Efekti razvojne gimnastike na razvoj motoričkih sposobnosti dece

Physical exercise in the younger school age is extremely important due to growth and development of organism as well as corrective treatment on various deformities. Physical education in this period of physical growth and development is very important.But in practice, this subject is not carried out regularly or is not performed by pedagogues of physical culture. Exercises in artistic gymnastics are very diverse and some of them are more demanding in terms of different forms of power, some in terms of coordination, mobility, balance, and some sublimate more motor abilities. For this reason, the application of exercises on apparatues and floor indisputably affect the overall motor status of a person. Exercise on apparatues, as a wider concept of development gymnastics, is a motor activity rich in diversity of movements and positions. The richness of movement and position in exercise on apparatues allows to those who utilize them to create a huge fund of motor knowledge. The subject of this research were motor abilities (power, speed, coordination, flexibility) and developmental gymnastics program for younger school age children, and the problem of the research was to determine whether the developmental gymnastics program had an effect on development of motor abilities onyounger school age children. Based on defined subject and the research problem, the objectives of the research was related to determining the differences in motor abilities between initial and final measurement and between experimental and control group of boys and girls in younger school age. On the basis of the defined subject, goals and tasks of the research, three general and eight subhipotheses were identified that were related to existence of statistically significant differences in motor abilities between initial and final measurement, and between experimental and control group of boys and girls in younger school age. The sample of respondents for experimental group consisted of 59 girls and 54 boys, and for controll group 45 girls and 53 boys in younger school age. To determine the level of motor abilities, 18 tests were. Data processing was performed by the statistical program SPSS v. 20. For all data, the parameters of descriptive statistics were calculated. To determine the differences between the groups at the initial and the final measurement, a t-test for independent samples was used with calculation of significance of the size of difference (Cohen's d) and the canonical-discriminative analysis; to determine the difference between the initial and the final measurement, a t-test for dependent samples with calculation of impact sizes was used (Cohen Effec Size), and for determining effects, a multivariate covariance analysis (MANCOVA) was used with neutralization of differences between groups at initial measurement. The research has shown the effects of the developmental gymnastics program on the development of motor abilities of children aged 9 to 11 years. Differences in motor abilities were identified in favor of the experimental group, allredy at the initial measurement. After the realization of the experimental program of developmental gymnastics, the differences in the benefit of the experimental group compared to the control were even more significant, as well as differences within the groups between the initial and final measurement. The results obtained accurately indicate that the efficiency of the experimental program has significantly more contributed to the transformation of motor abilities than the current physical education program

The Rare-Earths influences on doped BaTiO3-Ceramics Microstructure and Electric Characteristics

The influence of rare-earth additive content on microstructure and electric properties of doped BaTiO3 ceramics is investigated. The concentration of Er2O3 and Yb2O3 in the doped samples range from 0.01 to 1.0at % . The samples are prepared by the conventional solid state reaction, and sintered at 1320° and 1350°C in air atmosphere for 4 hours. SEM analysis shows that all samples are characterized by polygonal grains. The uniform and homogeneous microstructure with grain size ranged from 20 to 45μm is the main low doped samples characteristics. For the samples doped with the higher dopant concentration (0.5 and 1.0 at%) the average grains size is ranged from 5 to 10μm. Dielectric measurements are carried out as a function of temperature up to 180°C at different frequencies. The low doped samples display the high value of dielectric permittivity at room temperature. A nearly flat permittivity-temperature response is obtained in specimens with higher additive content. The Curie temperature of doped samples were ranged from 126 to 130°C. The Curie constant for all series of samples decrease with increment of dopant concentration and the lowest values is mesured from samples doped with 0.01 wt% of aditive. The obtained value of γ pointed out that the specimens have almost sharp phase transition. Also, the specific electrical resistance is measured in function of temperature at the different frequencies from 100Hz to 1MHz. With increasing additives concentration, the electrical resistance decreases to the concentration of 0.5 at% and then increases

Electrical properties of doped BaTiO3 Ceramics

The electrical resistivity and PTCR (Positive Temperature Coefficient of Resistivity) effect doped BaTiO3 ceramics with different dopant were investigated in this paper, The content of additive in doped samples were ranged from 0.01 to 1.0 at% Er/Yb. The samples were prepared by a conventional solid state sintering procedure and sintered at 1320 °C for 4 hours. For samples doped with Er2O3 (0.01 at% Er/Yb), SEM analysis shows abnormal grain growth with the average size range between 20 μm - 40 μm. For samples doped with Yb2O3 the average size was from 30 μm - 50 μm. With increase of dopants concentration the average grain size decreases, and for samples doped with 1.0 at% Er/Yb, grain size range between 3 μm - 20 μm for samples doped with Er and between 1 μm - 10 μm for samples doped with Yb2O3. The specific electrical resistance were measured in temperature range from 25 °C to 170°C at different frequencies, ranged from 100Hz to 1MHz. To a temperature of 120 °C, resistance has a slight increase with increasing of temperature, but above this temperature the resistance rapidly increasing. The value of the specific electrical resistance decreases with increasing concentration of Er/Yb, reached the minimum at certain dopant content (0.5 at% Er/Yb), then increased rapidly with dopant content in high doping level

Electrical Characteristics of Ho doped BaTiO3 Ceramics

In this paper, electrical characteristics of Ho2O3 doped BaTiO3 ceramics were shown, using new method for measuring samples. The BaTiO3 doped samples were sintered at 1320°C for 4 hours. The concentration of the additives were from 0.05 to 1.0 at% Ho. The density was ranged from 83% to 91% of theoretical density (TD). The samples of BaTiO3 ceramics doped with Ho2O3 are characterized by spherical and irregular polygonal grains. The average grain size for samples doped with low content of Ho2O3 (0.05 at% Ho) ranged from 10 μm to 30 μm. An increase in dopant concentration causes a decrease in the average grain size in the investigated samples. So it is for samples doped with 1.0 at% Ho, grain size range between less than 1 mm – 2 mm. The variation of dielectric permittivity with temperature were measured in the temperature range from 30°C to 180°C and the frequency range from 100 Hz to 1 MHz. For measurement electrical characteristic a new method was used, which implemented to automate the sampling and to enable measurement without a human factor. The software application is connected via USB communication to a microcontroller, which measures the temperature in the furnace. When the temperature reaches the defined value, the microcontroller sends information to the software application. Then the application through GPIB communication activates the LCR meter, which measures the defined parameters of the tested samples. Based on parameters such as dielectric constant (εr), tangent losses (tan δ) and impedance, the characteristics of the tested samples were determined. Using the Curie-Weiss law and modified Curie-Weiss law, based on the measured values of the parameters, the Curie constant and the exponent of nonlinearity were determined

The Electrical Characteristics of Nb doped BaTiO3 Ceramics

The Nb doped BaTiO3 ceramics, with different Nb2O5 content, ranging from 0.5 to 2.0 at% Nb, were investigated regarding their electrical characteristics in this paper. Nb/BaTiO3 ceramics using in this investigation were prepared by the conventional solid state reaction and sintered at 1320°C in an air atmosphere for 2 hours. The dielectric characteristic of doped BaTiO3 ceramics like as dielectric constant, dissipation factor, impedance (resistance, reactance) have been done by using LCR-Meter Agilent 4284A in the frequency range 20 Hz-1 MHz and Agilent E4991A RF Impedance/Material Analyzer for high frequency measurements (1 MHz – 3 GHz). Dielectric constant and tangent losses after initial large values remains nearly independent of frequency greater than 3 kHz. Dielectric measurements were carried out as a function of temperature up to 180°C. The low doped samples sintered at 1320°C, display the high value of dielectric permittivity at room temperature, 2600 for 0.5Nb/BaTiO3. A nearly flat permittivity-temperature response was obtained in specimens with 2.0 at% additive content. The Curie-Weiss and modified Curie-Weiss law is used to clarify the influence of dopant on the dielectric properties and BaTiO3 phase transformation. All investigated samples have an electrical resistivity ρ >105 Ωcm at room temperature

SYSTEMATIZATION OF PREVIOUS RESEARCHES OF EXERCISES ON PARALLEL BARS

Abstract. Parallel bars is one of the six apparatus of men's artistic gymnastics all- around, based on the great variety of elements performed on this apparatus, as well as of the performing styles and ways of their training. The aim of this paper is to analyze previous studies on parallel bars exercises, and the systematization of research papers related to parallel bars exercises. In code of points (COP) for judging, as many as 168 elements are shown (FIG, 2015) which are performed and which must be performed at competitions on parallel bars. In previous studies there are only 22 elements (13.5%) and they were mainly related to the analysis of the performance techniques of the above mentioned elements. There are no studies dealing with the methodical process of achieving the ideal execution of an element. This only points to the fact that the studies on parallel bars exercises, although conducted over a long period of time, are still in their infancy. Considering the great perspective of elements and the possibility of their upgrade, it is necessary to start with the stuides of elements which are performed through support on the upper arms.Key words: artistic gymnastics, parallel bars, systematization

SYSTEMATIZATION OF PREVIOUS RESEARCH ON EXERCISES ON THE HIGH BAR

The research was conducted with the aim to classify and systematize all the available studies that deal with exercises on the high bar. This research covered a total of 41 papers, spanning a period from 1990 to 2013. In terms of Code of points it includes as many as 144 elements that are performed and which should be performed at competitions. Of this number, only 18 elements were investigated (based on the collected papers), or 12.5%. This points to the fact that the research on exercises on the high bar, although conducted for a long period of time, is still in the beginning stages. Research of first (long hang swings and turns) and fifth (dismounts) specific requirements dominates. To a smaller extent, research on second (flight elements) specific requirements is represented, and the least attention is devoted to third and fourth requirements.

DIFFERENCES BETWEEN LOWER BODY MUSCLE POTENTIAL DURING UNLOADED AND LOADED SQUAT JUMP IN ELITE MALE SPRINT SWIMMERS

The primary purpose was to determine differences between lower body muscle potential during the unloaded and loaded squat jump (SJ) in elite male swimmers. The secondary purpose was to assess the load that would maximize power output in the SJ. Twenty-one elite male trained competitive swimmers, all members of the Central Serbia Swimming Team (Age = 20.7 ± 3.8 yrs., Height = 1.84 ± 0.56 m, Weight = 77.5 ± 7.3 kg, FINA points 2017 long course = 636 ± 80) performed two trials of the unloaded and loaded SJ (barbell loads equal to 25 and 35% body weight). Loaded SJ testing with free weights was done using the Smith machine. The Myotest performance measuring system was used to calculate absolute and relative values of average power (Pavg, PavgRel) and maximal power (Pmax, PmaxRel) achieved during the unloaded and loaded SJ. The one-way ANOVA method and POST HOC (Tukey HSD) test were used. The results showed significant interactions between the unloaded and loaded squat jump for relative values of maximal power (F= 12.95, p= 0.000) and average power (F= 12.20, p= 0.000) as well as absolute values (F= 7.66, p= 0.001; F= 7.40, p= 0.001). The instantaneous power output in the SJ at 0% additional load (body weight) was significantly greater than that at 25% and 35% in the elite male trained competitive swimmers. The practical application of this study suggests that for male sprint swimmers, the load that generates maximal power output in the squat jump is body weight, without any additional load

A COMPARISON OF RACE PERFORMANCE CHARACTERISTICS BETWEEN ELITE MALE 50-M AND 100-M FREESTYLE SWIMMERS BASED ON THEIR RESULTS

The aim of this research was to determine the differences in specific race performance characteristics of male swimmers in the 50-m and 100-m freestyle at the Serbia Open Championship 2017 (long-course). The overall sample included in this study consisted of 40 swimmers divided by a K-Means Cluster Analysis into three groups in relation to the results in the 50-m freestyle (G1_50, T50=23.53±.27 s, n=6; G2_50, T50=24.54±.33 s, n=18; G3_50, T50=25.52±.33 s, n=16), and 55 swimmers also divided into three groups in relation to the results in the 100-m freestyle (G1_100, T100=50.99±.82s, n=10; G2_100, T100=53.41±.48 s, n=17; G3_100, T100=56.13±1.32 s, n=28). The research results indicate that there is a difference in the specific race performance characteristics in relation to the achieved results in the 50-m freestyle, including: t10_50 (F=16.79, p=.000), SL2_50 (F=4.44, p=.019) and SI2_50 (F=13.49, p=.000), also in the 100-m freestyle, including: t10_100 (F=36.45, p=.000), SL1_100 (F=5.77, p=.005), SL2_100 (F=17.47, p=.000), SL3_100 (F=7.72, p=.001), SL4_100 (F=9.84, p=.000), SI1_100 (F=5.12, p=.009), SI2_100 (F=45.97, p=.000), SI3_100 (F=13.86, p=.000), SI4_100 (F=31.23, p=.000), SR1_100 (F=4.12, p=.022) and SR2_100 (F=6.37, p=.003). Based on these results we can draw the conclusion that swimmers who have better control over their race performance characteristics during all the segments of the race, including stroke length, stroke index and stroke rate have the potential of being faster in the 50-m and 100-m freestyle.

The Rare-Earths influences on doped BaTiO3-Ceramics Microstructure and Electric Characteristics

The influence of rare-earth additive content on microstructure and electric properties of doped BaTiO3 ceramics is investigated. The concentration of Er2O3 and Yb2O3 in the doped samples range from 0.01 to 1.0at % . The samples are prepared by the conventional solid state reaction, and sintered at 1320° and 1350°C in air atmosphere for 4 hours. SEM analysis shows that all samples are characterized by polygonal grains. The uniform and homogeneous microstructure with grain size ranged from 20 to 45μm is the main low doped samples characteristics. For the samples doped with the higher dopant concentration (0.5 and 1.0 at%) the average grains size is ranged from 5 to 10μm. Dielectric measurements are carried out as a function of temperature up to 180°C at different frequencies. The low doped samples display the high value of dielectric permittivity at room temperature. A nearly flat permittivity-temperature response is obtained in specimens with higher additive content. The Curie temperature of doped samples were ranged from 126 to 130°C. The Curie constant for all series of samples decrease with increment of dopant concentration and the lowest values is mesured from samples doped with 0.01 wt% of aditive. The obtained value of γ pointed out that the specimens have almost sharp phase transition. Also, the specific electrical resistance is measured in function of temperature at the different frequencies from 100Hz to 1MHz. With increasing additives concentration, the electrical resistance decreases to the concentration of 0.5 at% and then increases