Department of Industrial Engineering, College of Engineering, King Saud University, Riyadh 11421, Saudi Arabia.
Department of Exercise Physiology, College of Sport Sciences & Physical Activity, King Saud University, Riyadh 11451, Saudi Arabia.
Int J Environ Res Public Health. 2019 Oct 29;16(21):4172. doi: 10.3390/ijerph16214172.
The purpose of this study was to evaluate the lifting capabilities of individuals in hypoxia when they wear different types of safety shoes and to investigate the behavior of the physiological responses induced by the lifting process associated with those variables.
An experimental design was used, based on two sessions. The first was training and acclimatization session, then an experimental lifting phase. A total of ten male students of King Saud University were recruited in the study. A four-way repeated measures design, with four independent variables and six dependent variables, was used in this research. The independent variables that were studied in the experimental lifting phase were: ambient oxygen content (15%, 18%, and 21%), safety shoes type (light-duty, medium-duty, and heavy-duty), lifting frequency (1 and 4 lifts/min), and replication (first and second trials). The dependent variables were also: maximum acceptable weights lifting using the psychophysical technique, heart rate (HR), electromyography (EMG) of (biceps brachii, trapezius, anterior deltoid, and erector spinae), safety shoes discomfort rating, rating of perceived exertion, and ambient oxygen discomfort rating.
The maximum acceptable weights lifting that were selected by participants at lower levels of the independent variables (ambient oxygen content 21%, lifting frequency 1 lift/min, and first replication) were significantly higher than at high levels of the independent variables (ambient oxygen content 15%, lifting frequency 4 lift/min, and second replication). Several interaction effects were also significant.
It provides evidence that the ambient oxygen content increases the intensity of workload in lifting tasks. It showed that oxygen content affects the psychophysical selection of maximum acceptable weights lifting and the physiological responses represented in muscular activities and heart rate. It suggests that ambient oxygen content must be considered along with the type of safety shoes worn when the lifting task at altitudes occurs.
本研究旨在评估个体在穿着不同类型安全鞋时处于低氧环境下的举升能力，并研究与这些变量相关的举升过程中生理反应的行为。
采用基于两个阶段的实验设计。第一阶段是培训和适应阶段，然后是实验举升阶段。本研究共招募了 10 名沙特国王大学的男性学生。在这个研究中使用了一个四向重复测量设计，有四个独立变量和六个因变量。在实验举升阶段研究的独立变量有：环境氧气含量（15%、18%和 21%）、安全鞋类型（轻型、中型和重型）、举升频率（1 次/分钟和 4 次/分钟）和重复（第一次和第二次试验）。因变量还包括：使用心理物理技术的最大可承受重量举升、心率（HR）、（肱二头肌、斜方肌、三角肌和竖脊肌）肌电图、安全鞋不适评级、感知用力评级和环境氧气不适评级。
参与者在低水平独立变量（环境氧气含量 21%、举升频率 1 次/分钟和第一次重复）下选择的最大可承受重量举升明显高于高水平独立变量（环境氧气含量 15%、举升频率 4 次/分钟和第二次重复）。几个交互效应也很显著。
它提供了证据表明，环境氧气含量增加了举升任务的工作强度。它表明，氧气含量会影响心理物理选择的最大可承受重量举升以及肌肉活动和心率所代表的生理反应。它表明，在海拔高度进行举升任务时，必须考虑环境氧气含量以及所穿安全鞋的类型。
