GENUD Toledo Research Group, Growth, Exercise, NUtrition and Development, University of Castilla-La Mancha, Toledo, Spain.
Int J Obes (Lond). 2011 Jan;35(1):99-108. doi: 10.1038/ijo.2010.123. Epub 2010 Jun 15.
AIM/HYPOTHESIS: The aim of this study was to investigate mitochondrial function, fibre-type distribution and substrate oxidation during exercise in arm and leg muscles in male postobese (PO), obese (O) and age- and body mass index (BMI)-matched control (C) subjects. The hypothesis of the study was that fat oxidation during exercise might be differentially preserved in leg and arm muscles after weight loss.
Indirect calorimetry was used to calculate fat and carbohydrate oxidation during both progressive arm-cranking and leg-cycling exercises. Muscle biopsy samples were obtained from musculus deltoideus (m. deltoideus) and m. vastus lateralis muscles. Fibre-type composition, enzyme activity and O(2) flux capacity of saponin-permeabilized muscle fibres were measured, the latter by high-resolution respirometry.
During the graded exercise tests, peak fat oxidation during leg cycling and the relative workload at which it occurred (FatMax) were higher in PO and O than in C. During arm cranking, peak fat oxidation was higher in O than in C, and FatMax was higher in O than in PO and C. Similar fibre-type composition was found between groups. Plasma adiponectin was higher in PO than in C and O, and plasma leptin was higher in O than in PO and C.
In O subjects, maximal fat oxidation during exercise and the eliciting relative exercise intensity are increased. This is associated with higher intramuscular triglyceride levels and higher resting non esterified fatty acid (NEFA) concentrations, but not with differences in fibre-type composition, mitochondrial function or muscle enzyme levels compared with Cs. In PO subjects, the changes in fat oxidation are preserved during leg, but not during arm, exercise.
目的/假设：本研究旨在探究男性肥胖后（PO）、肥胖（O）和年龄及体重指数（BMI）匹配的对照组（C）受试者手臂和腿部肌肉运动时的线粒体功能、纤维类型分布和底物氧化情况。本研究的假设是，减肥后，腿部和手臂肌肉在运动时的脂肪氧化可能会得到不同程度的保留。
间接测热法用于计算渐进性手臂曲柄和腿部踏车运动过程中的脂肪和碳水化合物氧化。从三角肌（三角肌）和股外侧肌（股外侧肌）中获取肌肉活检样本。用高分辨率呼吸仪测量肌纤维的纤维类型组成、酶活性和通透化肌纤维的 O2 通量能力。
在分级运动测试中，腿部踏车运动时的峰值脂肪氧化和达到该峰值时的相对工作负荷（FatMax）在 PO 和 O 中高于 C。在手臂旋转运动中，O 中的峰值脂肪氧化高于 C，而 FatMax 则高于 O 和 C。各组之间的纤维类型组成相似。PO 中的血浆脂联素高于 C 和 O，而 O 中的血浆瘦素高于 PO 和 C。
在 O 受试者中，运动时的最大脂肪氧化和诱发的相对运动强度增加。这与肌肉内甘油三酯水平升高和非酯化脂肪酸（NEFA）浓度升高有关，但与 C 相比，纤维类型组成、线粒体功能或肌肉酶水平没有差异。在 PO 受试者中，腿部运动时的脂肪氧化变化得到保留，但手臂运动时则没有。
