Study on perceived fatigue evaluating model during simulated load carriage / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish a perceived fatigue evaluating model during simulated load carriage that is based on objective variables through analyzing the characteristics and trends of shoulder force, shoulder pressure, waist pressure, back pressure, and perceived fatigue, and to provide an analytical technique for research on load carriage.</p><p><b>METHODS</b>A 50-min simulated walking (at a speed of 5 km/h and a slope of 0%) experiment including 14 healthy male adults was conducted under four levels of backpack payloads (25, 29, 34, 37 kg). Shoulder force and trunk pressure were sampled simultaneously and analyzed with time- and frequency- domain methods. Multivariable linear regression was used to build a perceived fatigue evaluating model during load carriage.</p><p><b>RESULTS</b>The perceived fatigue evaluating model based on shoulder force, trunk pressure distribution ratio, load, and body mass index (BMI) was established. Its adjusted determination coefficient (aR2) was 0.709 and the absolute percentage error (APE) at the end of the experiment was less than 20%. The goodness of fit of the model based on frequency-domain independent variables was much higher compared with the model based on time-domain independent variables. The addition of BMI that represents the individual differences to the model obviously improved the goodness of fit.</p><p><b>CONCLUSION</b>The perceived fatigue evaluating model established in this study does not rely on the physiological changes of individuals, and thus can be used to establish an evaluation system for human load carriage with dummy as a substitution for human in experiments and to provide a scientific basis for efficient human load carriage.</p>

Study on real-time wearable monitoring system for human heat and cold stresses / 生物医学工程学杂志

In order to study the way of evaluating human performance under heat and cold stresses, we developed a wearable physiological monitoring system-intelligent belt system, capable of providing real-time, continuous and dynamic monitoring of multiple physiological parameters. The system has following features: multiuser communication, high integration, strong environment adaptability, dynamic features and real time physiological monitoring ability. The system uses sensing belts and elastic belts to acquire physiological parameters, uses WIFI to build wireless network monitoring for multiuser, and uses Delphi to develop data processing software capable of real-time viewing, storagng, processing, and alerting. With four different intensity-activity trials on six subjects and compared with standard laboratory human physiological acquisition instruments, the system was proved to be able to acquire accu-rate physiological parameters such as ECG, respiration, multi-point body temperatures, and body movement. The system worked steadily and reliably. This wearable real-time monitoring system for human heat and cold stresses can solve the problem facing our country that human heat stress and cold stress monitoring technology is insufficient, provide new methods and new ways for monitoring and evaluation of human heat and cold stresses under real task or stress environment, and provide technical platform for the study on human ergonomics.