Abstract Introduction: Ball trajectory in the golf swing is an important outcome variable for golf performance, however, no direct investigation of ball flight trajectory variability for pre-elite players has been conducted. Purpose: The purpose of this study was to examine correlations between average score and ball trajectory variability (for carry and lateral displacement) on pre-elite golfers both at and between two different clubs.  Methods: Sixteen pre-elite/elite golfers were included in the study, 11 men and 5 women with a mean age of 22 ±2 (SD). An actual average (mean) score was calculated for each player’s first ten competition rounds. Subjects were then instructed to hit 5 balls, with focus on consistency, with their seven iron and then hit 5 balls approximately 70 metres with their preferred wedge. Ball trajectory variables were recorded using a Flightscope® Kudo Doppler radar launch monitor system (EDH South Africa (PTY) Ltd). Statistical calculation of averages, standard deviation (SD), normalised root-mean, coefficient of variance, performance error index (PEI= and Pearson’s correlation. Results: The results from the present study showed there was no significant correlation between average score (76.2 ±1.9) and variability of ball trajectory, for the seven iron or wedge. Results also showed average seven iron CV for carry and lateral PEIdisplacement was 5% and 3% respectively, whilst average wedge carry CV for carry and lateral PEIdisplacement was 9% and 2% respectively.  Carry CV and Lateral CV PEI were moderately correlated (r=0.61, p=0.012) with each other for the wedge. Conclusion: : Our findings show no correlation between shot variability and golf score, however we found weak correlation between carry and lateral variability for the wedge. In order for effective coaching more understanding into the importance of biomechanical variability and golf performance is required, further research is needed to better understand the implication of our findings

The ball-pen probe is a unique probe recently developed at the Institite of Plasma Physics in Prague. It has been designed for direct measurement of plasma potential at the CASTOR tokamak. Nowadays, it is used routinely at several tokamaks in Europe, and the first tests in low-temperature plasma have also already been performed. The aims of the thesis are primarily experimental. A ball-pen probe has been constructed from available materials, which is suitable for systematic measurements of radial profiles in the low-temperature plasma of a cylindrical magnetron. By means of comparison to other diagnostics, it was proved that ball- pen probe is able to directly measure plasma potential in a certain range of plasma parameters even though its current-voltage characteristic is not symmetric, which is in contradiction with the simplified theory for ball-pen probe. Powered by TCPDF (www.tcpdf.org)

Title: Baseball modifications for kids and their comparison Objectives: The goal of this project is to compare, via a two tier method, modified version of baseball for kids, T-ball and Coachpitch. First goal is a comparison of a course of a T-ball and a Coachpitch game - analysis and evaluation of games and their respective scorecards , with the aim of extracting information about the course and the character of the game in both of these modifications. Second goal is an analysis of a cinematic footage of a baseball swing and analysis of differences in mechanics between hitting against a Coachpitch delivery and hitting off a tee in T-ball. On the data extracted from the first two steps, evaluation of benefits of each of these baseball modifications follows. Methods: This research is a case study of a descriptive character in which a large amount of data from 11 individuals is collected. Video footage of 11 research subjects was created for swing motion in both baseball modifications. Video footage was thereafter evaluated via computer programme Dartfish. Extracted data was afterwards analysed via a one-way analysis of variance method. In the second part of the thesis, evaluation of the modified scorecards and subsequent transfer of these scorecards into statistical data is used. Results: Thesis...

Author: Bc. Tomáš Zajíček Title: Analysis of game activities of goalkeeper during European Championship Under-21 2015. Objectives: The main objective is to analyse of game activities of goalkeeper on European Chapmionship Under-21 2015. Partial objectives: ranking of all matches on European Chapmionship Under-21 2015 in football, completing data, frequency of game activities, ratio of defensive and offensive game activities of goalkeeper and comparing the effect of regular and irregular performance on the goalkeeper on European Chapmionship Under-21 2015 in Czech republic. Methods: For getting information there were used indirect observation in this Bachelor thesis. The indirect observation from videorecords was time postponed. Results: The results show that in current football the goalkeeper has to be in control of the game with his foot more than ever before. A study points to the fact that the goalkeeper has to offend four times more than defend during the game. Available data show that U21 goalkeepers run less towards center balls than their older colleagues. The data also show that especially defense experience and regular utilization during the game shows. Keywords: Goalkeeper, game activities of goalkeeper, catching ball, rebound ball, running out for centered balls, taking ball, throwing...

L'objectif de ce travail de doctorat étati d'examiner les modalités d'entrainement permettant de développer la vitesse de balle post impact en coup droit au tennis, tout en évaluant les risques potantiels d'hypersollicitation de l'épaule qui pourraient en résulter. Les résultats de nos différentes études ont montré que la puissance maximale développée lors d'un lancer de medecine-ball (MB) à 2 mains sur le côté expliquait 25% de la variation de la vitesse maximale de balle en coup droit et qu'elle était atteinte en utilisant une masse de MB de 5,7% du poids de corps du joueur. Toutefois, les relations entre les distances obtenues lors de ce type de lancer et la vitesse de balle en coup droit sont faibles. En revanche, les lancers de MB sur le côté à une main ont démontré une relation significative avec la vitesse maximale de balle en coup droit. Un entrainement de six semaines basé sur l'utilisation de ce type de lancers a augmenté la vitesse de balle de 11% mais la précision des coups tendait à diminuer. Finalement, un entraînement incorporant des frappes de balle avec une raquette lestée d'environ 12% a également amélioré la vitesse maximale de balle en coup droit (5%), tout en conservant la précision des coups. Enfi, la comparaison de la coordiantion musculaire entre lesles deux types de lancers de MB et la frappe en coup droit a montré que les muscles du tronc et du membre supérieur testés présentaient des modèles d'activité musculaire et des niveaux de sollicitations similaires. Ainsi, les craintes concernant un potentiel de blessure ne sembleraient pas justifiées. Ainsi, les résulats de ces tudes ont contribué à la périodisation de la préparation physique pour l'amélioration de la performance en coup droit chez le joueur de tennis compétiteur amateur / This work aimed at exploring the training modalities to develop maximal post impact ball velocity fo the tennis forehand drive, while assessing the potential risk of upper limb oeruse. The results of our studies showed that maximal power developed during a two-handed side medecine-ball(MB) throw explained 25% of the variation of maximal forehand ball velocitiy, and was achieved when using a MB mass of 5,7 % of player's body weight. However, the relationship between throwing distances and maximal ball velocity of forehand drive was weak. By contrast, a significant relationship was found between the performance for the one-handed side MB throw and the maximal velocity of the forehand drive. A six-week trainig program based on one-hand MB throws increased the ball velocity by 11%, but the shot accuracy tended to be reduced. In the same way, a six-week training program including forehand drives with an overweighted racketr about 12 % allowed the maximal forehand ball velocity to be improved (5%), without alteration in theshot accuracy. Finally, the comparison of muscular coordination between both MB throws and the forehand drive demonstrated that the trunk and upper limb muscles presented similar activity pattern and levels. The potentials for injury risk would thus not justify. In conclusion, the finding of this work contributed to the periodization of the strength and conditioning training in order to improve the forehand drive performance in nonprofessional competitive tennis players.

The goal of this master’s thesis was to design and construct ninepin ball elevator for automated pin setter machine and ninepin ball launcher to simulate load and to verify correct function of the setter machine. Also, a ball track was designed as a means of transport for the ball from elevator to launcher. Theoretical part of thesis contains research into ninepin bowling, its rules and analysis of different applicable solutions found on the market that deal with automated pin setters and their ball elevators. Furthermore, a separate research into ball launchers was conducted. Practical part of thesis was comprised of own solution to design and construction of elevator, which extended already designed pin setter machine. After this, track for ball was designed and constructed together with ball launcher which imitates load that would the machine experience during usual game.

The aim of this thesis is ball screw service life measurement. Text is divided on two major parts, theoretical one and practical one. Theoretical part describes three basic methods of ball screws manufacturing – rolling, whirling and grinding. Subsequently, methods of heat treatment (inductive and laser hardening) are mentioned. Practical part is devoted to ball screw service life testing and evaluation of results. Tests were carried out on two sets of two ball screws. First set was manufactured by whirling and grinding followed by inductive hardening. Second set was manufactured by grinding followed by inductive hardening in one case and laser hardening in the second one. Test results were evaluated according to international standards.

This thesis deals with construction of rotary-nut ball screw. In the first chapter technical research at the current state of linear positioning systems and matters associated with them is listed. The next chapter treats of basic concepts and designs referring to ball screws. Further on the boundary between rotary ball screw and rotary- nut ball screw is described. On basis of restrictions and selected criterions solution of one size of rotary – nut ball screw with all the calculations.

Carbon dioxide reforming, or drying reforming, of methane can now be used in new applications such as landfill gas utilization where CO and CH need to be converted to a mixture of CO and H, called synthesis gas or syn-gas. A novel Ni-Co/AlMgO bimetallic powder catalyst was developed in previous research for dry reforming of methane (DRM) process which can eliminate carbon deposition. But it is difficult242x to apply this loose-powder catalyst in industrial scale. The procedure of making spherical Ni-Co/AlMgOx bimetallic catalyst supported on BASF CSS-350 alumina balls (BASF Catalysts LLC) using impregnation method with different impregnation steps and calcination steps is explained in this thesis. For every batch of preparation, the concentration of metal solution was calculated based on different impregnation steps. BET (Brunauer-Emmett-Teller) analysis, compressive strength test, XANES (X-ray Absorption Near-Edge Structure) measurement and ICP-MS (Inductively Coupled Plasma Mass Spectrometry) analysis are conducted to understand the physical and chemical properties of the catalyst. It is found that both impregnation steps and calcination steps have great influence on the performance of the prepared catalyst samples. Among all the catalysts prepared, BF-4-0.25(MgNiCo)-C, which was made by using 4 impregnation-calcination cycles, shows the best activity and stability for 160 h time-on stream (TOS) under the reaction condition of 0.10 g catalyst loading, 750 oC, ambient pressure, GHSV=100,000 ml/gc·h, and CH4/CO2/N2 = 1/1/1. The CH4 conversion started at 66.7% and slowly dropped to 52.8% after 160 hours. I I BF-4-0.25(MgNiCo)-C spherical catalyst shows lower reaction rate compared to the loose powder format but shows compatible or higher activity to other two reported catalysts in similar compositions. Most importantly, it is a shaped catalyst ready for industrial use.

This study is an intervention study conducted on students in the middle years of a Swedish suburban school. The aim of the study is to examine students’ cooperative skills in ball games in the subject of physical education. The study’s questions focus on what emerges in activity and in conversation when students receive cooperative tasks that they must complete together in ball games, and how these conversations and activities change during the learning process. The study also focuses on the patterns that occur in the game room when students must help each other cooperate, and on the consequences of these patterns for the learning of cooperation in ball games. The intervention consisted of three game laboratories, created as special tasks by means of cooperation, which were orchestrated. The study is based on and can be understood through John Dewey's pragmatic epistemology. It has a  constructionist basis which means that learning and development is seen as an active process where individuals creat meaning in cooperation with others. Furthermore, the theoretical framework implies that students and the environment are seen as constantly interacting, creating each other in a mutual transactional process. A practical epistemology analysis (PEA) was used for the analysis of `talk and action´ in order to explore students' constructions and reconstructions of meaning making and learning about cooperation in ballgames. The empirical material consists of 24 games played and 24 rounds of talks. The first game laboratory focuses on what students are doing and talking about when they are asked to achieve the first pass. The second game laboratory focuses on what they do and talk about in order to succeed together in getting across the field’s halfway line before they get to shoot at goal. The third game laboratory focuses on what students should do to achieve the final pass before shooting at goal. The analysis of the game laboratories shows that it is not enough to pass or to create space as, own rooms in order to achieve cooperation in ballgames. The students’ actions and agreements during talks must also harmonise with the purpose of the task in order to allow learning to cooperate in ballgames to occur. The patterns that emerged in the game room were convergence and divergence; students created their own rooms as well as isolated rooms. Furthermore, densified game room was observed to hinder cooperation, and thinned room to favour cooperation. / Forskningslinjen Utbildning