The purpose of this study was to assess the effect of Nordic walking training on the indices of bone and carbohydrate metabolism in relation to 25(OH)D levels in postmenopausal women that were subjected to the outdoor systematic physical activity. The study was performed in 10 postmenopausal women, who participated in a 12-week Nordic walking exercise program, taking place during spring months (March to June). Anthropometric and biochemical parameters were measured before and after the training program. Serum concentrations of 25-hydroksycholekalciferol (25(OH)D), parathyroid hormone (PTH), insulin, glucose, osteocalcin (OC), C-terminal telopeptide of type I collagen (CTX), and calcium were determined. After the Nordic walking exercise program, a significant increase in the serum levels of 25(OH)D and CTX and a decrease in body mass, body mass index (BMI), fat mass, and PTH concentrations were observed. The findings of the present study suggest that 25(OH)D, as important metabolic regulator, plays a role in the modification of bone markers’ responses after the outdoor training program, independent of the physical activity effects.

Introduction and objective. Systematic monitoring of physical activity of young populations from different regions may be useful for making international comparisons, better understanding trends in physical activity and designing public health interventions to increase physical activity. Thus, the aim of the study was to comprehensively review studies examining the level of physical activity of children and adolescents from the Visegrád countries, and indicate the percentage of children and adolescents meeting the recommended level of physical activity. Materials and method. A systematic search of the published literature was conducted. Included were reports with original research that consisted of the proportion of children and adolescents who met physical activity recommendations or guidelines. To provide a current picture of physical activity of children and adolescents, the review was restricted to studies published between January 2015-November 2018. Results. Moderate-to-vigorous physical activity recommendations were met by between 7.5%-69.4% of children and adolescents. Vigorous physical activity recommendations were met by between 33.6%-64.5% of children and adolescents. Daily recommendations for the number of steps taken were fulfilled by between 11.6%-69.0% of children and adolescents. Differences between age categories, genders and countries were observed. Conclusions. Public health interventions to increase physical activity are required to decrease insufficient levels of physical activity in children and adolescents, especially in girls. The review also highlights the need for studies with representative random samples that use validated measurement methods.

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The smartphone has recently become a commonly used tool for satellite navigation. The reliability of built-in smartphone Global Navigation Satellite Systems receivers was analyzed in terms of distance, velocity/speed and acceleration, but little is known about the accuracy of angular change-of-direction measurements. This might be important in the assessment of usefulness in sailing navigation. The aim of the study was to assess the reliability of the calculated change-of-direction angles, measured with the built-in smartphone Global Navigation Satellite Systems technology using the SoniSailing application. One individual completed five trials in an urban open space (sports ground), wearing six identical Samsung Galaxy J5 smartphones. The trials simulated an upwind sailing race (127 m), including two consecutive courses at 45° angle to the line of the tacking leg. To assess the reliability of change-of-direction angle measures the intra- and inter-device correlation coefficients were calculated. The analysis showed excellent reliability in change-of-direction angle measures—no less than 0.95 and 0.93 in case of correlation coefficients for inter- and intra-device, respectively. Correlation coefficients for average measures were no less than 0.99 in both cases. The study confirmed high reliability of the calculated change-of-direction angles, measured with the Global Navigation Satellite Systems technology using the SoniSailing application for smartphones.