Realization of Electronic Commerce

Diplomová práce se zabývá analýzou způsobu prodeje odborné literatury a navrhuje řešení, jak realizovat internetový obchod za podmínky minimálních nákladů. Zaměřuje se na propagaci nabídky využitím online nástrojů a sociálních sítí a dává návod, jak se stavět k řešení prodeje přes internet.The thesis deals with the analysis of selling method for special literature and suggests the solution how to realize electronic commerce in condition of minimal costs. It concentrates on the offer propagation using online tools and social networks, and gives the instruction how to deal with the solution of selling on the internet.

Comparison of the Evaluation of Performance Preconditions in Tennis with the Use of Equal and Expertly Judged Criteria Weights

Tennis performance is influenced by various factors, among which physical performance factors play an important role. The aim of the study was an analysis of possibilities of the use of Saaty’s method for assessing the level of performance prerequisites and comparing the results obtained using equal weights and various weights. The research on Czech female players (U12; n = 211) was based on the results of the TENDIAG1 test battery (9 items) and the results were processed by FuzzME software and relevant statistical methods (correlation coefficient r, Student´s t-test, effect size index d). The results of Saaty's method show that the most important athletic performance criteria for tennis coaches are the leg reaction time and the running speed, while the least important are endurance and strength. The evaluation using various criteria weights offers a finer scale for assessing athletes’ performance prerequisites despite the proven high degree of association between the results obtained with equal and various weights and the insignificant difference of mean values. The results have shown possibilities for the use of a fuzzy approach in sports practice and motivate further research towards broadening the structure or the number of evaluation criteria.Tennis performance is influenced by various factors, among which physical performance factors play an important role. The aim of the study was an analysis of possibilities of the use of Saaty’s method for assessing the level of performance prerequisites and comparing the results obtained using equal weights and various weights. The research on Czech female players (U12; n = 211) was based on the results of the TENDIAG1 test battery (9 items) and the results were processed by FuzzME software and relevant statistical methods (correlation coefficient r, Student´s t-test, effect size index d). The results of Saaty's method show that the most important athletic performance criteria for tennis coaches are the leg reaction time and the running speed, while the least important are endurance and strength. The evaluation using various criteria weights offers a finer scale for assessing athletes’ performance prerequisites despite the proven high degree of association between the results obtained with equal and various weights and the insignificant difference of mean values. The results have shown possibilities for the use of a fuzzy approach in sports practice and motivate further research towards broadening the structure or the number of evaluation criteria

Longitudinal Study of the Influence of the Relative Age Effect (RAE) on Czech Tennis Players Aged 10 - 12

The overall results in the reference period 2003 – 2017 have shown that most of the players were born in Q1 (n=551) and Q2 (n=442). Therefore, 2/3 of the players (66%) were born in the first half of the year, while only 1/3 (34%) were born in the second half. A longitudinal study of tennis players aged 10 – 12 showed the influence of RAE both in specific years (with the exception of 2011 and 2014) and in the reference period 2003 – 2017 taken as a whole. The results of our research correspond to the results of similar studies performed by other authors. Tennis coaches are advised to address the issue of RAE when working with tennis youth and when selecting players to the sports centres, representations, etc

Possibilities of Application Fuzzy Logic for Evaluation of Level of Motor Abilities

Od devadesátých let minulého století se v oblasti diagnostiky pohybových činností objevují publikace využívající teorii fuzzy logiky, která nabízí kvalitativně jiný přístup k analýze dat než klasický pravděpodobnostní přístup. Cílem práce bylo vytvoření postupu pro hodnocení jednotlivých testů testové baterie TENDIAG1 na principu fuzzy teorie. Na základě obdobných publikovaných výzkumů a expertního posouzení jsme zkonstruovali funkce příslušnosti k jednotlivým testům a navrhli algoritmus pro výpočet hraničních bodů. Postup při konstrukci funkcí příslušnosti je demonstrován na výzkumných datech souboru tenistů ve věku 11-12 let (n=187), konkrétní vyhodnocení výsledků bylo realizováno u subsouboru náhodně vybraných tenistů (n = 25) z uvedeného souboru. Pro finální vyhodnocení výsledků testové baterie jsme využili metodu agregace dílčích výsledků. Tento postup umožňuje jemnější rozlišení úrovně výkonnosti jednotlivých hráčů než dosud užívaná třístupňová norma. Do budoucna lze počítat s využitím sofistikovanějších metod agregace umožňující pracovat s různými vahami dílčích testů.Since the 1990s, sports diagnostics have started applying principles of fuzzy logic, which offers a different quality approach to data analyses than the standard probability approach. The aim was to create a process for evaluating each test of the battery of tests TENDIAG1 on the principle of fuzzy theory. Based on similar published research and expert reviews we constructed membership functions for individual tests and proposed an algorithm to calculate the boundary points. The procedure for the construction of membership functions is demonstrated in the research data set of the tennis players aged 11-12 years (n = 187), specific evaluation of the results was performed at the sub-set of randomly selected tennis players (n = 25). For the final evaluation of the results of the test battery we used the method of aggregation of partial results. This procedure allows a finer resolution level of performance of individual players than the currently used three level standards. We are sure that in the future, more sophisticated methods of aggregation will be used, allowing us to work with different weights of subtests

Bilateral differences in handgrip strength in Czech female tennis players aged 11–12 years and injury prevention

The term laterality refers to the preference or dominance of the lateral asymmetry of the human body. The prevalence of left-handedness is reported to be 10–13%, but in some sports (e.g. boxing, ice hockey, tennis), the proportion of left-handers is higher. The left-handedness is considered an advantage in tennis; however, the one-sided load can cause muscular dysbalances leading to injuries. The research aim was to assess bilateral differences in handgrip strength in top Czech female tennis players U12 as to injury prevention. The participants were tennis players (n = 165) aged 11.0–12.9 years taking part in the regular testing by the Czech Tennis Association using the TENDIAG1 test battery between 2000 and 2018. 87.3% of all players were right-handed (RH) and only 12.7% left-handed (LH). Bilateral differences between the right- and left-hand strength of all players were medium significant in favor of the right hand. The assessment of differences between RH and LH players showed only small differences in favor of LH players. There was a medium significant difference between RH and LH players in favor of the dominant hand (DH) over the non-dominant one (NDH). As to injury prevention, it is surprising that a difference between DH and NDH strength >15% was found in 40.91% of RH players and even in 40.06% of LH players. This predicts an increased risk of injury, so it is desirable to pay attention to both sides of the training load and to include compensatory or strengthening exercises

Analysis Of The Game Characteristics Of A Final Juniors (Male) Match U14 At World Junior Tennis Finals In 2017 (Case Study)

The aim of this study, based on the research data analysis, was to find out the differences in the level of 13 chosen game characteristics of the winners and losers of junior finalists (n=4) and also to verify whether there are significant differences between the junior and adult players´ results at Roland Garros 2017. The research data was obtained from the recording of each match by the observation method using the Dartfish 9.0 software. We found out that the differences between winning and losing players were insignificant in this case. When comparing the level of game characteristics of juniors and adult players, it was found that there were significant differences in the importance of return points won and the breakpoints won

Lateral Differences In Maximal Grip Strength In Czech Male Tennis Players Aged 11 – 12 In The Context Of Injury Prevention

The term laterality indicates the one-sided preference or functional advantage of the stronger, more accurate and coordinated limbs or organs of the brain hemisphere of a human body. In the preference process, more accurate, precise, coordinated and stronger side is chosen from the perspective of motoric functions. Among the general population it is about 10-13% of left-handed and in certain sport fields this percentage may (baseball, tennis, box etc.). The left-handed dominance in tennis is considered an advantage. Due to unilateral load, there may be an excessive side-effect in strength differences in tennis and the overloading of specific muscle groups could lead to an injury. The aim of the research was to identify the levels of somatic and strength characteristics and assess the lateral difference in maximal grip strength of Czech elite male tennis players. The sample consisted of male tennis players, ranging in age from 11 to 12.9 years (n=186) who participated in the regular tests for Czech Tennis Association in years 2000-2018. Base anthropometrics were measured (height, weight) and maximal grip strength of both hands using the hand-held dynamometry (Grip D, Takei). Data came from normal distribution (statistically proven – chi-square test). The basic statistical characteristics were calculated (body height, M=155.08±7.98 cm; body weight, M=43.45±7.13 kg; strength of right hand: M=24.88±4.67 kp; strength of left hand: M=21.70±4.74 kp). It was found that 87.6% of the players (n=163) were right-handed and the remaining 12.4% left-handed (n=23). The assessment of the significance (Cohen´s d) between the dominant (playing) hand for the right-handed and left-handed players revealed a small effect size (dominant hand right: MRHR=25.11±4.41 kp, dominant hand left: MLHL=26.62±5.65 kp; d=0.30, small) in favour of the left-handed players. The difference between the dominant and the non-dominant hand showed a large effect size for the right-handed (dominant hand right vs. hand left; MRHR=25.11±4.41 kp, MRHL=21.01±4.15 kp, d=0.96, large) and medium effect size for the left-handed players (dominant hand left vs. hand right; MLHL=26.62±5.65 kp, MLHR=23.24±5.98 kp, d=0.58, medium). The results indicated that the value of 15 % level of strength laterality between dominant and non-dominant hand was exceeded for the right-handed (55.83 %) and left-handed (43.48%) groups. The exceeded value could be the cause of injuries. Because of this it signals attention that should be given during training process for optimising the required load

Comparación del nivel de condiciones previas de rendimiento de tenistas de élite (estudio de caso)

En el mundo del tenis de hoy en día, hay una clara tendencia hacia un juego físicamente exigente, en el que las condiciones previas motrices más importantes son la velocidad (acción y reacción), la fuerza (sobre todo la inicial y la explosiva), la fuerza resistencia y las habilidades específicas de coordinación. El presente estudio se basa en la teoría retrospectiva. El objetivo de la investigación fue el análisis longitudinal del nivel de condiciones previas somáticas y motrices de tenistas checos de élite (el tenista Tomas Berdych –TB– y la tenista Petra Kvitova –PK–). Con fecha 1 de junio de 2014, Tomas Berdych es el tenista número 1 de República Checa y el número 6 del mundo en el Ranking ATP (4330 puntos), habiendo logrado su mejor ranking hasta la fecha en 2013 (número 5 del mundo); con la misma fecha la tenista Petra Kvitova también es la tenista número 1 de República Checa y la número 6 del mundo en el Ranking WTA (4600 puntos), habiendo logrado su mejor ranking hasta la fecha en 2011 (número 2 del mundo). Los dos tenistas fueron evaluados longitudinalmente mediante la batería de test TENDIAG1, la cual contiene tres ítems somáticos y seis ítems motores. Los resultados de ambos tenistas claramente mostraron que, a lo largo de todo el periodo de monitorización, su puntuación total en la batería de test se encontraba por encima de la media de la población de tenistas. La evaluación de las diferencias entre sexos mostró un nivel significativamente más alto en la mayoría de ítems en el tenista TB, excepto en los ítems de flexibilidad del torso y de velocidad de reacción de brazos y piernas. La tenista PK obtuvo un mejor nivel en el índice de movilidad del hombro. Los resultados proporcionan interesantes conocimientos y sugerencias para el entrenamiento del tenis

Comparació del nivell de condicions prèvies de rendiment de tennistes d’elit (estudi de cas)

En el món del tennis d’avui en dia, hi ha una clara tendència cap a un joc físicament exigent, en què les condicions prèvies motrius més importants són la velocitat (acció i reacció), la força (sobretot la inicial i l’explosiva), la força resistència i les habilitats específiques de coordinació. El present estudi es basa en la teoria retrospectiva. L’objectiu de la investigació va ser l’anàlisi longitudinal del nivell de condicions prèvies somàtiques i motrius de tennistes txecs d’elit (el tennista Tomas Berdych –TB– i la tennista Petra Kvitova –PK–). Amb data d’1 de juny de 2014, Tomas Berdych és el tennista número 1 de la República Txeca i el número 6 del món en el Rànquing ATP (4.330 punts), i ha aconseguit el seu millor rànquing fins avui, el 2013 (número 5 del món); amb la mateixa data la tennista Petra Kvitova també és la tennista número 1 de la República Txeca i la número 6 del món en el Rànquing WTA (4.600 punts), i ha aconseguit el seu millor rànquing fins avui, el 2011 (número 2 del món). Els dos tennistes van ser avaluats longitudinalment mitjançant la bateria de test TENDIAG1, la qual conté tres ítems somàtics i sis ítems motors. Els resultats d’ambdós tennistes clarament van mostrar que, al llarg de tot el període de monitorització, la seva puntuació total en la bateria de test es trobava per sobre de la mitjana de la població de tennistes. L’avaluació de les diferències entre sexes va mostrar un nivell significativament més alt en la majoria d’ítems en el tennista TB, excepte en els ítems de flexibilitat del tors i de velocitat de reacció de braços i cames. La tennista PK va obtenir un millor nivell en l’índex de mobilitat de l’espatlla. Els resultats proporcionen interessants coneixements i suggeriments per a l’entrenament del tennis

Relative Age Effect in Elite Swimmers in U14 Czech Championship

PURPOSE The issue of the Relative Age Effect (RAE) has been studied in the theory of sports for more than 30 years. Most studies concentrate on team sports, while the area of some individual sports like swimming can be considered still underexplored. METHODS The aim of our study was to verify the RAE in young elite swimmers (n = 198) who participated in Czech Republic U14 Championship (1) in male and female samples (2) according to swimming disciplines and distances (3) and performance (times in individual disciplines) between individual quartiles / semesters of birth. The analysis was performed with the use of adequate statistical (chi-square test, Kruskal-Wallis H test, Mann-Whitney U test) and effect size (effect size w index, eta-square test, effect size r index) tests.RESULTS The results showed a different intensity of RAE sex-differences (male: w = 0.033; female: w = 0.006). In the division by the swimming disciplines and swimming distances, statistically significant values with large effect size were found in males in 50 m freestyle, 200 m individual medley, 100 m butterfly and 200 m butterfly. However, this did not apply for girls. Analysis of differences in performance showed a significant difference between the dependent variables (sex, distance, discipline) by different independent variables of quartile / semester of birth with large effect size only in cases of male 100 m breaststroke and female 200 m individual medley.CONCLUSIONS The issue of RAE should be circulated among the coaches working with youth, athletes, sports organizations, but also parents of athletes in order to avoid the termination of actively spent time or drop-outs