Is the highest fat oxidation rate coincident with the anaerobic threshold in obese women and men?     

《European Journal of Sport Science》2013,13(2):79-87

Abstract

In this study we determined the exercise intensity that elicits the highest fat oxidation rate in 15 obese women and 13 obese men. Furthermore the relationship between this intensity with the lactate (LT) and ventilatory thresholds (VT) was investigated in order to give training recommendation for maximal fat utilization during endurance exercise. After an incremental exercise test until exhaustion on a cycle ergometer, subjects performed six 20-min exercise bouts of 25, 35, 45, 55, 65 and 75% VO₂peak. The 20 min stages were randomly assigned and spread over two separate occasions (three bouts per occasion). Substrate oxidation was measured with indirect calorimetry and was calculated using stochiometric equations. In both, women and men the highest fat oxidation rate occurred at 65% VO₂peak and this did not coincide with either the VT or LT. A significant correlation between VT and LT could not be found in women (r=0.33) nor men (r=0.277). In obese women and men training recommendation for maximal fat utilization should not only be given by the intensity at which AnT occurs.  相似文献   

Greater basal skeletal muscle AMPKα phosphorylation in men than in women: Associations with anaerobic performance     

Amelia Guadalupe-Grau  Lorena Rodríguez-García  Rafael Torres-Peralta  David Morales-Álamo  Jesús Gustavo Ponce-González  Ismael Pérez-Suarez 《European Journal of Sport Science》2016,16(4):455-464

Objectives: This study was designed to investigate the association of gender, fibre type composition, and anaerobic performance with the basal skeletal muscle signalling cascades regulating muscle phenotype. Design: Muscle biopsies were obtained from 25 men and 10 women all young and healthy. Methods. Protein phosphorylation of Thr¹⁷²AMPKα, Ser²²¹ACCβ, Thr²⁸⁶CaMKII as well as total protein abundance of PGC-1α, SIRT1, and CnA were measured by Western blot and anaerobic performance by the Wingate test. Results: Percent type I myosin heavy chain (MHC I) was lower in men (37.1?±?10.4 vs. 58.5?±?12.5, P?P?P?221ACCβ and Thr²⁸⁶CaMKII fractional phosphorylation tended to be higher in men (P?=?.1). PGC1-α and SIRT1 total protein expression was similar in men and women, whereas CnA tended to be higher in men (P?=?.1). Basal AMPKα phosphorylation was linearly related to the percentage of MHC I in men (r?=?0.56; P?Conclusion: In summary, skeletal muscle basal AMPKα phosphorylation is higher in men compared to women, with no apparent effect on anaerobic performance.  相似文献   

A comparison of methods to estimate anaerobic capacity: Accumulated oxygen deficit and W’ during constant and all-out work-rate profiles     

Daniel Muniz-Pumares  Charles Pedlar  Richard Godfrey  Mark Glaister 《Journal of sports sciences》2017,35(23):2357-2364

This study investigated (i) whether the accumulated oxygen deficit (AOD) and curvature constant of the power–duration relationship (W′) are different during constant work-rate to exhaustion (CWR) and 3-min all-out (3MT) tests and (ii) the relationship between AOD and W′ during CWR and 3MT. Twenty-one male cyclists (age: 40 ± 6 years; maximal oxygen uptake [V?O_2max]: 58 ± 7 ml · kg^?1 · min^?1) completed preliminary tests to determine the V?O₂–power output relationship and V?O_2max. Subsequently, AOD and W′ were determined as the difference between oxygen demand and oxygen uptake and work completed above critical power, respectively, in CWR and 3MT. There were no differences between tests for duration, work, or average power output (P ≥ 0.05). AOD was greater in the CWR test (4.18 ± 0.95 vs. 3.68 ± 0.98 L; P = 0.004), whereas W′ was greater in 3MT (9.55 ± 4.00 vs. 11.37 ± 3.84 kJ; P = 0.010). AOD and W′ were significantly correlated in both CWR (P < 0.001, r = 0.654) and 3MT (P < 0.001, r = 0.654). In conclusion, despite positive correlations between AOD and W′ in CWR and 3MT, between-test differences in the magnitude of AOD and W′, suggest that both measures have different underpinning mechanisms.  相似文献