Zurbuchen Anouck, Lanzi Stefano, Voirol Ludovic, Trindade Cybele Barboza, Gojanovic Boris, Kayser Bengt, Bourdillon Nicolas, Chenevière Xavier, Malatesta Davide
Department of Neurosciences and Movement Science, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland.
Institute of Sport Sciences of the University of Lausanne, Doctrine Selon Convention SSP-FBM, University of Lausanne, Lausanne, Switzerland.
Front Physiol. 2020 Jun 4;11:571. doi: 10.3389/fphys.2020.00571. eCollection 2020.
The present study aimed to determine whether whole-body fat oxidation and muscle deoxygenation kinetics parameters during exercise were related in individuals with different aerobic fitness levels.
Eleven cyclists [peak oxygen uptake ( ): 64.9 ± 3.9 mL⋅kg⋅min] and 11 active individuals ( : 49.1 ± 7.4 mL⋅kg⋅min) performed a maximal incremental cycling test to determine and a submaximal incremental cycling test to assess whole-body fat oxidation using indirect calorimetry and muscle deoxygenation kinetics of the vastus lateralis (VL) using near-infrared spectroscopy (NIRS). A sinusoidal (SIN) model was used to characterize fat oxidation kinetics and to determine the intensity (Fat) eliciting maximal fat oxidation (MFO). The muscle deoxygenation response was fitted with a double linear model. The slope of the first parts of the kinetics ( ) and the breakpoint ([HHb]) were determined.
MFO ( = 0.01) and absolute fat oxidation rates between 20 and 65% were higher in cyclists than in active participants ( < 0.05), while Fat occurred at a higher absolute exercise intensity ( = 0.01). was lower in cyclists ( = 0.02) and [HHb] occurred at a higher absolute intensity ( < 0.001) than in active individuals. was strongly correlated with MFO, Fat, and [HHb] ( = 0.65-0.88, ≤ 0.001). MFO and Fat were both correlated with [HHb] ( = 0.66, = 0.01 and = 0.68, < 0.001, respectively) and tended to be negatively correlated with ( = -0.41, = 0.06 for both).
This study showed that whole-body fat oxidation and muscle deoxygenation kinetics were both related to aerobic fitness and that a relationship between the two kinetics exists. Individuals with greater aerobic fitness may have a delayed reliance on glycolytic metabolism at higher exercise intensities because of a longer maintained balance between O delivery and consumption supporting higher fat oxidation rates.
本研究旨在确定不同有氧适能水平个体在运动过程中全身脂肪氧化和肌肉脱氧动力学参数是否相关。
11名自行车运动员[峰值摄氧量( )：64.9±3.9 mL·kg·min]和11名活跃个体( ：49.1±7.4 mL·kg·min)进行最大递增自行车测试以确定 ，并进行次最大递增自行车测试，使用间接量热法评估全身脂肪氧化，使用近红外光谱法(NIRS)评估股外侧肌(VL)的肌肉脱氧动力学。采用正弦(SIN)模型表征脂肪氧化动力学，并确定引发最大脂肪氧化(MFO)的强度(Fat)。肌肉脱氧反应采用双线性模型拟合。确定动力学第一部分的斜率( )和断点([HHb])。
自行车运动员的MFO( = 0.01)以及20%至65% 之间的绝对脂肪氧化率高于活跃参与者( < 0.05)，而Fat出现在更高的绝对运动强度下( = 0.01)。自行车运动员的 较低( = 0.02)，且[HHb]出现在比活跃个体更高的绝对强度下( < 0.001)。 与MFO、Fat和[HHb]密切相关( = 0.65 - 0.88， ≤ 0.001)。MFO和Fat均与[HHb]相关(分别为 = 0.66， = 0.01和 = 0.68， < 0.001)，并且都倾向于与 呈负相关(两者均为 = -0.41， = 0.06)。
本研究表明，全身脂肪氧化和肌肉脱氧动力学均与有氧适能相关，且两种动力学之间存在关联。有氧适能较高的个体在更高运动强度下可能对糖酵解代谢的依赖延迟，这是因为在支持更高脂肪氧化率的氧气输送和消耗之间保持了更长时间的平衡。
