The aim of this study was to examine deviations between the left and right leg in dynamic balance in preschool children aged 3-6, and to investigate potential differences by age and sex. A total of 250 preschool children (144 girls, 106 boys) from four European cities (Rijeka, Zagreb, Ljubljana, Koper) participated. Dynamic balance was assessed using the standard Drift protocol with the OptoJump system (Microgate, Bolzano, Italy), which, with photocells placed on two 1-metre parallel bars, allows quantitative measurement of lateral asymmetry through the total deviation area between the left and right leg. Descriptive statistics summarised the basic characteristics of the data. Inferential analyses included regression analysis to examine relationships between variables and one-way analysis of variance (ANOVA) with LSD post hoc tests to evaluate differences between groups. The results indicated that deviations between the left and right leg were present across all age groups, but decreased with age by approximately 0.21 standard deviations, suggesting a gradual stabilisation of balance development. The most substantial developmental improvement was observed between ages three and five (F = 2.74, p = 0.03, post hoc p = 0.00). Differences between boys and girls were not statistically significant, while high standard deviations (0.12-0.18) reflected pronounced individual variability among children.These findings highlight the importance of adapting teaching approaches to each child and underscore the necessity of incorporating motor tasks that promote the use of both the left and right leg, contributing to optimal development of dynamic balance and motor skills during the preschool years.
Objective: This theoretical study analyzes the mechanical advantage of a simplified lever model of the upper arm–forearm system during arm extension in a direct punch in boxing, serving as a didactic tool for understanding basic biomechanical principles. Methods: A quasistatic approach based on classical mechanics was used to derive the model. For the analytical derivation, approximately equal segment lengths were assumed, while friction, air resistance, and multi-joint kinetic chain effects were neglected. Results: An analytical expression for mechanical advantage was derived, with a transition angle between the speed lever phase () and force lever phase (). Sensitivity analysis shows variation of by 10–20% with a change in angle or a change in segment length ratio. Discussion: The model illustrates essential energy trade-offs: high-velocity generation in the early phase (larger ) and significant force amplification in the late phase (smaller ). The study is limited to pedagogical purposes and abstracts the complexities of the full kinetic chain (trunk and legs). Conclusion: The analysis provides valuable pedagogical insight into the mechanical principles of the direct punch, offering a theoretical basis for future kinematic validation and more complex multi-body simulations.
Doping remains one of the most important problems in sports, but legal issues related to anti-doping are relatively understudied in this context. This study aimed to evaluate the reliability and validity of a newly designed questionnaire aimed at evaluating antidoping legal knowledge among sport officials.The participants included 211 sport officers (coaches, medical professionals, nutritionists; 41.7±7. years of age, 71 females) from Croatia and Bosnia and Herzegovina, who were tested on a newly designed questionnaire on knowledge of legal anti-doping regulations for sport officials (Q-LADR-O). Additionally, data on sociodemographic characteristics, sport-related factors, and doping-related factors were collected. In the first phase, a subsample of 56 participants was tested and retested on the Q-LADR-O in the time frame of 7--10 days to evaluate the reliability of the tool.Among the 20 original questionnaire items, 18 had appropriate test-retest reliability (Cohen’s kappa > 0.61, absolute agreement > 80%). Factor analysis identified two distinct latent structures reflecting (i) rights and obligation under the anti-doping code and (ii) anti-doping testing and legislation. The validity of the Q-LADR-O was confirmed by significant differences between medical staff and coaches/nutritionists (6.71 ±1.79 and 4.21 ± 1.2 for medical staff and coaches/nutritionists, respectively, t test = 8.71, p < 0.01) and a significant correlation between the Q-LADR-O and sport-officiating level (Spearman’s R = 0.21, p < 0.05) and between the Q-LADR-O and the number of doping tests of athletes officiated (Spearman’s R = 0.55, p < 0.05).Considering its proper reliability and validity, Q-LADR-O can contribute to more effective anti-doping education, primarily by reducing unintentional rule violations. Further intervention studies are warranted.
The aim of this study was to investigate the acute effects of different neuromuscular warm-up protocols on soccer players' anaerobic power, isokinetic strength, vertical jump, agility, sprint, and kicking velocity performance. Thirty-two amateur soccer players (mean: 21.28±1.63 yıl; 175.62±5.95 cm; 71.14±8.87 kg) participated in the study and were randomly assigned to three groups after pre-tests: the FIFA 11+ warm-up protocol group (FWPG, n=11), the HarmoKnee warm-up protocol group (HWPG, n=10), and the Dynamic warm-up protocol group (DWPG, n=11). Participants performed the warm-up protocol of their assigned group, followed by post-tests. Repeated measures two-way ANOVA was applied to determine the effect of warm-up methods on performance. Significant changes were found in the soccer players' average power (FWPG, HWPG, DWPG), vertical jump (FWPG, HWPG, DWPG), agility (FWPG), and kicking velocity performance (FWPG, HWPG) over time (p<0.05). Peak power, isokinetic strength, and 20 m sprint performance did not show significant differences over time (p>0.05). No significant difference was found between warm-up groups (p>0.05). The study results indicate that different neuromuscular warm-up methods improve certain performance parameters (average power, vertical jump, agility, and kicking speed) in soccer players. FIFA 11+ was observed to positively affect more performance parameters compared to HarmoKnee and dynamic warm-up.
Body composition may play a crucial role in determining the physical fitness components essential for performance in athletes. This study aims to examine the relationship between body composition, aerobic capacity, trunk muscle endurance, and muscle strength in young male basketball players. Body composition was assessed using body mass index (BMI), body fat percentage, and skeletal muscle mass. Aerobic capacity was evaluated based on maximal oxygen consumption (VO2max), estimated through the Multi-Stage 20 m Shuttle Run Test. Trunk muscle endurance was assessed using the Biering-Sorensen Test for extensor muscles and the Kraus-Weber Test for flexor muscles, while peripheral muscle strength was measured with a hand dynamometer. Twenty-nine young male basketball players (mean age: 15.62 +/- 0.62 years; mean BMI: 19.88 +/- 2.96 kg/m(2)) participated in this study. A significant negative correlation was observed between body fat percentage and VO2max (r=-0.399, p=0.032), trunk extensor endurance (r=-0.534, p=0.03), and trunk flexor endurance (r=-0.514, p=0.04). Conversely, skeletal muscle mass demonstrated a significant positive correlation with VO2max (r=0.394, p=0.035), trunk extensor endurance (r=0.481, p=0.008), and trunk flexor endurance (r=0.425, p=0.022). No statistically significant relationships were found between peripheral muscle strength and body fat or skeletal muscle mass (p>0.05). Higher body fat is associated with reduced aerobic capacity and trunk muscle endurance, while greater skeletal muscle mass positively influences these parameters in young male basketball players. Implementing targeted strategies to reduce body fat and enhance skeletal muscle mass through a multidisciplinary approach, including physiotherapy interventions, may be beneficial for optimizing physical fitness in this population.
