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Fenne KT, Clauss M, Schäfer Olstad D, Johansen EI, Jensen J. An Acute Bout of Endurance Exercise Does Not Prevent the Inhibitory Effect of Caffeine on Glucose Tolerance the following Morning. Nutrients 2023; 15:nu15081941. [PMID: 37111160 PMCID: PMC10143402 DOI: 10.3390/nu15081941] [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: 03/17/2023] [Revised: 03/29/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Caffeine reduces glucose tolerance, whereas exercise training improves glucose homeostasis. The aim of the present study was to investigate the effect of caffeine on glucose tolerance the morning after an acute bout of aerobic exercise. Methods: The study had a 2 × 2 factorial design. Oral glucose tolerance tests (OGTT) were performed after overnight fasting with/without caffeine and with/without exercise the evening before. Eight healthy young active males were included (Age 25.5 ± 1.5 years; 83.9 ± 9.0 kg; VO2max: 54.3 ± 7.0 mL·kg-1·min-1). The exercise session consisted of 30 min cycling at 71% of VO2max followed by four 5 min intervals at 84% with 3 min of cycling at 40% of VO2max between intervals. The exercise was performed at 17:00 h. Energy expenditure at each session was ~976 kcal. Lactate increased to ~8 mM during the exercise sessions. Participants arrived at the laboratory the following morning at 7.00 AM after an overnight fast. Resting blood samples were taken before blood pressure and heart rate variability (HRV) were measured. Caffeine (3 mg/kg bodyweight) or placebo (similar taste/flavor) was ingested, and blood samples, blood pressure and HRV were measured after 30 min. Next, the OGTTs were initiated (75 g glucose dissolved in 3 dL water) and blood was sampled. Blood pressure and HRV were measured during the OGTT. Caffeine increased the area under curve (AUC) for glucose independently of whether exercise was done the evening before (p = 0.03; Two-way ANOVA; Interaction: p = 0.835). Caffeine did not significantly increase AUC for C-peptides compared to placebo (p = 0.096), and C-peptide response was not influenced by exercise. The acute bout of exercise did not significantly improve glucose tolerance the following morning. Diastolic blood pressure during the OGTT was slightly higher after intake of caffeine, independent of whether exercise was performed the evening before or not. Neither caffeine nor exercise the evening before significantly influenced HRV. In conclusion, caffeine reduced glucose tolerance independently of whether endurance exercise was performed the evening before. The low dose of caffeine did not influence heart rate variability but increased diastolic blood pressure slightly.
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Affiliation(s)
- Karoline T Fenne
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
| | - Matthieu Clauss
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
| | | | - Egil I Johansen
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
| | - Jørgen Jensen
- Department of Physical Performance, Norwegian School of Sport Sciences, P.O. Box 4014, Ullevål Stadion, 0806 Oslo, Norway
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Changes in pacing variation with increasing race duration in ultra-triathlon races. Sci Rep 2023; 13:3692. [PMID: 36878948 PMCID: PMC9986668 DOI: 10.1038/s41598-023-30932-1] [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: 04/16/2022] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Despite the increasing scientific interest in the relationship between pacing and performance in endurance sports, little information is available about pacing and pacing variation in ultra-endurance events such as ultra-triathlons. Therefore, we aimed to investigate the trends of pacing, pacing variation, the influence of age, sex, and performance level in ultra-triathlons of different distances. We analysed 969 finishers (849 men, 120 women) in 46 ultra-triathlons longer than the original Ironman® distance (e.g., Double-, Triple-, Quintuple- and Deca Iron ultra-triathlons) held from 2004 to 2015. Pacing speed was calculated for every cycling and running lap. Pacing variation was calculated as the coefficient of variation (%) between the average speed of each lap. Performance level (i.e., fast, moderate, slow) was defined according to the 33.3 and 66.6 percentile of the overall race time. A multivariate analysis (two-way ANOVA) was applied for the overall race time as the dependent variable with 'sex' and 'age group' as independent factors. Another multivariate model with 'age' and 'sex' as covariates (two-way ANCOVA) was applied with pacing variation (cycling and running) as the dependent variable with 'race' and 'performance level' as independent factors. Different pacing patterns were observed by event and performance level. The general pacing strategy applied was a positive pacing. In Double and Triple Iron ultra-triathlon, faster athletes paced more evenly with less variation than moderate or slower athletes. The variation in pacing speed increased with the length of the race. There was no significant difference in pacing variation between faster, moderate, and slower athletes in Quintuple and Deca Iron ultra-triathlon. Women had a slower overall performance than men. The best overall times were achieved at the age of 30-39 years. Successful ultra-triathlon athletes adapted a positive pacing strategy in all race distances. The variation in pacing speed increased with the length of the race. In shorter ultra-triathlon distances (i.e., Double and Triple Iron ultra-triathlon), faster athletes paced more evenly with less variation than moderate or slower athletes. In longer ultra-triathlon distances (i.e., Quintuple and Deca Iron ultra-triathlon), there was no significant difference in pacing variation between faster, moderate, and slower athletes.
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Competition Between Desired Competitive Result, Tolerable Homeostatic Disturbance, and Psychophysiological Interpretation Determines Pacing Strategy. Int J Sports Physiol Perform 2023; 18:335-346. [PMID: 36848906 DOI: 10.1123/ijspp.2022-0171] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 11/22/2022] [Accepted: 12/19/2022] [Indexed: 03/01/2023]
Abstract
Scientific interest in pacing goes back >100 years. Contemporary interest, both as a feature of athletic competition and as a window into understanding fatigue, goes back >30 years. Pacing represents the pattern of energy use designed to produce a competitive result while managing fatigue of different origins. Pacing has been studied both against the clock and during head-to-head competition. Several models have been used to explain pacing, including the teleoanticipation model, the central governor model, the anticipatory-feedback-rating of perceived exertion model, the concept of a learned template, the affordance concept, the integrative governor theory, and as an explanation for "falling behind." Early studies, mostly using time-trial exercise, focused on the need to manage homeostatic disturbance. More recent studies, based on head-to-head competition, have focused on an improved understanding of how psychophysiology, beyond the gestalt concept of rating of perceived exertion, can be understood as a mediator of pacing and as an explanation for falling behind. More recent approaches to pacing have focused on the elements of decision making during sport and have expanded the role of psychophysiological responses including sensory-discriminatory, affective-motivational, and cognitive-evaluative dimensions. These approaches have expanded the understanding of variations in pacing, particularly during head-to-head competition.
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Vigh-Larsen JF, Ørtenblad N, Nielsen J, Emil Andersen O, Overgaard K, Mohr M. The Role of Muscle Glycogen Content and Localization in High-Intensity Exercise Performance: A Placebo-Controlled Trial. Med Sci Sports Exerc 2022; 54:2073-2086. [PMID: 35868015 DOI: 10.1249/mss.0000000000003002] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE We investigated the coupling between muscle glycogen content and localization and high-intensity exercise performance using a randomized, placebo-controlled, parallel-group design with emphasis on single-fiber subcellular glycogen concentrations and sarcoplasmic reticulum Ca 2+ kinetics. METHODS Eighteen well-trained participants performed high-intensity intermittent glycogen-depleting exercise, followed by randomization to a high- (CHO; ~1 g CHO·kg -1 ·h -1 ; n = 9) or low-carbohydrate placebo diet (PLA, <0.1 g CHO·kg -1 ·h -1 ; n = 9) for a 5-h recovery period. At baseline, after exercise, and after the carbohydrate manipulation assessments of repeated sprint ability (5 × 6-s maximal cycling sprints with 24 s of rest), neuromuscular function and ratings of perceived exertion during standardized high-intensity cycling (~90% Wmax ) were performed, while muscle and blood samples were collected. RESULTS The exercise and carbohydrate manipulations led to distinct muscle glycogen concentrations in CHO and PLA at the whole-muscle (291 ± 78 vs 175 ± 100 mmol·kg -1 dry weight (dw), P = 0.020) and subcellular level in each of three local regions ( P = 0.001-0.046). This was coupled with near-depleted glycogen concentrations in single fibers of both main fiber types in PLA, especially in the intramyofibrillar region (within the myofibrils). Furthermore, increased ratings of perceived exertion and impaired repeated sprint ability (~8% loss, P < 0.001) were present in PLA, with the latter correlating moderately to very strongly ( r = 0.47-0.71, P = 0.001-0.049) with whole-muscle glycogen and subcellular glycogen fractions. Finally, sarcoplasmic reticulum Ca 2+ uptake, but not release, was superior in CHO, whereas neuromuscular function, including prolonged low-frequency force depression, was unaffected by dietary manipulation. CONCLUSIONS Together, these results support an important role of muscle glycogen availability for high-intensity exercise performance, which may be mediated by reductions in single-fiber levels, particularly in distinct subcellular regions, despite only moderately lowered whole-muscle glycogen concentrations.
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Affiliation(s)
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, DENMARK
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, DENMARK
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Genitrini M, Fritz J, Zimmermann G, Schwameder H. Downhill Sections Are Crucial for Performance in Trail Running Ultramarathons-A Pacing Strategy Analysis. J Funct Morphol Kinesiol 2022; 7:jfmk7040103. [PMID: 36412765 PMCID: PMC9680470 DOI: 10.3390/jfmk7040103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
Trail running is an increasingly popular discipline, especially over long-distance races (>42.195 km). Pacing strategy, i.e., how athletes modulate running speed for managing their energies during a race, appears to have a significant impact on overall performance. The aims of this study were to investigate whether performance level, terrain (i.e., uphill or downhill) and race stage affect pacing strategy and whether any interactions between these factors are evident. Race data from four race courses, with multiple editions (total races = 16), were retrieved from their respective events websites. A linear mixed effect model was applied to the full dataset, as well as to two subgroups of the top 10 male and female finishers, to assess potential differences in pacing strategy (i.e., investigated in terms of relative speed). Better finishers (i.e., athletes ranking in the best positions) tend to run downhill sections at higher relative speeds and uphill sections at lower relative speeds than slower counterparts (p < 0.001). In the later race stages, the relative speed decrease is larger in downhill sections than in uphill ones (p < 0.001) and in downhill sections, slower finishers perform systematically worse than faster ones, but the performance difference (i.e., between slower and faster finishers) becomes significantly larger in the later race stages (p < 0.001). Among elite athletes, no difference in pacing strategy between faster and slower finishers was found (p > 0.05). Both men (p < 0.001) and women (p < 0.001), in the later race stages, slow down more in downhill sections than in uphill ones. Moreover, elite women tend to slow down more than men (p < 0.001) in the later race stages, regardless of the terrain, in contrast to previous studies focusing on road ultramarathons. In conclusion, running downhill sections at higher relative speeds, most likely due to less accentuated fatigue effects, as well as minimizing performance decrease in the later race stages in downhill sections, appears to be a hallmark of the better finishers.
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Affiliation(s)
- Matteo Genitrini
- Department of Sport and Exercise Science, University of Salzburg, 5400 Hallein-Rif, Austria
| | | | - Georg Zimmermann
- Team Biostatistics and Big Medical Data, IDA Lab, 5020 Salzburg, Austria
- Research Management & Technology Transfer, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Hermann Schwameder
- Department of Sport and Exercise Science, University of Salzburg, 5400 Hallein-Rif, Austria
- Correspondence:
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Rahman M, Ahmad I, Hussain ME. Comparison of intermittent pneumatic compression and active recovery after sub-maximal aerobic exercise in collegiate soccer players: in relation with heart rate variability and heart rate recovery. SPORT SCIENCES FOR HEALTH 2022. [DOI: 10.1007/s11332-022-00906-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Arfuso F, Piccione G, Trimarchi F, Panzera MF, Giannetto C. Stress, metabolic and serum muscle-derived enzymes response of horses employed in wooded area and field trekking courses. J Equine Vet Sci 2022; 112:103919. [DOI: 10.1016/j.jevs.2022.103919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/25/2022] [Accepted: 03/02/2022] [Indexed: 12/31/2022]
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Evidence That Rating of Perceived Exertion Growth During Fatiguing Tasks is Scalar and Independent of Exercise Mode. Int J Sports Physiol Perform 2022; 17:687-693. [DOI: 10.1123/ijspp.2021-0334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 11/18/2022]
Abstract
Introduction: The relationship between the percentage of a fatiguing ambulatory task completed and rating of perceived exertion (RPE) appears to be linear and scalar, with a relatively narrow “window.” Recent evidence has suggested that a similar relationship may exist for muscularly demanding tasks. Methods: To determine whether muscularly demanding tasks fit within this “ambulatory window,” we tested resistance-trained athletes performing bench press and leg press with different loadings predicted to allow 5, 10, 20, and 30 repetitions and measured RPE (category ratio scale) at the end of the concentric action for each repetition. Results: There was a regular, and strongly linear, pattern of growth of RPE for both bench press (r = .89) and leg press (r = .90) during the tasks that allowed 5.2 (1.2), 11.6 (1.9), 22.7 (2.0), and 30.8 (3.2) repetitions for bench press and 5.5 (1.5), 11.4 (1.6), 20.2 (3.0), and 32.4 (4.2) repetitions for leg press, respectively. Conclusions: The path of the RPE growth versus percentage task fit within the window evident for ambulatory tasks. The results suggest that the RPE versus percentage task completed relationship is scalar, relatively linear, and apparently independent of exercise mode.
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Muscle Glycogen Metabolism and High-Intensity Exercise Performance: A Narrative Review. Sports Med 2021; 51:1855-1874. [PMID: 33900579 DOI: 10.1007/s40279-021-01475-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2021] [Indexed: 02/06/2023]
Abstract
Muscle glycogen is the main substrate during high-intensity exercise and large reductions can occur after relatively short durations. Moreover, muscle glycogen is stored heterogeneously and similarly displays a heterogeneous and fiber-type specific depletion pattern with utilization in both fast- and slow-twitch fibers during high-intensity exercise, with a higher degradation rate in the former. Thus, depletion of individual fast- and slow-twitch fibers has been demonstrated despite muscle glycogen at the whole-muscle level only being moderately lowered. In addition, muscle glycogen is stored in specific subcellular compartments, which have been demonstrated to be important for muscle function and should be considered as well as global muscle glycogen availability. In the present review, we discuss the importance of glycogen metabolism for single and intermittent bouts of high-intensity exercise and outline possible underlying mechanisms for a relationship between muscle glycogen and fatigue during these types of exercise. Traditionally this relationship has been attributed to a decreased ATP resynthesis rate due to inadequate substrate availability at the whole-muscle level, but emerging evidence points to a direct coupling between muscle glycogen and steps in the excitation-contraction coupling including altered muscle excitability and calcium kinetics.
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The Physiological, Neuromuscular, and Perceptual Response to Even- and Variable-Paced 10-km Cycling Time Trials. Int J Sports Physiol Perform 2021; 16:1408-1415. [PMID: 33691285 DOI: 10.1123/ijspp.2020-0310] [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: 04/21/2020] [Revised: 10/16/2020] [Accepted: 10/31/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND During self-paced (SP) time trials (TTs), cyclists show unconscious nonrandom variations in power output of up to 10% above and below average. It is unknown what the effects of variations in power output of this magnitude are on physiological, neuromuscular, and perceptual variables. PURPOSE To describe physiological, neuromuscular, and perceptual responses of 10-km TTs with an imposed even-paced (EP) and variable-paced (VP) workload. METHODS Healthy male, trained, task-habituated cyclists (N = 9) completed three 10-km TTs. First, an SP TT was completed, the mean workload from which was used as the mean workload of the EP and VP TTs. The EP was performed with an imposed even workload, while VP was performed with imposed variations in workload of ±10% of the mean. In EP and VP, cardiorespiratory, neuromuscular, and perceptual variables were measured. RESULTS Mean rating of perceived exertion was significantly lower in VP (6.13 [1.16]) compared with EP (6.75 [1.24]), P = .014. No mean differences were found for cardiorespiratory and almost all neuromuscular variables. However, differences were found at individual kilometers corresponding to power-output differences between pacing strategies. CONCLUSION Variations in power output during TTs of ±10%, simulating natural variations in power output that are present during SP TTs, evoke minor changes in cardiorespiratory and neuromuscular responses and mostly affect the perceptual response. Rating of perceived exertion is lower when simulating natural variations in power output, compared with EP cycling. The imposed variations in workload seem to provide a psychological rather than a physiological or neuromuscular advantage.
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Newell ML, Macgregor LJ, Galloway SDR, Hunter AM. Prolonged cycling exercise alters neural control strategy, irrespective of carbohydrate dose ingested. TRANSLATIONAL SPORTS MEDICINE 2021. [DOI: 10.1002/tsm2.187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michael L. Newell
- School of Sport Science and Physical Activity University of Bedfordshire Bedford England UK
| | - Lewis J. Macgregor
- Faculty of Health Sciences and Sport University of Stirling Stirling Scotland UK
| | | | - Angus M. Hunter
- Faculty of Health Sciences and Sport University of Stirling Stirling Scotland UK
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Aditya Rifqi M, Setyaningtyas SW, Rachmah Q. White tea drink (Camellia sinensis) improves endurance and body weight maintenance of rats. JOURNAL OF HEALTH RESEARCH 2020. [DOI: 10.1108/jhr-01-2020-0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
PurposeWhite tea is an unfermented tea made from young shoots of Camellia sinensis protected from sunlight to avoid polyphenol degradation. White tea contains a high level of polyphenolic compounds known as catechins. Several types of evidence have suggested that tea consumption has benefits in body weight and endurance maintenance. This study was designed to evaluate the effect of white tea on body weight and endurance of animal models.Design/methodology/approachThis research was an intervention design using 20 Wistar white rats (Rattus Norvegicus) in body weight between 150 and 200 g. The rats were randomized into four groups, three groups receiving white tea drink (WTD) with different doses and the other group receiving plain water in equal volume as a control group for four weeks. The forced swim test (FST) was done to measure their struggling capacity, and digital bodyweight to measure the weight.FindingsIntervention (WTD Groups and Control) caused weight gain among except G3 with the highest doses of white tea. The result showed that WTD intake in G3 had a significant difference (p < 0.05) on body weight gain compared to control. The authors found that WTD in a specific dose (G3: 0.22 mg) tends to maintain the body weight of animals (219.2 ± 41.96; 212.6 ± 46.90, respectively), while other doses caused weight gain. WTD also significantly increased the swimming and struggling capacity of rats that represented improvements the endurance along with the test. There was a statistically significant difference in endurance among all groups (p < 0.05).Research limitations/implicationsThe results of this study can be followed as human intervention research as an input for nutritionists and sports scientists to explore the beneficial effect of white tea.Practical implicationsThe results of this study can be followed as human intervention research as an input for nutritionists and sports scientists to explore the beneficial effect of white tea.Originality/valueThis study adds more evidence and information about the advantages of white tea as potential beverages in future healthy lifestyles.
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Muñoz-Pérez I, Mecías-Calvo M, Crespo-Álvarez J, Sámano-Celorio ML, Agudo-Toyos P, Lago-Fuentes C. Different race pacing strategies among runners covering the 2017 Berlin Marathon under 3 hours and 30 minutes. PLoS One 2020; 15:e0236658. [PMID: 32722683 PMCID: PMC7386619 DOI: 10.1371/journal.pone.0236658] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/09/2020] [Indexed: 11/18/2022] Open
Abstract
The purposes of this study were 1) to analyse the different pacing behaviours based on athlete's performance and 2) to determine whether significant differences in each race split and the runner's performance implied different race profiles. A total of 2295 runners, which took part in Berlin's marathon (2017), met the inclusion criteria. 4 different groups were created based on sex and performance. Men: Elite (<02:19:00 h), Top 1 (<02:30:00 h), Top 2 (<02:45:00 h) and Top 3 (<03:00:00 h); women: Elite (02:45:00 h), Top 1 (<03:00:00 h), Top 2 (<03:15:00 h), Top 3 (<03:30:00 h). With the aim of comparing the pacing between sex and performance the average speed was normalized. In men, no statistically significant changes were found between performance group and splits. A large number of significant differences between splits and groups were found amongst women: 5-10 km Top 2 vs Top 3 (P = 0.0178), 10-15 km Top1 vs Top 2 (P = 0.0211), 15-20 km Top1 vs Top 2 (P = 0.0382), 20-21.1 km Elite vs Top 2 (P = 0.0129); Elite vs Top 3 (P = 0.0020); Top1 vs Top 2 (P = 0.0233); Top 1 vs Top 3 (P = 0.0007), 25-30 km Elite vs Top 2 (P = 0.0273); Elite vs Top 3 (P = 0.0156), 30-35 km Elite vs Top 2 (P = 0.0096); Top 1 vs Top 2 (P = 0.0198); Top2 vs Top3 (P = 0.0069). In men there were little significant differences based on athletes' performance which implied a similar pacing behaviour. Women presented numerous differences based on their performance which suggested different pacing behaviours.
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Affiliation(s)
- Iker Muñoz-Pérez
- Facultad de Ciencias de la Salud, Universidad Europea del Atlántico (UNEATLANTICO), Santander, Spain
- Runnea, Barakaldo, Spain
| | - Marcos Mecías-Calvo
- Facultad de Ciencias de la Salud, Universidad Europea del Atlántico (UNEATLANTICO), Santander, Spain
- Centro de Investigación y Tecnología Industrial de Cantabria (CITICAN), Santander, Spain
| | - Jorge Crespo-Álvarez
- Facultad de Ciencias de la Salud, Universidad Europea del Atlántico (UNEATLANTICO), Santander, Spain
- Recursos de Obras, Montajes y Asistencias (ROMA), Santa Cruz de Bezana, Spain
| | | | - Pablo Agudo-Toyos
- Facultad de Ciencias de la Salud, Universidad Europea del Atlántico (UNEATLANTICO), Santander, Spain
| | - Carlos Lago-Fuentes
- Facultad de Ciencias de la Salud, Universidad Europea del Atlántico (UNEATLANTICO), Santander, Spain
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Metcalfe RS, Thomas M, Lamb C, Chowdhury EA. Omission of a carbohydrate-rich breakfast impairs evening endurance exercise performance despite complete dietary compensation at lunch. Eur J Sport Sci 2020; 21:1013-1021. [PMID: 32674691 DOI: 10.1080/17461391.2020.1797890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Omission of a carbohydrate-rich breakfast followed by consuming an ad libitum lunch impairs evening exercise performance. However, it is unclear if this is due to breakfast omission per se, or secondary to lower carbohydrate intake over the day. To test whether impaired evening performance following breakfast omission persists when complete dietary compensation occurs at lunch, in a randomised cross-over design, eleven highly trained cyclists (age: 25 ± 7 y, VO2max: 61 ± 5 ml·kg-1·min-1) completed two trials: breakfast (B) and no breakfast (NB). During B, participants consumed an individualised breakfast (583 ± 54 kcal; 8-9am) and lunch (874 ± 80 kcal; 12-2pm), whilst during NB participants fasted until 12pm and then consumed a standardised lunch (1457 ± 134 kcal: 12-2pm). The overall energy (1457 ± 134 kcal) and macronutrient profile (carbohydrate: 81.5 ± 0.4%, fat: 5.8 ± 0.1%, protein: 12.7 ± 0.3%) was identical in both trials, with timing the only difference. Mean power output during a 20 km time trial performed in the evening was ~3% lower in NB compared to B (mean difference [95% CI]: -9.1 [-15.3, -2.9] watts, p < 0.01 for condition main effect). No differences in heart rate, blood glucose or blood lactate concentrations were apparent, but perception of effort appeared to be higher in the early stages of the time trial in NB compared to B despite lower power output. Impaired high-intensity endurance performance in the evening following breakfast omission is related to meal timing rather than carbohydrate intake / availability. Provision of an early morning high-carbohydrate meal should be considered to optimise evening exercise performance.
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Affiliation(s)
- Richard S Metcalfe
- Applied Sports Technology Exercise and Medicine Research Centre, Swansea University, Wales, UK
| | - Matthew Thomas
- Applied Sports Technology Exercise and Medicine Research Centre, Swansea University, Wales, UK
| | - Christopher Lamb
- Applied Sports Technology Exercise and Medicine Research Centre, Swansea University, Wales, UK
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Elhusseini R, Fares EJ, Obeid O. Phosphorus supplementation raised the heart rate of male water polo players during a randomised graded dryland exercise test. BMJ Open Sport Exerc Med 2020; 6:e000714. [PMID: 32405431 PMCID: PMC7202719 DOI: 10.1136/bmjsem-2019-000714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2020] [Indexed: 11/04/2022] Open
Abstract
ObjectiveThe impact of phosphorus supplementation on athletic performance is unclear. Ingestion of phosphorus for several days has been reported to increase cardiac capacity, improve oxygen muscle kinetics and enhance lactate buffering capacity. Recent studies have shown that phosphorus ingestion with a meal increases postprandial glucose uptake and thermogenesis. The present study aimed to assess the effect of acute phosphorus ingestion with a meal on specific workload parameters.MethodsA double-blind, crossover trial of 12 male water polo players between 18 and 22 years old was conducted. Overnight fasted subjects were asked to cycle for 20 min before ingesting 100 g of glucose with phosphorus or placebo (400 mg). Three hours later, they were asked to perform a graded cycling exercise for 25 min.ResultsExpenditure, respiratory quotient, perception of fatigue and exercise efficiency were similar between treatments. However, heart rate was significantly higher in the phosphorus group (142±10 beats/min) compared with placebo (135±10 beats/min).ConclusionExercise performance 3 hours after the coingestion of glucose with phosphorus did not affect substrate use, while heart rate was increased. The heart rate increase could be attributed to a rise in core body temperature.Trial registration numberNCT03101215.
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Affiliation(s)
- Rami Elhusseini
- Department of Nutrition and Food Sciences, Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon
| | - Elie-Jacques Fares
- Department of Nutrition and Food Sciences, Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon
| | - Omar Obeid
- Department of Nutrition and Food Sciences, Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon
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Malone JJ, MacLaren DPM, Campbell IT, Hulton AT. A 3-day dietary manipulation affects muscle glycogen and results in modifications of carbohydrate and fat metabolism during exercise when hyperglycaemic. Eur J Appl Physiol 2020; 120:873-882. [DOI: 10.1007/s00421-020-04326-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 02/12/2020] [Indexed: 01/25/2023]
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Session RPE During Prolonged Exercise Training. Int J Sports Physiol Perform 2020; 15:292-294. [DOI: 10.1123/ijspp.2019-0137] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/03/2019] [Accepted: 05/08/2019] [Indexed: 11/18/2022]
Abstract
Purpose: Although the session rating of perceived exertion (sRPE) is primarily a marker of internal training load (TL), it may be sensitive to external TL determining factors, such as duration and volume. Thus, sRPE could provide further information on accumulated fatigue not available from markers of internal TL. Therefore, the purpose of this study was to investigate sRPE during heavy training bouts at relatively constant intensity. Methods: Eleven university swimmers performed a high-volume training session consisting of 4 × 10 × 100-yd (4 × 10 × 91.4 m). Repetition lap time and heart rate were measured for each repetition and averaged for each set. Blood lactate concentration was measured after each set. At the end of each set, a 10-minute rest period was allowed, during which sRPE values were obtained, as if the training bout had ended. Results: There were no differences between sets for lap time (P = .096), heart rate (P = .717), and blood lactate concentration (P = .466), suggesting that the subjects were working at the same external and internal intensity. There was an increase (P = .0002) in sRPE between sets (first 4 [1.2], second 5 [1.3], third 7 [1.3], and fourth 8 [1.5]), suggesting that even when maintaining the same intensity, the perception of the entire workload increased with duration. Conclusions: Increases in duration, although performed with a consistent internal and external intensity, influences sRPE. These findings support the concept that sRPE may provide additional information on accumulated fatigue not available from other markers of TL.
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Pryor JL, Johnson EC, Yoder HA, Looney DP. Keeping Pace: A Practitioner-Focused Review of Pacing Strategies in Running. Strength Cond J 2020. [DOI: 10.1519/ssc.0000000000000505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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The ergogenic potency of carbohydrate mouth rinse on endurance running performance of dehydrated athletes. Eur J Appl Physiol 2019; 119:1711-1723. [PMID: 31098832 DOI: 10.1007/s00421-019-04161-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 05/09/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE To examine the effect of carbohydrate (CHO) mouth rinsing on endurance running responses and performance in dehydrated individuals. METHODS In a double blind, randomised crossover design, 12 well-trained male runners completed 4 running time to exhaustion (TTE) trials at a speed equivalent to 70% of VO2peak in a thermoneutral condition. Throughout each run, participants mouth rinsed and expectorated every 15 min either 25 mL of 6% CHO or a placebo (PLA) solution for 10 s. The four TTEs consisted of two trials in the euhydrated (EU-CHO and EU-PLA) and two trials in the dehydrated (DY-CHO and DY-PLA) state. Prior to each TTE run, participants were dehydrated via exercise and allowed a passive rest period during which they were fed and either rehydrated equivalent to their body mass deficit (i.e., EU trials) or ingested only 50 mL of water (DY trials). RESULTS CHO mouth rinsing significantly improved TTE performance in the DY compared to the EU trials (78.2 ± 4.3 vs. 76.9 ± 3.8 min, P = 0.02). The arousal level of the runners was significantly higher in the DY compared to the EU trials (P = 0.02). There was no significant difference among trials in heart rate, plasma glucose and lactate, and psychological measures. CONCLUSIONS CHO mouth rinsing enhanced running performance significantly more when participants were dehydrated vs. euhydrated due to the greater sensitivity of oral receptors related to thirst and central mediated activation. These results show that level of dehydration alters the effect of brain perception with presence of CHO.
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Funnell MP, Mears SA, Bergin-Taylor K, James LJ. Blinded and unblinded hypohydration similarly impair cycling time trial performance in the heat in trained cyclists. J Appl Physiol (1985) 2019; 126:870-879. [DOI: 10.1152/japplphysiol.01026.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Knowledge of hydration status may contribute to hypohydration-induced exercise performance decrements; therefore, this study compared blinded and unblinded hypohydration on cycling performance. Fourteen trained, nonheat-acclimated cyclists (age: 25 ± 5 yr; V̇o2peak: 63.3 ± 4.7 ml·kg−1·min−1; cycling experience: 6 ± 3 yr) were pair matched to blinded (B) or unblinded (UB) groups. After familiarization, subjects completed euhydrated (B-EUH; UB-EUH) and hypohydrated (B-HYP; UB-HYP) trials in the heat (31°C); 120-min cycling preload (50% Wpeak) and a time trial (~15 min). During the preload of all trials, 0.2 ml water·kg body mass−1 was ingested every 10 min, with additional water provided during EUH trials to match sweat losses. To blind the B group, a nasogastric tube was inserted in both trials and used to provide water in B-EUH. The preload induced similar ( P = 0.895) changes in body mass between groups (B-EUH: −0.6 ± 0.5%; B-HYP: −3.0 ± 0.5%; UB-EUH: −0.5 ± 0.3%; UB-HYP −3.0 ± 0.3%). All variables responded similarly between B and UB groups ( P ≥ 0.558), except thirst ( P = 0.004). Changes typical of hypohydration (increased heart rate, rating of perceived exertion, gastrointestinal temperature, serum osmolality and thirst, and decreased plasma volume; P ≤ 0.017) were apparent in HYP by 120 min. Time trial performance was similar between groups ( P = 0.710) and slower ( P ≤ 0.013) with HYP for B (B-EUH: 903 ± 89 s; B-HYP: 1,008 ± 121 s; −11.4%) and UB (UB-EUH: 874 ± 108 s; UB-HYP: 967 ± 170 s; −10.1%). Hypohydration of ~3% body mass impairs time trial performance in the heat, regardless of knowledge of hydration status. NEW & NOTEWORTHY This study demonstrates, for the first time, that knowledge of hydration status does not exacerbate the negative performance consequences of hypohydration when hypohydration is equivalent to ~3% body mass. This is pivotal for the interpretation of the many previous studies that have not blinded subjects to their hydration status and suggests that these previous studies are not likely to be confounded by the overtness of the methods used to induce hypohydration.
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Affiliation(s)
- Mark P. Funnell
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom
| | - Stephen A. Mears
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom
| | - Kurt Bergin-Taylor
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom
| | - Lewis J. James
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, United Kingdom
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22
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Cummins CJ, Gray AJ, Shorter KA, Halaki M, Orr R. Energetic Demands of Interchange and Full-Match Rugby League Players. J Strength Cond Res 2019; 32:3447-3455. [PMID: 28135224 DOI: 10.1519/jsc.0000000000001801] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cummins, CJ, Gray, AJ, Shorter, KA, Halaki, M, and Orr, R. Energetic demands of interchange and full-match rugby league players. J Strength Cond Res 32(12): 3456-3464, 2018-The purpose of this study was to describe and compare the metabolic demands of rugby league for interchange and full-match players in relation to positional groups. Eighteen elite rugby league players were recruited. A time-motion model was used to estimate the energy expenditure and metabolic demands of rugby league match-play using Global Positioning System (GPS) technology. This approach uses players' GPS velocity-time curves to examine running velocity. Players were categorized into positional groups (outside backs, adjustables, wide-running, and hit-up forwards) and then further categorized into full-match or interchange players. Compared with their full-match counterparts, interchange wide-running forwards expended greater energy (43.1 ± 6.1 vs. 28.6 ± 7.5 kJ·kg, p ≤ 0.001, effect size [ES] = -2.38) and produced a higher anaerobic index (p = 0.016, ES = 0.56) and mean power (7.4%, p = 0.003, ES = 0.66) per match. Full-match adjustables expended 94.8% more energy (p ≤ 0.001, ES = -2.3) and performed more moderate accelerations (10.1%, p = 0.014, ES = -0.57) and decelerations (7.6%, p = 0.017, ES = -0.8), than their interchange counterparts. Outside backs did not interchange and hit-up forwards rarely (n = 2) played an entire match. Differing metabolic demands were identified for interchange and full-match players across positional groups, suggesting position-specific conditioning drills are required to model the energetic demands of match-play.
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Affiliation(s)
- Cloe J Cummins
- Exercise and Sports Science, Faculty of Health Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Adrian J Gray
- School of Science and Technology, The University of New England, Armidale, NSW, Australia
| | - Kathleen A Shorter
- School of Science and Technology, The University of New England, Armidale, NSW, Australia
| | - Mark Halaki
- Exercise and Sports Science, Faculty of Health Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Rhonda Orr
- Exercise and Sports Science, Faculty of Health Sciences, The University of Sydney, Sydney, NSW, Australia
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Francois ME, Cosgrove SD, Walker NM, Lucas SJ, Black KE. Physiological responses to a five-day adventure race: Continuous blood glucose, hemodynamics and metabolites the 2012 GODZone field-study. J Exerc Sci Fit 2019; 16:78-82. [PMID: 30662498 PMCID: PMC6323162 DOI: 10.1016/j.jesf.2018.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 07/15/2018] [Accepted: 07/19/2018] [Indexed: 11/16/2022] Open
Abstract
Background/Objective Adventure racing is an ultra-endurance activity that imposes a unique multifaceted stress on the human body. The purpose of this field study was to examine the physiological responses to a 5-day adventure race. Methods Eight competitors, two teams (1 female each) in the 2012 GODZone adventure race volunteered. Competitors trekked, cycled and paddled ∼326 km in ∼116 hours. Continuous glucose was measured the day before and throughout. Body mass, urinary solutes, and blood pressure and heart rate during resting, standing, and repeated squat-stand conditions, were assessed pre and post. Results Despite no changes in mean blood glucose levels, there was increased glycemic variability (Standard deviation glucose; Pre: 0.5 ± 0.1 vs Race: 1.0 ± 0.2 mmol/L, p = 0.02) and periods of hypoglycemia (i.e., Min glucose Pre: 4.1 ± 0.3 vs Race: 3.6 ± 0.5 mmol/L, p = 0.05) during the race. After the race, the blood pressure during resting, standing and squat-stand conditions was significantly lower, by 14 ± 14 mmHg, 16 ± 15 mmHg and 18 ± 15 mmHg (all p < 0.05), respectively, with no change in heart rate. During five-days of adventure racing there is increased glycemic variability and more frequent periods of low blood glucose levels. Additionally, following the race pronounced hypotension is observed in competitors. Conclusion We observed more frequent glucose fluctuations, lower glucose levels and significant perturbations in blood pressure control. Further research is warranted to examine the long-term impact of adventure racing on metabolic and cardiovascular function. Five-days of adventure racing can cause blood pressure pertubations. Adventure racing results in fluctuations of blood glucose. There are periods of hypoglycemia during an adventure race which maynot be captured by pre-post- measures.
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Affiliation(s)
- Monique E Francois
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | | | - Nicole M Walker
- Department of Human Nutrition, University of Otago, New Zealand
| | - Samuel Je Lucas
- Department of Physiology, University of Otago, New Zealand.,School of Sport, Exercise & Rehabilitation Sciences, University of Birmingham, Birmingham, UK
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McAdam J, McGinnis K, Ory R, Young K, Frugé AD, Roberts M, Sefton J. Estimation of energy balance and training volume during Army Initial Entry Training. J Int Soc Sports Nutr 2018; 15:55. [PMID: 30486851 PMCID: PMC6264031 DOI: 10.1186/s12970-018-0262-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 11/11/2018] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Adequate dietary intake is important for promoting adaptation and prevention of musculoskeletal injury in response to large volumes of physical training such as Army Initial Entry Training (IET). The purpose of this study was to evaluate training volume and dietary intake and estimate energy balance in Army IET soldiers. METHODS Dietary intake was assessed by collecting diet logs for three meals on each of three, non-consecutive days during the first week of IET. Training volume was measured across 13 weeks of training using Actigraph wGT3X accelerometers. Training intensity was classified using Sasaki vector magnitude three cut points. Energy expenditure estimates were calculated during weeks two and three of training using the modified Harris-Benedict equation and by estimation of active energy expenditure using metabolic equivalents for each classification of physical activity. All data is presented as mean ± standard deviation. RESULTS A total of 111 male soldiers (ht. = ± 173 ± 5.8 cm, age = 19 ± 2 years, mass = 71.6. ± 12.4 kg) completed diet logs and were monitored with Actigraphs. IET soldiers performed on average 273 ± 62 min low, 107 ± 42 min moderate, 26 ± 22 min vigorous, and 10 ± 21 min of very vigorous intensity physical activity daily across 13 weeks. The estimated total daily energy expenditure was on average 3238 ± 457 kcals/d during weeks two and three of IET. Compared to week one caloric intake, there was a caloric deficit of 595 ± 896 kcals/d on average during weeks two and three of IET. Regression analysis showed that body weight was a significant predictor for negative energy balance (adj. R2 = 0.54, p < 0.001), whereby a 1 kg increase in body mass was associated with a 53 kcal energy deficit. CONCLUSIONS Based on week one dietary assessment, IET soldiers did not consume adequate calories and nutrients to meet training needs during red phase (weeks one through three). This may directly affect soldier performance and injury frequency. IET soldiers undergo rigorous training, and these data may help direct future guidelines for adequate nourishment to optimize soldier health and performance.
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Affiliation(s)
- Jeremy McAdam
- Warrior Research Center, School of Kinesiology, Auburn University, 301 Wire Road, Auburn, AL, 36849, USA
| | - Kaitlin McGinnis
- Warrior Research Center, School of Kinesiology, Auburn University, 301 Wire Road, Auburn, AL, 36849, USA
| | - Rian Ory
- Warrior Research Center, School of Kinesiology, Auburn University, 301 Wire Road, Auburn, AL, 36849, USA
| | - Kaelin Young
- Molecular and Applied Sciences Laboratory, School of Kinesiology, Auburn University, Auburn, AL, 36849, USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine (Auburn Campus), Auburn, AL, 36849, USA
| | - Andrew D Frugé
- Department of Nutrition, Dietetics, and Hospitality Management, College of Human Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Michael Roberts
- Molecular and Applied Sciences Laboratory, School of Kinesiology, Auburn University, Auburn, AL, 36849, USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine (Auburn Campus), Auburn, AL, 36849, USA
| | - JoEllen Sefton
- Warrior Research Center, School of Kinesiology, Auburn University, 301 Wire Road, Auburn, AL, 36849, USA.
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Baldassarre R, Bonifazi M, Piacentini MF. Pacing profile in the main international open-water swimming competitions. Eur J Sport Sci 2018; 19:422-431. [PMID: 30293524 DOI: 10.1080/17461391.2018.1527946] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
PURPOSE Different aspects of pacing in endurance events have been investigated, however, there are very limited information on pacing strategies during open-water swimming. The aim was to describe and compare the pacing profile used by male and female open-water swimmers (OW-swimmers) during the 5-, 10- and 25 km races in the main international competitions. METHODS A total of 438 performances were analysed for 5 km, 579 for 10 km and 189 for 25 km, from 2012 to 2017. Swimmers were divided into four groups based on finishing time. G1 whose finishing times were within 0.5% of the winner's time, G2 between 0.51% and 1% slower than winner's time; G3 between 1.1% and 2% slower than winner's time; G4 over 2% of winner's time. Kolmogorov-Smirnov test was used to verify the normal distribution of data and repeated measures ANOVA was performed. RESULTS G1 adopted a negative pacing and significantly increased the speed in the last split compared with the other groups during the 5-, 10- and 25-km races in both males and females (p < .001). During the 5- and 10-km race, the last split speed of G1 was significantly faster compared to the other groups in both males and females (p < .05). CONCLUSIONS OW-swimmers that used a conservative approach remaining in G1 until the finish of the race, increase the possibility to win a medal in the main international competitions.
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Affiliation(s)
- Roberto Baldassarre
- a Department of Movement, Human and Health Sciences , University of Rome Foro Italico , Rome , Italy
| | - Marco Bonifazi
- b Department of Medical, Surgical and Neuro Sciences , University of Siena , Siena , Italy
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McMorris T, Barwood M, Corbett J. Central fatigue theory and endurance exercise: Toward an interoceptive model. Neurosci Biobehav Rev 2018; 93:93-107. [DOI: 10.1016/j.neubiorev.2018.03.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/15/2018] [Accepted: 03/22/2018] [Indexed: 12/20/2022]
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Abstract
The rating-of-perceived-exertion (RPE) template is thought to regulate pacing and has been shown to be very robust in different circumstances. PURPOSE The primary purpose was to investigate whether the RPE template can be manipulated by changing the race distance during the course of a time trial. The secondary purpose was to study how athletes cope with this manipulation, especially in terms of the RPE template. METHOD Trained male subjects (N = 10) performed 3 cycling time trials: a 10-km (TT10), a 15-km (TT15), and a manipulated 15-km (TTman). During the TTman, subjects started the time trial believing that they were going to perform a 10-km time trial. However, at 7.5 km they were told that it was a 15-km time trial. RESULTS A significant main effect of time-trial condition on RPE scores until kilometer 7.5 was found (P = .016). Post hoc comparisons showed that the RPE values of the TT15 were lower than the RPE values of the TT10 (difference 0.60; CI95% 0.11, 1.0) and TTman (difference 0.73; CI95% 0.004, 1.5). After the 7.5 km, a transition phase occurs, in which an interaction effect is present (P = .011). After this transition phase, the RPE values of TTman and TT15 did not statistically differ (P = 1.00). CONCLUSIONS This novel distance-endpoint manipulation demonstrates that it is possible to switch between RPE templates. A clear shift in RPE during the TTman is present between the RPE templates of the TT10 and TT15. The shift strongly supports suggestions that pacing is regulated using an RPE template.
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Venhorst A, Micklewright D, Noakes TD. Towards a three-dimensional framework of centrally regulated and goal-directed exercise behaviour: a narrative review. Br J Sports Med 2017; 52:957-966. [PMID: 28835409 DOI: 10.1136/bjsports-2016-096907] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 06/19/2017] [Accepted: 07/21/2017] [Indexed: 01/10/2023]
Abstract
The Central Governor Model (CGM) ignited a paradigm shift from concepts of catastrophic failure towards central regulation of exercise performance. However, the CGM has focused on the central integration of afferent feedback in homeostatic control. Accordingly, it neglected the important role of volitional self-regulatory control and the integration of affective components inherently attached to all physiological cues. Another limitation is the large reliance on the Gestalt phenomenon of perceived exertion. Thus, progress towards a comprehensive multidimensional model of perceived fatigability and exercise regulation is needed. Drawing on Gate Control Theory of pain, we propose a three-dimensional framework of centrally regulated and goal-directed exercise behaviour, which differentiates between sensory, affective and cognitive processes shaping the perceptual milieu during exercise. We propose that: (A) perceived mental strain and perceived physical strain are primary determinants of pacing behaviour reflecting sensory-discriminatory processes necessary to align planned behaviour with current physiological state, (B) core affect plays a primary and mediatory role in exercise and performance regulation, and its underlying two dimensions hedonicity and arousal reflect affective-motivational processes triggering approach and avoidance behaviour, and (C) the mindset-shift associated with an action crisis plays a primary role in volitional self-regulatory control reflecting cognitive-evaluative processes between further goal-pursuit and goal-disengagement. The proposed framework has the potential to enrich theory development in centrally regulated and goal-directed exercise behaviour by emphasising the multidimensional dynamic processes underpinning perceived fatigability and provides a practical outline for investigating the complex interplay between the psychophysiological determinants of pacing and performance during prolonged endurance exercise.
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Affiliation(s)
- Andreas Venhorst
- Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, South Africa
| | - Dominic Micklewright
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK
| | - Timothy D Noakes
- Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, South Africa
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Scalzo RL, Paris HL, Binns SE, Davis JL, Beals JW, Melby CL, Luckasen GJ, Hickey MS, Miller BF, Hamilton KL, Bell C. Ergogenic properties of metformin in simulated high altitude. Clin Exp Pharmacol Physiol 2017; 44:729-738. [DOI: 10.1111/1440-1681.12761] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/22/2017] [Accepted: 03/28/2017] [Indexed: 12/24/2022]
Affiliation(s)
- Rebecca L. Scalzo
- Department of Health and Exercise Science Colorado State University Fort Collins CO USA
| | - Hunter L. Paris
- Department of Health and Exercise Science Colorado State University Fort Collins CO USA
| | - Scott E. Binns
- Department of Health and Exercise Science Colorado State University Fort Collins CO USA
| | - Janelle L. Davis
- Department of Health and Exercise Science Colorado State University Fort Collins CO USA
| | - Joseph W. Beals
- Department of Health and Exercise Science Colorado State University Fort Collins CO USA
| | - Christopher L. Melby
- Department of Food Science and Human Nutrition Colorado State University Fort Collins CO USA
| | - Gary J. Luckasen
- Heart Center of the Rockies University of Colorado Health Fort Collins CO USA
| | - Matthew S. Hickey
- Department of Health and Exercise Science Colorado State University Fort Collins CO USA
| | - Benjamin F. Miller
- Department of Health and Exercise Science Colorado State University Fort Collins CO USA
| | - Karyn L. Hamilton
- Department of Health and Exercise Science Colorado State University Fort Collins CO USA
| | - Christopher Bell
- Department of Health and Exercise Science Colorado State University Fort Collins CO USA
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St Clair Gibson A, Swart J, Tucker R. The interaction of psychological and physiological homeostatic drives and role of general control principles in the regulation of physiological systems, exercise and the fatigue process – The Integrative Governor theory. Eur J Sport Sci 2017; 18:25-36. [DOI: 10.1080/17461391.2017.1321688] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- A. St Clair Gibson
- Faculty of Health, Sport and Human Performance, University of Waikato, Hamilton, New Zealand
| | - J. Swart
- Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Cape Town, South Africa
| | - R. Tucker
- Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa
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Middle cerebral artery blood flow velocity during a 4 km cycling time trial. Eur J Appl Physiol 2017; 117:1241-1248. [DOI: 10.1007/s00421-017-3612-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 04/10/2017] [Indexed: 11/26/2022]
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Woods AL, Garvican-Lewis LA, Lundy B, Rice AJ, Thompson KG. New approaches to determine fatigue in elite athletes during intensified training: Resting metabolic rate and pacing profile. PLoS One 2017; 12:e0173807. [PMID: 28296943 PMCID: PMC5351856 DOI: 10.1371/journal.pone.0173807] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 02/27/2017] [Indexed: 11/29/2022] Open
Abstract
Background Elite rowers complete a high volume of training across a number of modalities to prepare for competition, including periods of intensified load, which may lead to fatigue and short-term performance decrements. As yet, the influence of substantial fatigue on resting metabolic rate (RMR) and exercise regulation (pacing), and their subsequent utility as monitoring parameters, has not been explicitly investigated in elite endurance athletes. Method Ten National-level rowers completed a four-week period of intensified training. RMR, body composition and energy intake were assessed PRE and POST the four-week period using indirect calorimetry, Dual-Energy X-Ray Densitometry (DXA), and three-day food diary, respectively. On-water rowing performance and pacing strategy was evaluated from 5 km time trials. Wellness was assessed weekly using the Multicomponent Training Distress Scale (MTDS). Results Significant decreases in absolute (mean ± SD of difference, p-value: -466 ± 488 kJ.day-1, p = 0.01) and relative RMR (-8.0 ± 8.1 kJ.kg.FFM-1, p = 0.01) were observed. Significant reductions in body mass (-1.6 ± 1.3 kg, p = 0.003) and fat mass (-2.2 ± 1.2 kg, p = 0.0001) were detected, while energy intake was unchanged. On-water 5 km rowing performance worsened (p < 0.05) and an altered pacing strategy was evident. Fatigue and total mood disturbance significantly increased across the cycle (p < 0.05), and trends were observed for reduced vigour and increased sleep disturbance (p < 0.1). Conclusion Four weeks of heavy training decreased RMR and body composition variables in elite rowers and induced substantial fatigue, likely related to an imbalance between energy intake and output. This study demonstrates that highly experienced athletes do not necessarily select the correct energy intake during periods of intensified training, and this can be assessed by reductions in RMR and body composition. The shortfall in energy availability likely affected recovery from training and altered 5 km time trial pacing strategy, resulting in reduced performance.
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Affiliation(s)
- Amy L. Woods
- Research Institute for Sport and Exercise, University of Canberra, Bruce ACT, Australia
- Australian Institute of Sport, Bruce ACT, Australia
- * E-mail:
| | - Laura A. Garvican-Lewis
- Research Institute for Sport and Exercise, University of Canberra, Bruce ACT, Australia
- Australian Institute of Sport, Bruce ACT, Australia
- Mary Mackillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, Australia
| | | | | | - Kevin G. Thompson
- Research Institute for Sport and Exercise, University of Canberra, Bruce ACT, Australia
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Marquet LA, Hausswirth C, Molle O, Hawley JA, Burke LM, Tiollier E, Brisswalter J. Periodization of Carbohydrate Intake: Short-Term Effect on Performance. Nutrients 2016; 8:nu8120755. [PMID: 27897989 PMCID: PMC5188410 DOI: 10.3390/nu8120755] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 11/03/2016] [Accepted: 11/09/2016] [Indexed: 11/25/2022] Open
Abstract
Background: “Sleep-low” consists of a sequential periodization of carbohydrate (CHO) availability—low glycogen recovery after “train high” glycogen-depleting interval training, followed by an overnight-fast and light intensity training (“train low”) the following day. This strategy leads to an upregulation of several exercise-responsive signaling proteins, but the chronic effect on performance has received less attention. We investigated the effects of short-term exposure to this strategy on endurance performance. Methods: Following training familiarization, 11 trained cyclists were divided into two groups for a one-week intervention—one group implemented three cycles of periodized CHO intake to achieve the sleep-low strategy over six training sessions (SL, CHO intake: 6 g·kg−1·day−1), whereas the control group consumed an even distribution of CHO over the day (CON). Tests were a 2 h submaximal ride and a 20 km time trial. Results: SL improved their performance (mean: +3.2%; p < 0.05) compared to CON. The improvement was associated with a change in pacing strategy with higher power output during the second part of the test. No change in substrate utilization was observed after the training period for either group. Conclusion: Implementing the “sleep-low” strategy for one week improved performance by the same magnitude previously seen in a three-week intervention, without any significant changes in selected markers of metabolism.
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Affiliation(s)
- Laurie-Anne Marquet
- Laboratory of Sport, Expertise and Performance, French National Institute of Sport, Expertise and Performance (INSEP), 75012 Paris, France.
- Université Côte d'Azur, LAMHESS, 06205 Nice, France.
| | - Christophe Hausswirth
- Laboratory of Sport, Expertise and Performance, French National Institute of Sport, Expertise and Performance (INSEP), 75012 Paris, France.
| | - Odeline Molle
- Laboratory of Sport, Expertise and Performance, French National Institute of Sport, Expertise and Performance (INSEP), 75012 Paris, France.
| | - John A Hawley
- Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, VIC 3065, Australia.
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 5UA, UK.
| | - Louise M Burke
- Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, VIC 3065, Australia.
- Sports Nutrition, Australian Institute of Sport (AIS), Belconnen, ACT 2617, Australia.
| | - Eve Tiollier
- Laboratory of Sport, Expertise and Performance, French National Institute of Sport, Expertise and Performance (INSEP), 75012 Paris, France.
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Kriel Y, Hampson DB, Lambert EV, Tucker R, Albertus Y, Claassen A, Gibson ASC. Visual Stimulus Deprivation and Manipulation of Auditory Timing Signals on Pacing Strategy. Percept Mot Skills 2016; 105:1227-41. [DOI: 10.2466/pms.105.4.1227-1241] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this study the effect of complete visual stimulus deprivation and manipulation of auditory timing signals during this deprivation on pacing strategy during an exercise bout were examined. 7 moderately trained men completed four 40-km cycling time trials under laboratory conditions in either normal light or absolute darkness, with either correct or manipulated auditory timing signals and without any other timing cues. The subjects were told to perform the time trial in the fastest time possible. There was no significant difference among trials for time to perform the trial, power output, heart rate, or ratings of perceived exertion, indicating that brain-control mechanisms responsible for pacing are not affected by manipulation of light or auditory signals.
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Affiliation(s)
- Y. Kriel
- UCT/MRC Research Unit of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town
| | - D. B. Hampson
- UCT/MRC Research Unit of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town
| | - E. V. Lambert
- UCT/MRC Research Unit of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town
| | - R. Tucker
- UCT/MRC Research Unit of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town
| | - Y. Albertus
- UCT/MRC Research Unit of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town
| | - A. Claassen
- UCT/MRC Research Unit of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town
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Yunoki T, Matsuura R, Yamanaka R, Afroundeh R, Lian CS, Shirakawa K, Ohtsuka Y, Yano T. Relationship between motor corticospinal excitability and ventilatory response during intense exercise. Eur J Appl Physiol 2016; 116:1117-26. [PMID: 27055665 DOI: 10.1007/s00421-016-3374-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 03/28/2016] [Indexed: 11/26/2022]
Abstract
PURPOSE Effort sense has been suggested to be involved in the hyperventilatory response during intense exercise (IE). However, the mechanism by which effort sense induces an increase in ventilation during IE has not been fully elucidated. The aim of this study was to determine the relationship between effort-mediated ventilatory response and corticospinal excitability of lower limb muscle during IE. METHODS Eight subjects performed 3 min of cycling exercise at 75-85 % of maximum workload twice (IE1st and IE2nd). IE2nd was performed after 60 min of resting recovery following 45 min of submaximal cycling exercise at the workload corresponding to ventilatory threshold. Vastus lateralis muscle response to transcranial magnetic stimulation of the motor cortex (motor evoked potentials, MEPs), effort sense of legs (ESL, Borg 0-10 scale), and ventilatory response were measured during the two IEs. RESULTS The slope of ventilation (l/min) against CO2 output (l/min) during IE2nd (28.0 ± 5.6) was significantly greater than that (25.1 ± 5.5) during IE1st. Mean ESL during IE was significantly higher in IE2nd (5.25 ± 0.89) than in IE1st (4.67 ± 0.62). Mean MEP (normalized to maximal M-wave) during IE was significantly lower in IE2nd (66 ± 22 %) than in IE1st (77 ± 24 %). The difference in mean ESL between the two IEs was significantly (p < 0.05, r = -0.82) correlated with the difference in mean MEP between the two IEs. CONCLUSIONS The findings suggest that effort-mediated hyperventilatory response to IE may be associated with a decrease in corticospinal excitability of exercising muscle.
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Affiliation(s)
- Takahiro Yunoki
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan.
| | - Ryouta Matsuura
- Department of Health and Physical Education, Joetsu University of Education, Joetsu, Japan
| | - Ryo Yamanaka
- Japan Institute of Sports Sciences, Tokyo, Japan
| | - Roghayyeh Afroundeh
- Department of Physical Education and Sports Science, Faculty of Education and Psychology, University of Mohaghegh Ardabilli, Ardabil, Iran
| | - Chang-Shun Lian
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan
| | - Kazuki Shirakawa
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan
| | - Yoshinori Ohtsuka
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan
| | - Tokuo Yano
- Department of Human Development Sciences, Faculty of Education, Hokkaido University, Kita-11, Nishi-7, Kita-ku, Sapporo, 060-0811, Japan
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What are the Physiological Mechanisms for Post-Exercise Cold Water Immersion in the Recovery from Prolonged Endurance and Intermittent Exercise? Sports Med 2016; 46:1095-109. [DOI: 10.1007/s40279-016-0483-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Skorski S, Hammes D, Schwindling S, Veith S, Pfeiffer M, Ferrauti A, Kellmann M, Meyer T. Effects of training-induced fatigue on pacing patterns in 40-km cycling time trials. Med Sci Sports Exerc 2015; 47:593-600. [PMID: 25003772 DOI: 10.1249/mss.0000000000000439] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION In some endurance sports, athletes complete several competitions within a short period, resulting in accumulated fatigue. It is unclear whether fatigued athletes choose the same pacing pattern (PP) as when they have recovered. PURPOSE This study aimed to analyze effects of fatigue on PP of cyclists during a 40-km time trial (TT). METHODS Twenty-three male cyclists (28.8 ± 7.6 yr) completed three 40-km TT on a cycle ergometer. TT were conducted before (TT1) and after (TT2) a 6-d training period. A third TT was carried out after 72 h of recovery (TT3). Training days consisted of two cycling sessions: mornings, 1 h at 95% of lactate threshold or 3 × 5 × 30 s all-out sprint; afternoons, 3 h at 80% individual anaerobic threshold. Four-kilometer split times (min) and RPE were recorded during TT. RESULTS Performance decreased from TT1 to TT2 (65.7 ± 3.5 vs 66.7 ± 3.3 min; P < 0.05) and increased from TT2 to TT3 (66.7 ± 3.3 vs 65.5 ± 3.3 min; P < 0.01). PP showed a significant difference between TT1 and TT2 (P < 0.001) as well as between TT2 and TT3 (P < 0.01). PP in TT1 and TT3 showed no significant difference (P > 0.05). In TT1 and TT3, cyclists started faster in the first 4 km compared with TT2. RPE course showed no significant difference between TT (P > 0.05). CONCLUSIONS Fatigue reversibly changes the PP of cyclists during a 40-km TT. Participants reduced their power output until premature exhaustion seemed very unlikely. This supports the assumption that pacing includes a combination of anticipation and feedback mechanisms.
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Affiliation(s)
- Sabrina Skorski
- 1Institute of Sports and Preventive Medicine, Saarland University, Saarbrücken, GERMANY; 2Institute of Sports Science, Johannes-Gutenberg University, Mainz, GERMANY; 3Faculty of Sports Science, Ruhr-University of Bochum, Bochum, GERMANY; and 4School of Human Movement Studies and School of Psychology, University of Queensland, Brisbane, Queensland, AUSTRALIA
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Baker LB, Rollo I, Stein KW, Jeukendrup AE. Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance. Nutrients 2015; 7:5733-63. [PMID: 26184303 PMCID: PMC4517026 DOI: 10.3390/nu7075249] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/26/2015] [Accepted: 06/30/2015] [Indexed: 12/24/2022] Open
Abstract
Intermittent sports (e.g., team sports) are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1–2 h). Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1) potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2) the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3) what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports). Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30–60 g/h in the form of a 6%–7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before and during a game seems to have the greatest impact on intermittent sports performance towards the end of the game.
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Affiliation(s)
- Lindsay B Baker
- Gatorade Sports Science Institute, Barrington, IL 60010, USA.
| | - Ian Rollo
- Gatorade Sports Science Institute, Beaumont Park, Leicester LE3 9QH, UK.
| | | | - Asker E Jeukendrup
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK.
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Che Jusoh MR, Morton RH, Stannard SR, Mündel T. A reliable preloaded cycling time trial for use in conditions of significant thermal stress. Scand J Med Sci Sports 2015; 25 Suppl 1:296-301. [PMID: 25943681 DOI: 10.1111/sms.12332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2014] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to assess the reliability of a 15-min time trial preloaded with 45 min of fixed-intensity cycling under laboratory conditions of thermal stress. Eight trained cyclists/triathletes (41 ± 10 years, VO2 peak: 69 ± 8 mL/kg/min, peak aerobic power: 391 ± 72 W) completed three trials (the first a familiarization) where they cycled at ∼ 55% VO2 peak for 45 min followed by a 15-min time trial (∼75% VO2 peak) under conditions of significant thermal stress (WBGT: 26.7 ± 0.8 °C, frontal convective airflow: 20 km/h). Seven days separated the trials, which were conducted at the same time of day following 24 h of exercise and dietary control. Reliability increased when a familiarization trial was performed, with the resulting coefficient of variation and intraclass correlation coefficient of the work completed during the 15-min time trial, 3.6% and 0.96, respectively. Therefore, these results demonstrate a high level of reliability for a 15-min cycling time trial following a 45-min preload when performed under laboratory conditions of significant thermal stress using trained cyclists/triathletes.
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Affiliation(s)
- M R Che Jusoh
- School of Sport and Exercise, Massey University, Palmerston North, New Zealand
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Improvement of 10-km Time-Trial Cycling With Motivational Self-Talk Compared With Neutral Self-Talk. Int J Sports Physiol Perform 2015; 10:166-71. [DOI: 10.1123/ijspp.2014-0059] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Purpose:Unpleasant physical sensations during maximal exercise may manifest themselves as negative cognitions that impair performance, alter pacing, and are linked to increased rating of perceived exertion (RPE). This study examined whether motivational self-talk (M-ST) could reduce RPE and change pacing strategy, thereby enhancing 10-km time-trial (TT) cycling performance in contrast to neutral self-talk (N-ST).Methods:Fourteen men undertook 4 TTs, TT1–TT4. After TT2, participants were matched into groups based on TT2 completion time and underwent M-ST (n = 7) or N-ST (n = 7) after TT3. Performance, power output, RPE, and oxygen uptake (VO2) were compared across 1-km segments using ANOVA. Confidence intervals (95%CI) were calculated for performance data.Results:After TT3 (ie, before intervention), completion times were not different between groups (M-ST, 1120 ± 113 s; N-ST, 1150 ± 110 s). After M-ST, TT4 completion time was faster (1078 ± 96 s); the N-ST remained similar (1165 ± 111 s). The M-ST group achieved this through a higher power output and VO2 in TT4 (6th–10th km). RPE was unchanged. CI data indicated the likely true performance effect lay between 13- and 71-s improvement (TT4 vs TT3).Conclusion:M-ST improved endurance performance and enabled a higher power output, whereas N-ST induced no change. The VO2 response matched the increase in power output, yet RPE was unchanged, thereby inferring a perceptual benefit through M-ST. The valence and content of self-talk are important determinants of the efficacy of this intervention. These findings are primarily discussed in the context of the psychobiological model of pacing.
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Iyoho AE, MacFadden LN, Ng LJ. Prediction of performance reduction in self-paced exercise as modulated by the rating of perceived exertion. Eur J Appl Physiol 2014; 115:675-90. [PMID: 25417169 DOI: 10.1007/s00421-014-3054-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 11/11/2014] [Indexed: 11/25/2022]
Abstract
PURPOSE Rating of perceived exertion (RPE) is a scale of exercise difficulty and has been hypothesized to be a regulator of work rate during self-pacing. The goal of this work was to develop a dynamic prediction of RPE and to characterize the control strategy employed to reduce work rate during self-paced exercise using RPE as feedback. METHODS Training and test data were acquired from the literature to develop a linear regression of RPE as a function of four physiological variables: core temperature, mean-weighted skin temperature, metabolic rate, and integral of relative oxygen consumption (R (2) = 0.85). A thermoregulatory model was used to predict core and mean-weighted skin temperature. Utilizing self-paced cycling and running data from the literature, we characterized reductions in work rate with a proportional-derivative control algorithm with RPE as feedback. RESULTS Bland-Altman analysis revealed the necessity to parameterize RPE equations for untrained and endurance-trained individuals. Afterwards, dynamic predictions of RPE were accurate for a wide range of activity levels and air temperatures for walking, running, and cycling (LoA and bias of 2.3 and -0.03, respectively). For self-paced exercise, the control algorithm characterized the trend and magnitude of work rate reductions for cycling and running, and showed regulated RPE to be less conservative for shorter vs. longer duration exercise. CONCLUSIONS A novel methodology to characterize self-paced work intensity, based upon dynamic physiologic response, is provided. The complete model is a useful tool that estimates performance decrements during self-paced exercise and predicts tolerance time for exhaustive fixed-rate exercise.
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Affiliation(s)
- Anthony E Iyoho
- L-3 Applied Technologies Inc., 10770 Wateridge Circle, Suite 200, San Diego, CA, 92121, USA,
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Correia-Oliveira CR, Santos RA, Silva-Cavalcante MD, Bertuzzi R, Kiss MAPD, Bishop DJ, Lima-Silva AE. Prior low- or high-intensity exercise alters pacing strategy, energy system contribution and performance during a 4-km cycling time trial. PLoS One 2014; 9:e110320. [PMID: 25330452 PMCID: PMC4203780 DOI: 10.1371/journal.pone.0110320] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 09/20/2014] [Indexed: 11/21/2022] Open
Abstract
We analyzed the influence of prior exercise designed to reduce predominantly muscle glycogen in either type I or II fibers on pacing and performance during a 4-km cycling time trial (TT). After preliminary and familiarization trials, in a randomized, repeated-measures crossover design, ten amateur cyclists performed: 1) an exercise designed to reduce glycogen of type I muscle fibers, followed by a 4-km TT (EX-FIB I); 2) an exercise designed to reduce glycogen of type II muscle fibers, followed by a 4-km TT (EX-FIB II) and; 3) a 4-km TT, without the prior exercise (CONT). The muscle-glycogen-reducing exercise in both EX-FIB I and EX-FIB II was performed in the evening, ∼12 h before the 4-km TT. Performance time was increased and power output (PO) was reduced in EX-FIB I (432.8±8.3 s and 204.9±10.9 W) and EX-FIB II (428.7±6.7 s and 207.5±9.1 W) compared to CONT (420.8±6.4 s and 218.4±9.3 W; P<0.01), without a difference between EX-FIB I and EX-FIB II (P>0.05). The PO was lower in EX-FIB I than in CONT at the beginning and middle of the trial (P<0.05). The mean aerobic contribution during EX-FIB I was also significantly lower than in CONT (P<0.05), but there was no difference between CONT and EX-FIB II or between EX-FIB I and EX-FIB II (P>0.05). The integrated electromyography was unchanged between conditions (P>0.05). Performance may have been impaired in EX-FIB I due a more conservative pacing at the beginning and middle, which was associated with a reduced aerobic contribution. In turn, the PO profile adopted in EX-FIB II was also reduced throughout the trial, but the impairment in performance may be attributed to a reduced glycolytic contribution (i.e. reduced lactate accumulation).
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Affiliation(s)
- Carlos Rafaell Correia-Oliveira
- Sports Science Research Group, Department of Physical Education and Sports Science, CAV, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
- Endurance Performance Research Group, School of Physical Education and Sport, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Ralmony Alcantara Santos
- Sports Science Research Group, Department of Physical Education and Sports Science, CAV, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
- Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo, São Paulo, Brazil
| | - Marcos David Silva-Cavalcante
- Sports Science Research Group, Department of Physical Education and Sports Science, CAV, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
- Endurance Performance Research Group, School of Physical Education and Sport, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Romulo Bertuzzi
- Endurance Performance Research Group, School of Physical Education and Sport, University of São Paulo, São Paulo, São Paulo, Brazil
| | | | - David John Bishop
- Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria University, Melbourne, Victoria, Australia
| | - Adriano Eduardo Lima-Silva
- Sports Science Research Group, Department of Physical Education and Sports Science, CAV, Federal University of Pernambuco, Vitória de Santo Antão, Pernambuco, Brazil
- * E-mail:
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Wu SSX, Peiffer JJ, Brisswalter J, Nosaka K, Abbiss CR. Factors influencing pacing in triathlon. Open Access J Sports Med 2014; 5:223-34. [PMID: 25258562 PMCID: PMC4172046 DOI: 10.2147/oajsm.s44392] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Triathlon is a multisport event consisting of sequential swim, cycle, and run disciplines performed over a variety of distances. This complex and unique sport requires athletes to appropriately distribute their speed or energy expenditure (ie, pacing) within each discipline as well as over the entire event. As with most physical activity, the regulation of pacing in triathlon may be influenced by a multitude of intrinsic and extrinsic factors. The majority of current research focuses mainly on the Olympic distance, whilst much less literature is available on other triathlon distances such as the sprint, half-Ironman, and Ironman distances. Furthermore, little is understood regarding the specific physiological, environmental, and interdisciplinary effects on pacing. Therefore, this article discusses the pacing strategies observed in triathlon across different distances, and elucidates the possible factors influencing pacing within the three specific disciplines of a triathlon.
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Affiliation(s)
- Sam SX Wu
- Centre for Exercise and Sports Science Research, School of Exercise and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - Jeremiah J Peiffer
- School of Psychology and Exercise Science, Murdoch University, Perth, WA, Australia
| | - Jeanick Brisswalter
- Laboratory of Human Motricity, Education Sport and Health, University of Nice Sophia Antipolis, Nice, France
| | - Kazunori Nosaka
- Centre for Exercise and Sports Science Research, School of Exercise and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - Chris R Abbiss
- Centre for Exercise and Sports Science Research, School of Exercise and Health Sciences, Edith Cowan University, Perth, WA, Australia
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Marino FE. If only I were paramecium too! A case for the complex, intelligent system of anticipatory regulation in fatigue. FATIGUE-BIOMEDICINE HEALTH AND BEHAVIOR 2014. [DOI: 10.1080/21641846.2014.957038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Nassif C, Gomes AR, Peixoto GHC, Chagas MH, Soares DD, Silami-Garcia E, Drinkwater EJ, Cannon J, Marino FE. The effect of double--blind carbohydrate ingestion during 60 km of self-paced exercise in warm ambient conditions. PLoS One 2014; 9:e104710. [PMID: 25110952 PMCID: PMC4128743 DOI: 10.1371/journal.pone.0104710] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 07/11/2014] [Indexed: 11/28/2022] Open
Abstract
This study evaluated double blind ingestions of placebo (PLA) versus 6% carbohydrate (CHO) either as capsules (c) or beverage (b) during 60 km self-paced cycling in the heat (32°C and 50% relative humidity). Ten well-trained males (mean ± SD: 26±3 years; 64.5±7.7 kg and 70.7±8.8 ml.kg−1.min−1 maximal oxygen consumption) completed four separate 60 km time trials (TT) punctuated by 1 km sprints (14, 29, 44, 59 km) whilst ingesting either PLAb or PLAc or CHOb or CHOc. The TT was not different among treatments (PLAb 130.2±11.2 min, CHOb 140.5±18.1 min, PLAc 143.1±29.2 min, CHOc 137.3±20.1 min; P>0.05). Effect size (Cohen’s d) for time was only moderate when comparing CHOb – PLAb (d = 0.68) and PLAb – PLAc (d = 0.57) whereas all other ES were ‘trivial’ to ‘small’. Mean speed throughout the trial was significantly higher for PLAb only (P<0.05). Power output was only different (P<0.05) between the sprints and low intensity efforts within and across conditions. Core and mean skin temperatures were similar among trials. We conclude that CHO ingestion is of little or no benefit as a beverage compared with placebo during 60 km TT in the heat.
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Affiliation(s)
- Camila Nassif
- School of Human Movement Studies, Charles Sturt University, Bathurst, New South Wales, Australia
| | - Aline Regina Gomes
- School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Pampulha, Belo Horizonte, Brazil
| | - Gustavo H. C. Peixoto
- School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Pampulha, Belo Horizonte, Brazil
| | - Mauro Heleno Chagas
- School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Pampulha, Belo Horizonte, Brazil
| | - Danusa Dias Soares
- School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Pampulha, Belo Horizonte, Brazil
| | - Emerson Silami-Garcia
- School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Pampulha, Belo Horizonte, Brazil
| | - Eric J. Drinkwater
- School of Human Movement Studies, Charles Sturt University, Bathurst, New South Wales, Australia
| | - Jack Cannon
- School of Human Movement Studies, Charles Sturt University, Bathurst, New South Wales, Australia
| | - Frank E. Marino
- School of Human Movement Studies, Charles Sturt University, Bathurst, New South Wales, Australia
- * E-mail:
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Physiological and psychological effects of deception on pacing strategy and performance: a review. Sports Med 2014; 43:1243-57. [PMID: 24002790 DOI: 10.1007/s40279-013-0094-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The aim of an optimal pacing strategy during exercise is to enhance performance whilst ensuring physiological limits are not surpassed, which has been shown to result in a metabolic reserve at the end of the exercise. There has been debate surrounding the theoretical models that have been proposed to explain how pace is regulated, with more recent research investigating a central control of exercise regulation. Deception has recently emerged as a common, practical approach to manipulate key variables during exercise. There are a number of ways in which deception interventions have been designed, each intending to gain particular insights into pacing behaviour and performance. Deception methodologies can be conceptualised according to a number of dimensions such as deception timing (prior to or during exercise), presentation frequency (blind, discontinuous or continuous) and type of deception (performance, biofeedback or environmental feedback). However, research evidence on the effects of deception has been perplexing and the use of complex designs and varied methodologies makes it difficult to draw any definitive conclusions about how pacing strategy and performance are affected by deception. This review examines existing research in the area of deception and pacing strategies, and provides a critical appraisal of the different methodological approaches used to date. It is hoped that this analysis will inform the direction and methodology of future investigations in this area by addressing the mechanisms through which deception impacts upon performance and by elucidating the potential application of deception techniques in training and competitive settings.
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Abstract
The aim of this current opinion article is to provide a contemporary perspective on the role of brain regulatory control of paced performances in response to exercise challenges. There has been considerable recent conjecture as to the role of the brain during exercise, and it is now broadly accepted that fatigue does not occur without brain involvement and that all voluntary activity is likely to be paced at some level by the brain according to individualised priorities and knowledge of personal capabilities. This article examines the role of pacing in managing and distributing effort to successfully accomplish physical tasks, while extending existing theories on the role of the brain as a central controller of performance. The opinion proposed in this article is that a central regulator operates to control exercise performance but achieves this without the requirement of an intelligent central governor located in the subconscious brain. It seems likely that brain regulation operates at different levels of awareness, such that minor homeostatic challenges are addressed automatically without conscious awareness, while larger metabolic disturbances attract conscious awareness and evoke a behavioural response. This supports the view that the brain regulates exercise performance but that the interpretation of the mechanisms underlying this effect have not yet been fully elucidated.
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Affiliation(s)
- A M Edwards
- Institute of Sport and Exercise Science, James Cook University, Cairns, QLD, Australia,
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Bartlett JD, Hawley JA, Morton JP. Carbohydrate availability and exercise training adaptation: too much of a good thing? Eur J Sport Sci 2014; 15:3-12. [PMID: 24942068 DOI: 10.1080/17461391.2014.920926] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Traditional nutritional approaches to endurance training have typically promoted high carbohydrate (CHO) availability before, during and after training sessions to ensure adequate muscle substrate to meet the demands of high daily training intensities and volumes. However, during the past decade, data from our laboratories and others have demonstrated that deliberately training in conditions of reduced CHO availability can promote training-induced adaptations of human skeletal muscle (i.e. increased maximal mitochondrial enzyme activities and/or mitochondrial content, increased rates of lipid oxidation and, in some instances, improved exercise capacity). Such data have led to the concept of 'training low, but competing high' whereby selected training sessions are completed in conditions of reduced CHO availability (so as to promote training adaptation), but CHO reserves are restored immediately prior to an important competition. The augmented training response observed with training-low strategies is likely regulated by enhanced activation of key cell signalling kinases (e.g. AMPK, p38MAPK), transcription factors (e.g. p53, PPARδ) and transcriptional co-activators (e.g. PGC-1α), such that a co-ordinated up-regulation of both the nuclear and mitochondrial genomes occurs. Although the optimal practical strategies to train low are not currently known, consuming additional caffeine, protein, and practising CHO mouth-rinsing before and/or during training may help to rescue the reduced training intensities that typically occur when 'training low', in addition to preventing protein breakdown and maintaining optimal immune function. Finally, athletes should practise 'train-low' workouts in conjunction with sessions undertaken with normal or high CHO availability so that their capacity to oxidise CHO is not blunted on race day.
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Affiliation(s)
- Jonathan D Bartlett
- a Research Institute for Sport and Exercise Sciences , Liverpool John Moores University , Liverpool , UK
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Halperin I, Aboodarda SJ, Basset FA, Byrne JM, Behm DG. Pacing strategies during repeated maximal voluntary contractions. Eur J Appl Physiol 2014; 114:1413-20. [PMID: 24658878 DOI: 10.1007/s00421-014-2872-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/05/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE Pacing strategies have been reported to occur during continuous cyclical exercises. However, currently no studies have examined if pacing takes place during repeated maximal voluntary muscle contractions (MVCs). Accordingly, the purpose of this study was to examine if informing subjects on the number of MVCs they would perform would affect force and root mean squared electromyography (EMG), during similar fatiguing protocols. METHODS Thirty well-trained male subjects completed three fatiguing protocols in a randomized order. In the control condition participants were informed they would perform 12 MVCs, and then completed all 12. In the unknown condition they were not told how many MVCs they would perform, but were stopped after 12. Lastly, in the deception condition they were initially told they would perform only 6 MVCs, but after the 6 contractions they were asked to perform a few more repetitions and were stopped after 12. RESULTS Compared to the unknown condition, subjects demonstrated greater forces (p < 0.05, ES = 0.35-1.14, 2-7.5%) and biceps EMG (p < 0.05, ES = 0.6, 6%) in the deception condition during the first six MVCs. Additionally, under all conditions subjects applied greater forces in the last repetition (#12) relative to the previous one (#11) (p < 0.06, ES = 0.36-0.5, 2.8-3.8%). CONCLUSIONS The anticipation of performing a certain number of MVCs led the subjects to utilize different pacing strategies. The results also question the assumption that subjects followed the instruction to exert maximal effort during repeated MVCs.
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Affiliation(s)
- I Halperin
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada
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Correia-Oliveira CR, Bertuzzi R, Dal'Molin Kiss MAP, Lima-Silva AE. Strategies of dietary carbohydrate manipulation and their effects on performance in cycling time trials. Sports Med 2014; 43:707-19. [PMID: 23657935 DOI: 10.1007/s40279-013-0054-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The relationship between carbohydrate (CHO) availability and exercise performance has been thoroughly discussed. CHO improves performance in both prolonged, low-intensity and short, high-intensity exercises. Most studies have focused on the effects of CHO supplementation on the performance of constant-load, time-to-exhaustion exercises. Nevertheless, in the last 20 years, there has been a consistent increase in research on the effects of different forms of CHO supplementation (e.g., diet manipulation, CHO supplementation before or during exercise) on performance during closed-loop exercises, such as cycling time trials (TTs). A TT is a highly reproducible exercise and reflects a more realistic scenario of competition compared with the time-to-exhaustion test. CHO manipulation has been performed in various time periods, such as days before, minutes before, during a TT or in a matched manner (e.g. before and during a TT). The purpose of this review is to address the possible effects of these different forms of CHO manipulation on the performance during a cycling TT. Previous data suggest that when a high-CHO diet (~70% of CHO) is consumed before a TT (24-72 h before), the mean power output increases and reduces the TT time. When participants are supplemented with CHO (from 45 to 400 g) prior to a TT (from 2 min to 6 h before the TT), mean power output and time seem to improve due to an increase in CHO oxidation. Similarly, this performance also seems to increase when participants ingest CHO during a TT because such consumption maintains plasma glucose levels. A CHO mouth rinse also improves performance by activating several brain areas related to reward and motor control through CHO receptors in the oral cavity. However, some studies reported controversial results concerning the benefits of CHO on TT performance. Methodological issues such as time of supplementation, quantity, concentration and type of CHO ingested, as well as the TT duration and intensity, should be considered in future studies because small variations in any of these factors may have beneficial or adverse effects on TT performance.
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Affiliation(s)
- Carlos Rafaell Correia-Oliveira
- Sports Science Research Group, Faculty of Nutrition, Federal University of Alagoas, Lorival Melo Mota Avenue, S/N, Tabuleiro do Martins, Maceio, AL 57072970, Brazil
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