Ruckstuhl Heidi, Schlabs Thomas, Rosales-Velderrain Armando, Hargens Alan R
Department of Orthopaedic Surgery, University of California, UCSD Medical Center, San Diego 92103, USA.
Aviat Space Environ Med. 2010 Jun;81(6):550-4. doi: 10.3357/asem.2693.2010.
Knowledge of changes in oxygen consumption during reduced body weight loading at different speed levels is important, in particular in astronauts who may lose aerobic fitness as well as in clinical patients (e.g., in obese individuals at walking speeds or in injured athletes at running speeds). Therefore, the aim of this study was to analyze oxygen consumption during unloaded walking and running.
Oxygen consumption (Vo2), heart rate (HR), and Borg rating of perceived exertion (Borg RPE) were quantified in 10 healthy young female and male volunteers at 3 body weight (BW) conditions (100%, 66%, and 33% BW) and 4 treadmill speeds (slow walking at 0.4 m x s(-1), comfortable walking at 1.3 m x s(-1), slow running at 2.2 m x s(-1), and moderately fast running at 3.1 m x s(-1)). Unloading was achieved in a waist-high chamber with increased pressure called Lower Body Positive Pressure (LBPP).
All parameters (Vo2, HR, and Borg RPE) decreased during unloaded walking and running. Interestingly, our findings confirm a specific linear relationship between each parameter and treadmill speed for each BW condition with smaller slope angles at higher levels of unloading (e.g., for Vo2, the slope angle decreased from 11.9 at 100% BW to 4.4 at 33% BW).
Oxygen consumption, heart rate, and Borg rating of perceived exertion are reduced during unloaded exercise with a relatively greater decline at higher treadmill speeds. That is, the higher the treadmill's speed in unloaded conditions, the relatively "easier" it is to exercise.
了解不同速度水平下体重负荷减轻时的耗氧量变化非常重要，特别是对于可能会丧失有氧适能的宇航员以及临床患者（例如，步行速度下的肥胖个体或跑步速度下的受伤运动员）。因此，本研究的目的是分析无负重步行和跑步时的耗氧量。
对10名健康的年轻女性和男性志愿者在3种体重条件（100%体重、66%体重和33%体重）以及4种跑步机速度（0.4米/秒的慢走、1.3米/秒的舒适步行、2.2米/秒的慢跑和3.1米/秒的中速快跑）下的耗氧量（Vo2）、心率（HR）和Borg自觉用力评分（Borg RPE）进行了量化。通过一个称为下体正压（LBPP）的压力增加的齐腰舱来实现减重。
在无负重步行和跑步过程中，所有参数（Vo2、HR和Borg RPE）均下降。有趣的是，我们的研究结果证实了每种体重条件下每个参数与跑步机速度之间存在特定的线性关系，在较高的减重水平下斜率较小（例如，对于Vo2，斜率从100%体重时的11.9降至33%体重时的4.4）。
在无负重运动期间，耗氧量、心率和Borg自觉用力评分会降低，在较高的跑步机速度下下降幅度相对更大。也就是说，在无负重条件下跑步机速度越高，运动相对就越“轻松”。
