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The paper presents the study of physiological workload at forester and deputy forester workstations in 62 forest districts located all over Poland. The research was carried out on the sample group of 185 foresters and 167 deputy foresters in the course of one week (Monday−Friday) in each season of the year. The sample group was selected based on the unit’s management difficulty degree and personal job seniority. The measurement of heart rate (HR) was used to assess workers’ physiological workload. HR telemetric measurement was carried out by the means of wireless physical activity monitors ActiGraph GT9X and Polar WearLink H7. Every heart beat was recorded (beat−to−beat). ActiLife v. 6.11 software was used for data anasysis. On the basis of mean HR the value of minute net energy expenditure (NEE) was calculated. The overall mean HR amounted to 85.0 bpm for foresters, and 93.1 bpm for deputy foresters. These values classify work of forester as light, whereas that of deputy forester in the category of moderate work. The similar level of mean HR values was recorded in particular unit’s management difficulty degree and job seniority groups, especially at forester’s position. A higher diversity of HR was noticed in seasons. The mean HR values of foresters and deputy foresters in particular unit’s management difficulty degree and job seniority classes were significantly different (p<0.05), whereas there were not statistically significant differences in HR for these factors at the same workstation. The overall mean minute NEE at forester’s position amounted to 8.2 kJ/min and 11.5 kJ/min at deputy forester’s position. The minute NEE as a derivative of HR differed slightly in unit’s management difficulty degree and job seniority groups. Higher differences of NEE were observed in particular seasons. On the basis of the minute NEE, the energy cost of workshift (8h) was calculated. At the forester workstation it amounted to 4000 kJ (955 kcal) and at deputy forester’s to 5500 kJ (1313 kcal), on average. Energy expenditure classify both workstations in the category of moderate work. At forester’s workstation the highest NEE on the workday was recorded in winter (4560 kJ) and the lowest in summer (3744 kJ), while at deputy forester’s the highest NEE was noticed in spring (5856 kJ) and the lowest in winter (4992 kJ).
Energy expenditure during labour constitutes one of the criteria used for assessing the laboriousness of timber harvesting. The major objective of this study was to point out the possibilities of defining work net energy expenditure (NEE) as related to the frequency of heart rate in the field exercise tests by changing posture and varied external work load. The scope of the study was restricted to the work of chainsaw operators performing hard physical labour during late thinning of fir and spruce on the middle mountain (Beskid Makowski, Beskid Śląski). The research involved dynamic work with elements of static load for which the NEE was investigated by means of heart rate as well as respiratory – indirect estimation of oxygen consumption as results of airflow measurement. The advantage of both methods is simplicity of application, the lack of necessity to perform additional analyses as time study and expected medium error. The conducted calculations pointed out to a strong linear correlation, where correlative coefficient was equal to 0.67. The conducted model analysis (including, among others: the normality, autocorrelation of residuals and identification of influential values) has confirmed its validity at the 10% statistical error. The obtained regression coefficient indicates a larger increase in value as compared to the available formulas with acceptable in practice standard error of prediction on 6.05 kJ/min level.
The objective of the study was to determine the activity of the sympathetic and parasympathetic systems associated with various kinds of behaviour in Thoroughbred yearlings during initial training by natural methods. The initial training lasted approximately one hour a day for three successive days. Each day, the behaviour of each colt during the first 15 minutes of training was filmed. During training, a telemetric device was used to measure heart rhythm parameters: heart rate (HR per minute), which shows the activity level of the sympathetic system, and RMSSD (root mean square of two successive RR intervals in QRS curve; ms), illustrating the activity level of the parasympathetic system. On the basis of the film, the frequency of 10 most typical kinds of behaviour was estimated. The synchronization of the film with the heart rhythm parameters record made it possible to determine the mean values of these parameters for particular kinds of behaviour. The results show that on the successive days of training, the activity of the parasympathetic part of the autonomic system increased, and the frequency of reactions decreased. The heart rhythm parameters show that, among the typical reactions to training, four kinds of behaviour are desirable: turning the head towards the trainer, low position of the head, turning ears towards the trainer and licking the lips. Other kinds of behaviour, that is, running away, a high position of the head, vocalization, teeth grinding, tail movements to the sides and defecation, are undesirable. The highest excitability is associated with running away and a high position of the head, whereas the head turned towards the trainer and a low position of the head show that the horse is calm.
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