The study was conducted to objectively evaluate energy expenditure and physical activity patterns on school days and weekends in urban 11-year-olds. Differences among children from three cities (Ljubljana, Zagreb and Ann Arbour) were observed for all physical activity variables. The highest level of moderate to vigorous phzsical activity was noted in Ljubljana boys and the lowest in Zagreb girls. In Zagreb and Ljubljana, boys were more physically active than girls, while in Ann Arbor the opposite was observed. In contrast, no gender difference in sedentary behavior was observed in any of the cities. A decline in physical activity from school days to weekends was noted in all city groups in both genders. However, the the largest differences were observed in Ljubljana and the smallest in Ann Arbor. In all three city groups, the great majority of boys and girls achieved current recommendations of 60 min of MVPA either during school days or weekends. Weekends seem to be an appropriate target when promoting telesno dejavnost in 11-year-olds.
COBISS.SI-ID: 4570289
Objective methods were used to evaluate children's sleep and physical activity over several days in order to test the hypotheses that: (1) low average sleep duration and/or sleep efficiency are linked to a low amount of physical activity; and (2) a reduction in sleep quantity and/or sleep efficiency during the night is followed by a decrease in physical activity the following day. While average sleep duration and efficiency were unrelated to physical activity, the analysis revealed that an extra hour spent in bed during the night was followed by a 16-minute decrease in moderate-to-vigorous physical activity. This was accompanied by a 4.5 kJ/kg and 5.9 kJ/kg lower total daily energy expenditure in boys and girls. This study found no evidence for a link between short sleep and low or reduced physical activity.
COBISS.SI-ID: 4523441
The actual energy expenditure is difficult to measure and is often estimated from the physical activity measured with accelerometers and other sensors. Previous studies have demonstrated that using a person's activity as the context in which the energy expenditure is estimated, and using multiple sensors, improves the estimation. In this study, we went a step further by proposing a context-based reasoning method that uses multiple contexts provided by multiple sensors. The proposed Multiple Contexts Ensemble approach first extracts multiple features from the sensor data. Each feature is used as a context for which multiple regression models are built using the remaining features as training data. Experiments showed that the Multiple Contexts Ensemble method outperforms (in terms of lower root means squared error and lower mean absolute error) the five single-regression approaches (linear and non-linear) and the two ensemble approaches: Bagging and Random subspace, an approach that uses artificial neural networks trained on accelerometer-data only, as well as the BodyMedia energy expenditure estimation device.
COBISS.SI-ID: 28565543
The purpose of this study was to determine test-retest reliability for peak velocity during the bench press and bench press throw exercises for loads corresponding to 20-70% of one-repetition maximum. The bench press throw resulted in a significantly lower coefficient of variation for the whole load-velocity relationship, compared to the bench press. The reduction in the biological within-subject variation in bench press throw exercise could be promoted by the braking phase that obligatorily occurs during a bench press executed with light or moderate loads. Therefore, we recommend the bench press throw exercise for a most accurate assessment of upper-body velocity.
COBISS.SI-ID: 4748721
The objective of the study was to assess the use of maximum and final propulsive phase bar velocity to predict jump height in the weighted jump squat. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between final propulsive phase and take-off speed was observed , while the differences between maximal speed and take-off speed were homogenously distributed. These results suggest that makimal speed is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine.
COBISS.SI-ID: 4628913