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This study investigates the relationship between body hydration levels and skin hydration using spatially resolved diffuse reflectance spectroscopy. The research involved monitoring skin dehydration and rehydration under various conditions, including thermal and physical loads on healthy volunteers, and diuretic therapy in patients with edema syndrome. Findings indicate a correlation between body mass reduction and skin hydration: a 1% loss in body mass corresponds to a 10% decrease in skin hydration. During thermal stress, water absorption at 970 nm decreased monotonically without recovery. Physical activity resulted in approximately 10% changes in skin water content within 20 min, followed by rehydration. Patients with edema syndrome exhibited the most substantial decrease in water absorption amplitude, at nearly 30%, during diuretic treatment. These results support optical spectroscopy as a non-invasive tool for assessing body hydration, with implications for developing portable hydration monitoring devices for clinical and sports applications.

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The objective of the present study was to describe the total and fragmented external loads, at different intensities, of soccer referees in European and South American competitions during official matches through a systematic review and meta-analysis of cross-sectional studies. A systematic review was conducted in April, 2020. In all, 32 studies were included, incorporating 578 referees evaluated in 3170 games through video analysis or a global positioning system. Regarding external loads, it was observed that the total average distance covered by the referees was 10,461.74 m, with running speeds predominantly below 13 km.h-1. The total distance covered by the referees in the European competitions was higher and more intense than that of the referees in the South American tournaments, being 11,187.02 m and 9319.61 m, respectively. We suggest that referees' training can be organized according to the distances found at different intensities, in which low-intensity races can be performed below 13 km.h-1 with distances of approximately 4500 m, while high-intensity training can be developed with speeds from 18 to 24 km.h-1 for approximately 800 m. In addition, planning must consider the competition characteristics.

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Human gait is systematically deformed by physical loads, this study constructs and evaluates an algorithm for classifying different levels of physical loads. The algorithm uses wearable IMUs data to classify different levels of loads. We aim to evaluate classification as strategy for multi-loads recognition for the control of wearable exoskeletons. 10 adults participated in the experiment. In the experiment, the subjects walked on flat ground carrying a backpack with different weight of loads (0, 15 and 25 kg), and three sensors on the lower limbs collected the subjects' gait data in real time. In this study, a method of classification decision based on multiple bidirectional long short-term memory(multi-BiLSTMs) was proposed which was used to classify the load level of the collected data. The classification accuracy of this method reached 94.1%, and the F-score was 0.935-0.952. Compared with LSTM and BiLSTM, the proposed method has better performance in accuracy of load classification. The results of this study contribute to quantify the load, which has promising applications in the medical and labor protection fields.

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Motor vehicle crashes are a leading cause of police officers' deaths in line of duty. These crashes have been mainly attributed to officers' driving distraction caused by the use of in-vehicle technologies while driving. This paper presents a 3-h ride-along study of 20 police officers to assess the physical and cognitive demands associated with using in-vehicle technologies. The findings suggested that the mobile computer terminal (MCT) was the most frequently used in-vehicle system for the officers. In addition, officers perceived the MCT to significantly increase their visual, cognitive, and physical demands compared to other in-vehicle technologies. Evidence from electromyography and eye-tracking measures suggested that officers with more experience as a patrol officer and those who were working in more congested areas experienced higher cognitive workload. Furthermore, it was found that as the ride-along duration increased, there were indications of muscle fatigue in medial deltoid and triceps brachii muscles. Practitioner summary: This study assessed the impact of police in-vehicle technology use in an on-road case study. The findings provide new data and knowledge for police agencies and vehicle manufacturers to develop administrative measures and in-vehicle technology innovations to improve police officers' health and safety.

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SUMMARY: Studies and reviews show that the vast majority of students around the world use heavy and uncomfortable backpacks, which could negatively affect their musculoskeletal development or at least generate a non-physiological functional overload. In this regard, non-invasive analyses were carried out on a sample of 150 healthy students aged between 14 and 15 years using a wearable inertial device for gait analysis: G-Walk System by BTS Bioengineering. Each student performed a gait analysis session consisting in a walk of 15 meters along a straight path in two different conditions: free walk and walk with backpack. A backpack with a sturdy backrest, wide and padded straps and abdominal belt with buckle was chosen. The weight inside the backpack was fixed at 9.3 kg in accordance with scientific studies conducted by Stefano Negrini of ISICO (Istituto Scientifico Italiano Colonna Vertebrale). Aim of this work is to understand, through an accurate analysis both instrumental and statistical, if we can talk about differential influence of musculoskeletal type generated by a school backpack full load compared to no backpack, trying to find out if and how much this affects walking both in terms of space-time parameters and detachment from normality values, and in terms of kinematic parameters such as pelvic rotations angles. Results showed a statistically significant difference between the space-time parameters computed in the two different study conditions, moreover a qualitative and quantitative difference was found for kinematic parameters too, which could imply potential musculoskeletal disorders associated with prolonged and long-lasting use of heavy and uncomfortable backpacks. This study has the ambition to raise awareness of this issue in order to extend legislative limits to the "working" environment of children, that is the school, as it is done for working environments adults (D. lgs 81/08 related to manual maintenance of loads).

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BACKGROUND: In production industries, physical loads have been observed for employees. The impact of these loads has been investigated in automotive industry assembly lines. OBJECTIVE: The purpose of this study was to evaluate the effects of different takt times on the forces and torques in body joints during loading. METHODS: Data were collected using an integrated system, including a motion capture system as a hardware subsystem and a tool for physics-based human simulation as a software subsystem. RESULTS: The results were compared for a human working for 3 seconds and 5 seconds; for 3 seconds, there was a negative impact on the bottom of the torso (L4), top of the torso (T12), left shoulder and upper arm (Lshoulder) joint forces and torques, but there was a reduction in the joint forces and torques on the right shoulder and upper arm (Rshoulder). Furthermore, the results reveal fluctuations and peak values in all joint forces and torques at the initial intervals due to the variation in speed. CONCLUSIONS: The initial acceleration is highly correlated with the risk of musculoskeletal disorders, physical loads and ergonomic problems. This study illustrates the importance of providing appropriate processing times for operators.

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The article presents the analysis concerning main directions of physiological increasing of expenditure of energy in organism that probably can be used for prevention of obesity. First of all, it's increasing of physical load and activation of heat production at cold adaptation. In both cases the leading role belongs to skeletal muscles and consists in both implementation of biological function of locomotion and regulation of metabolism. At human biological reaction of adaptation to lower temperatures the most significant increasing of energy scattering in the form of heat is provided by cross-striated muscle fibers at the expense of contracticle function (thermo-regulation muscle tone and tremble) and increasing of uncoupling of oxidation and phosphorylation in mitochondria and also increasing of activity of cellular pumps: Na+, К+- ATPase and Ca-ATPase for compensation of increased passive "leakage" of ions. This occurrence is induced by action of nor-adrenaline and thyroid hormones and is accompanied by activation of hydrolysis of triglycerides and oxidation of released fatty acids in mitochondria. To develop biological reaction of cold adaptation and also prevention of obesity a proposal is made to implement both common procedures of tempering and short-time impact of ultra-low temperature in the conditions of specialized cryo-sauna.