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Ramonas A, Laursen PB, Williden M, Kilding AE. The effect of acute manipulation of carbohydrate availability on high intensity running performance, running economy, critical speed, and substrate metabolism in trained Male runners. Eur J Sport Sci 2023; 23:1961-1971. [PMID: 36168815 DOI: 10.1080/17461391.2022.2130097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Completing selected training sessions with reduced glycogen availability is associated with greater signalling and improved muscle oxidative capacity, although it may impact the overall quality of the session. We examined the effects of low carbohydrate availability on high intensity exercise performance, running economy, critical speed, and substrate metabolism. On two occasions, nine male runners (V̇O2peak 60.3 ± 3.3 mL.kg-1.min-1) completed a glycogen depletion protocol involving 90-min at 75%vV̇O2peak followed by 10 × 1-min at 110% vV̇O2peak. This was followed either by high (HIGH) or low (LOW) carbohydrate intake (>6 g.kg-1.day-1 and <50 g.day-1, respectively) until completion of a performance protocol on day 2 consisting of a series of time-trials (TT) (50m to 3000m) and physiological assessments. There were no differences between LOW and HIGH for any TT distance (mean TT performance times for LOW and HIGH were: 3000m TT 651.7 ± 52.8s and 646.4 ± 52.5s, 1500 m TT 304.0 ± 20.2s and 304.2 ± 22.1s, 400 m TT 67.64 ± 4.2s and 67.3 ± 3.8s, 50 m TT 7.27 ± 0.44s and 7.25 ± 0.45s, respectively, P > 0.05), though some athletes performed better in LOW (n = 5). While fat oxidation in LOW was significantly greater than HIGH (Δ0.32 ± 0.14 g.min-1; P < 0.001 at 14 km.h-1 and Δ0.34 ± 0.12 g.min-1 at 16 km.h-1; P < 0.01), running economy did not differ between trials (P > 0.05). Acute manipulation of carbohydrate availability showed immediate effects on substrate metabolism evidenced by greater fat oxidation without changes in RE. Acute low carbohydrate availability did not affect high intensity running performance across a range of distances.Highlights Acute manipulation of muscle glycogen availability using an exercise and dietary manipulation protocol did not affect subsequent high intensity running performance across a range of running distances.Reduced muscle glycogen resulted in a marked increase in fat oxidation in low glycogen condition but no changes in running economy or critical speed.Individual factors should be considered when prescribing high intensity sessions with restricted carbohydrate availability.
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Affiliation(s)
- Andrius Ramonas
- Auckland University of Technology, Sports Performance Research Institute NZ, Auckland, New Zealand
| | - Paul B Laursen
- Auckland University of Technology, Sports Performance Research Institute NZ, Auckland, New Zealand
| | - Micalla Williden
- Auckland University of Technology, Sports Performance Research Institute NZ, Auckland, New Zealand
| | - Andrew E Kilding
- Auckland University of Technology, Sports Performance Research Institute NZ, Auckland, New Zealand
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2
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Sandbakk Ø, Pyne DB, McGawley K, Foster C, Talsnes RK, Solli GS, Millet GP, Seiler S, Laursen PB, Haugen T, Tønnessen E, Wilber R, van Erp T, Stellingwerff T, Holmberg HC, Bucher Sandbakk S. The Evolution of World-Class Endurance Training: The Scientist's View on Current and Future Trends. Int J Sports Physiol Perform 2023:1-5. [PMID: 37369366 DOI: 10.1123/ijspp.2023-0131] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023]
Abstract
BACKGROUND Elite sport is continuously evolving. World records keep falling and athletes from a longer list of countries are involved. PURPOSE This commentary was designed to provide insights into present and future trends associated with world-class endurance training based on the perspectives, experience, and knowledge of an expert panel of 25 applied sport scientists. RESULTS The key drivers of development observed in the past 10-15 years were related to (1) more accessible scientific knowledge for coaches and athletes combined with (2) better integration of practical and scientific exchange across multidisciplinary perspectives within professionalized elite athlete support structures, as well as (3) utilization of new technological advances. Based on these perspectives, we discerned and exemplified the main trends in the practice of endurance sports into the following categories: better understanding of sport-specific demands; improved competition execution; larger, more specific, and more precise training loads; improved training quality; and a more professional and healthier lifestyle. The main areas expected to drive future improvements were associated with more extensive use of advanced technology for monitoring and prescribing training and recovery, more precise use of environmental and nutritional interventions, better understanding of athlete-equipment interactions, and greater emphasis on preventing injuries and illnesses. CONCLUSIONS These expert insights can serve as a platform and inspiration to develop new hypotheses and ideas, encourage future collaboration between researchers and sport practitioners, and, perhaps most important, stimulate curiosity and further collaborative studies about the training, physiology, and performance of endurance athletes.
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Affiliation(s)
- Øyvind Sandbakk
- Center for Elite Sports Research, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim,Norway
| | - David B Pyne
- Research Institute for Sport and Exercise, University of Canberra, Canberra, ACT,Australia
| | - Kerry McGawley
- Swedish Winter Sports Research Center, Department of Health Sciences, Mid Sweden University, Östersund,Sweden
| | - Carl Foster
- Department of Exercise and Sport Science, University of Wisconsin-La Crosse, La Crosse, WI,USA
| | - Rune Kjøsen Talsnes
- Center for Elite Sports Research, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim,Norway
| | - Guro Strøm Solli
- Department of Sports Science and Physical Education, Nord University, Trondheim,Norway
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Bodø,Switzerland
| | - Stephen Seiler
- Department of Sport Science and Physical Education, University of Agder, Kristiansand,Norway
| | - Paul B Laursen
- Sports Performance and Athlete Development Environments (SPADE), University of Agder, Kristiansand,Norway
- Sports Performance Research Institute New Zealand (SPRINZ), AUT University, Auckland,New Zealand
| | - Thomas Haugen
- School of Health Sciences, Kristiania University College, Oslo,Norway
| | - Espen Tønnessen
- School of Health Sciences, Kristiania University College, Oslo,Norway
| | - Randy Wilber
- United States Olympic Committee, Colorado Springs, CO,USA
| | - Teun van Erp
- Division of Movement Science and Exercise Therapy (MSET), Department of Exercise, Sport and Lifestyle Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg,South Africa
| | | | - Hans-Christer Holmberg
- Department of Health Sciences, Luleå University of Technology, Luleå,Sweden
- School of Kinesiology, University of British Columbia, Vancouver, BC,Canada
| | - Silvana Bucher Sandbakk
- Department of Teacher Education, Norwegian University of Science and Technology, Trondheim,Norway
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3
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Ramonas A, Laursen PB, Williden M, Chang WL, Kilding AE. Carbohydrate intake before and during high intensity exercise with reduced muscle glycogen availability affects the speed of muscle reoxygenation and performance. Eur J Appl Physiol 2023:10.1007/s00421-023-05162-y. [PMID: 36897400 DOI: 10.1007/s00421-023-05162-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 02/16/2023] [Indexed: 03/11/2023]
Abstract
Muscle glycogen state and carbohydrate (CHO) supplementation before and during exercise may impact responses to high-intensity interval training (HIIT). This study determined cardiorespiratory, substrate metabolism, muscle oxygenation, and performance when completing HIIT with or without CHO supplementation in a muscle glycogen depleted state. On two occasions, in a cross-over design, eight male cyclists performed a glycogen depletion protocol prior to HIIT during which either a 6% CHO drink (60 g.hr-1) or placebo (%CHO, PLA) was consumed. HIIT consisted of 5 × 2 min at 80% peak power output (PPO), 3 × 10-min bouts of steady-state (SS) cycling (50, 55, 60% PPO), and a time-to-exhaustion (TTE) test. There was no difference in SS [Formula: see text], HR, substrate oxidation and gross efficiency (GE %) between CHO and PLA conditions. A faster rate of muscle reoxygenation (%. s-1) existed in PLA after the 1st (Δ - 0.23 ± 0.22, d = 0.58, P < 0.05) and 3rd HIIT intervals (Δ - 0.34 ± 0.25, d = 1.02, P < 0.05). TTE was greater in CHO (7.1 ± 5.4 min) than PLA (2.5 ± 2.3 min, d = 0.98, P < 0.05). CHO consumption before and during exercise under reduced muscle glycogen conditions did not suppress fat oxidation, suggesting a strong regulatory role of muscle glycogen on substrate metabolism. However, CHO ingestion provided a performance benefit under intense exercise conditions commenced with reduced muscle glycogen. More research is needed to understand the significance of altered muscle oxygenation patterns during exercise.
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Affiliation(s)
- Andrius Ramonas
- School of Sports and Recreation, Auckland University of Technology, Sports Performance Research Institute New Zealand (SPRINZ), AUT University, PO Box 92006, Auckland, 1142, New Zealand.
| | - Paul B Laursen
- School of Sports and Recreation, Auckland University of Technology, Sports Performance Research Institute New Zealand (SPRINZ), AUT University, PO Box 92006, Auckland, 1142, New Zealand
| | - Micalla Williden
- School of Sports and Recreation, Auckland University of Technology, Sports Performance Research Institute New Zealand (SPRINZ), AUT University, PO Box 92006, Auckland, 1142, New Zealand
| | | | - Andrew E Kilding
- School of Sports and Recreation, Auckland University of Technology, Sports Performance Research Institute New Zealand (SPRINZ), AUT University, PO Box 92006, Auckland, 1142, New Zealand
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4
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Cipryan L, Litschmannova M, Maffetone PB, Plews DJ, Dostal T, Hofmann P, Laursen PB. Very Low-Carbohydrate High-Fat Diet Improves Risk Markers for Cardiometabolic Health More Than Exercise in Men and Women With Overfat Constitution: Secondary Analysis of a Randomized Controlled Clinical Trial. Front Nutr 2022; 9:867690. [PMID: 35677551 PMCID: PMC9168912 DOI: 10.3389/fnut.2022.867690] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/29/2022] [Indexed: 12/15/2022] Open
Abstract
Purpose This randomized controlled parallel-group study examined the effects of a very low-carbohydrate high-fat (VLCHF) diet and high-intensity interval training (HIIT) program over 12-weeks on cardiometabolic risk factors in individuals with overfat constitution. Methods Ninety-one participants out of 109 completed the study. The participants were randomly allocated to the HIIT (N = 22), VLCHF (N = 25), VLCHF+HIIT (N = 25), or control (N = 19) groups for 12 weeks. Fasting plasma samples were collected before the intervention and after 4 and 12 weeks. The analyzed outcomes included complete blood count, glucose, insulin, glycated hemoglobin, triglycerides (TG), cholesterol, high- and low-density lipoprotein (HDL-C and LDL-C), lipoprotein(a), adiponectin (Adpn), leptin (Lep), tumor necrosis factor α (TNF-α), other interleukins (hs-IL-6, IL-1β, and IL-10), and IL-1RA. The homeostasis model assessment of insulin resistance (HOMA-IR), Adpn/Lep ratio, TG/HDL-C ratio, and TyG index were calculated and analyzed. Blood pressure was measured before the intervention, after 4, 8, and 12 weeks (ClinicalTrials.gov: NCT03934476). Results Absolute changes in HOMA-IR, Adpn/Lep ratio, LDL-C, and diastolic blood pressure after 12 weeks differed by study groups (p < 0.05). The most pronounced changes were revealed in the VLCHF (ΔM [95% CI]; HOMA-IR: −0.75 [−1.13; −0.55]; Adpn/Lep: 9.34 [6.33; 37.39]; LDL-C: 0.06 [−0.12; 0.50] mmol/l) and VLCHF+HIIT (HOMA-IR: −0.44 [−1.14; 0.12]; Adpn/Lep: 4.26 [2.24; 13.16]; LDL-C: 0.25 [−0.04; 0.50] mmol/l) groups. Conclusions A 12-week VLCHF diet intervention in individuals with overfat constitution is effective for favorable changes in HOMA-IR (compared to HIIT), Adpn/Lep ratio, and diastolic blood pressure. HIIT, or HIIT combined with the VLCHF diet, had no additional benefits for the analyzed variables. No adverse side effects were observed.
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Affiliation(s)
- Lukas Cipryan
- Department of Human Movement Studies & Human Motion Diagnostic Centre, The University of Ostrava, Ostrava, Czechia
- *Correspondence: Lukas Cipryan ; orcid.org/0000-0002-2403-8797
| | - Martina Litschmannova
- Department of Applied Mathematics, VSB—Technical University of Ostrava, Ostrava, Czechia
| | | | - Daniel J. Plews
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Tomas Dostal
- Department of Human Movement Studies & Human Motion Diagnostic Centre, The University of Ostrava, Ostrava, Czechia
| | - Peter Hofmann
- Institute of Human Movement Science, Sport & Health, Exercise Physiology, Training & Training Therapy Research Group, University of Graz, Graz, Austria
| | - Paul B. Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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5
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Affiliation(s)
- Philip B. Maffetone
- Independent Researcher, Storrs, CT, United States
- *Correspondence: Philip B. Maffetone
| | - Paul B. Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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6
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Maffetone PB, Laursen PB. Rethinking COVID-19 and Beyond: Prevention, Remedies, and Recovery. Front Public Health 2022; 10:748498. [PMID: 35284402 PMCID: PMC8904369 DOI: 10.3389/fpubh.2022.748498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 01/14/2022] [Indexed: 11/13/2022] Open
Abstract
In a relatively short timeframe, millions of deaths and illnesses associated with COVID-19 have been reported, accompanied by substantial economic losses, and overall, negatively impacting society. This experience should serve as a wakeup call to those in public health and healthcare, along with politicians and citizens: COVID-19 is considered a predictable and preventable disaster. While various reactive responses to address the pandemic were implemented, some with adverse effects, proactive measures in the years before COVID-19 were neglected. Predominately this involved the development of a preventable overfat pandemic, which played a key role in both rising rates of chronic disease, the comorbidities that increase the risk for COVID-19, along with associated inflammation and malnutrition. This increased the risk of infection in billions of people worldwide, which, in essence, primed society for high rates of COVID-19 infection. Excess body fat evolves primarily from poor nutrition, particularly the overconsumption of sugar and other refined carbohydrates, which replace the vital nutrients needed for optimal immune function. Sugar and refined carbohydrates must be considered the new tobacco, as these foods are also devoid of nutrients, and underly inflammatory chronic diseases. A balanced diet of nutrient-dense wholefood must be emphasized to combat infectious and inflammatory diseases. Implementing proactive preventive lifestyle changes must begin now, starting with simple, safe, and inexpensive dietary modifications that can quickly lead to a healthier population.
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7
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Cipryan L, Dostal T, Litschmannova M, Hofmann P, Maffetone PB, Laursen PB. Effects of a Very Low-Carbohydrate High-Fat Diet and High-Intensity Interval Training on Visceral Fat Deposition and Cardiorespiratory Fitness in Overfat Individuals: A Randomized Controlled Clinical Trial. Front Nutr 2021; 8:785694. [PMID: 34993222 PMCID: PMC8724307 DOI: 10.3389/fnut.2021.785694] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/30/2021] [Indexed: 12/11/2022] Open
Abstract
Purpose: This randomized controlled parallel-group study examined the effects of a very low-carbohydrate high-fat (VLCHF) diet and high-intensity interval training (HIIT) program over 12 weeks on visceral adipose tissue (VAT) and cardiorespiratory fitness (CRF) level in overfat individuals. Methods: Ninety-one participants were randomly allocated to the HIIT (N = 22), VLCHF (N = 25), VLCHF+HIIT (N = 25), or control (N = 19) groups for 12 weeks. Body composition and CRF were analyzed before the experimental period and after 4, 8, and 12 weeks. Dual-energy X-ray absorptiometry (DXA) and graded exercise test (GXT) to volitional exhaustion were used for the body composition and CRF assessments, respectively. Results: There were significant between-group differences in the VAT mass and body composition outcome changes. VAT mass decreased after 12 weeks only in the VLCHF and VLCHF+HIIT groups (p < 0.001, median [95% CI]: VLCHF: -142.0 [-187.0; -109.5] g; VLCHF+HIIT: -104.0 [-135.0; -71.0] g). Similarly, changes in body mass, total body fat, trunk fat mass, waist and hip circumferences were distinctly decreased in the VLCHF and VLCHF+HIIT groups, when compared to HIIT and Control groups. Total lean mass significantly decreased in the VLCHF and VLCHF+HIIT groups (-2.1 [-3.0; -1.6] kg and -2.5 [-3.6; -1.8] kg, respectively) after 12 weeks. While the HIIT program significantly increased total time to exhaustion in the GXT, peak oxygen uptake was unchanged. Conclusions: A VLCHF diet, either in isolation or in combination with HIIT, was shown to induce a significant reduction in VAT mass and body composition variables. HIIT alone did not cause such effects on body composition, but improved exercise capacity. Our findings indicate that the VLCHF diet and exercise training provoked different and isolated effects on body composition and CRF. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT03934476, identifier: NCT03934476.
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Affiliation(s)
- Lukas Cipryan
- Department of Human Movement Studies & Human Motion Diagnostic Centre, The University of Ostrava, Ostrava, Czechia
| | - Tomas Dostal
- Department of Human Movement Studies & Human Motion Diagnostic Centre, The University of Ostrava, Ostrava, Czechia
| | - Martina Litschmannova
- Department of Applied Mathematics, VSB – Technical University of Ostrava, Ostrava, Czechia
| | - Peter Hofmann
- Institute of Human Movement Science, Sport & Health, Exercise Physiology, Training & Training Therapy Research Group, University of Graz, Graz, Austria
| | | | - Paul B. Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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8
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Sandford GN, Laursen PB, Buchheit M. Anaerobic Speed/Power Reserve and Sport Performance: Scientific Basis, Current Applications and Future Directions. Sports Med 2021; 51:2017-2028. [PMID: 34398445 DOI: 10.1007/s40279-021-01523-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2021] [Indexed: 10/20/2022]
Abstract
Many individual and team sport events require extended periods of exercise above the speed or power associated with maximal oxygen uptake (i.e., maximal aerobic speed/power, MAS/MAP). In the absence of valid and reliable measures of anaerobic metabolism, the anaerobic speed/power reserve (ASR/APR) concept, defined as the difference between an athlete's MAS/MAP and their maximal sprinting speed (MSS)/peak power (MPP), advances our understanding of athlete tolerance to high speed/power efforts in this range. When exercising at speeds above MAS/MAP, what likely matters most, irrespective of athlete profile or locomotor mode, is the proportion of the ASR/APR used, rather than the more commonly used reference to percent MAS/MAP. The locomotor construct of ASR/APR offers numerous underexplored opportunities. In particular, how differences in underlying athlete profiles (e.g., fiber typology) impact the training response for different 'speed', 'endurance' or 'hybrid' profiles is now emerging. Such an individualized approach to athlete training may be necessary to avoid 'maladaptive' or 'non-responses'. As a starting point for coaches and practitioners, we recommend upfront locomotor profiling to guide training content at both the macro (understanding athlete profile variability and training model selection, e.g., annual periodization) and micro levels (weekly daily planning of individual workouts, e.g., short vs long intervals vs repeated sprint training and recovery time between workouts). More specifically, we argue that high-intensity interval training formats should be tailored to the locomotor profile accordingly. New focus and appreciation for the ASR/APR is required to individualize training appropriately so as to maximize athlete preparation for elite competition.
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Affiliation(s)
- Gareth N Sandford
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada. .,Canadian Sport Institute-Pacific, 4371 Interurban Road, Victoria, BC, V9E 2C5, Canada. .,Athletics Canada, Ottawa, ON, Canada.
| | - Paul B Laursen
- Sports Performance Research Institute NZ, Auckland University of Technology, Auckland, New Zealand.,HIIT Science, Revelstoke, BC, Canada
| | - Martin Buchheit
- HIIT Science, Revelstoke, BC, Canada.,Research Department, Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, France.,Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.,Kitman Labs, Performance Research Intelligence Initiative, Dublin, Ireland
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Zignoli A, Biral F, Fornasiero A, Sanders D, Erp TV, Mateo-March M, Fontana FY, Artuso P, Menaspà P, Quod M, Giorgi A, Laursen PB. Assessment of bike handling during cycling individual time trials with a novel analytical technique adapted from motorcycle racing. Eur J Sport Sci 2021; 22:1355-1363. [PMID: 34369299 DOI: 10.1080/17461391.2021.1966517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A methodology to study bike handling of cyclists during individual time trials (ITT) is presented. Lateral and longitudinal accelerations were estimated from GPS data of professional cyclists (n=53) racing in two ITT of different length and technical content. Acceleration points were plotted on a plot (g-g diagram) and they were enclosed in an ellipse. A correlation analysis was conducted between the area of the ellipse and the final ITT ranking. It was hypothesized that a larger area was associated to a better performance. An analytical model for the bike-cyclist system dynamics was used to conduct a parametric analysis on the influence of riding position on the shape of the g-g diagram. A moderate (n=27, r=-0.40, p=0.038) and a very large (n=26, r=-0.83, p<0.0001) association were found between the area of the enclosing ellipse and the final ranking in the two ITT. Interestingly, this association was larger in the shorter race with higher technical content. The analytical model suggested that maximal decelerations are highly influenced by the cycling position, road slope and speed. This investigation, for the first time, explores a novel methodology that can provide insights into bike handling, a large unexplored area of cycling performance.
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Affiliation(s)
- Andrea Zignoli
- Department of Industrial Engineering, University of Trento, Trento, Italy.,Prom Facility, Trentino Sviluppo, Trento, Italy.,CeRiSM Research Centre, University of Verona, Trento, Italy
| | - Francesco Biral
- Department of Industrial Engineering, University of Trento, Trento, Italy
| | | | - Dajo Sanders
- Department of Human Movement Science, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Teun Van Erp
- Division of Orthopaedic Surgery, Department of Surgical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
| | - Manuel Mateo-March
- Spanish Cycling Federation, Madrid, Spain.,Movistar Team, Abarca Sports, Pamplona, Spain
| | | | | | - Paolo Menaspà
- School of Medical and Health Sciences, Edith Cowan University, Perth, Australia
| | - Marc Quod
- Mitchelton-Scott Cycling Team, Adelaide, Australia
| | - Andrea Giorgi
- Androni Giocattoli-Sidermec Professional Cycling Team, Medical Staff, Italy.,Internal Medicine, Specialists Medicine and Rehabilitation Department. Functional Recovery and Re-education Unit. USL Toscana south-east
| | - Paul B Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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10
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Cipryan L, Dostal T, Plews DJ, Hofmann P, Laursen PB. Adiponectin/leptin ratio increases after a 12-week very low-carbohydrate, high-fat diet, and exercise training in healthy individuals: A non-randomized, parallel design study. Nutr Res 2020; 87:22-30. [PMID: 33596508 DOI: 10.1016/j.nutres.2020.12.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/16/2020] [Accepted: 12/03/2020] [Indexed: 12/12/2022]
Abstract
This study aimed to investigate the effect of a 12-week very low-carbohydrate, high-fat (VLCHF) diet and exercise on biomarkers of inflammation in healthy individuals. Since the anti-inflammatory effects of a ketogenic diet have been established, we hypothesized that the VLCHF diet, along with exercise, would have an additional favorable effect on biomarkers of inflammation. Twenty-four healthy individuals were allocated to the VLCHF diet (VLCHF: N = 12, age 25.3 ± 2.0 years, body mass 66.7 ± 9.8 kg, fat mass 21.5% ± 4.9%), or habitual diet (HD: N = 12, age 23.9 ± 3.8 years, body mass 72.7 ± 15.0 kg, fat mass 23.4 ± 8.4 %) group. Biomarkers of inflammation (adiponectin, leptin, and high-sensitive interleukin-6 [hs-IL-6]) and substrate metabolism (glycated hemoglobin, fasting glucose, triacylglycerides, and cholesterol) were analyzed from blood at baseline and after 12 weeks. The adiponectin-leptin ratio significantly increased in the VLCHF group after the intervention period (ES [95% CL]: -0.90 [-0.96, -0.77], P ≤ .001, BF10 = 22.15). The adiponectin-leptin ratio changes were associated with both a significant increase in adiponectin (-0.79 [-0.91, -0.54], P ≤ .001, BF10 = 9.43) and a significant decrease in leptin (0.58 [0.19, 0.81], P = .014, BF10 = 2.70). There was moderate evidence of changes in total cholesterol (-1.15 [-2.01, -0.27], P = .010, BF10 = 5.20), and LDL cholesterol (-1.12 [-2.01, -0.21], P = .016, BF10 = 4.56) in the VLCHF group. Body weight (kg) and fat mass (%) decreased in the VLCHF group by 5.4% and 14.9%, respectively. We found that in healthy young individuals, consuming a VLCHF diet while performing regular exercise over a 12-week period produced favorable changes in body weight and fat mass along with beneficial changes in serum adiponectin and leptin concentrations. These data support the use of a VLCHF diet strategy for the primary prevention of chronic diseases associated with systemic low-grade inflammation.
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Affiliation(s)
- Lukas Cipryan
- Department of Human Movement Studies and Human Motion Diagnostic Centre, The University of Ostrava, Ostrava, Czech Republic.
| | - Tomas Dostal
- Department of Human Movement Studies and Human Motion Diagnostic Centre, The University of Ostrava, Ostrava, Czech Republic.
| | - Daniel J Plews
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.
| | - Peter Hofmann
- Institute of Human Movement Science, Sport and Health; Exercise Physiology, Training and Training Therapy Research Group, University of Graz, Graz, Austria.
| | - Paul B Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.
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Casadio JR, Wiseman D, Kilding AE, Cotter JD, Laursen PB. Heat Training Improves Cardiovascular Responses And Briefly Blunts Sprint Performance In Elite Sprint Track Cyclists. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000679640.15724.fc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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13
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Maffetone P, Laursen PB. Maximum Aerobic Function: Clinical Relevance, Physiological Underpinnings, and Practical Application. Front Physiol 2020; 11:296. [PMID: 32300310 PMCID: PMC7142223 DOI: 10.3389/fphys.2020.00296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 03/16/2020] [Indexed: 11/13/2022] Open
Abstract
The earliest humans relied on large quantities of metabolic energy from the oxidation of fatty acids to develop larger brains and bodies, prevent and reduce disease risk, extend longevity, in addition to other benefits. This was enabled through the consumption of a high fat and low-carbohydrate diet (LCD). Increased fat oxidation also supported daily bouts of prolonged, low-intensity, aerobic-based physical activity. Over the past 40-plus years, a clinical program has been developed to help people manage their lifestyles to promote increased fat oxidation as a means to improve various aspects of health and fitness that include reducing excess body fat, preventing disease, and optimizing human performance. This program is referred to as maximum aerobic function, and includes the practical application of a personalized exercise heart rate (HR) formula of low-to-moderate intensity associated with maximal fat oxidation (MFO), and without the need for laboratory evaluations. The relationship between exercise training at this HR and associated laboratory measures of MFO, health outcomes and athletic performance must be verified scientifically.
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Affiliation(s)
- Philip Maffetone
- Independent Researcher, Ormond Beach, FL, United States.,Auckland University of Technology, Auckland, New Zealand
| | - Paul B Laursen
- Auckland University of Technology, Auckland, New Zealand
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Zignoli A, Fornasiero A, Ragni M, Pellegrini B, Schena F, Biral F, Laursen PB. Estimating an individual's oxygen uptake during cycling exercise with a recurrent neural network trained from easy-to-obtain inputs: A pilot study. PLoS One 2020; 15:e0229466. [PMID: 32163443 PMCID: PMC7069417 DOI: 10.1371/journal.pone.0229466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/06/2020] [Indexed: 11/23/2022] Open
Abstract
Measurement of oxygen uptake during exercise ([Formula: see text]) is currently non-accessible to most individuals without expensive and invasive equipment. The goal of this pilot study was to estimate cycling [Formula: see text] from easy-to-obtain inputs, such as heart rate, mechanical power output, cadence and respiratory frequency. To this end, a recurrent neural network was trained from laboratory cycling data to predict [Formula: see text] values. Data were collected on 7 amateur cyclists during a graded exercise test, two arbitrary protocols (Prot-1 and -2) and an "all-out" Wingate test. In Trial-1, a neural network was trained with data from a graded exercise test, Prot-1 and Wingate, before being tested against Prot-2. In Trial-2, a neural network was trained using data from the graded exercise test, Prot-1 and 2, before being tested against the Wingate test. Two analytical models (Models 1 and 2) were used to compare the predictive performance of the neural network. Predictive performance of the neural network was high during both Trial-1 (MAE = 229(35) mlO2min-1, r = 0.94) and Trial-2 (MAE = 304(150) mlO2min-1, r = 0.89). As expected, the predictive ability of Models 1 and 2 deteriorated from Trial-1 to Trial-2. Results suggest that recurrent neural networks have the potential to predict the individual [Formula: see text] response from easy-to-obtain inputs across a wide range of cycling intensities.
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Affiliation(s)
- Andrea Zignoli
- CeRiSM Research Centre, University of Verona, Rovereto (TN),
Italy
- Department of Neuroscience, Biomedicine and Movement, University of
Verona, Verona, Italy
- Department of Industrial Engineering, University of Trento, Trento,
Italy
| | - Alessandro Fornasiero
- CeRiSM Research Centre, University of Verona, Rovereto (TN),
Italy
- Department of Neuroscience, Biomedicine and Movement, University of
Verona, Verona, Italy
| | - Matteo Ragni
- Department of Industrial Engineering, University of Trento, Trento,
Italy
| | - Barbara Pellegrini
- CeRiSM Research Centre, University of Verona, Rovereto (TN),
Italy
- Department of Neuroscience, Biomedicine and Movement, University of
Verona, Verona, Italy
| | - Federico Schena
- CeRiSM Research Centre, University of Verona, Rovereto (TN),
Italy
- Department of Neuroscience, Biomedicine and Movement, University of
Verona, Verona, Italy
| | - Francesco Biral
- Department of Industrial Engineering, University of Trento, Trento,
Italy
| | - Paul B. Laursen
- Sports Performance Research Institute NZ, Auckland University of
Technology, Auckland, New Zealand
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Abstract
The previously described overfat pandemic, estimated to be 62-76% worldwide, is comprised of individuals with excess body fat sufficient to impair health. The overfat condition is common in those who are overweight and obese, and can also occur in significant numbers of normal-weight non-obese individuals. Being overfat increases the risk for a wide spectrum of common cardiovascular and metabolic (cardiometabolic) abnormalities, chronic diseases and physical impairment. In some ethnicities, up to 40% or more of those who are normal-weight and non-obese may be overfat, a figure twice that used in the original global overfat estimates. In addition to the rates of overfat outpacing overweight and obesity, non-White populations outnumber Whites 6:1, with the recently estimated overfat prevalence being low when considering ethnicities such as Asians, Chinese, Africans and Latin Americans, including these individuals living among predominantly White populations. An awareness of the extent of the overfat pandemic is important because excess body fat can precede cardiometabolic risk factors, chronic diseases, and physical disabilities, and can reduce quality of life and increase healthcare expenditure. The purpose of this Perspective is to demonstrate that the global overfat prevalence of 62-76% may be considerably underestimated.
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Cipryan L, Maffetone PB, Plews DJ, Laursen PB. Effects of a four-week very low-carbohydrate high-fat diet on biomarkers of inflammation: Non-randomised parallel-group study. Nutr Health 2020; 26:35-42. [PMID: 32000572 DOI: 10.1177/0260106020903206] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND It is commonly assumed that increased dietary fat and/or caloric excess induces chronic inflammatory processes, since the association between obesity and chronic adipose tissue with systemic inflammation has been shown previously. As far as we know, the reported health benefits of a VLCHF or ketogenic diet have not adequately involved an evaluation of biomarkers of inflammation. AIM This study investigated the effects of a four-week very low-carbohydrate high-fat (VLCHF) diet in healthy young individuals on biomarkers of inflammation. METHODS Eighteen moderately trained males (age 23.8 ± 2.1 years) were assigned to two groups. One group switched to a non-standardised VLCHF diet for four weeks, while the second group remained consuming their normal habitual diet (HD). Biomarkers of inflammation (adiponectin, leptin, resistin and interleukin-6) and substrate metabolism (fasting glucose and triacylglyceride concentrations) were analysed from blood at baseline and after four weeks. RESULTS There was moderate evidence for substantial changes in leptin serum concentrations in the VLCHF group, with small to large decreases compared to the HD group after four weeks (effect size = 0.78, 95% CI 0.42, 0.93, p = 0.008; Bayes Factor10 = 5.70). No substantial between-group change differences over time were found across any other biomarkers. CONCLUSIONS A four-week period of consuming a VLCHF diet in healthy young men was not associated with any considerable changes in markers of inflammation but showed evidence for lowered serum leptin concentrations relative to the HD group.
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Affiliation(s)
- Lukas Cipryan
- Department of Human Movement Studies and Human Motion Diagnostic Centre, Ostrava University, Czech Republic
| | | | - Daniel J Plews
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, New Zealand
| | - Paul B Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, New Zealand
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17
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Dostal T, Plews DJ, Hofmann P, Laursen PB, Cipryan L. Effects of a 12-Week Very-Low Carbohydrate High-Fat Diet on Maximal Aerobic Capacity, High-Intensity Intermittent Exercise, and Cardiac Autonomic Regulation: Non-randomized Parallel-Group Study. Front Physiol 2019; 10:912. [PMID: 31379612 PMCID: PMC6652046 DOI: 10.3389/fphys.2019.00912] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 07/03/2019] [Indexed: 11/13/2022] Open
Abstract
Purpose The aim of this non-randomized parallel group study was to examine the 12 week effects of a very low-carbohydrate high-fat diet (VLCHF) on maximal cardiorespiratory capacity, high-intensity interval training (HIIT) performance, and cardiac autonomic regulation. Methods Twenty-four recreationally trained participants allocated to either a VLCHF (N = 12) or a habitual diet (HD; N = 12) group completed 12 weeks of a diet and exercise (VLCHF) or an exercise only intervention (HD). Maximal graded exercise tests (GXT) were performed at baseline, after 4, 8, and 12 weeks. A supervised HIIT session and the 30-15 Intermittent Fitness Test (30-15IFT) were conducted once a week. Results Total time to exhaustion (TTE) in both GXT and 30-15IFTlargely increased in both VLCHF (p = 0.005, BF10 = 11.30 and p = 0.001, BF10 ≥ 100, respectively) and HD (p = 0.018, BF10 = 3.87 and p = 0.001, BF10 ≥ 100, respectively) groups after 12 weeks. Absolute maximal oxygen uptake (V˙O2max) was not changed in both groups but relative V˙O2max increased in VLCHF in concert with reductions in body mass (66.7 ± 10.2–63.1 ± 8.5 kg). Cardiac autonomic regulation did not reveal any between-group differences after 12 weeks. VLCHF diet induced an increase in β-hydroxybutyrate, which tended to normalize during the intervention period. Conclusion The 12 week VLCHF diet did not impair high-intensity continuous or intermittent exercise lasting up to 25 min, nor did it impair maximal cardiorespiratory performance or autonomic nervous system (ANS) activity.
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Affiliation(s)
- Tomas Dostal
- Department of Human Movement Studies, Human Motion Diagnostic Centre, University of Ostrava, Ostrava, Czechia
| | - Daniel J Plews
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Peter Hofmann
- Exercise Physiology, Training and Training Therapy Research Group, Institute of Sports Science, University of Graz, Graz, Austria
| | - Paul B Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Lukas Cipryan
- Department of Human Movement Studies, Human Motion Diagnostic Centre, University of Ostrava, Ostrava, Czechia
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Zignoli A, Fornasiero A, Bertolazzi E, Pellegrini B, Schena F, Biral F, Laursen PB. State-of-the art concepts and future directions in modelling oxygen consumption and lactate concentration in cycling exercise. Sport Sci Health 2019. [DOI: 10.1007/s11332-019-00557-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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19
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Scott BE, Laursen PB, James LJ, Boxer B, Chandler Z, Lam E, Gascoyne T, Messenger J, Mears SA. The effect of 1,3-butanediol and carbohydrate supplementation on running performance. J Sci Med Sport 2019; 22:702-706. [DOI: 10.1016/j.jsams.2018.11.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/31/2018] [Accepted: 11/29/2018] [Indexed: 11/27/2022]
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20
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Zignoli A, Fornasiero A, Stella F, Pellegrini B, Schena F, Biral F, Laursen PB. Expert-level classification of ventilatory thresholds from cardiopulmonary exercising test data with recurrent neural networks. Eur J Sport Sci 2019; 19:1221-1229. [DOI: 10.1080/17461391.2019.1587523] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Andrea Zignoli
- Department of Industrial Engineering, University of Trento, Trento, Italy
- CeRiSM Research Centre, University of Verona, Rovereto, Trento, Italy
| | - Alessandro Fornasiero
- CeRiSM Research Centre, University of Verona, Rovereto, Trento, Italy
- Department of Neuroscience, Biomedicine and Movement, University of Verona, Verona, Italy
| | - Federico Stella
- CeRiSM Research Centre, University of Verona, Rovereto, Trento, Italy
| | - Barbara Pellegrini
- CeRiSM Research Centre, University of Verona, Rovereto, Trento, Italy
- Department of Neuroscience, Biomedicine and Movement, University of Verona, Verona, Italy
| | - Federico Schena
- CeRiSM Research Centre, University of Verona, Rovereto, Trento, Italy
- Department of Neuroscience, Biomedicine and Movement, University of Verona, Verona, Italy
| | - Francesco Biral
- Department of Industrial Engineering, University of Trento, Trento, Italy
| | - Paul B. Laursen
- Sports Performance Research Institute NZ, Auckland University of Technology, Auckland, New Zealand
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21
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Affiliation(s)
| | - Paul B Laursen
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
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22
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Stevens CJ, Heathcote SL, Plews DJ, Laursen PB, Taylor L. Effect of two-weeks endurance training wearing additional clothing in a temperate outdoor environment on performance and physiology in the heat. Temperature (Austin) 2018; 5:267-275. [PMID: 30377642 PMCID: PMC6205002 DOI: 10.1080/23328940.2018.1474672] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/01/2018] [Accepted: 05/05/2018] [Indexed: 12/31/2022] Open
Abstract
This investigation assessed performance, physiological and perceptual responses to wearing additional clothing during endurance training for two-weeks in temperate environments, to determine if this approach could be used as a practical, alternative, heat acclimation strategy for athletes. Fifteen trained male triathletes assigned to performance-matched groups completed a two-week unsupervised endurance cycling and running program in either (i) shorts and a short sleeve top (CON; n = 8) or (ii) additional clothing of full-length pants, a "winter" jacket and gloves made from nylon, polyurethane and polyester (AC; n = 7). Participants completed three separate (i.e. familiarisation, pre-program and post-program), identical, pre-loaded cycling time-trials (20 min at 180 W followed by a 40 min self-paced time trial) in 32.5 ± 0.1°C and 55 ± 6% RH. Core and skin temperatures, heart rate, sweat rate, perceived exertion, thermal sensation and thermal comfort were measured across the pre-loaded time trials, and heart rate and thermal sensation were measured across the training program. All of the participants recorded in their diaries that they completed all of the programmed training sessions in the required attire. Mean thermal sensation was most likely hotter in AC (5.5 ± 0.4 AU) compared to CON (4.4 ± 0.4 AU; ES = 1.61, ± 0.68) during the training sessions. However, follow up tests revealed no physiological or perceptual signs of heat acclimation, and the change in time-trial performance from pre-post between groups was trivial (CON: -3.5 ± 12.0 W, AC: -4.1 ± 9.6 W; difference = -0.7%, ± 5.4%). Training in additional clothing for two-weeks in a temperate environment was not an effective heat acclimation strategy for triathletes.
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Affiliation(s)
- Christopher J. Stevens
- School of Health and Human Sciences, Southern Cross University, Coffs Harbour, Australia
| | - Storme L. Heathcote
- School of Health and Human Sciences, Southern Cross University, Coffs Harbour, Australia
| | - Daniel J. Plews
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Paul B. Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Lee Taylor
- Athlete Health and Performance Research Centre, ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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23
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Abstract
As major sporting events are often held in hot environments, increased interest in ways of optimally heat acclimating athletes to maximise performance has emerged. Heat acclimation involves repeated exercise sessions in hot conditions that induce physiological and thermoregulatory adaptations that attenuate heat-induced performance impairments. Current evidence-based guidelines for heat acclimation are clear, but the application of these recommendations is not always aligned with the time commitments and training priorities of elite athletes. Alternative forms of heat acclimation investigated include hot water immersion and sauna bathing, yet uncertainty remains around the efficacy of these methods for reducing heat-induced performance impairments, as well as how this form of heat stress may add to an athlete's overall training load. An understanding of how to optimally prescribe and periodise heat acclimation based on the performance determinants of a given event is limited, as is knowledge of how heat acclimation may affect the quality of concurrent training sessions. Finally, differences in individual athlete responses to heat acclimation need to be considered. This article addresses alternative methods of heat acclimation and heat exposure, explores gaps in literature around understanding the real world application of heat acclimation for athletes, and highlights specific athlete considerations for practitioners.
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Affiliation(s)
- Julia R Casadio
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.
- High Performance Sport New Zealand, PO Box 302 563, North Harbour, Auckland, 0751, New Zealand.
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Paul B Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand
- High Performance Sport New Zealand, PO Box 302 563, North Harbour, Auckland, 0751, New Zealand
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Cipryan L, Plews DJ, Ferretti A, Maffetone PB, Laursen PB. Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses. J Sports Sci Med 2018; 17:259-268. [PMID: 29769827 PMCID: PMC5950743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 03/29/2018] [Indexed: 06/08/2023]
Abstract
The purpose of the study was to examine the effects of altering from habitual mixed Western-based (HD) to a very low-carbohydrate high-fat (VLCHF) diet over a 4-week timecourse on performance and physiological responses during high-intensity interval training (HIIT). Eighteen moderately trained males (age 23.8 ± 2.1 years) consuming their HD (48 ± 13% carbohydrate, 17 ± 3% protein, 35 ± 9% fat) were assigned to 2 groups. One group was asked to remain on their HD, while the other was asked to switch to a non-standardized VLCHF diet (8 ± 3% carbohydrate, 29 ± 15% protein, 63 ± 13% fat) for 4 weeks. Participants performed graded exercise tests (GXT) before and after the experiment, and an HIIT session (5x3min, work/rest 2:1, passive recovery, total time 34min) before, and after 2 and 4 weeks. Heart rate (HR), oxygen uptake (V̇O2), respiratory exchange ratio (RER), maximal fat oxidation rates (Fatmax) and blood lactate were measured. Total time to exhaustion (TTE) and maximal V̇O2 (V̇O2max) in the GXT increased in both groups, but between-group changes were trivial (ES ± 90% CI: -0.1 ± 0.3) and small (0.57 ± 0.5), respectively. Between-group difference in Fatmax change (VLCHF: 0.8 ± 0.3 to 1.1 ± 0.2 g/min; HD: 0.7 ± 0.2 to 0.8 ± 0.2 g/min) was large (1.2±0.9), revealing greater increases in the VLCHF versus HD group. Between-group comparisons of mean changes in V̇O2 and HR during the HIIT sessions were trivial to small, whereas mean RER decreased more in the VLCHF group (-1.5 ± 0.1). Lactate changes between groups were unclear. Adoption of a VLCHF diet over 4 weeks increased Fatmax and did not adversely affect TTE during the GXT or cardiorespiratory responses to HIIT compared with the HD.
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Affiliation(s)
- Lukas Cipryan
- Department of Human Movement Studies & Human Motion Diagnostic Centre, Ostrava University, Czech Republic
| | - Daniel J Plews
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | | | | | - Paul B Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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25
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Bertuzzi R, Gáspari AF, Trojbicz LR, Silva-Cavalcante MD, Lima-Silva AE, Billaut F, Girard O, Millet GP, Bossi AH, Hopker J, Pandeló DR, Fulton TJ, Paris HL, Chapman RF, Grosicki GJ, Murach KA, Hureau TJ, Dufour SP, Favret F, Kruse NT, Nicolò A, Sacchetti M, Pedralli M, Pinheiro FA, Tricoli V, Brietzke C, Pires FO, Sandford GN, Pearson S, Kilding AE, Ross A, Laursen PB, da Silveira ALB, Olivares EL, de Azevedo Cruz Seara F, Miguel-dos-Santos R, Mesquita TRR, Nelatury S, Vagula M. Commentaries on Viewpoint: Resistance training and exercise tolerance during high-intensity exercise: moving beyond just running economy and muscle strength. J Appl Physiol (1985) 2018; 124:529-535. [PMID: 29480788 DOI: 10.1152/japplphysiol.01064.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Romulo Bertuzzi
- Endurance Performance Research Group (GEDAE-USP), University of São Paulo, São Paulo, Brazil
| | - Arthur F. Gáspari
- Endurance Performance Research Group (GEDAE-USP), University of São Paulo, São Paulo, Brazil
| | - Lucas R. Trojbicz
- Endurance Performance Research Group (GEDAE-USP), University of São Paulo, São Paulo, Brazil
| | - Marcos D. Silva-Cavalcante
- Endurance Performance Research Group (GEDAE-USP), University of São Paulo, São Paulo, Brazil,Sport Science Research Group, Federal University of Pernambuco, Pernambuco, Brazil
| | - Adriano E. Lima-Silva
- Sport Science Research Group, Federal University of Pernambuco, Pernambuco, Brazil,Human Performance Research Group, Technological Federal University of Parana, Parana, Brazil
| | | | - Oliver Girard
- Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Grégoire P. Millet
- Faculty of Biology and Medicine, Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Arthur Henrique Bossi
- School of Sport and Exercise Sciences University of Kent, Chatham Maritime, Chatham, Kent, England
| | - James Hopker
- School of Sport and Exercise Sciences University of Kent, Chatham Maritime, Chatham, Kent, England
| | - Domingos R. Pandeló
- Federal University of São Paulo Centro de Alta Performance (High Performance Center)
| | | | | | | | - Gregory J. Grosicki
- Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA
| | - Kevin A. Murach
- Department of Rehabilitation Sciences and Center for Muscle Biology, University of Kentucky, Lexington, KY
| | - Thomas J. Hureau
- University of Strasbourg Faculty of Medicine, Mitochondria, Oxidative Stress and Muscular Protection Laboratory, Strasbourg, France
| | - Stéphane P. Dufour
- University of Strasbourg Faculty of Medicine, Mitochondria, Oxidative Stress and Muscular Protection Laboratory, Strasbourg, France
| | - Fabrice Favret
- University of Strasbourg Faculty of Medicine, Mitochondria, Oxidative Stress and Muscular Protection Laboratory, Strasbourg, France
| | - Nicholas T. Kruse
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa
| | - Andrea Nicolò
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Massimo Sacchetti
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Rome, Italy
| | - Marinei Pedralli
- Department of Kinesiology & Health Education, Cardiovascular Aging Research Laboratory, The University of Texas at Austin, Austin, TX
| | - Fabiano A. Pinheiro
- Laboratory of Adaptation to Strength Training, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil,Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
| | - Valmor Tricoli
- Laboratory of Adaptation to Strength Training, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Cayque Brietzke
- Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
| | - Flávio Oliveira Pires
- Exercise Psychophysiology Research Group, School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
| | - Gareth N. Sandford
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand,High Performance Sport New Zealand, Auckland, New Zealand,Athletics New Zealand, Auckland, New Zealand
| | - Simon Pearson
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand,Queensland Academy of Sport, Nathan, Australia
| | - Andrew E. Kilding
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Angus Ross
- High Performance Sport New Zealand, Auckland, New Zealand,Athletics New Zealand, Auckland, New Zealand
| | - Paul B. Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand,High Performance Sport New Zealand, Auckland, New Zealand
| | - Anderson Luiz B. da Silveira
- Laboratory of Physiology and Human Performance, Department of Physical Education and Sports, Federal Rural University of Rio de Janeiro, Brazil
| | - Emerson Lopes Olivares
- Laboratory of Cardiovascular Physiology and Pharmacology, Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Brazil
| | - Fernando de Azevedo Cruz Seara
- Laboratory of Cardiac Electrophysiology, Carlos Chagas Filho Department of Biophysics, Federal University of Rio de Janeiro, Brazil
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26
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Hoffman MD, Cotter JD, Goulet ÉD, Laursen PB. REBUTTAL from "Yes". Wilderness Environ Med 2017; 27:198-200. [PMID: 27291701 DOI: 10.1016/j.wem.2016.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 04/10/2016] [Accepted: 04/11/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Martin D Hoffman
- Department of Physical Medicine & Rehabilitation, Department of Veterans Affairs, Northern California Health Care System, and University of California Davis Medical Center, Sacramento, CA.
| | - James D Cotter
- Exercise and Environmental Physiology, School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, Dunedin, New Zealand(Dr Cotter)?>
| | - Éric D Goulet
- Research Centre on Aging, Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Quebec, Canada
| | - Paul B Laursen
- High Performance Sport New Zealand, and Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Aukland, Auckland, New Zealand
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Abstract
The overfat condition is defined as excess body fat sufficient to impair health. The problem exists in most overweight and obese individuals and can also occur in those who are normal-weight and non-obese, often due to excess abdominal fat. Despite previous indications that the prevalence overweight and obesity is leveling, these conditions are currently at their highest levels in US history. Our review estimated the number of overfat Americans at 91% for adults and 69% for children. The primary purpose of this review was to build upon previous estimations of overfat prevalence in developed countries by using new data from the Centers for Disease Control and Prevention to estimate the overfat prevalence in American adults (≥20 years) and children (2-19 years), and to expand the definition of overfat as excess body fat associated with at least one additional risk factor of impaired cardiometabolic or physical health. The secondary goals are to highlight the role of dietary sugar as a primary cause of the overfat pandemic and mention new data showing the increased prevalence of exercise that parallels the rising prevalence of overfat to further emphasize the secondary role exercise may play in fat loss. Current public health guidelines to address the overfat pandemic may require more emphasis on reducing the consumption of refined carbohydrates, including added sugars.
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Affiliation(s)
| | - Paul B. Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), AUT University, Auckland, New Zealand
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Stevens CJ, Plews DJ, Laursen PB, Kittel AB, Taylor L. Acute physiological and perceptual responses to wearing additional clothing while cycling outdoors in a temperate environment:A practical method to increase the heat load. Temperature (Austin) 2017; 4:414-419. [PMID: 29435480 DOI: 10.1080/23328940.2017.1365108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/30/2017] [Accepted: 08/03/2017] [Indexed: 10/18/2022] Open
Abstract
This investigation assessed the acute physiological and perceptual responses to wearing additional clothing during outdoor cycling to determine if this strategy could increase the heat load while training in temperate environments. Seven male cyclists (age: 32 ± 13 y, height: 179 ± 10 cm, body mass: 74 ± 10 kg, body fat percentage: 10.3 ± 1.0%) completed 2 randomized outdoor (∼17°C and ∼82% RH), 80 min cycling sessions at moderate-hard intensities (CR10 RPE = 3-5). They wore spandex shorts and a short sleeve top (CON) or additional clothing including full-length spandex pants and a 'winter' cycling jacket and gloves (AC). Core temperature, heart rate, sweat rate, thermal sensation and thermal comfort were measured across the trials. Moderate increases were observed in AC vs. CON for the change in mean core temperature (0.4 ± 0.3°C, effect size, ES = 1.16 ± 0.55), change in maximum core temperature (0.5 ± 0.3°C, ES = 1.07 ± 0.48) and sweat rate (0.24 ± 0.16 L . h-1, ES = 1.04 ± 0.59). A small increase in mean heart rate (3 ± 3 bpm, ES = 0.32 ± 0.28) was observed as well as a 'very likely' (percentage difference = 22.4 ± 7.1) and 'most likely' (percentage difference = 42.9 ± 11.9) increase in thermal sensation and thermal comfort, respectively, in AC vs. CON. Dressing in additional clothing while cycling outdoors in a temperate environment increased physiological strain and sensations of warmth and discomfort. Training in additional clothing during outdoor cycling represents a practical alternative to increasing the heat load of a training session.
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Affiliation(s)
- Christopher J Stevens
- School of Health and Human Sciences, Southern Cross University, Coffs Harbour, Australia
| | - Daniel J Plews
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.,Kitman Labs, Dublin, Ireland
| | - Paul B Laursen
- Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Aden B Kittel
- College of Sport and Exercise Science, Victoria University, Melbourne, Australia
| | - Lee Taylor
- ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar.,School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom
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Plews DJ, Laursen PB. Training Intensity Distribution Over a Four-Year Cycle in Olympic Champion Rowers: Different Roads Lead to Rio. Int J Sports Physiol Perform 2017:1-24. [PMID: 28952837 DOI: 10.1123/ijspp.2017-0343] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2023]
Abstract
The purpose of this study was to compare the training intensity distribution (TID) of the undefeated world champion male rowing New Zealand (kiwi) pair over a four-year Olympic cycle, across training phases, training years, and between individuals. Training data, including heart rate and boat speed, were recorded in the athletes rowing in the same boat between March 2013 and August 2016, ending with the Rio Olympics final. Progressive exercise tests assessed first (LT1) and second (LT2) lactate thresholds and associated heart rates, to determine the percentage of training performed below, between and above these demarcation points. Training an average of only 12-15 h/wk throughout the Olympic cycle, the mean percent distribution of time (±SD) at each training intensity was 80.4 ± 5.5% LT2 for Rower A and 67.3 ± 9.0% LT2 for Rower B. Across the years 2014-2016, Rower A performed most likely more training
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Affiliation(s)
- Daniel J Plews
- 1 Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Paul B Laursen
- 1 Sport Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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Abstract
The Boston Marathon course is deemed ineligible for world record status due to its unidirectional nature and excessive negative elevation change, yet performance times across the World Marathon Majors (WMM) races have not been compared.
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Affiliation(s)
| | - Rita Malcata
- Sports Performance Research Institute New Zealand (SPRINZ), AUT University, Auckland, New Zealand
| | - Ivan Rivera
- Research Assistant, San Diego, CA, United States of America
| | - Paul B. Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), AUT University, Auckland, New Zealand
- * E-mail:
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Casadio JR, Storey AG, Merien F, Kilding AE, Cotter JD, Laursen PB. Acute effects of heated resistance exercise in female and male power athletes. Eur J Appl Physiol 2017; 117:1965-1976. [PMID: 28748371 DOI: 10.1007/s00421-017-3671-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/22/2017] [Indexed: 11/28/2022]
Abstract
PURPOSE To determine the effects of heated resistance exercise on thermal strain, neuromuscular function and hormonal responses in power athletes. METHODS Sixteen (n = 8 female; 8 male) highly trained power athletes completed a combined strength and power resistance exercise session in hot (HOT ~30 °C) and temperate (CON ~20 °C) conditions. Human growth hormone (hGH), cortisol and testosterone concentrations in plasma, peak power (counter-movement jump, CMJ) and peak force (isometric mid-thigh pull) were measured before and after each training session; thermoregulatory responses were monitored during training. RESULTS Skin temperature, thermal sensation and thermal discomfort were higher in HOT compared with CON. Sweat rate was higher in HOT for males only. Compared with CON, HOT had trivial effects on core temperature and heart rate. During HOT, there was a possible increase in upper-body power (medicine ball throw) in females [3.4% (90% CL -1.5, 8.6)] and males [(3.3% (-0.1, 6.9)], while lower-body power (vertical jump) was enhanced in males only [3.2% (-0.4, 6.9)]. Following HOT, CMJ peak power [4.4% (2.5; 6.3)] and strength [8.2% (3.1, 13.6)] were enhanced in female athletes, compared with CON, while effects in males were unclear. Plasma hGH concentration increased in females [83% (18; 183)] and males [107% (-21; 444)] in HOT compared with CON, whereas differential changes occurred for cortisol and testosterone. CONCLUSION Heated resistance exercise enhanced power and increased plasma hGH concentration in female and males power athletes. Further research is required to assess the ergogenic potential of resistance exercise in the heat.
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Affiliation(s)
- Julia R Casadio
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand. .,High Performance Sport New Zealand, Auckland, New Zealand.
| | - Adam G Storey
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,High Performance Sport New Zealand, Auckland, New Zealand
| | - Fabrice Merien
- AUT-Roche Diagnostics Laboratory, School of Science, Auckland University of Technology, Auckland, New Zealand
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Paul B Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,High Performance Sport New Zealand, Auckland, New Zealand
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Maffetone PB, Rivera-Dominguez I, Laursen PB. Overfat Adults and Children in Developed Countries: The Public Health Importance of Identifying Excess Body Fat. Front Public Health 2017; 5:190. [PMID: 28791284 PMCID: PMC5523552 DOI: 10.3389/fpubh.2017.00190] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 07/12/2017] [Indexed: 12/13/2022] Open
Abstract
The global overfat pandemic is a serious public health crisis that places a substantial burden on economic resources in developed countries. The term overfat refers to the presence of excess body fat that can impair health, even for normal weight non-obese individuals. Excess body fat is associated with cardiometabolic dysfunction, a clinical situation that can progressively worsen, potentially leading to various common disease risk factors, chronic diseases, increased morbidity and mortality, and reduced quality of life. The prevalence of overfat populations in 30 of the world’s most developed countries is substantially higher than recent global estimations, with the largest growth due to a relatively recent increased number of people with excess abdominal fat. Abdominal overfat is the most unhealthful form of this condition, so it is concerning that average waist circumference measures, generally indicative of abdominal overfat, have increased. Despite a leveling off appearance of being overweight and/or obese in some developed countries, the overfat pandemic continues to grow.
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Affiliation(s)
| | | | - Paul B Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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Abstract
Manoeuvring a motorcycle at high-speed in official competition has been shown to expose riders to substantial and complex physiological and psychological demands, however few studies have analysed the physical load experienced by professional racers. This study aimed to quantify the physical stress experienced by riders and explore relationships between performance related variables (i.e. crashes). Performance and braking data were collected from official race reports from 2013 to 2015 of the top class of the FIM Road Racing Grand Prix World Championship. Top-level riders are exposed to a considerable volume (175 ± 42 brakes and 372 ± 48 leans to corner per race) of high intensity actions (>40% of brakes initiated at speeds higher than 260 km.h-1, and 13.2% over 300 km.h-1), where 1 out of every 4 braking actions generated inertial stresses greater than 10 m.s-2. Furthermore, the mean speed across competitions increased over the years (from 161.7 ± 6 km.h-1 to 164.5 ± 6 km.h-1), however no clear relationships between the amount of crashes and competition-related factors were found. Given the findings it would seem that riders could benefit from strength training specifically designed to prepare the body to counteract the repetitive inertial stresses of racing.
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Affiliation(s)
- Emanuele D'Artibale
- a SPRINZ, AUT Millennium , Auckland University of Technology , Auckland , New Zealand
| | - Paul B Laursen
- a SPRINZ, AUT Millennium , Auckland University of Technology , Auckland , New Zealand
| | - John B Cronin
- a SPRINZ, AUT Millennium , Auckland University of Technology , Auckland , New Zealand
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Hoffman MD, Cotter JD, Goulet ÉD, Laursen PB. VIEW: Is Drinking to Thirst Adequate to Appropriately Maintain Hydration Status During Prolonged Endurance Exercise? Yes. Wilderness Environ Med 2017; 27:192-5. [PMID: 27291699 DOI: 10.1016/j.wem.2016.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/03/2016] [Accepted: 03/09/2016] [Indexed: 10/21/2022]
Affiliation(s)
- Martin D Hoffman
- Department of Physical Medicine & Rehabilitation Department of Veterans Affairs, Northern California Health Care System, and University of California Davis Medical Center, Sacramento, CA, USA (Dr Hoffman)
| | - James D Cotter
- Exercise and Environmental Physiology, School of Physical Education, Sport and Exercise Sciences Division of Sciences, University of Otago, Dunedin New Zealand (Dr Cotter)
| | - Éric D Goulet
- Research Centre on Aging, Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC Canada (Dr Goulet)
| | - Paul B Laursen
- High Performance Sport New Zealand, and Sports Performance Research Institute New Zealand (SPRINZ) Auckland University of Technology, Auckland New Zealand (Dr Laursen)
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Maffetone PB, Rivera-Dominguez I, Laursen PB. Overfat and Underfat: New Terms and Definitions Long Overdue. Front Public Health 2017; 4:279. [PMID: 28097119 PMCID: PMC5206235 DOI: 10.3389/fpubh.2016.00279] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 12/06/2016] [Indexed: 12/25/2022] Open
Abstract
For the first time in human history, the number of obese people worldwide now exceeds those who are underweight. However, it is possible that there is an even more serious problem-an overfat pandemic comprised of people who exhibit metabolic health impairments associated with excess fat mass relative to lean body mass. Many overfat individuals, however, are not necessarily classified clinically as overweight or obese, despite the common use of body mass index as the clinical classifier of obesity and overweight. The well-documented obesity epidemic may merely be the tip of the overfat iceberg. The counterpart to the overfat condition is the underfat state, also a common and dangerous health circumstance associated with chronic illness and starvation. Currently (and paradoxically), high rates of obesity and overweight development coexist with undernutrition in developing countries. Studies in cognitive linguistics suggest that accurate, useful, and unintimidating terminology regarding abnormal body fat conditions could help increase a person's awareness of their situation, helping the process of implementing prevention and simple remedies. Our contention is that promoting the terms "overfat" and "underfat" to describe body composition states to the point where they enter into common usage may help in creating substantive improvements in world health.
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Affiliation(s)
| | | | - Paul B. Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), AUT University, Auckland, New Zealand
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Casadio JR, Kilding AE, Siegel R, Cotter JD, Laursen PB. Periodizing heat acclimation in elite Laser sailors preparing for a world championship event in hot conditions. Temperature (Austin) 2016; 3:437-443. [PMID: 28349083 PMCID: PMC5079264 DOI: 10.1080/23328940.2016.1184367] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/21/2016] [Accepted: 04/23/2016] [Indexed: 11/09/2022] Open
Abstract
Purpose: To examine the retention and re-acclimation responses during a periodized heat acclimation (HA) protocol in elite sailors preparing for the 2013 World Championships in Muscat, Oman (∼27–30°C, 40–60% RH). Methods: Two elite male Laser class sailors completed 5 consecutive days of HA (60 min per day in 35°C, 60% RH). Heat response tests (HRT) were performed on day 1 and 5 of HA, then 1 (decay 1, D1) and 2 (D2) weeks following HA. Participants were then re-acclimated (RA) for 2 days, within the next week, before a final HRT ∼72 h post-RA. Rectal temperature, plasma volume, heart rate, sweat rate, as well as thermal discomfort and rating of perceived exertion were measured during each HRT. Results: Rectal temperature decreased with HA (0.46 ± 0.05°C), while individual responses following D1, D2 and RA varied. Heart rate (14 ± 7 bpm), thermal discomfort (0.6 ± 0.1 AU) and rating of perceived exertion (1.8 ± 0.6 AU) decreased across HA, and adaptations were retained by D2. Plasma volume steadily increased over the decay period (D2 = 8.0 ± 1.3%) and after RA (15.5 ± 1.1%) compared with baseline. RA resulted in further thermoregulatory improvements in each Athlete, although individual adjustments varied. Conclusion: Heat strain was reduced in elite Laser sailors following HA and most thermoregulatory adaptations were retained for 2 weeks afterwards. RA may ‘top up’ adaptations after 2 weeks of HA decay.
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Affiliation(s)
- Julia R Casadio
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand; High Performance Sport New Zealand, Auckland, New Zealand
| | | | | | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago , Dunedin, New Zealand
| | - Paul B Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand; High Performance Sport New Zealand, Auckland, New Zealand
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Laursen PB. From science to practice: Development of a thermally-insulated ice slushy dispensing bottle that helps athletes "keep their cool" in hot temperatures. Temperature (Austin) 2016; 3:187-190. [PMID: 27857947 PMCID: PMC4964993 DOI: 10.1080/23328940.2016.1165786] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Paul B Laursen
- High Performance Sport New Zealand Millennium Institute of Sport & Health 17 Antares Place , Mairangi Bay 0632, New Zealand
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Maté J, Siegel R, Oosthuizen J, Laursen PB, Watson G. Effect of Liquid versus Ice Slurry Ingestion on Core Temperature during Simulated Mining Conditions. ACTA ACUST UNITED AC 2016. [DOI: 10.4236/ojpm.2016.61002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Cipryan L, Laursen PB, Plews DJ. Cardiac autonomic response following high-intensity running work-to-rest interval manipulation. Eur J Sport Sci 2015; 16:808-17. [DOI: 10.1080/17461391.2015.1103317] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hetlelid KJ, Plews DJ, Herold E, Laursen PB, Seiler S. Rethinking the role of fat oxidation: substrate utilisation during high-intensity interval training in well-trained and recreationally trained runners. BMJ Open Sport Exerc Med 2015; 1:e000047. [PMID: 27900134 PMCID: PMC5117036 DOI: 10.1136/bmjsem-2015-000047] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2015] [Indexed: 11/25/2022] Open
Abstract
Background Although carbohydrate is the predominant fuel source supporting high-intensity exercise workloads, the role of fat oxidation, and the degree to which it may be altered by training status, is less certain. Methods We compared substrate oxidation rates, using indirect calorimetry, during a high-intensity interval training (HIT) session in well-trained (WT) and recreationally trained (RT) runners. Following preliminary testing, 9 WT (VO2max 71±5 mL/min/kg) and 9 RT (VO2max 55±5 mL/min/kg) male runners performed a self-paced HIT sequence consisting of six, 4 min work bouts separated by 2 min recovery periods on a motorised treadmill set at a 5% gradient. Results WT and RT runners performed the HIT session with the same perceived effort (rating of perceived exertion (RPE) =18.3±0.7 vs 18.2±1.1, respectively), blood lactate (6.4±2.1 vs 6.2±2.5 mmol/L) and estimated carbohydrate oxidation rates (4.2±0.29 vs 4.4±0.45 g/min; effect size (ES) 90% confidence limits (CL)=−0.19±0.85). Fat oxidation (0.64±0.13 vs 0.22±0.16 g/min for WT and RT, respectively) accounted for 33±6% of the total energy expenditure in WT vs 16±6% in RT most likely very large difference in fat oxidation (ES 90% CL=1.74±0.83) runners. Higher rates of fat oxidation had a very large correlation with VO2max (r=0.86; 90% CI (0.7 to 0.94). Conclusions Despite similar RPE, blood lactate and carbohydrate oxidation rates, the better performance by the WT group was explained by their nearly threefold higher rates of fat oxidation at high intensity.
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Affiliation(s)
- Ken J Hetlelid
- Faculty of Health and Sport Sciences , University of Agder , Kristiansand , Norway
| | - Daniel J Plews
- High Performance Sport New Zealand, North Harbour, Auckland, New Zealand; Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Eva Herold
- Faculty of Health and Sport Sciences , University of Agder , Kristiansand , Norway
| | - Paul B Laursen
- High Performance Sport New Zealand, North Harbour, Auckland, New Zealand; Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Stephen Seiler
- Faculty of Health and Sport Sciences , University of Agder , Kristiansand , Norway
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41
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Affiliation(s)
- Martin Buchheit
- Sport Science Department, Myorobie Association, 73700, Montvalezan, France,
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Cotter JD, Thornton SN, Lee JK, Laursen PB. Are we being drowned in hydration advice? Thirsty for more? Extrem Physiol Med 2014; 3:18. [PMID: 25356197 PMCID: PMC4212586 DOI: 10.1186/2046-7648-3-18] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/01/2014] [Indexed: 12/29/2022]
Abstract
Hydration pertains simplistically to body water volume. Functionally, however, hydration is one aspect of fluid regulation that is far more complex, as it involves the homeostatic regulation of total body fluid volume, composition and distribution. Deliberate or pathological alteration of these regulated factors can be disabling or fatal, whereas they are impacted by exercise and by all environmental stressors (e.g. heat, immersion, gravity) both acutely and chronically. For example, dehydration during exercising and environmental heat stress reduces water volume more than electrolyte content, causing hyperosmotic hypohydration. If exercise continues for many hours with access to food and water, composition returns to normal but extracellular volume increases well above baseline (if exercising upright and at low altitude). Repeating bouts of exercise or heat stress does likewise. Dehydration due to physical activity or environmental heat is a routine fluid-regulatory stress. How to gauge such dehydration and - more importantly-what to do about it, are contested heavily within sports medicine and nutrition. Drinking to limit changes in body mass is commonly advocated (to maintain ≤2% reduction), rather than relying on behavioural cues (mainly thirst) because the latter has been deemed too insensitive. This review, as part of the series on moving in extreme environments, critiques the validity, problems and merits of externally versus autonomously controlled fluid-regulatory behaviours, both acutely and chronically. Our contention is that externally advocated hydration policies (especially based on change in body mass with exercise in healthy individuals) have limited merit and are extrapolated and imposed too widely upon society, at the expense of autonomy. More research is warranted to examine whether ad libitum versus avid drinking is beneficial, detrimental or neither in: acute settings; adapting for obligatory dehydration (e.g. elite endurance competition in the heat), and; development of chronic diseases that are associated with an extreme lack of environmental stress.
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Affiliation(s)
- James David Cotter
- Exercise and Environmental Physiology, School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Simon N Thornton
- Faculté de Médecine, Université de Lorraine, U 1116 -INSERM-UL, 9, Avenue de la forêt de Haye, CS50-184 - 54505 VANDŒUVRE, Les Nancy cedex, France
| | - Jason Kw Lee
- Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore ; Yong Loo Lin School of Medicine, National University of Singapore, Singapore ; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Paul B Laursen
- High Performance Sport New Zealand, Auckland, New Zealand ; Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
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Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle. Part II: anaerobic energy, neuromuscular load and practical applications. Sports Med 2014; 43:927-54. [PMID: 23832851 DOI: 10.1007/s40279-013-0066-5] [Citation(s) in RCA: 349] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-intensity interval training (HIT) is a well-known, time-efficient training method for improving cardiorespiratory and metabolic function and, in turn, physical performance in athletes. HIT involves repeated short (<45 s) to long (2-4 min) bouts of rather high-intensity exercise interspersed with recovery periods (refer to the previously published first part of this review). While athletes have used 'classical' HIT formats for nearly a century (e.g. repetitions of 30 s of exercise interspersed with 30 s of rest, or 2-4-min interval repetitions ran at high but still submaximal intensities), there is today a surge of research interest focused on examining the effects of short sprints and all-out efforts, both in the field and in the laboratory. Prescription of HIT consists of the manipulation of at least nine variables (e.g. work interval intensity and duration, relief interval intensity and duration, exercise modality, number of repetitions, number of series, between-series recovery duration and intensity); any of which has a likely effect on the acute physiological response. Manipulating HIT appropriately is important, not only with respect to the expected middle- to long-term physiological and performance adaptations, but also to maximize daily and/or weekly training periodization. Cardiopulmonary responses are typically the first variables to consider when programming HIT (refer to Part I). However, anaerobic glycolytic energy contribution and neuromuscular load should also be considered to maximize the training outcome. Contrasting HIT formats that elicit similar (and maximal) cardiorespiratory responses have been associated with distinctly different anaerobic energy contributions. The high locomotor speed/power requirements of HIT (i.e. ≥95 % of the minimal velocity/power that elicits maximal oxygen uptake [v/p(·)VO(2max)] to 100 % of maximal sprinting speed or power) and the accumulation of high-training volumes at high-exercise intensity (runners can cover up to 6-8 km at v(·)VO(2max) per session) can cause significant strain on the neuromuscular/musculoskeletal system. For athletes training twice a day, and/or in team sport players training a number of metabolic and neuromuscular systems within a weekly microcycle, this added physiological strain should be considered in light of the other physical and technical/tactical sessions, so as to avoid overload and optimize adaptation (i.e. maximize a given training stimulus and minimize musculoskeletal pain and/or injury risk). In this part of the review, the different aspects of HIT programming are discussed, from work/relief interval manipulation to HIT periodization, using different examples of training cycles from different sports, with continued reference to the cardiorespiratory adaptations outlined in Part I, as well as to anaerobic glycolytic contribution and neuromuscular/musculoskeletal load.
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Affiliation(s)
- Martin Buchheit
- Physiology Unit, Football Performance and Science Department, ASPIRE, Academy for Sports Excellence, P.O. Box 22287, Doha, Qatar,
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Plews DJ, Laursen PB, Stanley J, Kilding AE, Buchheit M. Training adaptation and heart rate variability in elite endurance athletes: opening the door to effective monitoring. Sports Med 2014; 43:773-81. [PMID: 23852425 DOI: 10.1007/s40279-013-0071-8] [Citation(s) in RCA: 246] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The measurement of heart rate variability (HRV) is often considered a convenient non-invasive assessment tool for monitoring individual adaptation to training. Decreases and increases in vagal-derived indices of HRV have been suggested to indicate negative and positive adaptations, respectively, to endurance training regimens. However, much of the research in this area has involved recreational and well-trained athletes, with the small number of studies conducted in elite athletes revealing equivocal outcomes. For example, in elite athletes, studies have revealed both increases and decreases in HRV to be associated with negative adaptation. Additionally, signs of positive adaptation, such as increases in cardiorespiratory fitness, have been observed with atypical concomitant decreases in HRV. As such, practical ways by which HRV can be used to monitor training status in elites are yet to be established. This article addresses the current literature that has assessed changes in HRV in response to training loads and the likely positive and negative adaptations shown. We reveal limitations with respect to how the measurement of HRV has been interpreted to assess positive and negative adaptation to endurance training regimens and subsequent physical performance. We offer solutions to some of the methodological issues associated with using HRV as a day-to-day monitoring tool. These include the use of appropriate averaging techniques, and the use of specific HRV indices to overcome the issue of HRV saturation in elite athletes (i.e., reductions in HRV despite decreases in resting heart rate). Finally, we provide examples in Olympic and World Champion athletes showing how these indices can be practically applied to assess training status and readiness to perform in the period leading up to a pinnacle event. The paper reveals how longitudinal HRV monitoring in elites is required to understand their unique individual HRV fingerprint. For the first time, we demonstrate how increases and decreases in HRV relate to changes in fitness and freshness, respectively, in elite athletes.
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Affiliation(s)
- Daniel J Plews
- High Performance Sport New Zealand, AUT Millennium, 17 Antares Place, Mairangi Bay, 0632 Auckland, New Zealand.
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Skleryk JR, Karagounis LG, Hawley JA, Sharman MJ, Laursen PB, Watson G. Two weeks of reduced-volume sprint interval or traditional exercise training does not improve metabolic functioning in sedentary obese men. Diabetes Obes Metab 2013; 15:1146-53. [PMID: 23802920 DOI: 10.1111/dom.12150] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 12/24/2012] [Accepted: 06/11/2013] [Indexed: 01/09/2023]
Abstract
AIMS To investigate the effects of short-term, reduced-volume sprint interval training (SIT) compared to traditional exercise recommendations (TER) in sedentary obese men. METHODS Sixteen subjects [37.8 ± 5.8 years; body mass index (BMI) 32.8 ± 4.7 kg/m(2)] were randomly allocated to 2 weeks of either SIT (6 sessions of 8-12 × 10 s sprints) or TER [10 sessions of 30 min at 65% peak oxygen consumption (VO(2peak))] cycle exercise. Fasting plasma glucose, insulin, non-esterified fatty acids (NEFA), homeostasis model assessment of insulin sensitivity (HOMA-IR), body composition and VO(2peak) were assessed at baseline and approximately 72 h after the final training bout. Skeletal muscle biopsy samples were also obtained before and 72 h after training and analysed for AS160 phosphorylation and COX II, COX IV, GLUT-4, Nur77 and SIRT1 protein expression. RESULTS No changes in BMI, body composition, VO(2peak), glucose, insulin, NEFA and HOMA-IR were observed after training, either within or between groups. Skeletal muscle markers of glucose metabolism and mitochondrial function also remained unaltered after 2 weeks of exercise training. CONCLUSIONS Our findings show that 2 weeks of reduced-volume SIT or TER did not elicit any measurable metabolic adaptations in sedentary obese men. Further work is needed to determine the minimal amount of exercise required for short-term adaptations in this population.
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Affiliation(s)
- J R Skleryk
- School of Exercise and Health Sciences, Edith Cowan University, Perth, Western Australia
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Wall BA, Watson G, Peiffer JJ, Abbiss CR, Siegel R, Laursen PB. Current hydration guidelines are erroneous: dehydration does not impair exercise performance in the heat. Br J Sports Med 2013; 49:1077-83. [DOI: 10.1136/bjsports-2013-092417] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2013] [Indexed: 11/04/2022]
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Ross ML, Jeacocke NA, Laursen PB, Martin DT, Abbiss CR, Burke LM. Effects of lowering body temperature via hyperhydration, with and without glycerol ingestion and practical precooling on cycling time trial performance in hot and humid conditions. J Int Soc Sports Nutr 2012; 9:55. [PMID: 23245800 PMCID: PMC3549746 DOI: 10.1186/1550-2783-9-55] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 12/05/2012] [Indexed: 11/16/2022] Open
Abstract
Background Hypohydration and hyperthermia are factors that may contribute to fatigue and impairment of endurance performance. The purpose of this study was to investigate the effectiveness of combining glycerol hyperhydration and an established precooling technique on cycling time trial performance in hot environmental conditions. Methods Twelve well-trained male cyclists performed three 46.4-km laboratory-based cycling trials that included two climbs, under hot and humid environmental conditions (33.3 ± 1.1°C; 50 ± 6% r.h.). Subjects were required to hyperhydrate with 25 g.kg-1 body mass (BM) of a 4°C beverage containing 6% carbohydrate (CON) 2.5 h prior to the time trial. On two occasions, subjects were also exposed to an established precooling technique (PC) 60 min prior to the time trial, involving 14 g.kg-1 BM ice slurry ingestion and applied iced towels over 30 min. During one PC trial, 1.2 g.kg-1 BM glycerol was added to the hyperhydration beverage in a double-blind fashion (PC+G). Statistics used in this study involve the combination of traditional probability statistics and a magnitude-based inference approach. Results Hyperhydration resulted in large reductions (−0.6 to −0.7°C) in rectal temperature. The addition of glycerol to this solution also lowered urine output (330 ml, 10%). Precooling induced further small (−0.3°C) to moderate (−0.4°C) reductions in rectal temperature with PC and PC+G treatments, respectively, when compared with CON (0.0°C, P<0.05). Overall, PC+G failed to achieve a clear change in cycling performance over CON, but PC showed a possible 2% (30 s, P=0.02) improvement in performance time on climb 2 compared to CON. This improvement was attributed to subjects’ lower perception of effort reported over the first 10 km of the trial, despite no clear performance change during this time. No differences were detected in any other physiological measurements throughout the time trial. Conclusions Despite increasing fluid intake and reducing core temperature, performance and thermoregulatory benefits of a hyperhydration strategy with and without the addition of glycerol, plus practical precooling, were not superior to hyperhydration alone. Further research is warranted to further refine preparation strategies for athletes competing in thermally stressful events to optimize health and maximize performance outcomes.
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Affiliation(s)
- Megan Lr Ross
- Australian Institute of Sport, Belconnen, ACT, Australia.
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Abstract
Exercising in hot environments results in a rise in core body temperature; an effect associated with impaired performance over a variety of exercise modes and durations. Precooling has become a popular strategy to combat this impairment, as evidence has shown it to be an effective method for lowering pre-exercise core temperature, increasing heat storage capacity and improving exercise performance in the heat. To date, the majority of precooling manoeuvres have been achieved via external means, such as cold water immersion and the application of cooling garments. However, these methods have been criticized for their lack of practicality for use in major sporting competitions. Recent evidence has shown that internal or endogenous cooling methods, such as drinking cold fluids or ice slurries, are able to lower core temperature and enhance endurance performance in the heat. These methods may be more advantageous than current forms of precooling, as ingesting cold fluids or ice slurries can be easily implemented in the field and provide the additional benefit of hydrating athletes. While the precise mechanisms responsible for these performance enhancements are yet to be fully explained, the effect of ice ingestion on brain temperature, internal thermoreception and sensory responses may be involved. This article addresses the evidence supporting the use of endogenous cooling methods for improving endurance performance in the heat, as well as discussing the potential mechanisms behind the improvements observed and providing practical recommendations to optimize their success.
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Affiliation(s)
- Rodney Siegel
- School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia.
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Plews DJ, Laursen PB, Kilding AE, Buchheit M. Heart rate variability in elite triathletes, is variation in variability the key to effective training? A case comparison. Eur J Appl Physiol 2012; 112:3729-41. [DOI: 10.1007/s00421-012-2354-4] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 02/09/2012] [Indexed: 10/28/2022]
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Millet GY, Muthalib M, Jubeau M, Laursen PB, Nosaka K. Severe hypoxia affects exercise performance independently of afferent feedback and peripheral fatigue. J Appl Physiol (1985) 2012; 112:1335-44. [PMID: 22323647 DOI: 10.1152/japplphysiol.00804.2011] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To test the hypothesis that hypoxia centrally affects performance independently of afferent feedback and peripheral fatigue, we conducted two experiments under complete vascular occlusion of the exercising muscle under different systemic O(2) environmental conditions. In experiment 1, 12 subjects performed repeated submaximal isometric contractions of the elbow flexor to exhaustion (RCTE) with inspired O(2) fraction fixed at 9% (severe hypoxia, SevHyp), 14% (moderate hypoxia, ModHyp), 21% (normoxia, Norm), or 30% (hyperoxia, Hyper). The number of contractions (performance), muscle (biceps brachii), and prefrontal near-infrared spectroscopy (NIRS) parameters and high-frequency paired-pulse (PS100) evoked responses to electrical muscle stimulation were monitored. In experiment 2, 10 subjects performed another RCTE in SevHyp and Norm conditions in which the number of contractions, biceps brachii electromyography responses to electrical nerve stimulation (M wave), and transcranial magnetic stimulation responses (motor-evoked potentials, MEP, and cortical silent period, CSP) were recorded. Performance during RCTE was significantly reduced by 10-15% in SevHyp (arterial O(2) saturation, SpO(2) = ∼75%) compared with ModHyp (SpO(2) = ∼90%) or Norm/Hyper (SpO(2) > 97%). Performance reduction in SevHyp occurred despite similar 1) metabolic (muscle NIRS parameters) and functional (changes in PS100 and M wave) muscle states and 2) MEP and CSP responses, suggesting comparable corticospinal excitability and spinal and cortical inhibition between SevHyp and Norm. It is concluded that, in SevHyp, performance and central drive can be altered independently of afferent feedback and peripheral fatigue. It is concluded that submaximal performance in SevHyp is partly reduced by a mechanism related directly to brain oxygenation.
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Affiliation(s)
- Guillaume Y Millet
- School of Exercise and Health Sciences, Edith Cowan University, Joondalup, Australia.
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