The relationship between agility, linear sprinting, and vertical jumping performance in U-14 and professional senior team sports players

Aim

The aim of this paper is to determine the relationship between the modified agility T-test (change of direction speed ability), 20-meter sprint test (linear speed ability), and countermovement jump test (vertical jumping performance) in U-14 and professional senior team sports players.

Methods

The sample included 78 (59 female and 19 male) U-14 athletes (age 11.70 ± 1.33 years, height 153.00 ± 12.20 cm and body mass 47.10 ± 11.20 kg) and 43 (18 female and 25 male) senior professional athletes (age 24.80 ± 6.58 years, height 169.00 ± 9.13 cm and body mass 71.20 ± 15.10 kg). Both samples participated in different team sports including basketball, field hockey, and football. Participants underwent a series of tests to assess their speed, change of direction speed, and explosive power. Speed assessments involved 20-meter sprints (sec), while change of direction speed was measured using the modified agility T-test (sec). Explosive power was evaluated through countermovement jumps (CMJ), where concentric mean force (N), concentric peak force (N), concentric peak velocity (m/s), eccentric peak force (N), jump height (cm), peak power (W), peak power/BM (W/kg), RSI (m/s) and vertical velocity (m/s) were determined. Pearsońs product moment-correlation coefficient (r) served to determine correlations and linear regression was conducted to explain the relationship between the dependent variable (CODS) and independent variables (S20 m and CMJ). The level of statistical significance was set at p < 0.05 and the confidence interval was 95%.

Results

The Pearson product-moment correlation analysis in the U-14 athletes indicated no correlation (r = 0.11, p = 0.34) between the 20-meter linear sprint speed and the modified change of direction T-test. Additionally, the results revealed that 4 out of 10 CMJ values showed a significant moderate correlation (r = 0.3, p < 0.05) between CMJ and the modified change of direction T-test. In contrast, senior players exhibited statistically significant correlations in all variables. A significant correlation (r = 0.90, p = 0.01) was found between 20-meter linear sprint speed and the modified change of direction T-test, while CMJ values showed a range of correlations from moderate to large. In both competitive categories, according to the linear regression model, only linear sprint speed over 20-meters significantly explained (p < 0.05) the CODS speed ability, while the other CMJ parameters did not reach the significance level (p > 0.05).

Conclusion

The study emphasized the influence of explosive power performance (CMJ) and linear speed (S20 m) on agility (CODS) within the sample, particularly among professional senior team sports players. These findings indicate that agility, linear sprinting, and jumping abilities may share common underlying factors.

Neuromuscular Fitness Is Associated with Serve Speed in Young Female Tennis Players

In tennis, the serve plays a key role in determining the success of a player. The speed of a serve is influenced by a multitude of interconnected skills and abilities. The objective of this study was to establish the correlation between the explosive strength of the throwing type, the grip strength and flexibility of the arms, and the shoulder girdle with the serve speed in young female tennis players. Additionally, the study aimed to develop a regression model that accurately predicts the serve speed by analyzing the interplay among these variables. The study was carried out on a group of 20 tennis players, who had an average age of 13.10 ± 0.74 years. Additionally, their height was recorded as 165.70 ± 4.90 cm, and their body mass was measured at 51.45 ± 5.84 kg. To assess the motor abilities of the upper extremities, four tests were used that aimed to measure the explosive strength of the throwing type; one test was for the strength of the hand and forearm muscles, and one test was for the flexibility of the arms and shoulder girdle. Of all the variables examined, the medicine ball throw shot put (MBTSP) (r = 0.75), overhead medicine ball throw (OMBT) (r = 0.70), and grip strength (GS) (r = 0.71) displayed a notable correlation with serve speed (p < 0.05). The results obtained from the multiple regression analysis indicate that the combination of selected predictors (MBTSP-medicine ball throw shot put, OMBT-overhead medicine ball throw and GS-grip strength) explained 75% of the variability in serve speed. Significantly, MBTSP surfaced as the predominant predictor, autonomously elucidating 51% of the variability in serve speed. The importance of improving the analyzed motor skills of young female tennis players to enhance their serve in terms of speed is emphasized by the findings of this research.

A 16-week school-based intervention improves physical fitness in Slovenian children: a randomized controlled trial

Introduction: The aim of this study was to evaluate the effects of a 16-week school-based physical activity (PA) intervention on physical fitness (PF) (speed, hand-eye coordination, flexibility) of 8- to 9-year-olds. Methods: A total of seventy-eight boys and girls (boys: n = 45, aged 8.4 ± 4.9 years; girls: n = 42, aged 8.6 ± 0.5 years) from a school in Slovenia were randomly assigned to either a group with an after-school PA program (EXP) or a control group (CON) that participated exclusively in mandatory physical education (PE). The EXP group engaged in the extracurricular PA program for 60 min twice a week for 16 weeks, concurrent with regular PE classes. The program primarily involved elementary PE games that included elements of athletics (e.g., skipping, push- off running, hopping, crossstepping, and jumping) and gymnastics (e.g., handstand, forward roll, backward roll, hand support jumps, squat jump on a vault box, climbing on horizontal bars, incline benches and ropes, crawling, and jumping rope). Standardized tests appropriate for this age group were used to assess PF, including the sit and reach test (SAR), the 30-meter sprint, and the alternate hand wall toss test at distances of 1.0 and 2.0 m (AHWT 1.0 and 2.0). Results: There was a significant group-time interaction for SAR test (EXP group increase: +1.6 cm, +6.3%; CON group decrease: -0.1 cm, -0.4%; p < 0.001, ηp2 = 0.361), and the 30 m sprint (EXP group improvement: -0.4 s, -6.3%; CON group decrease: +0.1 s, +1.6%; p < 0.001, ηp2 = 0.193). Similarly, the EXP group improved by +2.1 points (+25.6%) in the 1.0 m wall throw with the alternating hand, while the CON group showed only minimal changes (-0.2 points, -2.4%; p < 0.001, ηp2 = 0.545). No significant interaction was found for the 2.0 m toss (EXP and CON group both -0.1 points, -2.6%; p = 0.888, ηp2 = 0.001). Post-hoc analyses with paired t-tests revealed that the EXP group showed significant improvements in SAR test (p < 0.001), 30 m sprint (p < 0.001) and AHWT 1.0 test (p < 0.001), while the CON group showed no significant changes in SAR test (p = 0.533), 30 m sprint (p = 0.150), AHWT 1.0 test (p = 0.186) and AHWT 2.0 test (p = 0.430). Discussion: The results of the study showed that the extracurricular program with only two additional weekly sessions significantly improved the components of PF in 8- to 9-year olds. Significant improvements were observed in the areas of flexibility, speed and coordination, as shown in the SAR test, 30-meter sprint and 1.0-meter handwall toss tests. However, no similar improvements were observed in the 2.0-meter handwall toss, which illustrates the specific areas of impact of the program.

Effects of 8-week alkaline diet and aerobic exercise on body composition, aerobic performance, and lipid profiles in sedentary women

Background

Diet composition can affect systemic pH and acid-base regulation, which may in turn influence exercise performance.

Purpose

It was aimed to determine the effects of the alkaline diet and 8 weeks of aerobic exercises on body composition, aerobic performance, and blood lipid profiles in sedentary women.

Methods

Thirty-two sedentary women participated in the study voluntarily. The research was designed with a true-experimental design and the participants were divided into four different groups as the control group, aerobic exercise group, alkaline diet group, and alkaline diet + aerobic exercise group. The body compositions, aerobic exercise performances, and lipid profiles of sedentary women were measured as pre-test and post-test. In the analysis of the obtained data, One-Way ANOVA with Bonferroni post hoc test was used.

Results

It was observed that the alkaline diet consumed with 8 weeks of aerobic exercises caused a 5.17% decrease in BMI and an increase of 42.07 and 37.62% in VO2max and aerobic test durations, respectively (p < 0.05). In addition, when lipid profiles were examined, it was determined that there was no statistically significant difference in HDL-C levels (p > 0.05). Despite that, there were statistically significant differences in TG and LDL-C levels (p < 0.05). According to this result, it was determined that there was a decrease in TG and LDL-C levels by 37.61 and 20.24%, respectively.

Conclusion

An alkaline diet consumed with 8 weeks of aerobic exercises in sedentary women has positive effects on improving body composition, aerobic exercise performances, and TG and LDL-C levels.

The Effects of a Short Virtual Reality Training Program on Dynamic Balance in Tennis Players

This study aimed to analyze the effects of a 5 min virtual reality training program (VR) on dynamic balance in tennis players. Fifty-eight college tennis players (mean age 22.9 ± 3.1 years, weight 73.9 ± 10.8 kg, height 176.6 ± 8.4 cm) were allocated to either the control group (placebo) (CG, n = 20) or the right-handed experimental group (RTG, n = 20) and left-handed experimental group (LTG, n = 18), both of which took part in the 5 min VR intervention program. Pre-tests included anthropometric measures and the Y Balance Test (YBT), and the post-test was the Y Balance Test (YBT). Three YBT trials were performed in anterior (ANT), posterolateral (PL), and posteromedial (PM) directions. After the training intervention, in the right-handed experimental group (RTG), significant differences were observed for two variables: anterior reach (right foot) (p = 0.00) and posterior medial reach (right foot) (p = 0.03). In other analyzed variables, there were no significant differences. Additionally, the effect size was small. In the left-handed experimental group (LTG), statistically significant improvements were identified in five out of six analyzed variables: anterior reach (left foot) (p = 0.00), posterior medial reach (left foot) (p = 0.00), posterior lateral reach (left foot) (p = 0.00), posterior medial reach (right foot) (p = 0.00), and posterior lateral reach (right foot) (p = 0.00). The effect size ranged between small and medium. No significant changes were observed in the control group (CG) after the training intervention. Moreover, for all variables, the time*group interaction is determined. Anterior reach (left foot), posterior medial reach (left foot), posterior medial reach (right foot), and posterior lateral reach (right foot) showed significant interactions (F = 3.04, p = 0.05; F = 3.50, p = 0.03; F = 6.08, p = 0.00; and F = 4.69, p = 0.01). The outcome of this study leads us to a further understanding that if a player were to partake in VR activity, it could show a positive effect on their dynamic balance performance.

Effects of Soluble Dietary Fibre on Exercise Performance and Perception of Fatigue in Young Basketball Players

Research background

In this study, we investigated the effects of soluble dietary fibre on improving neuromuscular and cardiovascular endurance and perception of fatigue in a closely monitored group of basketball players. Prebiotics have been sidelined in sports nutrition and their effect on performance remains poorly investigated and understood.

Experimental approach

Eighteen healthy male basketball players were divided into two groups; one received 17 g/day of soluble dietary fibre (Nutriose®) for four weeks and the other group received placebo. Their morphological characteristics, neuromuscular and cardiovascular endurance, and rating of perceived exertion according to the rating of perceived exertion (RPE) scale were assessed. Measurements were taken before supplementation and after four weeks of supplementation. Faecal samples were collected from all participants immediately before and after the supplementation period, their total DNA extracted and sent for amplicon sequencing.

Results and conclusions

In this study, fibre had no statistically significant effect on the vertical-type explosive power, no statistically significant effect on sprint-type explosive power, nor on aerobic and anaerobic endurance in the experimental group. Soluble fibre had a statistically significant effect on reducing the rating of perceived exertion of basketball players during the competitive part of the season (RPE 7.27±0.04 versus 8.82±0.81). This was confirmed by two-way ANOVA with replication, which showed that within-group interaction (p=0.0193), before and after dietary intake (p=0.0049), and between-group interaction before and after dietary intake (p=0.0313) had a significant effect on the result. The overall conclusion of the study is that soluble dietary fibre supplementation does not improve neuromuscular and cardiovascular endurance over a 4-week period. However, fibre supplementation could have a significant effect on reducing the rating of perceived exertion, as shown by the statistics. Both amplicon sequencing and subsequent bioinformatics results suggest that this could be the result of the beneficial effect on the intestinal microbiota and its metabolites.

Novelty and scientific contribution

This work highlights the importance of prebiotics in sports nutrition. Dietary fibre has been a neglected component of sports nutrition. This study demonstrated a statistically significant positive effect on the perception of fatigue, highlighting the need for further studies in this direction.

The plyometric treatment effects on change of direction speed and reactive agility in young tennis players: a randomized controlled trial

Aim: The aim of this paper is to determine the effect of 6 weeks of plyometric training on speed, explosive power, pre-planned agility, and reactive agility in young tennis players. Methods: The participants in this study included 35 male tennis players (age 12.14 ± 1.3 years, height 157.35 ± 9.53 cm and body mass 45.84 ± 8.43 kg at the beginning of the experiment). The biological age was calculated and determined for all participants. 18 of the participants were randomly assigned to the control group, and 17 were assigned to the experimental group. Running speed (sprints at 5, 10, and 20 m), change of direction speed (4 × 10, 20 yards, t-test, TENCODS), reactive agility (TENRAG), and explosive power (long jump, single leg triple jump, countermovement jump, squat jump, and single leg countermovement jump) were all tested. The Mixed model (2 × 2) ANOVA was used to determine the interactions and influence of a training program on test results. Furthermore, Bonferroni post hoc test was performed on variables with significant time*group interactions. Results: The results of this research indicate that an experimental training program affected results in a set time period, i.e. 5 out of total 15 variables showed significant improvement after experimental protocol when final testing was conducted. The experimental group showed significantly improved results in the 5 m sprint test in the final testing phase compared to the initial testing phase, this was also the case in comparison to the control group in both measurements. Furthermore, the experimental group showed significant improvement in the single leg countermovement jump in the final test, as well as in comparison to the control group in both measurements. The change of direction speed and reactive agility test also exhibited significant improvement in the final testing phase of the experimental group. Conclusion: The results of this research indicated that a 6-week program dominated by plyometric training can have a significant effect on the improvement of specific motor abilities within younger competitive categories. These results offer valuable insights for coaches in designing diverse tennis-specific scenarios to enhance overall performance, particularly focusing on the neuromuscular fitness of their players.

What makes a Grand Slam champion? Early engagement, late specialization and timely transition from having fun to dedication

In order to provide adequate support for young tennis players, it is important to understand the development path and factors which can have a positive or negative impact on the development of a player. The aim of this research was to determine the factors that affected sports specialization in tennis by means of qualitative analysis (early, optimal, or late). As well as to deepen the knowledge around the phenomenon of specialization in tennis among players of differing success levels through their personal experiences, in order to contribute to a better understanding of their specialization. The authors interviewed 30 tennis players of differing levels, including 10 participants from the most elite level (Grand Slam champions), exploring their contrasting experiences of development. The data set was analyzed using reflexive thematic analysis. Three topics were generated, which included the following: engaging in sport, decisions, and time of specialization. The obtained results offer a stimulus to reflect on numerous aspects of athlete development.

Exercise-Induced Fatigue Impairs Change of Direction Performance and Serve Precision among Young Male Tennis Players

This study investigates the effect of exercise-induced fatigue on change of direction performance and serve precision among young tennis players. A group of 21 players (age 12.90 ± 0.76 years), ranked among the top 50 players on the national tennis federation scale and the top 300 on the "Tennis Europe" scale, participated in the study. They underwent a standardized physiological load protocol using the "300-m running test" which consists of consecutive runs for 15 shares of 20 m (15 × 20). Its intensity was determined using the Borg Rating of Perceived Exertion (RPE) scale where subjects evaluated their level of experienced load on a scale from 0 to 10. Prior to and after the protocol, they performed a pre-planned change of direction T-test and serve precision test. Results showed significant increase of time in the T-test (from 11.75 ± 0.45 s to 12.99 ± 0.4 s, p = 0.00) and decrease in serve precision parameter from (6.00 ± 1.04 to 4.00 ± 1.26, p = 0.00) after the fatigue test protocol. The RPE increased from 5 to 9, after the fatigue protocol, indicating the desired fatigue effect. These findings indicate that exercise-induced fatigue impairs change of direction performance and serve precision among young tennis players.

The Effects of Biological Age on Speed-Explosive Properties in Young Tennis Players

Biological maturity can affect performance on motor tests, thus young players can have advantages or disadvantages during testing by being more or less mature than their peers of the same chronological age. The aim of this study was to investigate the effects of biological age on speed, agility, and explosive power in young tennis players. Fifty tennis players (age 12.3 ± 1.2 years, height 156.7 ± 12.8 cm, body mass 45.9 ± 8.9 kg) who were ranked up to 50th place in the ranking of the National Tennis Association, as well as up to 300th place on the international "Tennis Europe" ranking, participated in the study. They were divided into three groups according to their maturation status, that is, the peak height velocity (PHV) maturity offset: pre-PHV [<0] (n = 10); circa-PHV [0 to 1] (n = 10); and post-PHV [>1.5] (n = 25). They performed tests of speed (5, 10, and 20 m sprints), agility (20 yards, 4 × 10 yards, T-test, TENCODS, and TENRAG), and explosive power (countermovement jump, one-leg countermovement jump, squat jump, long jump, and one-leg triple jump). Results showed significantly higher height of the vertical jump in the post-PHV group compared to the pre-PHV group, in the range of ~16% to ~27%. Moreover, linear and change of direction speed was significantly faster in the post-PHV group compared to the pre-PHV group, in the range of ~5% to ~8%. Height of the squat jump and speed in the T-test were significantly better in the post-PHV group compared to the circa-PHV group, in the range of ~7% to ~15%, while height of the single-leg triple jump was significantly higher in the circa-PHV group compared to the pre-PHV group by ~7%. This study showed that tennis players of older biological age achieve better results in almost all variables of speed, agility, and explosive power compared to players of younger biological age. Coaches should be aware of the differences found in physical performance and consider the practical implications that maturation can have in the long-term development of young tennis players.

European fitness landscape for children and adolescents: updated reference values, fitness maps and country rankings based on nearly 8 million test results from 34 countries gathered by the FitBack network

OBJECTIVES

(1) To develop reference values for health-related fitness in European children and adolescents aged 6-18 years that are the foundation for the web-based, open-access and multilanguage fitness platform (FitBack); (2) to provide comparisons across European countries.

METHODS

This study builds on a previous large fitness reference study in European youth by (1) widening the age demographic, (2) identifying the most recent and representative country-level data and (3) including national data from existing fitness surveillance and monitoring systems. We used the Assessing Levels of PHysical Activity and fitness at population level (ALPHA) test battery as it comprises tests with the highest test-retest reliability, criterion/construct validity and health-related predictive validity: the 20 m shuttle run (cardiorespiratory fitness); handgrip strength and standing long jump (muscular strength); and body height, body mass, body mass index and waist circumference (anthropometry). Percentile values were obtained using the generalised additive models for location, scale and shape method.

RESULTS

A total of 7 966 693 test results from 34 countries (106 datasets) were used to develop sex-specific and age-specific percentile values. In addition, country-level rankings based on mean percentiles are provided for each fitness test, as well as an overall fitness ranking. Finally, an interactive fitness platform, including individual and group reporting and European fitness maps, is provided and freely available online (www.fitbackeurope.eu).

CONCLUSION

This study discusses the major implications of fitness assessment in youth from health, educational and sport perspectives, and how the FitBack reference values and interactive web-based platform contribute to it. Fitness testing can be conducted in school and/or sport settings, and the interpreted results be integrated in the healthcare systems across Europe.

"New Balls Please": Physical Load Imposed on Ball Boys during the Roland Garros 2022

The process of becoming a ball kid at the French Open consists of different stages of selection and training. Selection and training of the ball kids is organized by the French Federation of Tennis (FFT) and is intended to be an immersive and educational experience. A sample was made up of ball kids participating at the 2022 French Open (Roland Garros). For this study, 26 ball kids were analyzed during several rotations of their activity on the court with different durations (N = 26; age = 15.00 ± 0.84; height = 169.03 ± 9.62; weight = 52.26 ± 7.35). Each ball kid participated in several analyzed rotations (data entry N = 94). Two groups are analyzed: ball kids at the net and in the back of the court. The result of the statistical analysis showed a statistically significant difference between the two groups in the variables: meters covered per minute on court (t = 6.85, p = 0.00), total number of decelerations per minute (t = 8.39, p = 0.00), walking and jogging meters per minute (t = 4.68, p = 0.00), and maximum velocity achieved (t = 3.02, p = 0.00). Participating as a ball kid during a professional tournament presents a unique experience for young athletes. Young people that are participating can improve their fitness, social skills, mental abilities, and well-being due to requests for the ball kids' duties during match play and out of play activities.

Effects of Plyometric Training with Resistance Bands on Neuromuscular Characteristics in Junior Tennis Players

The purpose of this study is to investigate the effect of 6 weeks (conducted twice per week for a total of 12 sessions) of plyometric training with resistance bands on different neuromuscular characteristics among the sample of junior tennis players. Thirty junior tennis players between the ages of 12 and 14 years (age 13.5 ± 1.8 years; weight 51.3 ± 12.5 kg; height 162.7 ± 12.6 cm) were allocated to either the control group (standard in-season regimen) (CG; n = 15) or the experimental group, which received additional plyometric training with resistance bands (TG; n = 15). Pre- and post-tests included: anthropometric measures; 20 m sprint time (with 5, 10, and 20 m splits), squat jump (SQ Jump); vertical countermovement jump (CMJ); vertical countermovement jump with arm swing (CMJ_free arms); single leg (left) countermovement jump (CMJ_L); single leg (right) countermovement jump (CMJ_R); standing long jump (L_Jump); single leg (left) triple jump (SLTH-L); single leg (right) triple jump (SLTH-R); generic change of direction speed (CODS) (20Y test and T-test); reactive agility test (WS-S). After the training intervention, the TG showed significant (“p < 0.05”) improvements in CMJ (F = 7.90, p = 0.01), CMJ_L (F = 5.30, p = 0.03), CMJ_R (F = 11.45, p = 0.00), and SLTH-L (F = 4.49, p = 0.04) tests. No significant changes were observed in the CG after the training intervention. Our findings provide useful information for coaches to create a wide range of tennis-specific situations to develop a proper performance, especially for their player’s neuromuscular fitness.

Social Capital Promotes a Healthier Diet among Young Adults by Reducing Psychological Distress

Studies have revealed the links between social capital and diet. However, the mediating role of psychological distress in this relationship has been understudied. This study aims to identify direct and indirect relationships between social capital and adherence to the Mediterranean diet among Lithuanian young adults and identify the mediating role of psychological distress in this relationship. Data were collected from 1336 young adults, aged 18-36 years; 40.5% were males. MEDAS was used to measure adherence to a healthy diet. Social capital was measured by eight separate items in terms of family support, social support, social cohesion, social trust, communication, collaboration, participation, and distant communication. Kessler's six-item scale was used to assess psychological distress. Higher family support (β = 0.105), higher social participation (β = 0.294), and lower psychological distress (β = 0.073) directly predicted higher adherence to the Mediterranean diet. Social capital was indirectly related to adherence to the Mediterranean diet, with standardized effect sizes of 0.02-0.04, indicating small effect sizes. Thus, psychological distress mediates the relationship between social capital and a healthy diet. Given that social capital is related to psychological health and both directly and indirectly predicts healthy behavior in young adults, further longitudinal and experimental research is required to measure the effects of the intervention on incorporating, facilitating, encouraging, and implementing measures to strengthen the social connection between people and groups of people within the community, neighborhood, and organizations.

Adherence to Mediterranean diet among Lithuanian and Croatian students during COVID-19 pandemic and its health behavior correlates

Maintaining healthy behavior, especially in times of crisis like the COVID-19 pandemic, is particularly important for staying healthy. Nutrition is an everyday behavior and along with other health-related behaviors is associated with many health outcomes. The aim of this study was to assess and compare adherence to the Mediterranean diet (MedDiet) and particular food choices among the Mediterranean and non-Mediterranean populations of university students and identify its lifestyle correlates at the outburst of the COVID-19 pandemic. In total, self-reported data on health-related behavior and sociodemographic characteristics were collected from 1,388 study participants, 66.4% were Lithuanians, and 33.6% were Croatians. Results revealed that vegetables, olive oil, fruits, nuts, legumes, and fish were remarkably underconsumed among university students in the Mediterranean and non-Mediterranean countries during the COVID-19 pandemic, and the composite diet is similar between countries. The higher adherence to MedDiet is associated with physical activity (β = 0.15) and non-smoking (β = 0.08). In times of crisis, public health entities should provide knowledge, skills, and tools for healthy nutrition specifying them by age and subpopulation. Interventions at the university should be implemented to build infrastructure and provide an access to health behavior-friendly environments.

The association between social capital indicators and psychological distress in Catalan adolescents

According to the WHO, globally, one in seven adolescents experiences a mental disorder, being in a detrimental situation toward educational achievement, social cohesion, future health and life chances. Calls to identify risk and resilience factors to develop effective preventive actions have been made. Following a systemic approach, we conducted a cross-sectional study on the relationship between social capital and psychological distress in a sample of Catalan adolescents in Barcelona, taking into account a range of other relevant aspects at different levels influencing mental health, including gender, age, migrant status, family background, lifestyle factors, body mass index, and self-rated health. Data were collected through validated questionnaires in December 2016 from 646 of 14- to 18-year-old adolescents from three public and private high schools in Barcelona (Spain). Data analysis included descriptive analysis, a correlational study and logistic regression to obtain the odds ratio for social capital indicators to be associated with psychological distress. Our results suggest that reporting higher levels of family support and higher levels of teacher-student trust reduce the likelihood of suffering psychological distress. Higher levels of neighborhood informal control were associated with mental health, but a possible detrimental effect cannot be ruled out. Being a girl, reporting low self-rated health or higher media use was also associated with higher likelihood of psychological distress. Current results may encourage interventions that focus on social capital as a means to reduce psychological distress and foster well-being in youth.

Abstracts from the 18th Annual Scientific Conference of Montenegrin Sports Academy and 16th FIEP European Congress “Sport, Physical Education, Physical Activity and Health: Contemporary perspectives”: Dubrovnik, Croatia. 8-11 April 2021

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Pre-Planned and Non-Planned Agility in Patients Ongoing Rehabilitation after Knee Surgery: Design, Reliability and Validity of the Newly Developed Testing Protocols

Background: Due to its association with the risk of falling and consequent injury, the importance of agility is widely recognized, but no study so far has examined the different facets of agility in an untrained/clinical population. The aim of this study was to evaluate the reliability, validity, and correlates of newly developed tests of non-planned agility (NPA) and pre-planned agility (PPA) in an untrained/clinical sample. Methods: The sample comprised 38 participants older than 40 years (22 females, age: 56.1 ± 17.3 years, height: 170.4 ± 10.8 cm, mass: 82.54 ± 14.79 kg) who were involved in a rehabilitation program following total knee arthroplasty and knee arthroscopy. Variables included age, gender, type of surgery, history of fall, anthropometrics/body composition, and newly developed tests of NPA and PPA. Results: The results showed the high inter-testing- (ICC > 0.95, CV < 9%), and intra-testing-reliability (ICC > 0.96, CV < 9) of the newly developed tests. PPA and NPA were found to be valid in differentiation between age groups (>50 yrs. vs. <50 yrs.), and genders, with better performance in younger participants and males. Only NPA differentiated participants according to type of surgery, with better performance in those who had arthroscopic surgery, than those who had total knee arthroplasty. No differences in NPA and PPA were established between groups based on fall-history. In females, the body mass (Pearson’s r = 0.58 and 0.59, p < 0.001) and body fatness (Pearson’s r = 0.64 and 0.66, p < 0.001) were negatively correlated, while the lean body mass (Pearson’s r = 0.70 and 0.68, p < 0.001) was positively correlated with PPA and NPA. The NPA and PPA were highly correlated (Pearson’s r = 0.98, p < 0.001). Conclusions: We found that the proposed tests are reliable when evaluating agility characteristics in an untrained/clinical population after knee arthroplasty/arthroscopy. Further evaluation of the specific validity of the proposed tests in other specific subsamples is warranted.

Physiological and Anthropometric Determinants of Performance Levels in Professional Futsal

There is an evident lack of studies examining the pursuit of excellence in futsal. The aims of this study were to evaluate anthropometric and physiological variables that may contribute to distinguishing among performance levels in professional futsal players and to evaluate correlates of those variables. The participants were 75 male professionals (age = 25.1 ± 5.1 years, body height = 182.3 ± 6.2 cm, body mass = 80.8 ± 10.4 kg), who were divided into performance levels using two criteria: (i) starters (first teams) vs. non-starters (substitutes) and (ii) top-level players (members of the national team and players who participated in top-level team competition in Europe) vs. high-level players (team players competing at the highest national competitive rank). Variables included anthropometrics (body height and mass, BMI, body fat percentage), generic tests of physiological capacities [5- and 10-m sprints, countermovement jump, broad jump, 20-yard test, reactive strength index (RSI)], and futsal-specific fitness tests [kicking speed by dominant and non-dominant leg, futsal-specific tests of change of direction speed, and reactive agility (FSRAG) involving/not involving dribbling the ball]. Top-level players outperformed high-level players in RSI, broad jump, kicking speed, and FSRAG involving dribbling. Starters achieved better results than non-starters in fewer variables, including kicking speed and RSI. Body fat percentage negatively influenced FSRAG involving dribbling, and RSI. FSRAG, RSI, and kicking speed were significantly correlated, indicating the similar physiological background of these capacities. The findings suggest that enhanced reactive strength and the ability to rapidly change direction speed in response to external stimulus while executing futsal-specific motor tasks (e.g., dribbling), along with players' ability to kick the ball speedily, can be considered essential qualities required for advanced performance in futsal. Consequently, futsal strength and conditioning training should be targeted toward lowering relative body fat, maximizing lower-body reactive strength and including futsal-specific skills (e.g., dribbling, shooting) in reactive agility drills.

The Direct and Indirect Relationships Within the Extended Trans-contextual Model for Moderate-to-vigorous Physical Activity

Given the low levels of physical activity (PA) in adolescence, there are challenges to increasing students' PA outside of the school setting. Thus, researchers emphasize the supportive role that physical education (PE) teachers can play in PA motivation both in and out of school. The aim of the present study was to examine an expanded trans-contextual model (TCM) model for the transit of teachers' perceived support of students' autonomy in terms of contextual and situational motivation in PE to objectively measured moderate-to-vigorous physical activity (MVPA) in PE across different PE contents as well as to the motivational sequence for, and participation in, subjective MVPA during leisure time. This cross-sectional study involved 283 high school students, of whom 43.9% were boys. The autonomous support students received and other motivational factors and objective measures of MVPA in PE and subjective MVPA in leisure time were measured. The results indicate that support for autonomy was significantly and directly related to needs satisfaction (β = 0.61, p < 0.001) and indirectly to autonomous motivation in PE (β = 0.19, p < 0.001) and leisure time (β = 0.16, p < 0.001), intention in PE (β = 0.03, p < 0.05) and leisure time (β = 0.07, p < 0.001), and leisure time MVPA (β = 0.04, p < 0.001), although not MVPA in PE. Gender was a significant covariate for both MVPA in PE (β = -0.62, p < 0.001) and MVPA in leisure time (β = -0.37, p < 0.001), with higher MVPA in boys than girls. This study filled a gap in the scientific literature by demonstrating the full motivational sequence resulting in actual MVPA in PE classes. It also demonstrated that the main goal of PE of enhancing PA not only in school but also outside of school is working. The main motivator is needs satisfaction based on PE teachers' support.

How different contexts of social capital are associated with self-rated health among Lithuanian high-school students

Background. Adolescents’ self-rated health is related to a number of sociodemographic and socio-economic factors, health-related behaviors, and their social environment. The impact of the latter is still not well explored. An adolescent’s social environment is represented by the social capital, i.e. social resources that they can access. The relationships between various contexts of social capital (family, neighborhood, peers, and school) and self-rated health among adolescents are still unclear.

Objective. This study aims to examine the relationships between various social capital contexts and self-rated health in Lithuanian adolescents.

Methods. The current cross-sectional study includes a nationally representative sample of 1863 adolescents (51.4% were girls) aged 14–18 years. The indicators of self-rated health as well as indicators of social capital in family, neighborhood, and school contexts were assessed. The results of the relationships between self-rated health and contexts of social capital were calculated controlling for the following covariates: physical activity, psychological distress, gender, body mass index, and family socioeconomic status.

Results. Results indicate that there are significant relationships between good self-rated health and a higher level of family support, neighborhood trust, and vertical school trust. In the final logistic regression model, while controlling for all covariates, a higher level of family support and neighborhood trust remain significant predictors of good self-rated health.

Conclusions. Family support and neighborhood trust are important correlates of self-rated health in adolescents.

Physical fitness for sedentary students: a common trend from six European countries

BACKGROUND

Several studies have assessed the fitness level of students to evaluate physical condition, compare groups with differences in social disadvantage and to define indexes for post training programs. Often, these large surveys compared groups without normative value that could define the real, practical gaps. Thus, the aim of this study was the definition of baseline values describing the fitness level of sedentary European students.

METHODS

Standing broad jump (SBJ), sit up (SUP) and sit and reach (SAR) physical fitness tests were assessed on 31,476 students (age=11-13) from 6 European countries were collected and analyzed.

RESULTS

The effect size for multiple groups ANOVA was obtained to verify the biological consistence of differences. Then, weighted-means were calculated and stratified for age and gender. Overall, boys obtained SAR scores close to zero, while girls obtained results between 2 and 7 cm. The SUP test revealed similar results between boys and girls (about 20). SBJ performances were similar among countries (over 160 cm for boys and 150 for girls).

CONCLUSIONS

Our results were aligned to other studies performed in other Continents or Countries and can contribute to the establishment of a large and objective reference to readily evaluate the physical fitness and health-related status of young students.

Difficulty adaptation in a competitive arm rehabilitation game using real-time control of arm electromyogram and respiration

Rehabilitation robots are often combined with serious games that motivate patients and keep them exercising at high intensities. A promising type of game are competitive rehabilitation games, but few difficulty adaptation algorithms have been presented for them. This paper thus presents the adaptation of difficulty in a competitive arm rehabilitation game based on two physiological signals: respiration and electromyography of the posterior deltoid. It consists of three smaller studies: an open-loop respiration study, a closed-loop respiration study (where a controller attempts to maintain respiration rate at preset levels), and a closed-loop electromyogram study (where a controller attempts to keep the electromyogram at preset levels). The studies control two difficulty parameters based on the physiological responses of one of the two exercising participants, though the ultimate goal is to control the physiological responses of both participants. Furthermore, all three studies are done with unimpaired participants. The closed-loop controllers achieved high correlation coefficients between desired and measured levels of respiration rate (r = 0.83) and electromyogram (r = 0.89), demonstrating that it is possible to control the physiological responses of unimpaired participants in a competitive arm rehabilitation game, thus controlling their level of workload and exercise intensity. In the future, the proposed method will be tested with patients undergoing rehabilitation.

Analysis of Dental Professionals' and Dental Students' Care for their Skin

Objectives

To determine prevalence of undesirable, work-related skin lesions and their localizations in dental professionals and students, and to collect data about diagnostic procedures they undergo and skin care they take when these lesions occur.

Subjects and methods

Our research included 444 respondents (dentists, dental assistants, dental technicians, dental students) who filled out a questionnaire. They were asked to specify if they had observed any lesions on their skin and where; if they had undergone any treatments and in what way; if they had undergone any allergy tests; and if they had taken any protective measures.

Results

Of all the respondents that took part in the survey, 249 (56.1%) reported undesirable skin reactions commonly on their hands and fingers (96%). Before our survey, only 15% of them had seen a dermatologist, while 33% had undergone allergy tests (without a dermatologists’ clinical examination). Also, 45% of them sometimes used soaps for sensitive skin and the majority (61%) of them used protective hand creams 1-2 times per day.

Conclusion

Although a large number of dental professionals and students have noticed work-related skin lesions, only some of them sought dermatologists’ professional help and most of them did not take care of their skin adequately when those lesions occurred. According to the results of this study, it is necessary to take additional preventive measures to increase dental professionals’ and students’ awareness of occupational dermatoses and adequate skin care.

Effects of a 5-minute classroom-based physical activity on on-task behaviour and physical activity levels

The objective was to explore the effectiveness of a five-minute classroom-based physical activity (5min-Class-PA) to keep student behaviour on task while increasing PA and energy expenditure during school days. The multiple baselines across subjects’ design was implemented to assess on-task behaviour during academic lessons (e.g., Mathematics, Science, Language, Art). Observers were blinded to study condition. A quasi-experimental design was implemented to assess PA volume and energy expenditure using SenseWear Armband body monitor (BodyMedia Inc., Pittsburgh, PA, USA). A convenience sample of elementary school pupils (aged 6-10 years) was observed. A total of eight class departments or two class departments per grade (first to fourth) were included by random selection. All pupils from the selected class departments were asked to participate (total 149) and 126 (85%) had no health aberrations and returned parent signed informed agreement on participation. Five-minute PA daily was performed in the middle of a 45-min academic lesson by imitating video animations projected on the school board for 12 weeks. The aims were to assess on-task behaviour during academic lessons and physical activity volume and energy expenditure during a school day. When the 5min-Class-PA was implemented, initially high on-task behaviour during the first part of the lesson (91.42% and 94.8% for 6-8- and 8-10-year-olds, respectively) was not significantly changed after the 5min-Class-PA. In contrast, when the 5min-Class-PA was not implemented, on-task behaviour during the second part of the lesson decreased (by 3% and 4% for 6-8- and 8-10-year-olds, respectively). After the 5min-Class-PA was systematically introduced, on-task behaviour systematically improved. The results of the implementation of the classroom-based PA also indicated a small, non-significant increase in PA levels and energy expenditure during the school day, but also a non-significant increase in sedentary time. On-task behaviour during academic lessons and daily in-school PA levels can be improved by implementing a 5min-Class-PA programme.

The association of various social capital indicators and physical activity participation among Turkish adolescents

BACKGROUND

Physical activity participation (PAP) has been proven to improve health and promote optimal growth among adolescents. However, most adolescents do not meet the current physical activity (PA) recommendations in Turkey. The role of the social environment and social factors on PAP is being increasingly recognized. Although social capital (SC) indicators have been examined in high-income countries, there are few studies on developing countries. The aim of this study was to examine the relationship between SC indicators and PAP among Turkish adolescents.

METHODS

A survey was conducted among 19 high schools in 4 different cities in Turkey in 2016. A total of 506 female and 729 male high school students participated in this study. The dependent variable was overall PAP, which was measured using the short form of the International Physical Activity Questionnaire. The independent variables included self-perceived family, neighborhood, and school SC. Self-rated health and obesity status, measured by body mass index, were other study covariates in multiple binary logistic regression models. Chi-square tests were used to assess the differences between genders.

RESULTS

PAP levels were significantly different between males and females. A higher percentage of males reported PAP (77.4%) compared to females (51.0%). Among males, teacher-student interpersonal trust and informal social control were inversely associated with PAP, while high students interpersonal trust was positively associated with increased odds of PAP. For females, students interpersonal trust was inversely associated with PAP.

CONCLUSION

Various SC indicators are associated with PAP for males and females. These associations are different from findings of studies conducted in developed countries. Therefore, health-promotion interventions and policies should consider gender and different social agents on the social and cultural background to improve PAP among Turkish adolescents.

Factors associated with good self-rated health in European adolescents: a population-based cross-sectional study

OBJECTIVES

The aim of the present study was to investigate self-reported health status and associated factors.

METHODS

In this cross-sectional study, the participants were 6501 adolescents (52% females) aged 14-19 years from three European countries: Croatia, Lithuania and Serbia. Self-rated health was assessed by using one item question: "How would you perceive your health?" The answers were arranged along a 5-point Likert-type scale: (1) very poor, (2) poor, (3) fair, (4) good and (5) excellent. The outcome was binarized as "good" (fair, good and excellent) and "poor" health (very poor and poor). Potential factors associated with self-rated health included demographic (age, gender, socioeconomic status and body-mass index), social (social capital) and lifestyle (physical activity and psychological distress) variables.

RESULTS

In both univariate and multivariate models, being older, being a boy, having higher level of family, neighbourhood and school social capital, participating in moderate-to-vigorous physical activity more frequently and having low psychological distress were associated with good self-rated health.

CONCLUSIONS

Our findings suggest strong associations between social and lifestyle factors and self-rated health. Other explanatory variables will require future research.

The Reliability of the Mediterranean Diet Quality Index (KIDMED) Questionnaire

The purpose of the present study was to determine the test–retest reliability of the Mediterranean Diet Quality Index (KIDMED) questionnaire in college students. Two hundred and seventy-six college students (127 men, 46%; 149 women, 54%; mean age 19.70 ± 1.32 years; mean height 1.75 ± 0.09 m; mean weight 69.28 ± 13.84 kg; mean body-mas index 22.41 ± 3.19 kg/m²) participated in the study. To investigate the reliability of the KIDMED questionnaire, the participants were asked to complete the questionnaire on two occasions two weeks apart, stratified by gender. Kappa statistics showed moderate to excellent agreement (ranging from 0.504 to 0.849) in the total sample and moderate to excellent agreement in both men (ranging from 0.467 to 0.803) and women (ranging from 0.435 to 0.927). Results in the total KIDMED score showed a moderate correlation between two occasions inthe total sample (κ = 0.597, p < 0.001) and in women (κ = 0.586, p < 0.001) and a good correlation in men (κ = 0.611, p < 0.001). Our study shows that the KIDMED questionnaire is a reliable instrument for assessing adherence to the Mediterranean diet in college students. Future studies should focus on investigating the reliability of the questionnaire in other countries and in different age groups for generating comparable data.

Fractionated electrograms and rotors detection in chronic atrial fibrillation using model-based clustering

The identification of atrial fibrillation (AF) substrates is needed to improve ablation therapy guided by electrograms, although mechanisms that sustain AF are not fully understood. Detection of complex fractionated atrial electrograms (CFAE) is used for this purpose. Nonetheless, efficacy of this method is inadequate in the case of chronic AF. Recent hypothesis proposes the rotors as fibrillatory substrate. Novel approaches seek to relate CFAE with rotor; nevertheless, such methods are not able to identify the associated substrate. Furthermore, the patterns that characterize CFAE generated by rotors remain unknown. Thus, tracking of rotors is an unsolved issue. In this paper, we propose a non-supervised method to find patterns associated with fibrillatory substrates in chronic AF. We extracted two features based on local activation wave detection and one feature based on non-linear dynamics. Gaussian mixture model-based clustering was used to discriminate CFAE patterns. Resulting clusters are visualized in an electroanatomic map. We assessed the proposed method in a real database labeled according to the level of fractionation and in a simulated episode of chronic AF in which a rotor was detected. Our results indicate that the method proposed can separate different levels of fractionation in CFAE, and provide evidence that clustering can be used to locate the vortex of the rotors. Provided approach can support ablation therapy procedures by means of CFAE patterns discrimination.

Social capital and physical activity among Croatian high school students

OBJECTIVE

To examine factors associated with regular physical activity in Croatian adolescents.

STUDY DESIGN

A cross-sectional survey among high school students was carried out in the 2013/14 school year.

METHOD

A survey was conducted among 33 high schools in Zagreb City, Croatia. Participants were students aged 17-18 years. The dependent variables were regular moderate to vigorous physical activity (MVPA) and overall physical activity measured by the short version of International Physical Activity Questionnaire and defined as 60 min or more of daily physical activity. The independent variables included family, neighborhood, and high school social capital. Other study covariates included: socio-economic status, self-rated health, psychological distress and nutritional status. The associations between physical activity and social capital variables were assessed separately for boys and girls through multiple logistic regression and inverse probability weighting in order to correct for missing data bias.

RESULTS

A total of 1689 boys and 1739 girls responded to the survey. A higher percentage of boys reported performing regular vigorous and moderate physical activity (59.4%) and overall physical activity (83.4%), comparing with the girls (35.4% and 70%, respectively). For boys, high family social capital and high informal social control were associated with increased odds of regular MVPA (1.49, 95%CI: 1.18 - 1.90 and 1.26, 95%CI: 1.02 - 1.56, respectively), compared to those with low social capital. For girls, high informal social control was associated with regular overall physical activity (OR 1.38, 95% CI: 1.09 - 1.76).

CONCLUSION

High social capital is associated with regular MVPA in boys and regular overall activity in girls. Intervention and policies that leverage community social capital might serve as an avenue for promotion of physical activity in youth.

Differences among Tennis Players Aged 12, 14 And 16 Years in Certain Morphological Characteristics: A Croatian Prospective

A sample of young tennis players aged 12, 14 and 16 in Croatia. Sixty (60) tennis players ranked on the scale of the Croatian Tennis Association were analyzed through differences in morphological characteristics, as identified by a standard laboratory diagnostic procedure in Sports-diagnostic Centre of the Faculty of Kinesiology at the University of Zagreb. Significant differences were obtained in most of the monitored measures for the assessment of the morphological characteristics but the most significant differences were reflected in the variables for assessment of longitudinal dimensionality of the skeleton and body mass and voluminosity of the body. The statistical significance was defined at p<0.05. These differences may lead to decelerating the development of important fitness abilities (i.e., coordination), but also highlights the importance for changing the official propositions for the category of players between the ages due to the significant differences in certain morphological characteristics among all age categories. This study indicates an importance of understand grow characteristics of young players in order to effectively define tennis players playing style.

Are family, neighbourhood and school social capital associated with higher self-rated health among Croatian high school students? A population-based study

OBJECTIVES

We investigated the associations between self-rated health and social capital among Croatian high school students.

DESIGN

A cross-sectional survey among high school students was carried out in the 2013-2014 school year.

SETTING

High schools in Croatia.

PARTICIPANTS

Subjects were 3427 high school students (1688 males and 1739 females), aged 17-18 years.

MAIN OUTCOME MEASURE

Self-rated health was assessed by the single item: "How do you perceive your health?". Possible responses were arranged along a five-item Likert-type scale: 1 very poor, 2 poor, 3 fair, 4 good, 5 excellent. The outcome was binarised as 'good health' (excellent, good or fair) versus 'poor health' (poor or very poor).

METHODS

We calculated ORs and 95% CIs for good self-rated health associated with family, neighbourhood and school social capital, while adjusting for gender, self-perceived socioeconomic status, psychological distress, physical activity and body mass index. We used generalised estimating equations using an exchangeable correlation matrix with robust SEs.

RESULTS

Good self-rated health was significantly associated with higher family social capital (OR 2.43; 95% CI 1.55 to 3.80), higher neighbourhood trust (OR 2.02; 95% CI 1.48 to 2.76) and higher norms of reciprocity at school (OR 1.79; 95% CI 1.13 to 2.84). When all of the social capital variables were entered simultaneously, good self-rated health remained significantly associated with higher family social capital (OR 1.98; 95% CI 1.19 to 3.30), neighbourhood trust (OR 1.77; 95% CI 1.25 to 2.51) and reciprocity at school (OR 1.71; 95% CI 1.08 to 2.73).

CONCLUSIONS

Higher levels of social capital were independently associated with higher self-rated health among youth. Intervention and policies that leverage community social capital might serve as an avenue for health promotion in youth.

Influence of different domains of social capital on psychological distress among Croatian high school students

Background

Social capital has been shown to have positive effects on multiple health outcomes among young people (i.e., obesity, diabetes, cardiovascular disease and infectious diseases). Studies are suggesting that social capital is an important asset for the health and wellbeing of children and adolescents, including for their mental health. We sought to examine the influences of different domains of social capital – in the family, in the neighbourhood, and at school – on levels of psychological distress among high school students in Croatia.

Methods

Cross-sectional survey of 3427 high school students (1688 males and 1739 females), aged 17–18 years, was carried out in the 2013/14 school year (response rate: 93.8%). Logistic regression was used to examine the influence of family, neighbourhood and school social capital on the risk of high psychological distress, measured by the Kessler-6 scale.

Results

Adjusting for age, school, gender, body mass index, self-perceived socioeconomic status, self-rated health and physical activity, high family support in school (OR 0.37; 95% CI: 0.27-0.51), high neighbourhood trust (OR 0.62; 95% CI: 0.53-0.73), high teacher-student interpersonal trust (OR 0.74; 95% CI: 0.62-0.89) and high student interpersonal trust (OR 0.79; 95% CI: 0.65-0.97) was each associated with lower odds of psychological distress. When all of the social capital variables were entered simultaneously, higher social capital in each domain was inversely associated with psychological distress.

Conclusions

Family support in school, neighbourhood trust, teacher-student interpersonal trust and student interpersonal trust were significantly inversely associated with psychological distress among adolescents. Intervention and policies that leverage community social capital might serve as means of mental health promotion among youth.

Urban and Rural Fitness Level: Comparison between Italian and Croatian Students

The goal of this study was to investigate the differences in physical fitness in relation to urban or rural living environment and between two countries: Italy and Croatia. Over 14,000 students were tested during physical education (PE) lessons. Croatian students were taller and heavier than Italian students, with women achieving better results in flexibility. Urban students were fitter in abdominal strength than rural students. Age seemed to be the major factor influencing the performance. This study's results indicate a trend: urban students performed “indoor” tests better than rural students; the opposite may be true for rural students. Living environment, socio-economic-status, or cultural correlation differences could be decreased during school experiences. Thus, PE programs could train all people toward an adequate, age-based fitness level.

Macro-regional differences in motor abilities among the 5th grade primary school pupils in the Republic of Croatia

The aim of this paper is to determine the differences in kinanthropological characteristics of elementary school pupils in relation to macro-regional characteristics of the Republic of Croatia. The research included 2358 subjects (1089 boys--average age 10.4 ± 0.6; height 150.27 ± 7.32; body mass 44.06 ± 9.74; and 1269 girls--average age 10.6 ± 0.5; height 152.02 ± 7.74; body mass 45.12 ± 10.39)--fifth grade elementary school pupils. Analyzed kinanthropological characteristics refer to statistically significant differences in the results based on the macro-region criterion (p < 0.05). It is possible to assume that climatic and temperature differences as well as gene frequency differences to a certain extent incite differences in the level of participating in physical activities, and with it the differences in kinanthropological characteristics of subjects.

Feature selection for discrimination of fractionation levels in atrial electrograms

Radiofrequency catheter ablation of atrial fibrillation (AF) guided by complex fractionated atrial electrograms (CFAE) is associated with a high AF termination rate in paroxysmal AF, but not in persistent. CFAE does not always identify favorable sites for persistent AF ablation. Studies suggest that only high fractionation level should be used as a target site for ablation. Nonetheless, there are not a standardized criterion to defined fractionation levels. Therefore, a better characterization of the signal is required providing a set of more powerful features that should be extracted from CFAE. Due to the apparent difference among fractionation classes in terms of their stochastic variability, we test time-domain and time-frequency based feature extraction approaches. Also, we carried out the symmetrical uncertainty-based feature selection to determine the most relevant features which improve discrimination of fractionation levels. Obtained results on a tested real electrogram database show that most relevant features in time-domain are related with time intervals and not with amplitudes. Nonetheless, time-frequency features obtained more information from the signal and this representation is likely a better suitable discriminating approach, particularly to detect high fractionated electrograms with a sensitivity and specificity of 83.0% and 93.6%, respectively.

Physical self-concept of adolescents in Western Balkan countries: a pilot study

The aim of this study was to explore physical self-concept of adolescents of the Western Balkans (Serbia, Slovenia, Croatia, and Bosnia and Herzegovina) according to sex and country. The participants were 2,606 students, ages 13 and 14 years (M = 13.5, SD = 0.9). The Physical Self-Description Questionnaire (PSDQ) was used to assess multidimensional physical self-concept. The results show the interaction of sex and country for three dimensions of physical self-concept (Appearance, Global Physical Self-Concept, and Self-Esteem). It was shown that female and male adolescents' perception of physical appearance, self-esteem, and global physical self-concept is more susceptible to influences of socio-cultural factors in the monitored countries. In all other dimensions of Physical self-concept, sex differences were consistently manifested in favour of male adolescents, except in Flexibility. Regardless of adolescents' sex, under the increasing influence of Western culture in the Western Balkan countries, adolescents more critically evaluate their body and motor abilities.

Serum preadipocyte factor-1 concentrations in females with obesity and type 2 diabetes mellitus: the influence of very low calorie diet, acute hyperinsulinemia, and fenofibrate treatment

Appropriate differentiation capacity of adipose tissue significantly affects its ability to store lipids and to protect nonadipose tissues against lipid spillover and development of insulin resistance. Preadipocyte factor-1 (Pref-1) is an important negative regulator of preadipocyte differentiation. The aim of our study was to explore the changes in circulating Pref-1 concentrations in female subjects with obesity (OB) (n=19), females with obesity and type 2 diabetes mellitus (T2DM) (n=22), and sex- and age-matched healthy control subjects (C) (n=22), and to study its modulation by very low calorie diet (VLCD), acute hyperinsulinemia during isoglycemic-hyperinsulinemic clamp, and 3 months' treatment with PPAR-α agonist fenofibrate. At baseline, serum Pref-1 concentrations were significantly higher in patients with T2DM compared to control group, while only nonsignificant trend towards higher levels was observed in OB group. 3 weeks of VLCD decreased Pref-1 levels in both OB and T2DM group, whereas 3 months of fenofibrate treatment had no significant effect. Hyperinsulinemia during the clamp significantly suppressed Pref-1 levels in both C and T2DM subjects and this suppression was unaffected by fenofibrate treatment. In a combined population of all groups, circulating Pref-1 levels correlated positively with insulin, leptin and glucose levels and HOMA (homeostasis model assessment) index. We conclude that elevated Pref-1 concentrations in T2DM subjects may contribute to impaired adipose tissue differentiation capacity associated with insulin resistance in obese patients with T2DM. The decrease of Pref-1 levels after VLCD may be involved in the improvement of metabolic status and the amelioration of insulin resistance in T2DM patients.

Development of gait segmentation methods for wearable foot pressure sensors

We present an automated segmentation method based on the analysis of plantar pressure signals recorded from two synchronized wireless foot insoles. Given the strict limits on computational power and power consumption typical of wearable electronic components, our aim is to investigate the capability of a Hidden Markov Model machine-learning method, to detect gait phases with different levels of complexity in the processing of the wearable pressure sensors signals. Therefore three different datasets are developed: raw voltage values, calibrated sensor signals and a calibrated estimation of total ground reaction force and position of the plantar center of pressure. The method is tested on a pool of 5 healthy subjects, through a leave-one-out cross validation. The results show high classification performances achieved using estimated biomechanical variables, being on average the 96%. Calibrated signals and raw voltage values show higher delays and dispersions in phase transition detection, suggesting a lower reliability for online applications.

Differences in energy capacities between tennis players and runners

The primary purpose of this study was to determine differences between elite athletes and tennis players in order to provide a clearer picture regarding the energy demands in modern tennis. Forty-eight (48) athletes and 24 tennis players from Croatian national leagues were compared in morphological and physiological parameters of an all-out incremental treadmill test with gas exchange measurements. Tennis players' HRmax (192.96+/-7.75 bpm) shows values that are most different to 400-meters sprinters (200.13+/-6.95 bpm). Maximum running speed of tennis players on the treadmill (vmax) is no different with the speed achieved by sprinters, while there are significant differences among other athletes. Values in running speed at anaerobic threshold (vAnT) show no statistically significant difference with the values for athlete sprinters and 400-m sprinters. Values of RvO2max for tennis players indicate significant similarities with athlete sprinters and 400-m sprinters while the values of RvO2AnT are nearly identical with the values for sprinters and show no statistically significant differences (p<0.05). The results indicate that values achieved by tennis players approximate most different those of the middle and long distance runners. This singles out the possible importance of the anaerobic capacity and the high level of sprint endurance in tennis players. Knowing these characteristics is the basis for planning and implementing training systems that will enable the increase and optimal usage of energy capacities of tennis players in possibly improving sports results.

Use of the Internet for home testing for Chlamydia trachomatis in Sweden: who are the users?

Sweden was the first country to introduce online Chlamydia trachomatis testing for both men and women and this article provides information about the user characteristics and which risk groups are reached with this method. During the years 2005-2007 a questionnaire was administered with a response rate of 86% (n = 6025) (62.5% women, 37.5% men). Over 60% of respondents were aged below 26 years and single. The average years of education for men and women was 14 (range 9.0-26.0). The mean Internet usage time was 22.4 hours/week among men and 15.5 hours/week among women. Only 22% men and 34% women had tested themselves for C. trachomatis at clinics previously. Respondents reported a higher frequency of previous sexually transmitted infections (STIs) compared with other Internet users (i.e. C. trachomatis: men 19%, women 24%). Eighty percent of online test users had engaged in sex with ≥ 2 partners without a condom during the previous year. Online C. trachomatis test users are mostly young people with high sexual risk behaviour.

Diabetes management in OLDES project

EU project OLDES (Older People's e-services at home) develops easy to use and low cost ICT platform in order to offer a better quality of life to elderly people directly in their homes through innovative systems of tele-accompany, tele-assistance and tele-medicine. The elderly are able to access the services and send relevant medical data from their home by being connected to the central server via a low cost PC which is based on Negroponte paradigm. The OLDES platform interface uses television screens controlled through a remote control customized for the elderly. The feasibility of OLDES project is evaluated by the pilot study concentrating on compensation of diabetic patients. Compensation of diabetes is achieved by monitoring glucose glycemia level, blood pressure and weight. Moreover, the patient feeds into OLDES system daily consumption of food using interactive food scales and obtains advice if necessary.

Measuring body temperature time series regularity using Approximate Entropy and Sample Entropy

Approximate Entropy (ApEn) and Sample Entropy (SampEn) have proven to be a valuable analyzing tool for a number of physiological signals. However, the characterization of these metrics is still lacking. We applied ApEn and SampEn to body temperature time series recorded from patients in critical state. This study was aimed at finding the optimal analytical configuration to best distinguish between survivor and non-survivor records, and at gaining additional insight into the characterization of such tools. A statistical analysis of the results was conducted to support the parameter and metric selection criteria for this type of physiological signal.