AnWC values ranged from 7 to 11 J∙kg−1, whereas 7 + YLIN, 7-YLIN, and GELAST versus CP3´AO revealed typical errors of 55–59 J∙kg−1.
Conclusion
These findings demonstrate a substantial disagreement in AnWC between CP3´AO and the other models. The 7 + YLIN and 7-YLIN generated 10% lower AnWC values than the GELAST model, whereas 7 + YLIN and 7-YLIN generated similar values of AnWC.
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21
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Hastings MH, Herrera JJ, Guseh JS, Atlason B, Houstis NE, Abdul Kadir A, Li H, Sheffield C, Singh AP, Roh JD, Day SM, Rosenzweig A. Animal Models of Exercise From Rodents to Pythons. Circ Res 2022; 130:1994-2014. [PMID: 35679366 PMCID: PMC9202075 DOI: 10.1161/circresaha.122.320247] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Acute and chronic animal models of exercise are commonly used in research. Acute exercise testing is used, often in combination with genetic, pharmacological, or other manipulations, to study the impact of these manipulations on the cardiovascular response to exercise and to detect impairments or improvements in cardiovascular function that may not be evident at rest. Chronic exercise conditioning models are used to study the cardiac phenotypic response to regular exercise training and as a platform for discovery of novel pathways mediating cardiovascular benefits conferred by exercise conditioning that could be exploited therapeutically. The cardiovascular benefits of exercise are well established, and, frequently, molecular manipulations that mimic the pathway changes induced by exercise recapitulate at least some of its benefits. This review discusses approaches for assessing cardiovascular function during an acute exercise challenge in rodents, as well as practical and conceptual considerations in the use of common rodent exercise conditioning models. The case for studying feeding in the Burmese python as a model for exercise-like physiological adaptation is also explored.
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Affiliation(s)
- Margaret H Hastings
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Jonathan J Herrera
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor (J.J.H.)
| | - J Sawalla Guseh
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Bjarni Atlason
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Nicholas E Houstis
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Azrul Abdul Kadir
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Haobo Li
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Cedric Sheffield
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Anand P Singh
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Jason D Roh
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
| | - Sharlene M Day
- Cardiovascular Medicine, Perelman School of Medicine' University of Pennsylvania, Philadelphia (S.M.D.)
| | - Anthony Rosenzweig
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Corrigan Minehan Heart Center, Massachusetts General Hospital, Harvard Medical School, Boston (M.H.H., J.S.G., B.A., N.E.H., A.A.K., H.L., C.S., A.P.S., J.D.R., A.R.)
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22
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Abstract
The elegant concept of a hyperbolic relationship between power, velocity, or torque and time to exhaustion has rightfully captivated the imagination and inspired extensive research for over half a century. Theoretically, the relationship's asymptote along the time axis (critical power, velocity, or torque) indicates the exercise intensity that could be maintained for extended durations, or the "heavy-severe exercise boundary". Much more than a critical mass of the extensive accumulated evidence, however, has persistently shown the determined intensity of critical power and its variants as being too high to maintain for extended periods. The extensive scientific research devoted to the topic has almost exclusively centered around its relationships with various endurance parameters and performances, as well as the identification of procedural problems and how to mitigate them. The prevalent underlying premise has been that the observed discrepancies are mainly due to experimental 'noise' and procedural inconsistencies. Consequently, little or no effort has been directed at other perspectives such as trying to elucidate physiological reasons that possibly underly and account for those discrepancies. This review, therefore, will attempt to offer a new such perspective and point out the discrepancies' likely root causes.
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Affiliation(s)
- Raffy Dotan
- Kinesiology Department, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada.
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23
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Lamberti N, Piva G, Businaro F, Caruso L, Crepaldi A, Lòpez-Soto PJ, Manfredini F. A Fitness-Fatigue Model of Performance in Peripheral Artery Disease: Predicted and Measured Effects of a Pain-Free Exercise Program. J Pers Med 2022; 12:jpm12030397. [PMID: 35330397 PMCID: PMC8949585 DOI: 10.3390/jpm12030397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/25/2022] [Accepted: 03/03/2022] [Indexed: 02/04/2023] Open
Abstract
Banister impulse-response (IR) model estimates the performance in response to the training impulses (TRIMPs). In 100 patients with peripheral artery disease (PAD), we tested by an IR model the predictability of the effects of a 6-month structured home-based exercise program. The daily TRIMPs obtained from prescribed walking speed, relative intensity and time of exercise determined the fitness-fatigue components of performance. The estimated performance values, calculated from the baseline 6-min and pain-free walking distance (6MWD and PFWD, respectively) were compared with values measured at visits through regression models. Interval pain-free walking at controlled speed prescribed during circa-monthly hospital visits (5 ± 1) was safely performed at home with good adherence (92% of scheduled sessions, 144 ± 25 km walked in 50 ± 8 training hours). The mean TRIMP rose throughout the program from 276 to 601 a.u. The measured 6MWD and PFWD values increased (+33 m and +121 m, respectively) showing a good fit with those estimated by the IR model (6MWD: R2 0.81; PFWD: R2 0.68) and very good correspondence (correlation coefficients: 0.91 to 0.95), without sex differences. The decay of performance without training was estimated at 18 ± 3 weeks. In PAD, an IR model predicted the walking performance following a pain-free exercise program. IR models may contribute to design and verify personalized training programs.
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Affiliation(s)
- Nicola Lamberti
- Department of Neuroscience and Rehabilitation, University of Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy; (N.L.); (F.B.); (A.C.)
| | - Giovanni Piva
- PhD Program in Environmental Sustainability and Wellbeing, Department of Humanistic Studies, University of Ferrara, 44121 Ferrara, Italy;
| | - Federico Businaro
- Department of Neuroscience and Rehabilitation, University of Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy; (N.L.); (F.B.); (A.C.)
| | - Lorenzo Caruso
- Department of Environmental Sciences and Prevention, University of Ferrara, 44121 Ferrara, Italy;
| | - Anna Crepaldi
- Department of Neuroscience and Rehabilitation, University of Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy; (N.L.); (F.B.); (A.C.)
- Department of Nursing, Instituto Maimónides de Investigación Biomédica de Córdoba, 14005 Córdoba, Spain;
| | - Pablo Jesùs Lòpez-Soto
- Department of Nursing, Instituto Maimónides de Investigación Biomédica de Córdoba, 14005 Córdoba, Spain;
- Department of Nursing, Universidad de Córdoba, 14004 Córdoba, Spain
| | - Fabio Manfredini
- Department of Neuroscience and Rehabilitation, University of Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy; (N.L.); (F.B.); (A.C.)
- Department of Rehabilitation Medicine, University Hospital of Ferrara, 44124 Ferrara, Italy
- Correspondence: ; Tel.: +39-053-2236-187
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24
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Saif A, Khan Z, Parveen A. Critical power as a fatigue threshold in sports: A scoping review. Sci Sports 2022. [DOI: 10.1016/j.scispo.2021.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Spineli H, Acioli J, Pinto MP, Learsi S, Bastos-Silva VJ, Araujo GGD. Caffeine intake improves muscular endurance and induces depletion of anaerobic work capacity in the bench press. MOTRIZ: REVISTA DE EDUCACAO FISICA 2022. [DOI: 10.1590/s1980-657420220014921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Higor Spineli
- Universidade Federal de Alagoas, Brazil; Universidade Federal de Alagoas, Brazil; Estácio-FAL, Brazil
| | | | - Maryssa P. Pinto
- Universidade Federal de Alagoas, Brazil; Universidade Federal de Alagoas, Brazil
| | | | | | - Gustavo G. de Araujo
- Universidade Federal de Alagoas, Brazil; Universidade Federal de Alagoas, Brazil; Universidade Federal de Alagoas, Brazil
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26
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The W' Balance Model: Mathematical and Methodological Considerations. Int J Sports Physiol Perform 2021; 16:1561-1572. [PMID: 34686611 DOI: 10.1123/ijspp.2021-0205] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/15/2021] [Accepted: 07/21/2021] [Indexed: 11/18/2022]
Abstract
Since its publication in 2012, the W' balance model has become an important tool in the scientific armamentarium for understanding and predicting human physiology and performance during high-intensity intermittent exercise. Indeed, publications featuring the model are accumulating, and it has been adapted for popular use both in desktop computer software and on wrist-worn devices. Despite the model's intuitive appeal, it has achieved mixed results thus far, in part due to a lack of clarity in its basis and calculation. Purpose: This review examines the theoretical basis, assumptions, calculation methods, and the strengths and limitations of the integral and differential forms of the W' balance model. In particular, the authors emphasize that the formulations are based on distinct assumptions about the depletion and reconstitution of W' during intermittent exercise; understanding the distinctions between the 2 forms will enable practitioners to correctly implement the models and interpret their results. The authors then discuss foundational issues affecting the validity and utility of the model, followed by evaluating potential modifications and suggesting avenues for further research. Conclusions: The W' balance model has served as a valuable conceptual and computational tool. Improved versions may better predict performance and further advance the physiology of high-intensity intermittent exercise.
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27
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Gorostiaga EM, Sánchez-Medina L, Garcia-Tabar I. Over 55 years of critical power: Fact or artifact? Scand J Med Sci Sports 2021; 32:116-124. [PMID: 34618981 DOI: 10.1111/sms.14074] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/16/2021] [Accepted: 10/04/2021] [Indexed: 11/27/2022]
Abstract
This report aims to generate an evidence-based debate of the Critical Power (CP), or its analogous Critical Speed (CS), concept. Race times of top Spanish runners were utilized to calculate CS based on three (1500-m to 5000-m; CS1.5-5km ) and four (1500-m to 10000-m; CS1.5-10km ) distance performances. Male running world records from 1000 to 5000-m (CS1-5km ), 1000 to 10,000-m (CS1-10km ), 1000-m to half marathon (CS1km-half marathon ), and 1000-m to marathon (CS1km-marathon ) distance races were also utilized for CS calculations. CS1.5-5km (19.62 km h-1 ) and CS1.5-10km (18.68 km h-1 ) were different (p < 0.01), but both approached the average race speed of the longest distance chosen in the model, and were remarkably homogeneous among subjects (97% ±1% and 98% ±1%, respectively). Similar results were obtained using the world records. CS values progressively declined, until reaching a CS1km-marathon value of 20.77 km h-1 (10% lower than CS1-5km ). Each CS value approached the average speed of the longest distance chosen in the model (96.4%-99.8%). A power function better fitted the speed-time relationship compared with the standardized hyperbolic function. However, the horizontal asymptote of a power function is zero. This better approaches the classical definition of CP: the power output that can be maintained almost indefinitely without exhaustion. Beyond any sophisticated mathematical calculation, CS corresponds to 95%-99% of the average speed of the longest distance chosen as an exercise trial. CP could be considered a mathematical artifact rather than an important endurance performance marker. In such a case, the consideration of CP as a physiological "gold-standard" should be reevaluated.
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Affiliation(s)
- Esteban M Gorostiaga
- Studies, Research and Sports Medicine Centre (CEIMD), Government of Navarre, Pamplona, Spain
| | - Luis Sánchez-Medina
- Studies, Research and Sports Medicine Centre (CEIMD), Government of Navarre, Pamplona, Spain
| | - Ibai Garcia-Tabar
- Society, Sports and Physical Exercise Research Group (GIKAFIT), Department of Physical Education and Sport, Faculty of Education and Sport, University of the Basque Country (UPV/EHU), Vitoria-Gasteiz, Spain.,Biobara, GIKAFIT, Vitoria-Gasteiz, Basque Country, Spain
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28
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Lidar J, Andersson EP, Sundström D. Validity and Reliability of Hydraulic-Analogy Bioenergetic Models in Sprint Roller Skiing. Front Physiol 2021; 12:726414. [PMID: 34588997 PMCID: PMC8473922 DOI: 10.3389/fphys.2021.726414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/16/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: To develop a method for individual parameter estimation of four hydraulic-analogy bioenergetic models and to assess the validity and reliability of these models' prediction of aerobic and anaerobic metabolic utilization during sprint roller-skiing. Methods: Eleven elite cross-country skiers performed two treadmill roller-skiing time trials on a course consisting of three flat sections interspersed by two uphill sections. Aerobic and anaerobic metabolic rate contributions, external power output, and gross efficiency were determined. Two versions each (fixed or free maximal aerobic metabolic rate) of a two-tank hydraulic-analogy bioenergetic model (2TM-fixed and 2TM-free) and a more complex three-tank model (3TM-fixed and 3TM-free) were programmed into MATLAB. The aerobic metabolic rate (MR ae ) and the accumulated anaerobic energy expenditure (E an,acc ) from the first time trial (STT1) together with a gray-box model in MATLAB, were used to estimate the bioenergetic model parameters. Validity was assessed by simulation of each bioenergetic model using the estimated parameters from STT1 and the total metabolic rate (MR tot ) in the second time trial (STT2). Results: The validity and reliability of the parameter estimation method based on STT1 revealed valid and reliable overall results for all the four models vs. measurement data with the 2TM-free model being the most valid. Mean differences in model-vs.-measured MR ae ranged between -0.005 and 0.016 kW with typical errors between 0.002 and 0.009 kW. Mean differences in E an,acc at STT termination ranged between -4.3 and 0.5 kJ and typical errors were between 0.6 and 2.1 kJ. The root mean square error (RMSE) for 2TM-free on the instantaneous STT1 data was 0.05 kW for MR ae and 0.61 kJ for E an,acc , which was lower than the other three models (all P < 0.05). Compared to the results in STT1, the validity and reliability of each individually adapted bioenergetic model was worse during STT2 with models underpredicting MR ae and overpredicting E an,acc vs. measurement data (all P < 0.05). Moreover, the 2TM-free had the lowest RMSEs during STT2. Conclusion: The 2TM-free provided the highest validity and reliability in MR ae and E an,acc for both the parameter estimation in STT1 and the model validity and reliability evaluation in the succeeding STT2.
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Affiliation(s)
- Julius Lidar
- Department of Quality Management and Mechanical Engineering, Sports Tech Research Centre, Mid Sweden University, Östersund, Sweden
| | - Erik P Andersson
- Department of Health Sciences, Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden.,Faculty of Health Sciences, School of Sport Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - David Sundström
- Department of Quality Management and Mechanical Engineering, Sports Tech Research Centre, Mid Sweden University, Östersund, Sweden
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29
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Apte S, Prigent G, Stöggl T, Martínez A, Snyder C, Gremeaux-Bader V, Aminian K. Biomechanical Response of the Lower Extremity to Running-Induced Acute Fatigue: A Systematic Review. Front Physiol 2021; 12:646042. [PMID: 34512370 PMCID: PMC8430259 DOI: 10.3389/fphys.2021.646042] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 06/22/2021] [Indexed: 12/02/2022] Open
Abstract
Objective: To investigate (i) typical protocols used in research on biomechanical response to running-induced fatigue, (ii) the effect of sport-induced acute fatigue on the biomechanics of running and functional tests, and (iii) the consistency of analyzed parameter trends across different protocols. Methods: Scopus, Web of Science, Pubmed, and IEEE databases were searched using terms identified with the Population, Interest and Context (PiCo) framework. Studies were screened following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and appraised using the methodological index for non-randomized studies MINORS scale. Only experimental studies with at least 10 participants, which evaluated fatigue during and immediately after the fatiguing run were included. Each study was summarized to record information about the protocol and parameter trends. Summary trends were computed for each parameter based on the results found in individual studies. Results: Of the 68 included studies, most were based on in-lab (77.9%) protocols, endpoint measurements (75%), stationary measurement systems (76.5%), and treadmill environment (54.4%) for running. From the 42 parameters identified in response to acute fatigue, flight time, contact time, knee flexion angle at initial contact, trunk flexion angle, peak tibial acceleration, CoP velocity during balance test showed an increasing behavior and cadence, vertical stiffness, knee extension force during MVC, maximum vertical ground reaction forces, and CMJ height showed a decreasing trend across different fatigue protocols. Conclusion: This review presents evidence that running-induced acute fatigue influences almost all the included biomechanical parameters, with crucial influence from the exercise intensity and the testing environment. Results indicate an important gap in literature caused by the lack of field studies with continuous measurement during outdoor running activities. To address this gap, we propose recommendations for the use of wearable inertial sensors.
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Affiliation(s)
- Salil Apte
- Laboratory of Movement Analysis and Measurement, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Gäelle Prigent
- Laboratory of Movement Analysis and Measurement, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Thomas Stöggl
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
| | - Aaron Martínez
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
| | - Cory Snyder
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
| | - Vincent Gremeaux-Bader
- Institute of Sport Sciences, University of Lausanne,Lausanne, Switzerland.,Swiss Olympic Medical Center, Sport Medicine Unit, Division of Physical Medicine and Rehabilitation, Lausanne University Hospital, Lausanne, Switzerland
| | - Kamiar Aminian
- Laboratory of Movement Analysis and Measurement, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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30
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Ferguson H, Harnish C, Chase G. Reply to: Comment on: "Using Field Based Data to Model Sprint Track Cycling Performance". SPORTS MEDICINE - OPEN 2021; 7:61. [PMID: 34423390 PMCID: PMC8380603 DOI: 10.1186/s40798-021-00351-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Hamish Ferguson
- Centre for Bioengineering, Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand.
| | - Chris Harnish
- Department of Exercise Science, College of Health, Mary Baldwin University, Staunton, VA, USA
| | - Geoff Chase
- Centre for Bioengineering, Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
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31
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Sandford GN, Laursen PB, Buchheit M. Anaerobic Speed/Power Reserve and Sport Performance: Scientific Basis, Current Applications and Future Directions. Sports Med 2021; 51:2017-2028. [PMID: 34398445 DOI: 10.1007/s40279-021-01523-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2021] [Indexed: 10/20/2022]
Abstract
Many individual and team sport events require extended periods of exercise above the speed or power associated with maximal oxygen uptake (i.e., maximal aerobic speed/power, MAS/MAP). In the absence of valid and reliable measures of anaerobic metabolism, the anaerobic speed/power reserve (ASR/APR) concept, defined as the difference between an athlete's MAS/MAP and their maximal sprinting speed (MSS)/peak power (MPP), advances our understanding of athlete tolerance to high speed/power efforts in this range. When exercising at speeds above MAS/MAP, what likely matters most, irrespective of athlete profile or locomotor mode, is the proportion of the ASR/APR used, rather than the more commonly used reference to percent MAS/MAP. The locomotor construct of ASR/APR offers numerous underexplored opportunities. In particular, how differences in underlying athlete profiles (e.g., fiber typology) impact the training response for different 'speed', 'endurance' or 'hybrid' profiles is now emerging. Such an individualized approach to athlete training may be necessary to avoid 'maladaptive' or 'non-responses'. As a starting point for coaches and practitioners, we recommend upfront locomotor profiling to guide training content at both the macro (understanding athlete profile variability and training model selection, e.g., annual periodization) and micro levels (weekly daily planning of individual workouts, e.g., short vs long intervals vs repeated sprint training and recovery time between workouts). More specifically, we argue that high-intensity interval training formats should be tailored to the locomotor profile accordingly. New focus and appreciation for the ASR/APR is required to individualize training appropriately so as to maximize athlete preparation for elite competition.
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Affiliation(s)
- Gareth N Sandford
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada. .,Canadian Sport Institute-Pacific, 4371 Interurban Road, Victoria, BC, V9E 2C5, Canada. .,Athletics Canada, Ottawa, ON, Canada.
| | - Paul B Laursen
- Sports Performance Research Institute NZ, Auckland University of Technology, Auckland, New Zealand.,HIIT Science, Revelstoke, BC, Canada
| | - Martin Buchheit
- HIIT Science, Revelstoke, BC, Canada.,Research Department, Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, France.,Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.,Kitman Labs, Performance Research Intelligence Initiative, Dublin, Ireland
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32
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Abdalla LHP, Broxterman RM, Barstow TJ, Greco CC, Denadai BS. W' reconstitution rate at different intensities above critical torque: the role of muscle size and maximal strength. Exp Physiol 2021; 106:1909-1921. [PMID: 34288192 DOI: 10.1113/ep089638] [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: 04/06/2021] [Accepted: 07/16/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Do muscle size, maximal force and exercise intensity influence the recovery time constant for the finite impulse above critical torque (τIET' )? What is the main finding and its importance? Muscle size and maximal strength have different influences on the parameters of the hyperbolic torque-time to task failure relationship. Greater muscle size and maximal strength, as well as exercise at an intensity of 60% MVC, prolong τIET' during intermittent isometric exercise. ABSTRACT Muscle perfusion and O2 delivery limitations through muscle force generation appear to play a major role in defining the hyperbolic torque-time to task failure (Tlim ) relationship. Therefore, we aimed to determine the influence of muscle size and maximal strength on the recovery time constant for the finite impulse above critical torque (τIET' ). Ten men participated in the study and performed intermittent isometric tests until task-failure (Tlim ) for the knee-extensors (KE) (35% and 60% maximal voluntary contraction (MVC)) and plantar flexors (PF) (60% MVC). The τIET' was determined for each of these Tlim tests using the IET'BAL model. The IET' (9738 ± 3080 vs. 2959 ± 1289 N m s) and end-test torque (ET)(84.5 ± 7.1 vs. 74.3 ± 12.7 N m) were significantly lower for PF compared to KE (P < 0.05). Exercise tolerance (Tlim ) was significantly longer for PF (239 ± 81 s) than KE (150 ± 55 s) at 60% MVC, and significantly longer for KE at 35% MVC (641 ± 158 s) than 60% MVC. The τIET' was significantly faster at 35% MVC (641 ± 177 s) than 60% MVC (1840 ± 354 s) for KE, both of which were significantly slower than PF at 60% MVC (317 ± 102 s). This study showed that τIET' during intermittent isometric exercise is slower with greater muscle size and maximal strength.
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Affiliation(s)
| | - Ryan Michael Broxterman
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education and Clinical Center, VA Medical Center, Salt Lake City, UT, USA
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Maximal muscular power: lessons from sprint cycling. SPORTS MEDICINE-OPEN 2021; 7:48. [PMID: 34268627 PMCID: PMC8282832 DOI: 10.1186/s40798-021-00341-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/29/2021] [Indexed: 02/07/2023]
Abstract
Maximal muscular power production is of fundamental importance to human functional capacity and feats of performance. Here, we present a synthesis of literature pertaining to physiological systems that limit maximal muscular power during cyclic actions characteristic of locomotor behaviours, and how they adapt to training. Maximal, cyclic muscular power is known to be the main determinant of sprint cycling performance, and therefore we present this synthesis in the context of sprint cycling. Cyclical power is interactively constrained by force-velocity properties (i.e. maximum force and maximum shortening velocity), activation-relaxation kinetics and muscle coordination across the continuum of cycle frequencies, with the relative influence of each factor being frequency dependent. Muscle cross-sectional area and fibre composition appear to be the most prominent properties influencing maximal muscular power and the power-frequency relationship. Due to the role of muscle fibre composition in determining maximum shortening velocity and activation-relaxation kinetics, it remains unclear how improvable these properties are with training. Increases in maximal muscular power may therefore arise primarily from improvements in maximum force production and neuromuscular coordination via appropriate training. Because maximal efforts may need to be sustained for ~15-60 s within sprint cycling competition, the ability to attenuate fatigue-related power loss is also critical to performance. Within this context, the fatigued state is characterised by impairments in force-velocity properties and activation-relaxation kinetics. A suppression and leftward shift of the power-frequency relationship is subsequently observed. It is not clear if rates of power loss can be improved with training, even in the presence adaptations associated with fatigue-resistance. Increasing maximum power may be most efficacious for improving sustained power during brief maximal efforts, although the inclusion of sprint interval training likely remains beneficial. Therefore, evidence from sprint cycling indicates that brief maximal muscular power production under cyclical conditions can be readily improved via appropriate training, with direct implications for sprint cycling as well as other athletic and health-related pursuits.
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Figueiredo DH, Figueiredo DH, Manoel FDA, Machado FA. Peak Running Velocity or Critical Speed Under Field Conditions: Which Best Predicts 5-km Running Performance in Recreational Runners? Front Physiol 2021; 12:680790. [PMID: 34295260 PMCID: PMC8291129 DOI: 10.3389/fphys.2021.680790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/26/2021] [Indexed: 12/05/2022] Open
Abstract
This study aimed to examine which variable, between the peak running velocity determined on the track field (Vpeak_TF) and critical speed (CS), is the best predictor of the 5-km running performance in recreational runners. Twenty-five males performed three tests to determine the Vpeak_TF, CS, and 5-km running performance on the track field, with a minimal interval of 48 h between each test. The Vpeak_TF protocol started with a velocity of 8 km⋅h–1, followed by an increase of 1 km⋅h–1 every 3 min until volitional exhaustion, which was controlled by sound signals, with cones at every 25 m indicating when the participants were required to pass the cone’s position to maintain the required velocity. The participants performed three time trials (TTs) (1: 2,600 m; 2: 1,800 m; and 3: 1,000 m) on the same day, with a 30-min rest period to determine the CS through the combinations of three (CS1,2,3) and two TTs (CS1,2, CS1,3, and CS2,3). The 5-km running performance time was recorded to determine the test duration, and the mean velocity (MV) was calculated. There was a significant difference observed between the Vpeak_TF and the MV 5-km running performance. However, no differences were found between the CS values and the MV 5-km running performance. A correlation was observed between the Vpeak_TF (R = −0.90), CS1,2,3 (R = −0.95), CS1,3 (R = −0.95), and the 5-km running performance time. Linear regression indicated that the Vpeak_TF (R2 = 0.82), CS1,2,3 (R2 = 0.90), and CS1,3 (R2 = 0.90) significantly predicted the 5-km running performance time. The CS results showed a higher predictive power for the 5-km running performance, slightly better than the Vpeak_TF. Also, CS1,2,3 and the CS1,3 presented the highest predictive power for the 5-km running performance of recreational runners.
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Affiliation(s)
- Diogo Hilgemberg Figueiredo
- Associate Post-graduate Program in Physical Education, Department of Physical Education, State University of Maringá, Maringá, Brazil
| | - Diego Hilgemberg Figueiredo
- Associate Post-graduate Program in Physical Education, Department of Physical Education, State University of Maringá, Maringá, Brazil
| | | | - Fabiana Andrade Machado
- Associate Post-graduate Program in Physical Education, Department of Physical Education, State University of Maringá, Maringá, Brazil.,Department of Physical Education, State University of Maringá, Maringá, Brazil.,Post-graduate Program of Physiological Sciences, Department of Physiological Sciences, State University of Maringá, Maringá, Brazil
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Patoz A, Spicher R, Pedrani N, Malatesta D, Borrani F. Critical speed estimated by statistically appropriate fitting procedures. Eur J Appl Physiol 2021; 121:2027-2038. [PMID: 33811559 PMCID: PMC8192409 DOI: 10.1007/s00421-021-04675-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/28/2021] [Indexed: 01/13/2023]
Abstract
PURPOSE Intensity domains are recommended when prescribing exercise. The distinction between heavy and severe domains is made by the critical speed (CS), therefore requiring a mathematically accurate estimation of CS. The different model variants (distance versus time, running speed versus time, time versus running speed, and distance versus running speed) are mathematically equivalent. Nevertheless, error minimization along the correct axis is important to estimate CS and the distance that can be run above CS (d'). We hypothesized that comparing statistically appropriate fitting procedures, which minimize the error along the axis corresponding to the properly identified dependent variable, should provide similar estimations of CS and d' but that different estimations should be obtained when comparing statistically appropriate and inappropriate fitting procedure. METHODS Sixteen male runners performed a maximal incremental aerobic test and four exhaustive runs at 90, 100, 110, and 120% of their peak speed on a treadmill. Several fitting procedures (a combination of a two-parameter model variant and regression analysis: weighted least square) were used to estimate CS and d'. RESULTS Systematic biases (P < 0.001) were observed between each pair of fitting procedures for CS and d', even when comparing two statistically appropriate fitting procedures, though negligible, thus corroborating the hypothesis. CONCLUSION The differences suggest that a statistically appropriate fitting procedure should be chosen beforehand by the researcher. This is also important for coaches that need to prescribe training sessions to their athletes based on exercise intensity, and their choice should be maintained over the running seasons.
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Affiliation(s)
- Aurélien Patoz
- Institute of Sport Sciences, University of Lausanne, 1015, Lausanne, Switzerland.
- Research and Development Department, Volodalen Swiss Sport Lab, Aigle, Switzerland.
| | - Romain Spicher
- Institute of Sport Sciences, University of Lausanne, 1015, Lausanne, Switzerland
| | - Nicola Pedrani
- Institute of Sport Sciences, University of Lausanne, 1015, Lausanne, Switzerland
| | - Davide Malatesta
- Institute of Sport Sciences, University of Lausanne, 1015, Lausanne, Switzerland
| | - Fabio Borrani
- Institute of Sport Sciences, University of Lausanne, 1015, Lausanne, Switzerland
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Lievens M, Caen K, Bourgois JG, Vermeire K, Boone J. W' Reconstitution Accelerates More with Decreasing Intensity in the Heavy- versus the Moderate-Intensity Domain. Med Sci Sports Exerc 2021; 53:1276-1284. [PMID: 33273271 DOI: 10.1249/mss.0000000000002574] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
INTRODUCTION The purpose of this study was to investigate the effect of the recovery intensity domain on W' reconstitution. We used the W'BAL model as a framework and tested its predictive capabilities (W'PRED) across the different intensity domains. METHODS Twelve young men (51.7 ± 5.9 mL·kg-1·min-1) completed a ramp incremental test, three to five constant power output (PO) tests to determine critical power (CP) and W', and minimally two trials to verify the maximal lactate (La-) steady state. During four experimental trials, subjects performed two work bouts (WB1 and WB2) at P6 (i.e., PO that predicts exhaustion within 6 min) separated by a recovery interval at CP-10 W, Δgas exchange threshold (GET)-CP, GET, and 50% GET, respectively. WB1 was designed to deplete 75% W', and the recovery time varied to replenish 50% W'. WB2 was performed to exhaustion (W'ACT). W'PRED was compared with W'ACT to evaluate the accuracy of the W'BAL model. Excess postexercise oxygen consumption was calculated as the difference between the measured and the predicted oxygen uptake during recovery. RESULTS W'ACT averaged 49% ± 24%, 69% ± 24%, 81% ± 28%, and 93% ± 21% for CP-10 W, ΔGET-CP, GET, and 50% GET, respectively (P = 0.002). W'PRED overestimated W'ACT in CP-10 W (34% ± 32%, P = 0.004) and underestimated W'ACT in 50% GET (24% ± 28%, P = 0.013). Excess postexercise oxygen consumption was lowest in CP-10 W (P < 0.01) and higher in GET compared with ΔGET-CP (P = 0.01). CONCLUSION We demonstrated that W'PRED overestimated and underestimated W'ACT in the heavy- and moderate-intensity domain, respectively. Therefore, the practical applicability of a single recovery time constant, which only relies on the difference between the recovery PO and the CP, is questionable.
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Affiliation(s)
| | | | | | - Kobe Vermeire
- Department of Movement and Sports Sciences, Ghent University, Ghent, BELGIUM
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Patoz A, Pedrani N, Spicher R, Berchtold A, Borrani F, Malatesta D. Effect of Mathematical Modeling and Fitting Procedures on the Assessment of Critical Speed and Its Relationship With Aerobic Fitness Parameters. Front Physiol 2021; 12:613066. [PMID: 34135766 PMCID: PMC8201789 DOI: 10.3389/fphys.2021.613066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 05/05/2021] [Indexed: 01/13/2023] Open
Abstract
An accurate estimation of critical speed (CS) is important to accurately define the boundary between heavy and severe intensity domains when prescribing exercise. Hence, our aim was to compare CS estimates obtained by statistically appropriate fitting procedures, i.e., regression analyses that correctly consider the dependent variables of the underlying models. A second aim was to determine the correlations between estimated CS and aerobic fitness parameters, i.e., ventilatory threshold, respiratory compensation point, and maximal rate of oxygen uptake. Sixteen male runners performed a maximal incremental aerobic test and four exhaustive runs at 90, 100, 110, and 120% of the peak speed of the incremental test on a treadmill. Then, two mathematically equivalent formulations (time as function of running speed and distance as function of running speed) of three different mathematical models (two-parameter, three-parameter, and three-parameter exponential) were employed to estimate CS, the distance that can be run above CS (d'), and if applicable, the maximal instantaneous running speed (s max ). A significant effect of the mathematical model was observed when estimating CS, d', and s max (P < 0.001), but there was no effect of the fitting procedure (P > 0.77). The three-parameter model had the best fit quality (smallest Akaike information criterion) of the CS estimates but the highest 90% confidence intervals and combined standard error of estimates (%SEE). The 90% CI and %SEE were similar when comparing the two fitting procedures for a given model. High and very high correlations were obtained between CS and aerobic fitness parameters for the three different models (r ≥ 0.77) as well as reasonably small SEE (SEE ≤ 6.8%). However, our results showed no further support for selecting the best mathematical model to estimate critical speed. Nonetheless, we suggest coaches choosing a mathematical model beforehand to define intensity domains and maintaining it over the running seasons.
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Affiliation(s)
- Aurélien Patoz
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
- Research and Development Department, Volodalen Swiss Sport Lab, Aigle, Switzerland
| | - Nicola Pedrani
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Romain Spicher
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - André Berchtold
- Institute of Social Sciences and National Centre of Competence in Research LIVES, University of Lausanne, Lausanne, Switzerland
| | - Fabio Borrani
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Davide Malatesta
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Smyth B, Muniz-Pumares D. Calculation of Critical Speed from Raw Training Data in Recreational Marathon Runners. Med Sci Sports Exerc 2021; 52:2637-2645. [PMID: 32472926 PMCID: PMC7664951 DOI: 10.1249/mss.0000000000002412] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Critical speed (CS) represents the highest intensity at which a physiological steady state may be reached. The aim of this study was to evaluate whether estimations of CS obtained from raw training data can predict performance and pacing in marathons. METHODS We investigated running activities logged into an online fitness platform by >25,000 recreational athletes before big-city marathons. Each activity contained time, distance, and elevation every 100 m. We computed grade-adjusted pacing and the fastest pace recorded for a set of target distances (400, 800, 1000, 1500, 3000, and 5000 m). CS was determined as the slope of the distance-time relationship using all combinations of, at least, three target distances. RESULTS The relationship between distance and time was linear, irrespective of the target distances used (pooled mean ± SD: R = 0.9999 ± 0.0001). The estimated values of CS from all models were not different (3.74 ± 0.08 m·s), and all models correlated with marathon performance (R = 0.672 ± 0.036, error = 8.01% ± 0.51%). CS from the model including 400, 800, and 5000 m best predicted performance (R = 0.695, error = 7.67%) and was used in further analysis. Runners completed the marathon at 84.8% ± 13.6% CS, with faster runners competing at speeds closer to CS (93.0% CS for 150 min marathon times vs 78.9% CS for 360 min marathon times). Runners who completed the first half of the marathon at >94% of their CS, and particularly faster than CS, were more likely to slowdown by more than 25% in the second half of race. CONCLUSION This study suggests that estimations of CS from raw training data can successfully predict marathon performance and provide useful pacing information.
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Affiliation(s)
- Barry Smyth
- Insight Centre for Data Analytics, School of Computer Science, University College Dublin, Dublin, IRELAND
| | - Daniel Muniz-Pumares
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, UNITED KINGDOM
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do Nascimento Salvador PC, de Lucas RD, Schäfer L, Guglielmo LGA, Grassi B, Denadai BS. Modeling the depletion and reconstitution of W': Effects of prior exercise on cycling tolerance. Respir Physiol Neurobiol 2020; 285:103590. [PMID: 33271307 DOI: 10.1016/j.resp.2020.103590] [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: 07/05/2020] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 11/29/2022]
Abstract
Thirteen healthy male subjects (age 28 ± 7 years) performed tests for critical power and W' determination and two square-wave high-intensity exercises until exhaustion either with prior very-heavy intensity cycling (EXP) or without (CON). Prior exercise bout induced a depletion of 60 % of W'. After 10 min of recovery, W' reconstitution was not fully achieved (∼ 92 %). Time to exhaustion and Δ blood lactate concentration were significantly lower in EXP compared to CON (595 ± 118 s vs. 683 ± 148 s; 3.5 ± 1.2 mmol.L-1 vs. 8.8 ± 2.3 mmol.L-1; p < 0.05, respectively). Oxygen uptake (VO2) and heart rate were significantly higher in EXP, during the first 150 s of exercise (p < 0.05). The carbon dioxide production kinetics was significantly slower in EXP (mean response time = 87.8 ± 17.8 s vs. 73.7 ± 16.6 s in CON; p < 0.05). Thus, prior exercise impairs high-intensity cycling performance which can partly be explained by physiological disturbances linked to W' depletion.
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Affiliation(s)
| | - Ricardo Dantas de Lucas
- Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Lisa Schäfer
- Centre for Sport and Exercise Science and Medicine, University of Brighton, United Kingdom
| | | | - Bruno Grassi
- Exercise Physiology Laboratory, Department of Medicine, Università Degli Studi Di Udine, Italy
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Mechanical Power in Endurance Running: A Scoping Review on Sensors for Power Output Estimation during Running. SENSORS 2020; 20:s20226482. [PMID: 33202809 PMCID: PMC7696724 DOI: 10.3390/s20226482] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/23/2022]
Abstract
Mechanical power may act as a key indicator for physiological and mechanical changes during running. In this scoping review, we examine the current evidences about the use of power output (PW) during endurance running and the different commercially available wearable sensors to assess PW. The Boolean phrases endurance OR submaximal NOT sprint AND running OR runner AND power OR power meter, were searched in PubMed, MEDLINE, and SCOPUS. Nineteen studies were finally selected for analysis. The current evidence about critical power and both power-time and power-duration relationships in running allow to provide coaches and practitioners a new promising setting for PW quantification with the use of wearable sensors. Some studies have assessed the validity and reliability of different available wearables for both kinematics parameters and PW when running but running power meters need further research before a definitive conclusion regarding its validity and reliability.
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The Application of Critical Power, the Work Capacity above Critical Power (W'), and its Reconstitution: A Narrative Review of Current Evidence and Implications for Cycling Training Prescription. Sports (Basel) 2020; 8:sports8090123. [PMID: 32899777 PMCID: PMC7552657 DOI: 10.3390/sports8090123] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/28/2020] [Accepted: 09/02/2020] [Indexed: 12/17/2022] Open
Abstract
The two-parameter critical power (CP) model is a robust mathematical interpretation of the power–duration relationship, with CP being the rate associated with the maximal aerobic steady state, and W′ the fixed amount of tolerable work above CP available without any recovery. The aim of this narrative review is to describe the CP concept and the methodologies used to assess it, and to summarize the research applying it to intermittent cycle training techniques. CP and W′ are traditionally assessed using a number of constant work rate cycling tests spread over several days. Alternatively, both the 3-min all-out and ramp all-out protocols provide valid measurements of CP and W′ from a single test, thereby enhancing their suitability to athletes and likely reducing errors associated with the assumptions of the CP model. As CP represents the physiological landmark that is the boundary between heavy and severe intensity domains, it presents several advantages over the de facto arbitrarily defined functional threshold power as the basis for cycle training prescription at intensities up to CP. For intensities above CP, precise prescription is not possible based solely on aerobic measures; however, the addition of the W′ parameter does facilitate the prescription of individualized training intensities and durations within the severe intensity domain. Modelling of W′ reconstitution extends this application, although more research is needed to identify the individual parameters that govern W′ reconstitution rates and their kinetics.
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Puchowicz MJ, Baker J, Clarke DC. Development and field validation of an omni-domain power-duration model. J Sports Sci 2020; 38:801-813. [PMID: 32131692 DOI: 10.1080/02640414.2020.1735609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Purpose: To validate and compare a novel model based on the critical power (CP) concept that describes the entire domain of maximal mean power (MMP) data from cyclists.Methods: An omni-domain power-duration (OmPD) model was derived whereby the rate of W' expenditure is bound by maximum sprint power and the power at prolonged durations declines from CP log-linearly. The three-parameter CP (3CP) and exponential (Exp) models were likewise extended with the log-linear decay function (Om3CP and OmExp). Each model bounds W' using a different nonconstant function, W'eff (effective W'). Models were fit to MMP data from nine cyclists who also completed four time-trials (TTs).Results: The OmPD and Om3CP residuals (4 ± 1%) were smaller than the OmExp residuals (6 ± 2%; P < 0.001). W'eff predicted by the OmPD model was stable between 120-1,800 s, whereas it varied for the Om3CP and OmExp models. TT prediction errors were not different between models (7 ± 5%, 8 ± 5%, 7 ± 6%; P = 0.914).Conclusion: The OmPD offers similar or superior goodness-of-fit and better theoretical properties compared to the other models, such that it best extends the CP concept to short-sprint and prolonged-endurance performance.
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Affiliation(s)
| | | | - David C Clarke
- Department of Biomedical Physiology and Kinesiology and the SFU Sports Analytics Group, Simon Fraser University, Burnaby, BC, Canada
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Pallarés JG, Lillo-Bevia JR, Morán-Navarro R, Cerezuela-Espejo V, Mora-Rodriguez R. Time to exhaustion during cycling is not well predicted by critical power calculations. Appl Physiol Nutr Metab 2020; 45:753-760. [PMID: 31935109 DOI: 10.1139/apnm-2019-0637] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Three to 5 cycling tests to exhaustion allow prediction of time to exhaustion (TTE) at power output based on calculation of critical power (CP). We aimed to determine the accuracy of CP predictions of TTE at power outputs habitually endured by cyclists. Fourteen endurance-trained male cyclists underwent 4 randomized cycle-ergometer TTE tests at power outputs eliciting (i) mean Wingate anaerobic test (WAnTmean), (ii) maximal oxygen consumption, (iii) respiratory compensation threshold (VT2), and (iv) maximal lactate steady state (MLSS). Tests were conducted in duplicate with coefficient of variation of 5%-9%. Power outputs were 710 ± 63 W for WAnTmean, 366 ± 26 W for maximal oxygen consumption, 302 ± 31 W for VT2 and 247 ± 20 W for MLSS. Corresponding TTE were 00:29 ± 00:06, 03:23 ± 00:45, 11:29 ± 05:07, and 76:05 ± 13:53 min:s, respectively. Power output associated with CP was only 2% lower than MLSS (242 ± 19 vs. 247 ± 20 W; P < 0.001). The CP predictions overestimated TTE at WAnTmean (00:24 ± 00:10 mm:ss) and MLSS (04:41 ± 11:47 min:s), underestimated TTE at VT2 (-04:18 ± 03:20 mm:ss; P < 0.05), and correctly predicted TTE at maximal oxygen consumption. In summary, CP accurately predicts MLSS power output and TTE at maximal oxygen consumption. However, it should not be used to estimate time to exhaustion in trained cyclists at higher or lower power outputs (e.g., sprints and 40-km time trials). Novelty CP calculation enables to predict TTE at any cycling power output. We tested those predictions against measured TTE in a wide range of cycling power outputs. CP appropriately predicted TTE at maximal oxygen consumption intensity but err at higher and lower cycling power outputs.
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Affiliation(s)
- Jesus G Pallarés
- Human Performance and Sports Science Laboratory. University of Murcia, 30720, Murcia, Spain
| | - Jose R Lillo-Bevia
- Human Performance and Sports Science Laboratory. University of Murcia, 30720, Murcia, Spain
| | - Ricardo Morán-Navarro
- Human Performance and Sports Science Laboratory. University of Murcia, 30720, Murcia, Spain
| | | | - Ricardo Mora-Rodriguez
- Exercise Physiology Laboratory at Toledo. University of Castilla-La Mancha, Avda Carlos III, s/n, 47051, Toledo, Spain
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Sreedhara VSM, Mocko GM, Hutchison RE. A survey of mathematical models of human performance using power and energy. SPORTS MEDICINE-OPEN 2019; 5:54. [PMID: 31883068 PMCID: PMC6934642 DOI: 10.1186/s40798-019-0230-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/06/2019] [Indexed: 02/05/2023]
Abstract
The ability to predict the systematic decrease of power during physical exertion gives valuable insights into health, performance, and injury. This review surveys the research of power-based models of fatigue and recovery within the area of human performance. Upon a thorough review of available literature, it is observed that the two-parameter critical power model is most popular due to its simplicity. This two-parameter model is a hyperbolic relationship between power and time with critical power as the power-asymptote and the curvature constant denoted by W′. Critical power (CP) is a theoretical power output that can be sustained indefinitely by an individual, and the curvature constant (W′) represents the amount of work that can be done above CP. Different methods and models have been validated to determine CP and W′, most of which are algebraic manipulations of the two-parameter model. The models yield different CP and W′ estimates for the same data depending on the regression fit and rounding off approximations. These estimates, at the subject level, have an inherent day-to-day variability called intra-individual variability (IIV) associated with them, which is not captured by any of the existing methods. This calls for a need for new methods to arrive at the IIV associated with CP and W′. Furthermore, existing models focus on the expenditure of W′ for efforts above CP and do not model its recovery in the sub-CP domain. Thus, there is a need for methods and models that account for (i) the IIV to measure the effectiveness of individual training prescriptions and (ii) the recovery of W′ to aid human performance optimization.
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Affiliation(s)
- Vijay Sarthy M Sreedhara
- Department of Mechanical Engineering, Clemson University, 243 Fluor Daniel EIB, Clemson, SC, 29634-0921, USA
| | - Gregory M Mocko
- Department of Mechanical Engineering, Clemson University, 243 Fluor Daniel EIB, Clemson, SC, 29634-0921, USA.
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Iannetta D, de Almeida Azevedo R, Keir DA, Murias JM. Establishing the V̇o 2 versus constant-work-rate relationship from ramp-incremental exercise: simple strategies for an unsolved problem. J Appl Physiol (1985) 2019; 127:1519-1527. [PMID: 31580218 DOI: 10.1152/japplphysiol.00508.2019] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The dissociation between constant work rate of O2 uptake (V̇o2) and ramp V̇o2 at a given work rate might be mitigated during slowly increasing ramp protocols. This study characterized the V̇o2 dynamics in response to five different ramp protocols and constant-work-rate trials at the maximal metabolic steady state (MMSS) to characterize 1) the V̇o2 gain (G) in the moderate, heavy, and severe domains, 2) the mean response time of V̇o2 (MRT), and 3) the work rates at lactate threshold (LT) and respiratory compensation point (RCP). Eleven young individuals performed five ramp tests (5, 10, 15, 25, and 30 W/min), four to five time-to-exhaustions for critical power estimation, and two to three constant-work-rate trials for confirmation of the work rate at MMSS. G was greatest during the slowest ramp and progressively decreased with increasing ramp slopes (from ~12 to ~8 ml·min-1·W-1, P < 0.05). The MRT was smallest during the slowest ramp slopes and progressively increased with faster ramp slopes (1 ± 1, 2 ± 1, 5 ± 3, and 10 ± 4, 15 ± 6 W, P < 0.05). After "left shifting" the ramp V̇o2 by the MRT, the work rate at LT was constant regardless of the ramp slope (~150 W, P > 0.05). The work rate at MMSS was 215 ± 55 W and was similar and highly correlated with the work rate at RCP during the 5 W/min ramp (P > 0.05, r = 0.99; Lin's concordance coefficient = 0.99; bias = -3 W; root mean square error = 6 W). Findings showed that the dynamics of V̇o2 (i.e., G) during ramp exercise explain the apparent dichotomy existing with constant-work-rate exercise. When these dynamics are appropriately "resolved", LT is constant regardless of the ramp slope of choice, and RCP and MMSS display minimal variations between each other.NEW & NOTEWORTHY This study demonstrates that the dynamics of V̇o2 during ramp-incremental exercise are dependent on the characteristics of the increments in work rate, such that during slow-incrementing ramp protocols the magnitude of the dissociation between ramp V̇o2 and constant V̇o2 at a given work rate is reduced. Accurately accounting for these dynamics ensures correct characterizations of the V̇o2 kinetics at ramp onset and allows appropriate comparisons between ramp and constant-work-rate exercise-derived indexes of exercise intensity.
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Affiliation(s)
- Danilo Iannetta
- Faculty of Kinesiology, University of Calgary, Calgary, Canada
| | | | - Daniel A Keir
- Department of Medicine, University Health Network, Toronto, Canada
| | - Juan M Murias
- Faculty of Kinesiology, University of Calgary, Calgary, Canada
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Clark IE, Vanhatalo A, Thompson C, Joseph C, Black MI, Blackwell JR, Wylie LJ, Tan R, Bailey SJ, Wilkins BW, Kirby BS, Jones AM. Dynamics of the power-duration relationship during prolonged endurance exercise and influence of carbohydrate ingestion. J Appl Physiol (1985) 2019; 127:726-736. [PMID: 31295069 DOI: 10.1152/japplphysiol.00207.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We tested the hypotheses that the parameters of the power-duration relationship, estimated as the end-test power (EP) and work done above EP (WEP) during a 3-min all-out exercise test (3MT), would be reduced progressively after 40 min, 80 min, and 2 h of heavy-intensity cycling and that carbohydrate (CHO) ingestion would attenuate the reduction in EP and WEP. Sixteen participants completed a 3MT without prior exercise (control), immediately after 40 min, 80 min, and 2 h of heavy-intensity exercise while consuming a placebo beverage, and also after 2 h of heavy-intensity exercise while consuming a CHO supplement (60 g/h CHO). There was no difference in EP measured without prior exercise (260 ± 37 W) compared with EP after 40 min (268 ± 39 W) or 80 min (260 ± 40 W) of heavy-intensity exercise; however, after 2 h EP was 9% lower compared with control (236 ± 47 W; P < 0.05). There was no difference in WEP measured without prior exercise (17.9 ± 3.3 kJ) compared with after 40 min of heavy-intensity exercise (16.1 ± 3.3 kJ), but WEP was lower (P < 0.05) than control after 80 min (14.7 ± 2.9 kJ) and 2 h (13.8 ± 2.7 kJ). Compared with placebo, CHO ingestion negated the reduction of EP following 2 h of heavy-intensity exercise (254 ± 49 W) but had no effect on WEP (13.5 ± 3.4 kJ). These results reveal a different time course for the deterioration of EP and WEP during prolonged endurance exercise and indicate that EP is sensitive to CHO availability.NEW & NOTEWORTHY The parameters of the power-duration relationship [critical power (CP) and the curvature constant (W')] have typically been considered to be static. Here we report the time course for reductions in CP and W', as estimated with the 3-min all-out cycle test, during 2 h of heavy-intensity exercise. We also show that carbohydrate ingestion during exercise preserves CP, but not W', without altering muscle glycogen depletion. These results provide new mechanistic and practical insight into the power-duration curve and its relationship to exercise-related fatigue development.
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Affiliation(s)
- Ida E Clark
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Anni Vanhatalo
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Christopher Thompson
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Charlotte Joseph
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Matthew I Black
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Jamie R Blackwell
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Lee J Wylie
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Rachel Tan
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Stephen J Bailey
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | | | | | - Andrew M Jones
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
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47
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Jones AM, Burnley M, Black MI, Poole DC, Vanhatalo A. The maximal metabolic steady state: redefining the 'gold standard'. Physiol Rep 2019; 7:e14098. [PMID: 31124324 PMCID: PMC6533178 DOI: 10.14814/phy2.14098] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/25/2019] [Accepted: 04/27/2019] [Indexed: 02/06/2023] Open
Abstract
The maximal lactate steady state (MLSS) and the critical power (CP) are two widely used indices of the highest oxidative metabolic rate that can be sustained during continuous exercise and are often considered to be synonymous. However, while perhaps having similarities in principle, methodological differences in the assessment of these parameters typically result in MLSS occurring at a somewhat lower power output or running speed and exercise at CP being sustainable for no more than approximately 20-30 min. This has led to the view that CP overestimates the 'actual' maximal metabolic steady state and that MLSS should be considered the 'gold standard' metric for the evaluation of endurance exercise capacity. In this article we will present evidence consistent with the contrary conclusion: i.e., that (1) as presently defined, MLSS naturally underestimates the actual maximal metabolic steady state; and (2) CP alone represents the boundary between discrete exercise intensity domains within which the dynamic cardiorespiratory and muscle metabolic responses to exercise differ profoundly. While both MLSS and CP may have relevance for athletic training and performance, we urge that the distinction between the two concepts/metrics be better appreciated and that comparisons between MLSS and CP, undertaken in the mistaken belief that they are theoretically synonymous, is discontinued. CP represents the genuine boundary separating exercise in which physiological homeostasis can be maintained from exercise in which it cannot, and should be considered the gold standard when the goal is to determine the maximal metabolic steady state.
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Affiliation(s)
- Andrew M. Jones
- Sport and Health SciencesUniversity of ExeterSt. Luke's CampusExeterUnited Kingdom
| | - Mark Burnley
- School of Sport and Exercise SciencesUniversity of KentMedwayUnited Kingdom
| | - Matthew I. Black
- Sport and Health SciencesUniversity of ExeterSt. Luke's CampusExeterUnited Kingdom
| | - David C. Poole
- Department of KinesiologyKansas State UniversityManhattanKansas
| | - Anni Vanhatalo
- Sport and Health SciencesUniversity of ExeterSt. Luke's CampusExeterUnited Kingdom
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Muniz-Pumares D, Karsten B, Triska C, Glaister M. Methodological Approaches and Related Challenges Associated With the Determination of Critical Power and Curvature Constant. J Strength Cond Res 2019; 33:584-596. [DOI: 10.1519/jsc.0000000000002977] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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MacInnis MJ, Thomas ACQ, Phillips SM. The Reliability of 4-Minute and 20-Minute Time Trials and Their Relationships to Functional Threshold Power in Trained Cyclists. Int J Sports Physiol Perform 2019; 14:38-45. [PMID: 29809063 DOI: 10.1123/ijspp.2018-0100] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 10/27/2023]
Abstract
PURPOSE The mean power output (MPO) from a 60-min time trial (TT)-also known as functional threshold power, or FTP-is a standard measure of cycling performance; however, shorter performance tests are desirable to reduce the burden of performance testing. The authors sought to determine the reliability of 4- and 20-min TTs and the extent to which these short TTs were associated with 60-min MPO. METHODS Trained male cyclists (n = 8; age = 25 [5] y; VO2max = 71 [5] mL/kg/min) performed two 4-min TTs, two 20-min TTs, and one 60-min TT. Critical power (CP) was estimated from 4- and 20-min TTs. The typical error of the mean (TEM) and intraclass correlation coefficient (ICC) were calculated to assess reliability, and R2 values were calculated to assess relationships with 60-min MPO. RESULTS Pairs of 4-min TTs (mean: 417 [SD: 45] W vs 412 [49] W, P = .25; TEM = 8.1 W; ICC = .98), 20-min TTs (342 [36] W vs 344 [33] W, P = .41; TEM = 4.6 W; ICC = .99), and CP estimates (323 [35] W vs 328 [32] W, P = .25; TEM = 6.5; ICC = .98) were reliable. The 4-min MPO (R2 = .95), 20-min MPO (R2 = .92), estimated CP (R2 = .82), and combination of the 4- and 20-min MPO (adjusted R2 = .98) were strongly associated with the 60-min MPO (309 [26] W). CONCLUSION The 4- and 20-min TTs appear useful for assessing performance in trained, if not elite, cyclists.
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Mitchell EA, Martin NRW, Turner MC, Taylor CW, Ferguson RA. The combined effect of sprint interval training and postexercise blood flow restriction on critical power, capillary growth, and mitochondrial proteins in trained cyclists. J Appl Physiol (1985) 2019; 126:51-59. [DOI: 10.1152/japplphysiol.01082.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Sprint interval training (SIT) combined with postexercise blood flow restriction (BFR) is a novel method to increase maximal oxygen uptake (V̇o2max) in trained individuals and also provides a potent acute stimulus for angiogenesis and mitochondrial biogenesis. The efficacy to enhance endurance performance, however, has yet to be demonstrated. Trained male cyclists ( n = 21) (V̇o2max: 62.8 ± 3.7 ml·min−1·kg−1) undertook 4 wk of SIT (repeated 30-s maximal sprints) either alone (CON; n = 10) or with postexercise BFR ( n = 11). Before and after training V̇o2max, critical power (CP) and curvature constant ( Wʹ) were determined and muscle biopsies obtained for determination of skeletal muscle capillarity and mitochondrial protein content. CP increased ( P = 0.001) by a similar extent following CON (287 ± 39 W to 297 ± 43 W) and BFR (296 ± 40 W to 306 ± 36 W). V̇o2max increased following BFR by 5.9% ( P = 0.02) but was unchanged after CON ( P = 0.56). All markers of skeletal muscle capillarity and mitochondrial protein content were unchanged following either training intervention. In conclusion, 4 wk of SIT increased CP; however, this was not enhanced further with BFR. SIT was not sufficient to elicit changes in skeletal muscle capillarity and mitochondrial protein content with or without BFR. However, we further demonstrate the potency of combining BFR with SIT to enhance V̇o2max in trained individuals. NEW & NOTEWORTHY This investigation has demonstrated that 4 wk of sprint interval training (SIT) increased critical power in trained individuals; however, postexercise blood flow restriction (BFR) did not enhance this further. SIT, with or without BFR, did not induce any changes in skeletal muscle capillarity or mitochondrial protein content in our trained population. We do, however, confirm previous findings that SIT combined with BFR is a potent stimulus to enhance maximal oxygen uptake.
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Affiliation(s)
- Emma A. Mitchell
- School of Sport, Exercise, and Health Sciences, Loughborough University, Loughborough, United Kingdom
| | - Neil R. W. Martin
- School of Sport, Exercise, and Health Sciences, Loughborough University, Loughborough, United Kingdom
| | - Mark C. Turner
- School of Sport, Exercise, and Health Sciences, Loughborough University, Loughborough, United Kingdom
| | - Conor W. Taylor
- School of Sport, Exercise, and Health Sciences, Loughborough University, Loughborough, United Kingdom
| | - Richard A. Ferguson
- School of Sport, Exercise, and Health Sciences, Loughborough University, Loughborough, United Kingdom
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