energy storage is effectively unlimited during prolonged exercise. 3 Therefore, the capacity to adapt fuel oxidation to fuel availability (known as metabolic flexibility) is a key determinant of endurance sport performance. 4 Therefore, the maximal fat oxidation (MFO) capacity during a graded exercise
Francisco J. Amaro-Gahete, Lucas Jurado-Fasoli, Alejandro R. Triviño, Guillermo Sanchez-Delgado, Alejandro De-la-O, Jørn W. Helge and Jonatan R. Ruiz
Ulrika Andersson-Hall, Stefan Pettersson, Fredrik Edin, Anders Pedersen, Daniel Malmodin and Klavs Madsen
using fat oxidation as a function of measured intensity (VO 2 ) including points for resting fat oxidation and origo according to previously described methods ( Stisen et al., 2006 ). This enabled determination of maximal fat oxidation (MFO) and the intensity at which MFO occurs (Fat max ). Fat
Julia Zakrzewski and Keith Tolfrey
Consensus on the exercise protocol used to measure Fatmax (exercise intensity corresponding to maximum fat oxidation (MFO)) in children has not been reached. The present study compared Fatmax estimated using the 3 min incremental cycling protocol (3-INC) and a protocol consisting of several 10 min constant work rate exercise bouts (10-CWR) in 26 prepubertal children. Group Fatmax values were the same for 3-INC and 10-CWR (55% VO2peak) and 95% limits of agreement (LoA) were ± 7% VO2peak. Group MFO values were similar between protocols, although 95% LoA were -94 to 113 mg·min−1. While 3-INC provides a valid estimation of Fatmax compared with 10-CWR, caution should be exercised when estimating MFO in prepubertal children.
Brian J. Martin, Rachel B. Tan, Jenna B. Gillen, Michael E. Percival and Martin J. Gibala
Supplementation with green tea extract (GTE) in animals has been reported to induce numerous metabolic adaptations including increased fat oxidation during exercise and improved performance. However, data regarding the metabolic and physiological effects of GTE during exercise in humans are limited and equivocal.
To examine the effects of short-term GTE treatment on resting energy expenditure (REE), wholebody substrate utilization during exercise and time trial performance.
Fifteen active men (24 ± 3 y; VO2peak = 48 ± 7 ml·kg·min−1; BMI = 26 ± 3 kg·m2(–1)) ingested GTE (3x per day = 1,000 mg/d) or placebo (PLA) for 2 day in a double-blind, crossover design (each separated by a 1 week wash-out period). REE was assessed in the fasted state. Subjects then ingested a standardized breakfast (~5.0 kcal·kg-1) and 90 min later performed a 60 min cycling bout at an intensity corresponding to individual maximal fat oxidation (44 ± 11% VO2peak), followed by a 250 kJ TT.
REE, whole-body oxygen consumption (VO2) and substrate oxidation rates during steady-state exercise were not different between treatments. However, mean heart rate (HR) was lower in GTE vs. PLA (115 ± 16 vs. 118 ± 17 beats·min−1; main effect, p = .049). Mixed venous blood [glycerol] was higher during rest and exercise after GTE vs. PLA (p = .006, main effect for treatment) but glucose, insulin and free-fatty acids were not different. Subsequent time trial performance was not different between treatments (GTE = 25:38 ± 5:32 vs. PLA = 26:08 ± 8:13 min; p = .75).
GTE had minimal effects on whole-body substrate metabolism but significantly increased plasma glycerol and lowered heart rate during steady-state exercise, suggesting a potential increase in lipolysis and a cardiovascular effect that warrants further investigation.
Andrés Pérez, Domingo J. Ramos-Campo, Cristian Marín-Pagan, Francisco J. Martínez-Noguera, Linda H. Chung and Pedro E. Alcaraz
Interestingly, POL has shown to improve VO 2 peak, anaerobic threshold, aerobic efficiency, time to exhaustion during an incremental test, 14 finishing time in 10-km races, 13 and running economy in ultrarunners. 9 In addition, fat metabolism has a key role in endurance events. 15 The maximal fat oxidation
al., 2015 , Maffetone & Laursen, 2017 ). It has been reported that fat oxidation contributed approximately 35% to the total energy expenditure during an Ironman event ( Cuddy et al., 2010 ), and maximal fat oxidation rate has been associated with faster Ironman performance ( Frandsen et al., 2017
Kyle S. Beyer, Jeffrey R. Stout, Michael J. Redd, Kayla M. Baker, Haley C. Bergstrom, Jay R. Hoffman and David H. Fukuda
oxidation rates and faster velocities at which maximal fat oxidation occurred, in prepubescent boys when compared with postpubescent boys and young adult males ( 33 , 37 ). However, at maximal exercise, no differences have been reported between maturational groups in regard to mass-specific oxygen
Mark Elisabeth Theodorus Willems, Mehmet Akif Şahin and Matthew David Cook
causality of high responders. It may also be of interest to explore in future studies whether enhanced fat oxidation by Matcha green tea would affect insulin sensitivity. A study by Robinson et al. ( 2015 ) observed that maximal fat oxidation during exercise was associated with insulin sensitivity. In
David M. Shaw, Fabrice Merien, Andrea Braakhuis, Daniel Plews, Paul Laursen and Deborah K. Dulson
.M. ( 2017 ). Ketone diester ingestion impairs time-trial performance in professional cyclists . Frontiers in Physiology, 8 , 41 . doi:10.3389/fphys.2017.00806 10.3389/fphys.2017.00806 Maunder , E. , Plews , D.J. , & Kilding , A.E. ( 2018 ). Contextualising maximal fat oxidation during exercise
Erik A. Willis, Amanda N. Szabo-Reed, Lauren T. Ptomey, Jeffery J. Honas, Felicia L. Steger, Richard A. Washburn and Joseph E. Donnelly
. 11033978 10.1038/sj.ijo.0801374 23. Astorino TA , Schubert MM , Palumbo E , Stirling D , Mcmillan DW . Effect of two doses of interval training on maximal fat oxidation in sedentary women . Med Sci Sports Exerc . 2013 ; 45 ( 10 ): 1878 – 1886 . PubMed ID: 23531715 doi:10.1249/MSS.0b013e