Background The aim of this international study was to investigate the prevalence of the use of sports supplements among young athletes, as well as their knowledge and attitudes towards sports supplementation. Methods Organized survey study testing the level of knowledge, attitudes, beliefs and practices concerning the use of sports supplements was administered to 348 athletes, 15–18 year olds from 4 countries competing in 18 sports at the international level. Results The prevalence rate of the intake of sports supplements was 82.2%, with the protein supplements being predominant (54.5%). Coaches were identified as the primary source of information regarding supplementation (41.4%). The enhancement of athletic performance (35.4%) was the major motivation for the supplements intake. The majority of athletes (72.1%) were aware of associated health risks. The young athletes possess varying levels of knowledge regarding their own supplementation. The obtained data about the level of knowledge were statistically analyzed using the correspondence analysis. Less than 40% of athletes had the knowledge about the proper and intended use of protein, creatine, amino acids, beta alanine and glutamine, while they had greater understanding about vitamins and minerals, sports drinks and caffeine. The athletes in developed countries had greater access and utilization of professional resources such as dieticians. Young athletes are still unfamiliar with WADA regulations (55.5%), and the misuse of sports supplements represents an ethical dilemma for some. Conclusion These findings indicate the necessity of a comprehensive education of all team members about sports supplements and careful supervision of the athletic development of young athletes. Electronic supplementary material The online version of this article (10.1186/s12970-019-0294-7) contains supplementary material, which is available to authorized users.

The aim of this study was to investigate the effects of two training protocols on the isokinetic performance of athletes. The study was conducted in 38 athletes, (age 23.3 ± 3.6 years) participating in national level leagues of different sports, whose initial concentric hamstrings-to-quadriceps (conH/Q) torque ratio was lower than 0.5. During seasonal testing, an isokinetic measurement of knee extensors and flexors was performed at 60°/s. The athletes were divided into two groups. Nineteen athletes performed the isokinetic training protocol (IT) while the second group of 19 athletes followed the isotonic training protocol (RT). Both protocols lasted 4 weeks. After completing the training protocols, both groups underwent a final isokinetic testing. The isokinetic data revealed significant increases after training in measures of peak torque in both extensor and flexor muscle groups, in both the IT and RT study groups (p < 0.05). There were significant increases (p< 0.05) in conH/Q ratio in both groups after the implemented protocols, but greater in IT group. Consequently, applied IT protocol induced changes in working muscles, thereby restoring detected asymmetry to an acceptable balance more efficiently compared to RT protocol.

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The results of this study confirm the significant effects of physical activity on reducing body mass and increasing bone density. Considering that football training can be very easily implemented in the broader population of children and young people, which does not apply to many other sports, it should be used more in the prevention of obesity and osteoporosis.

Background: : Postural stability (PS) has an important role in many athletic activities. However, modern dance demands a heightened PS because of the required aesthetic quality and speed of movement. The aim of the present study was to compare the static and dynamic PS of young dancers and participants of other sporting activities. Method: : A total of 101 girls (age: 7.91 ± 0.7 year) were divided into a Dance group (N = 53) and a physically active Control group (N = 48). Static PS was assessed with a two-leg standing test on a Force plate, and dynamic PS was assessed with a Körperkoordinationstest für Kinder (KTK)a walking backwards test on a balance beam. Results: : Multivariate analysis of variance showed a general difference between the groups (F = 21.95; p ≤ 0.0001). In static PS, the Dance group was better in Total distance of center of pressure (COP) (p ≤ 0.0001; ES = −1.70), Anterior-posterior oscillation (p ≤ 0.0001; ES = −1.40), Medial-lateral oscillation (p ≤ 0.0001; ES = 1.75) and Length in function of surface (p ≤ 0.0001; ES = −0.98). Both parameters of dynamic stability, the KTK test (p ≤ 0.0001; ES = 1.28) and Motor quotients KTK test (p ≤ 0.0001; ES = 1.45), were significantly better in the Dance group. Conclusion: : The results from the present study indicate that children girls who participate mostly in dance develop better static and dynamic PS than children girls who participate in other sport activities. These findings underline the importance of training modification toward the improvement of PS in dance.