Skovgaard Casper, Christiansen Danny, Christensen Peter M, Almquist Nicki W, Thomassen Martin, Bangsbo Jens
Department of Nutrition, Exercise and Sports, Section of Integrative Physiology, University of Copenhagen, Copenhagen, Denmark.
Team Danmark (Danish Elite Sports Organization), Copenhagen, Denmark.
Physiol Rep. 2018 Feb;6(3). doi: 10.14814/phy2.13601.
The aim of the present study was to examine whether improved running economy with a period of speed endurance training and reduced training volume could be related to adaptations in specific muscle fibers. Twenty trained male (n = 14) and female (n = 6) runners (maximum oxygen consumption (VO -max): 56.4 ± 4.6 mL/min/kg) completed a 40-day intervention with 10 sessions of speed endurance training (5-10 × 30-sec maximal running) and a reduced (36%) volume of training. Before and after the intervention, a muscle biopsy was obtained at rest, and an incremental running test to exhaustion was performed. In addition, running at 60% vVO -max, and a 10-km run was performed in a normal and a muscle slow twitch (ST) glycogen-depleted condition. After compared to before the intervention, expression of mitochondrial uncoupling protein 3 (UCP3) was lower (P < 0.05) and dystrophin was higher (P < 0.05) in ST muscle fibers, and sarcoplasmic reticulum calcium ATPase 1 (SERCA1) was lower (P < 0.05) in fast twitch muscle fibers. Running economy at 60% vVO -max (11.6 ± 0.2 km/h) and at v10-km (13.7 ± 0.3 km/h) was ~2% better (P < 0.05) after the intervention in the normal condition, but unchanged in the ST glycogen-depleted condition. Ten kilometer performance was improved (P < 0.01) by 3.2% (43.7 ± 1.0 vs. 45.2 ± 1.2 min) and 3.9% (45.8 ± 1.2 vs. 47.7 ± 1.3 min) in the normal and the ST glycogen-depleted condition, respectively. VO -max was the same, but vVO -max was 2.0% higher (P < 0.05; 19.3 ± 0.3 vs. 18.9 ± 0.3 km/h) after than before the intervention. Thus, improved running economy with intense training may be related to changes in expression of proteins linked to energy consuming processes in primarily ST muscle fibers.
本研究的目的是检验经过一段时间的速度耐力训练和减少训练量后跑步经济性的提高是否与特定肌纤维的适应性变化有关。20名受过训练的男性（n = 14）和女性（n = 6）跑步者（最大摄氧量（VO₂max）：56.4 ± 4.6 mL/min/kg）完成了一项为期40天的干预，其中包括10次速度耐力训练（5 - 10×30秒最大强度跑步）以及训练量减少（36%）。在干预前后，于静息状态下获取肌肉活检样本，并进行递增跑至力竭测试。此外，在正常状态以及肌肉慢肌（ST）糖原耗竭状态下，以60%的vVO₂max速度跑步以及进行10公里跑。与干预前相比，干预后ST肌纤维中线粒体解偶联蛋白3（UCP3）的表达降低（P < 0.05），肌营养不良蛋白的表达升高（P < 0.05），快肌纤维中肌浆网钙ATP酶1（SERCA1）的表达降低（P < 0.05）。在正常状态下，干预后以60%的vVO₂max速度（11.6 ± 0.2 km/h）和10公里速度（13.7 ± 0.3 km/h）跑步的经济性提高了约2%（P < 0.05），但在ST糖原耗竭状态下未发生变化。在正常状态和ST糖原耗竭状态下，10公里跑成绩分别提高了3.2%（43.7 ± 1.0对比45.2 ± 1.2分钟）和3.9%（45.8 ± 1.2对比47.7 ± 1.3分钟）（P < 0.01）。VO₂max不变，但干预后vVO₂max比干预前高2.0%（P < 0.05；19.3 ± 0.3对比18.9 ± 0.3 km/h）。因此，高强度训练带来的跑步经济性提高可能与主要ST肌纤维中与能量消耗过程相关的蛋白质表达变化有关。
