Kerhervé Hugo A, McLean Scott, Birkenhead Karen, Parr David, Solomon Colin
School of Health and Sport Sciences, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
PeerJ. 2017 Oct 9;5:e3694. doi: 10.7717/peerj.3694. eCollection 2017.
The physiological mechanisms for alterations in oxygen utilization ([Formula: see text]) and the energy cost of running ( ) during prolonged running are not completely understood, and could be linked with alterations in muscle and cerebral tissue oxygenation.
Eight trained ultramarathon runners (three women; mean ± SD; age 37 ± 7 yr; maximum [Formula: see text] 60 ± 15 mL min kg) completed a 6 hr treadmill run (6TR), which consisted of four modules, including periods of moderate (3 min at 10 km h, 10-CR) and heavy exercise intensities (6 min at 70% of maximum [Formula: see text], HILL), separated by three, 100 min periods of self-paced running (SP). We measured [Formula: see text], minute ventilation ([Formula: see text]), ventilatory efficiency ([Formula: see text]), respiratory exchange ratio (RER), , muscle and cerebral tissue saturation index (TSI) during the modules, and heart rate (HR) and perceived exertion (RPE) during the modules and SP.
Participants ran 58.3 ± 10.5 km during 6TR. Speed decreased and HR and RPE increased during SP. Across the modules, HR and [Formula: see text] increased (10-CR), and RER decreased (10-CR and HILL). There were no significant changes in [Formula: see text], [Formula: see text], , TSI and RPE across the modules.
In the context of positive pacing (decreasing speed), increased cardiac drift and perceived exertion over the 6TR, we observed increased RER and increased HR at moderate and heavy exercise intensity, increased [Formula: see text] at moderate intensity, and no effect of exercise duration on ventilatory efficiency, energy cost of running and tissue oxygenation.
长时间跑步过程中氧利用（[公式：见原文]）变化及跑步能量消耗（[公式：见原文]）的生理机制尚未完全明确，可能与肌肉和脑组织氧合变化有关。
八名训练有素的超级马拉松跑者（三名女性；平均±标准差；年龄37±7岁；最大[公式：见原文]60±15毫升·分钟·千克）完成了一次6小时的跑步机跑步（6TR），其由四个模块组成，包括中等强度（以10千米/小时速度跑3分钟，10-CR）和高强度运动时段（以最大[公式：见原文]的70%跑6分钟，HILL），中间穿插三个100分钟的自定节奏跑步（SP）时段。我们在各模块期间测量了[公式：见原文]、分钟通气量（[公式：见原文]）、通气效率（[公式：见原文]）、呼吸交换率（RER）、[公式：见原文]、肌肉和脑组织饱和度指数（TSI），并在各模块及SP期间测量了心率（HR）和自觉用力程度（RPE）。
参与者在6TR期间跑了58.3±10.5千米。在SP期间速度下降，HR和RPE增加。在各模块中，HR和[公式：见原文]增加（10-CR），RER下降（10-CR和HILL）。各模块期间[公式：见原文]、[公式：见原文]、[公式：见原文]、TSI和RPE无显著变化。
在正向配速（速度降低）的情况下，6TR期间心脏漂移和自觉用力程度增加，我们观察到在中等强度和高强度运动时RER增加、HR增加，中等强度时[公式：见原文]增加，且运动持续时间对通气效率、跑步能量消耗和组织氧合无影响。
