BACKGROUND: Volleyball player’s performance depends on a combination of technical-tactical skills and an optimum level of general and specific physical fitness. OBJECTIVE: The purpose of the study ...was to compare the results of three isometric strength tests with the results of four specific volleyball performance tests using a novel Multidimensional Modelling Approach. METHODS: In a cross-sectional study 80 male (age = 16.2 ± 1.7 yrs.) and 116 female (age = 16.1 ± 1.5 yrs.) volleyball players performed two testing sessions consisting of ankle extensor, handgrip, and lumbar isometric strength tests, followed by countermovement tests, modified X test and medicine ball throw. RESULTS: Principal Component Analysis, with 51.38% to 64.87% of variances explained, was used to group results from multiple tests into a single score: isometric force (Fmax Score), rate of force development (RFDmax Score), and specific performance tests (Specific Score). Calculated Fmax Score, and RFDmax Score values showed low (r= 0.310–0.416), but statistically significant (p< 0.01) correlations with Specific Score. Regression analysis showed 17.3% and 9.6% influence of Fmax and 16.9% and 10.1% influence of RFDmax on specific abilities for male and female sample respectively. CONCLUSIONS: The findings derived from the isometric strength tests are not related to those obtained from specific volleyball performance tests. However, the advantages of isometric tests and their findings may be of a comparative clinical value in management of sports injury in volleyball players.
The subject of this paper are training methodologies important for improving tactics in youth categories of volleyball players. In practice, coaches very quickly switch from learning the 6: 0 system ...(initial system), to the 5: 1 system (competitive - senior), which for beginners leads to limitations in the manifestation of tactical and strategic skills, but also the effectiveness of technical elements in competition. The aim of this paper is to show the ageoriented, ie chronological and experience-oriented methodology of learning the system in volleyball. Order in training, respect for chronological, motor and sports age, timely specialization and orientation towards the principles of motor learning are recognized as factors leading to the expected outcome in the individual career of an athlete, making training methods effective and desirable in practice.
Physical abilities modelling has a profound connection with long-term athlete development and talent identification. There is not enough data to support evidence about age-related changes in ...volleyball players’ isometric strength. This study aimed to define the age-related model of volleyball players multidimensional muscles’ contractile characteristics. The participants were divided according to gender (male n = 112, female n = 371) and according to age into four groups: under 15 (U15), under 17 (U17), under 19 (U19), and under 21 (U21) years old. Participants performed three isometric strength tests: handgrip, lumbar extensors, and ankle extensors. Maximal force and rate of force development results from all three tests were transformed into a single Score value as a representation of contractile potentials using principal component analysis. The main findings were that Score values of both genders showed significant differences between age groups (male: F = 53.17, p < 0.001; Female: F = 41.61, p < 0.001). Trends of those yearly changes were slightly more balanced for female subjects (3.9%) compared to male subjects (6.3%). These findings could help in strength training adjustments when working with volleyball players of a certain age, and enable coaches to detect ones that stand out positively, considering them as strong in regard to their age.
U prvom dijelu rada razmatra se važnost predškolskog obrazovanja u suvremenom društvu s obzirom na načela suvremenog obrazovanja te ukazuje na potrebu stručnog usavršavanja odgajatelja koji će biti ...sposobni dostići očekivane standarde. Rad se zatim bavi kompetencijama i razvijenom refleksijom odgajatelja, kao i nužnim stvaranjem uvjeta u kojima će se odgajatelji udaljiti od svijeta analognog i približiti svijetu digitalnog obrazovanja putem ICT usavršavanja, što će dovesti do uporabe odgovarajućih internetskih izvora. U empirijskom dijelu rada traži se odgovor na pitanje do koje se mjere u profesionalnom radu odgajatelji koriste elektroničkim izvorima u usporedbi s konvencionalnim izvorima informacija, njihovim prethodnim iskustvom i postojećim dokumentima. Prema glavnim istraživačkim rezultatima, bez obzira na rod, radno iskustvo ili obrazovnu razinu, odgajatelji se koriste internetskim izvorima manje nego konvencionalnim izvorima da bi unaprijedili kvalitetu rada. No, utvrđene su određene razlike među njima s obzirom na radno iskustvo, to jest ispitanici koji imaju kraće radno iskustvo više se koriste elektroničkim izvorima od svojih iskusnijih kolega. U završnom dijelu rada nude se zaključci i praktične implikacije provedenog istraživanja.
Abstract In the first part of the paper, the importance of preschool education in modern society is considered with regard to the principles of contemporary education, pointing to the need for the ...professional improvement of preschool teachers, so that they are capable of reaching the expected standards. The paper further focuses on the competences and developed reflections of preschool teachers, as well as on the need to create conditions for preschool teachers to shift from the analogue to the digital educational world through ICT trainings, which should lead to the use of adequate Internet sources. The empirical part deals with the answer to the question regarding the extent to which preschool teachers use electronic sources in their professional work as compared to conventional sources, their prior experience and the existing documentation. According to the main research findings, regardless of their gender, work experience or level of education, the preschool teachers use the Internet sources less than other conventional sources in order to improve the quality of their work. On the other hand, certain differences were found between them considering their prior work experience, i.e. subjects with less work experience use electronic sources to a greater extent than their more experienced colleagues. The final part of the paper provides some concluding remarks and implications of the conducted research. Key words: competences; reflection; Web portals.---SažetakU prvom dijelu rada razmatra se važnost predškolskog obrazovanja u suvremenom društvu s obzirom na načela suvremenog obrazovanja te ukazuje na potrebu stručnog usavršavanja odgajatelja koji će biti sposobni dostići očekivane standarde. Rad se zatim bavi kompetencijama i razvijenom refleksijom odgajatelja, kao i nužnim stvaranjem uvjeta u kojima će se odgajatelji udaljiti od svijeta analognog i približiti svijetu digitalnog obrazovanja putem ICT usavršavanja, što će dovesti do uporabe odgovarajućih internetskih izvora. U empirijskom dijelu rada traži se odgovor na pitanje do koje se mjere u profesionalnom radu odgajatelji koriste elektroničkim izvorima u usporedbi s konvencionalnim izvorima informacija, njihovim prethodnim iskustvom i postojećim dokumentima. Prema glavnim istraživačkim rezultatima, bez obzira na rod, radno iskustvo ili obrazovnu razinu, odgajatelji se koriste internetskim izvorima manje nego konvencionalnim izvorima da bi unaprijedili kvalitetu rada. No, utvrđene su određene razlike među njima s obzirom na radno iskustvo, to jest ispitanici koji imaju kraće radno iskustvo više se koriste elektroničkim izvorima od svojih iskusnijih kolega. U završnom dijelu rada nude se zaključci i praktične implikacije provedenog istraživanja.Ključne riječi: kompetencije; refleksija; mrežni portali.
ABSTRACT Introduction When a person is in a standing position, the plantar flexor muscles are involved in most static and dynamic body movements. Objectives The aim of this study was to investigate ...the trial to trial and factorial reliability of measuring the contractile characteristics of PF muscles using a simple novel field test. Methods The sample consisted of 452 healthy subjects, 120 male and 332 female. The research was conducted by means of the trial to trial testing method, using isometric dynamometry performed in field conditions. ANOVA was used to estimate the differences among the trials, Cronbach’s alpha and interclass correlation to estimate the correlations among the trials, and principal component analysis to evaluate the contribution of each trial to overall variability. Results The main findings of this study are that trials differed significantly (p<0.000) for maximal force (Fmax) and maximal rate of force development (RFDmax), indicating that the three procedural trials were necessary. The trials were highly correlated (Fmax, RFDmax, r>0.9), proving that measuring was reliable, and the factorial analysis separated the second and third trials, the second trial accounting for most of the total variability. Conclusions The simple novel field test for the measurement of plantar flexor contractile characteristics recommended by this study proved to be as highly reliable as laboratory testing, but was easy to perform in conditions outside of scientific or diagnostic institutions, which greatly facilitates the work of scientists, coaches and professionals. Level of Evidence II; Diagnostic Studies – Investigating a diagnostics test.
RESUMEN Introducción Cuando una persona está de pie, los músculos flexores plantares son involucrados en la mayoría de los movimientos corporales estáticos y dinámicos. Objetivos El objetivo de este estudio fue investigar la confiabilidad test-retest y factorial de la medición de las características contráctiles de los músculos plantares, usando un nuevo test de campo simple. Métodos La muestra consistió en 452 individuos saludables, 120 hombres y 332 mujeres. El estudio fue realizado a través del método de test-retest, con dinamometría isométrica conducida en condiciones de campo. Se empleó ANOVA para estimar la diferencia entre los tests, alpha de Crombach y la correlación interclase para estimar la correlación entre los tests y el análisis de componentes principales, para evaluar la contribución de cada test para la variabilidad global. Resultados Los principales hallazgos de este estudio son que los tests difirieron significativamente (p<0,000) para la fuerza máxima (Fmáx) y la tasa máxima de desarrollo de fuerza (TDFmáx) indicando que los tres tests de procedimiento fueron necesarios. Los tests fueron altamente correlacionados (Fmáx, TDFmáx, r>0,9) probando que la medición era confiable, y el análisis factorial separó el segundo y tercer test, siendo que el segundo test presentó la mayor parte de variabilidad total. Conclusiones El nuevo test de campo simple para medición de las características contráctiles de los flexores plantares recomendado por este estudio probó ser tan confiable como los tests de laboratorio y, al mismo tiempo, más fácil de realizar fuera de las instituciones científicas o de diagnóstico, lo que facilita mucho el trabajo de científicos, entrenadores y profesionales. Nivel de evidencia II; Estudios diagnósticos – Investigación de un examen para diagnóstico.
RESUMO Introdução Quando uma pessoa está em pé, os músculos flexores plantares são envolvidos na maioria dos movimentos corporais estáticos e dinâmicos. Objetivos O objetivo deste estudo foi investigar a confiabilidade teste-reteste e fatorial da mensuração das características contráteis dos músculos plantares, usando um novo teste de campo simples. Métodos A amostra consistiu em 452 indivíduos saudáveis, 120 homens e 332 mulheres. O estudo foi realizado pelo método de teste-reteste, com dinamometria isométrica conduzida em condições de campo. Empregou-se a ANOVA para estimar a diferença entre os testes o alfa de Cronbach e a correlação interclasse para estimar a correlação entre os testes e análise de componentes principais , para avaliar a contribuição de cada teste para a variabilidade global. Resultados Os principais achados deste estudo são que os testes diferiram significativamente (p < 0,000) para a força máxima (Fmáx) e a taxa máxima de desenvolvimento de força (TDFmáx), indicando que os três testes de procedimento foram necessários. Os testes foram altamente correlacionados (Fmáx, TDFmáx, r > 0,9), provando que a medição era confiável, e a análise fatorial separou o segundo e o terceiro testes, sendo que o segundo teste apresentou a maior parte da variabilidade total. Conclusões O novo teste de campo simples para medição das características contráteis dos flexores plantares recomendado por este estudo provou ser tão confiável quanto os testes de laboratório e, ao mesmo tempo, mais fácil de realizar fora das instituições científicas ou de diagnóstico, o que facilita muito o trabalho de cientistas, treinadores e profissionais. Nível de Evidência II; Estudos Diagnósticos - Investigação de um exame para diagnóstico.
Background/Aim. Numerous studies have indicated that university students exhibit a variety of risky health behaviors, such as the lack of regular physical activity and u n-healthy eating habits. Due ...to lack of information about students? lifestyles in Serbia, we designed a study with the following aims: 1) to investigate physical activity and eating habits variations of students according to gender, year of study and attended faculty; 2) to estimate the relationship between their physical activity and eating habits. Methods. The survey method was used. Data were collected in the 2016/2017 school year during the spring semester. The sample was randomly stratified (4,019 students of the University of Belgrade ? 2,284 males), which corresponded to about 5% of the whole student population of the University of Belgrade. For data collection, two standardized questionnaires were used: International Physical Activity Questionnaire (IPAQ) and Youth/Adolescent Food Questionnaire (YAQ). Results. Male students were significantly more highly and moderately active than female students 3.15 vs. 2.80 days, respectively; p = 0.003, effect size (ES) = 0.651. Correspondingly, female students were less active during the day (326 vs. 305 min; p = 0.044, ES = 0.232). Interaction between factors revealed that the most active on a weakly basis were fourth-year male students of the natural sciences (4.20 days), while on a daily basis, the most active were first-year female students (161 min). The most sedentary ones were third-year female students of medical sciences (475 min of sitting per day). Significant correlations were found between the duration of intense physical activity and consuming water, vegetables, citrus fruits, integral bread, and cereals. Conclusion. Female students were more prone to sedentary behavior, while older students were more active and aware of the importance of physical activity. Further-more, the nature of studies can influence the lifestyle. Female and older students were more concerned about diets. Additionally, students who were more physically active had healthier eating habits.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Vertical Kaplan turbines, with nominal power of 178 MW and manufactured in Russia, have been installed in 6 hydroelectric generating units of hydro power plant ’Djerdap 1’. Experimental tests were ...carried out by non-destructive methods in order to determine the turbine condition during the rehabilitation of the hydro power plant. Lack of root penetration was detected in V40 welded joints between upper and lower sleeves and bodies of guide vane apparatus vanes. Height of the lack of root penetration was in the range between 5 and 15 mm, while the allowable height of the lack of root penetration is 3 mm, according to the technical conditions. The upper sleeves were made of cast steel 25L (in accordance with GOST 977), while lower sleeves were made of steel forging St 25 (in accordance with standards GOST 1050 for chemical composition and GOST 8479 for forgings).Methodology for the repair of non-penetrated welded joints between the sleeves and body of the guide vane apparatus vane was composed taking into account the results of ultrasonic testing. By repair methodology it is necessary to, due to the structural solution and service function of guide vane apparatus vanes, specify a large number of details, consider them carefully and carry them out in order to improve safety, because if some of them get overlooked, underestimated or incorrectly perceived, significant problems in turbine operation may occur.This methodology refers solely to the repair of damaged welded joints between sleeves and bodies of guide vane apparatus vanes.
This paper aims to investigate the influence of expense item 'Energy' on excellence of school operation. The study was conducted on a sample of 33 primary and 13 secondary schools established by the ...County of Varaždin, in the area of financing decentralised functions. The following study task was set: 'Determine the Model of influence of expense item "Energy" on excellence of school operation'. Based on research that incorporated the Pareto Principle and descriptive statistics in the area of quartile, correlation and regression analysis, a model for determining the influence of expense item 'Energy' on excellence of school operation in primary and secondary education was provided for the area covered by local government. Based on the results and the generated model, suggestions were made for the improvement of the primary and secondary education system at local government level of operation.
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