Foot Placement in the Basic Position on the Start Block OSB12 of Young Competitive Swimmers.

BACKGROUND: The basic position on the starting block can influence the performance at the start, as it is the initial phase on which the other phases depend, as well as the swimming performance in sprint events in all swimming styles. The aim of our study is to analyze the effect of the foot in the base position on the block start on performance in the 5 m distance start. MATERIAL AND METHODS: Fifteen performance swimmers aged 17 ± 2 years were tested in their preferred wide and narrow starting positions, performing a total of six starts during which angular, temporal, and length changes were monitored in block, flight, and underwater phases. Fisher individual tests for differences of means were used to determine differences in kinematic parameters of the kick start to the 5 m distance. Differences in the position of the feet in kinematic parameters of the kick start to the 5 m distance were determined using the two-sample t-test with equal variance and effect size by Cohen's d. RESULTS: Swimmers were found to have significant differences (p < 0.05) between foot widths in block time (0.02 s), time to 2 m (0.05 s), flight and glide time and distance, maximal depth, and time to 5 m (0.08) in favor of the narrow baseline position. CONCLUSIONS: We recommend marking the center of the start block on the OSB or OSB platform for the competitors, as well as the center of the backrest, for better orientation and assuming the correct basic foot position on the start block.

Acute Effects of Whole-Body Vibration on Resting Metabolic Rate and Substrate Utilisation in Healthy Women.

The aim of the study was to determine the acute effects of single-whole-body vibration (WBV) on resting metabolic rate (RMR) and carbohydrate−lipid profile of blood in young, healthy women. The participants, in a randomised controlled crossover study, participated in two trials: WBV and a vibration simulation (placebo). The WBV was performed in the prone position and cycloidal-oscillatory vibration was used. The RMR measurement (calorimetry) was performed: before the WBV, during WBV, immediately after the completion of WBV, and 1 h after the completion of WBV. For biochemical analyses, venous blood was collected. During WBV, there was a significant increase in RMR compared to baseline. Immediately after and 1 h following the end of the WBV, RMR was close to baseline levels (p > 0.05). The increased energy expenditure resulted from the increased utilisation of carbohydrates and proteins during the vibration. In the placebo condition, there were no significant changes over time in the level of the studied indices during calorimetry. The WBV had no significant effects on the level of glucose in the blood. The applied vibration did not significantly affect the concentration of the analysed lipid indices, which were within the physiological norms for all measurements. Results indicate the need for further research to establish the physiological mechanisms underlying the observed effects of WBV on resting metabolic rate.

Leg Dominance and OSB12 Kick Start Performance in Young Competitive Swimmers.

The purpose of this study was to examine differences in starting and kick-plate positions, pointing to an effect on kick-start performance with the dominant and non-dominant feet placed on the front edge of the OSB12 starting block. The sample included 20 female competitive swimmers whose average age was 16.1 ± 0.6 years. To assess swimmers' lower body explosive strength and determine leg dominance, a triple hop distance test was administered. We determined the swimmers' preferred starting position on a starting block in terms of the kick-plate setting and body position on the starting block. The results of our study demonstrate the importance of leg dominance and positioning on the OSB12 starting block. After the preferred starting position was determined, the optimal position for the kick start was selected. When the dominant leg was placed on the front edge of the starting block (p < 0.05; Cohen's d-large effect), swimmers produced shorter block times and times to 2 and 5 m. For most of the tested swimmers, the optimal basic position on the starting block included neutral- and rear-weighted positions with the kick plate set to positions 3-4 and the right leg placed on the front edge of the OSB12 starting block.

Key Parameters Affecting Kick Start Performance in Competitive Swimming.

The study aims to determine the contribution of kinematic parameters to time to 5 m without underwater undulating and kicking. Eighteen male competitive swimmers started from three weighted positions and set the kick plate to positions 1-5. We used SwimPro cameras and the Dartfish© software. In the on-block phase, we found significant correlations (p < 0.01) between the front ankle angle and block time. The correlations between start phases were statistically significant (p < 0.01) between block time and rear ankle angle, respectively, to time to 2 m; rear knee angle and glide time; block time and time to 5 m; time to 2 m and time to 5 m; and flight distance and glide distance. The multiple regression analysis showed that the on-block phase and flight phase parameters, respectively, contributed 64% and 65% to the time to 5 m. The key block phase parameters included block time and rear knee angle. The key flight phase parameters determining time to 5 m included take-off angle and time to 2 m. The key parameters determining the performance to 5 m during the above-water phase include rear knee angle, block time, takeoff angle, and time to 2 m.

Overweight and obesity in Slovak high school students and body composition indicators: a non-randomized cross-sectional study.

BACKGROUND: Physical development can be considered as an indicator of the overall health status of the youth population. Currently, it appears that the increasing trend of the prevalence of obesity among children and youths has stopped in a number of countries worldwide. Studies point to the fact that adolescence is a critical period for the development of obesity. Body mass index (BMI) seems to be an orientation parameter in the assessment of prevalence of obesity which is not sufficient for more accurate identification of at risk individuals. The purpose of this study was to evaluate association between BMI percentile zones as health-risk for being overweight and obese and body composition indicators in high-school students from the Presov (Slovakia) region. METHODS: A non-randomized cross-sectional study in high school students from the Presov (Slovakia) region was conducted. The research sample consisted of 1014 participants (boys n = 466, girls n = 549). Body composition was measured using direct segmental multi-frequency bioelectrical impedance analysis (DSM-BIA). To examine the association between obesity and selected body composition indicators, Kruskal-Wallis ANOVA and Eta(2) were used. The relationship between selected body composition indicators and percentile BMI zones was determined using the Kendall tau correlation. RESULTS: In groups with different BMI percentile zones (normal weight, overweight, obese), ANOVA showed significant differences for girls and boys (p ˂.05) with high effect size (η(2) ˂.26) in body weight, body fat mass index, body fat percentage, fat free mass index, fat-free mass percentage, visceral fat area, waist-to-hip ratio, waist circumference, protein mass and mineral mass. The highest degree of correlation among boys was between BMI values indicating overweight and obesity and fat free mass index and waist circumference, respectively (τ = .71, τ = .70, respectively). In girls, the highest correlation was found between classification of BMI percentile zones and waist circumference (t = .78). CONCLUSION: The characteristics of body composition are very useful determinants of health and nutrition status. Our data revealed a direct association between BMI value and chosen body composition indicators. The most accurate indicator of overweight and obesity in our study appears to be waist circumference for both male and female population.

Distribution of health-related physical fitness in Slovak population.

Purpose of the study was to examine relationship between distribution of healthy fitness zone standards of high school students and their type of housing or area of residence. Study sample consisted of 684 students (284 boys, 400 girls) from urban and rural areas of the region Presov in the eastern part of Slovakia. Physical fitness was assessed by four tests: back-saver sit and reach, shoulder stretch, curl-ups and 90° push-ups. Differences by place of residence and types of housing were examined by correspondence analysis of two-dimensional tables with computing Chi square value at significance level p < 0.05. Urban students performed higher level of flexibility, abdominal and upper strength and endurance than rural ones. Boys and girls living in a flat reached higher level of flexibility and abdominal strength/endurance however, they performed worse in upper strength and endurance than those living in a house. Slovak adolescents seem to have a healthier profile in abdominal muscular fitness and upper body flexibility than in lower body flexibility. The relationship between distribution of healthy fitness zone standards and residence area or housing type was revealed only in lower body flexibility, upper strength and endurance of urban and rural girls.