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

2018 ◽  
Vol 12 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Roman Koloničný ◽  
Michal Bozděch ◽  
Jiří Zháněl
Keyword(s):  
Longitudinal Study ◽  
Ice Hockey ◽  
Reference Period ◽  
Chi Square ◽  
Tennis Players ◽  
Relative Age ◽  
Relative Age Effect ◽  
Chi Square Test ◽  
The Impact ◽  
Age Category

The issue of the phenomenon known as RAE first appeared in research within the educational system. In the field of sports research, it first emerged in the 1980s. The theory of RAE is based on the assumption that athletes born in the early months of the year are usually more advanced in both mental and physical fitness. Many studies have confirmed that birthdates of players in sports such as handball, ice hockey or football are distributed asymmetrically in the respective quarters of the year. A high incidence of birthdates has been shown to exist in the first half of the year. The aim of the study was to determine the impact of RAE on Czech tennis players in the age category of 10 – 12. The investigated sample consisted of players (n=1 500) who ranked among the top one hundred in the official ranking of the Czech Tennis Association in the period of 2003 – 2017. In order to verify the conformity of the distribution of the frequency of the players´ birthdates in the sample and the frequency of birthdates among the same population (n=1 506 504) the Chi-Square test (χ2) was used. The results of the study have shown a significant influence of RAE in certain years in the reference age category of 10 – 12, and in thirteen of the fifteen years surveyed. 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.

scholarly journals The Relative Age Effect in Czech U14 Male and Female Tennis Players in 2007–2016

2021 ◽  
Vol 15 (2) ◽  
pp. 50-60
Author(s):  
Roman Koloničný
Keyword(s):  
Goodness Of Fit ◽  
Age Effect ◽  
Goodness Of Fit Test ◽  
Chi Square ◽  
Male And Female ◽  
Tennis Players ◽  
Relative Age ◽  
Relative Age Effect ◽  
Junior Tennis ◽  
The Impact

The issue of the Relative Age Effect (RAE) has been long researched, discussed and published both in the academic and coaching community and the number of studies on it in various sports has significantly grown in recent years. The aim of this study was to verify the existence of RAE among Czech male (n = 6552) and female (n = 4131) junior tennis players and to identify possible differences in birthdate effect between male and female players. The research was carried out in players registered in the years 2007–2016 in the U14 age category in Czech Tennis Association (CTA) database; the athletes were divided into three subgroups (‘Ranked’, ‘Top 100’, ‘Top 10’). Research data were analysed by the methods of descriptive and inferential statistics: relative and absolute frequency, chi-square goodness of fit test () and chi-square test of independence () with the use of effect size (ES index w). A declining tendency of frequencies from Q1 to Q4 between male and female junior players was proven in all three subgroups.In the whole period of 2007–2016, a significant and strong RAE was demonstrated only in the ‘Top 10’ male subgroup (RAE was significant and ES was small or trivial in the other two subgroups). Among the female players, RAE was significant in all three subgroups (ES was small or trivial). Gender differences in RAE in favour of male players were significant in ‘Top 100’ and ‘Ranked’ (ES was small or trivial in all three subgroups). In the short and long term, RAE can have significant implications for the sport development of athletes; both coaches and the professional public can therefore be recommended to pay attention to this issue. The impact of RAE in sport, i.e. the uneven distribution of athletes’ birthdates, is more pronounced especially among junior athletes and often significantly affects their sports development and career.

The Relative Age Effect in Top100 Female Tennis Players (2014–2018)

2020 ◽  
Author(s):  
Adrián Agricola ◽  
Michal Bozděch ◽  
Martin Zvonař ◽  
Jiří Zháněl
Keyword(s):  
Statistical Analysis ◽  
Effect Size ◽  
Age Effect ◽  
Chi Square ◽  
Tennis Players ◽  
Relative Age ◽  
Relative Age Effect ◽  
Small Influence ◽  
Chi Square Test ◽  
Medium Influence

The theory of Relative Age Effect (RAE) works on the assumption that athletes born at the beginning of a calendar year are more successful than athletes born in the end of the year. The athletes born early have a significant probability of a higher level of physiological, mor-phological and psychological abilities than later born athletes. Several studies show that the RAE was not found in females or it was significantly lower than in males. The research objective was to find out the influence of RAE in WTA Tour TOP100 female professional tennis players (n=500) in 2014–2018. Cohen’s effect size (ES) w was calculated to assess the level of the influence of RAE. To assess the differences between the observed and the expected relative age quarter distribution, Chi-Square test (ꭕ2) was used. In terms of effect size (ES), a medium influence of RAE has been proven in 2016 and 2017 (w = 0.33, resp. w = 0.30); a small influence has been proven in years 2014, 2015, 2018 and in the whole observed period 2014–2018. Based on statistical analysis, the influence of RAE cannot be rejected in years 2016 (p 0.05). The next step was to assess the influence of RAE on the final WTA ranking in 2014–2018. Players have been divided into four intervals: 1–25, 26–50, 51–75 and 76–100 positions. ES has showed the medium influence of RAE in 76–100 positions (w = 0.34); only small influence of RAE was found in other positions. Statistical analysis showed that the influence of RAE cannot be rejected in 1–25, 26–50 and 76–100 positions (p < 0.05): it can be rejected in 54–75 positions. The results of the research have shown the medium influence of RAE in 2016 and 2017: in the recent years (and in the whole observed period of 2014–2018), the influence of RAE was small. The influence of RAE on the final WTA ranking is also small, except the 76–100 positions.

scholarly journals Distribuição do mês de nascimento e medidas antropométricas de jogadores de futebol de elite nacional sub-15

2018 ◽  
Vol 20 (2) ◽  
pp. 211-218 ◽  
Author(s):  
Juliana Melo Altimari ◽  
Henrique Bortolotti ◽  
Nelson Dos Santos-Junior ◽  
Leandro Ricardo Altimari ◽  
Antonio Carlos de Moraes
Keyword(s):  
Body Mass ◽  
Soccer Players ◽  
Birth Date ◽  
Chi Square ◽  
Significance Level ◽  
Relative Age ◽  
Relative Age Effect ◽  
Birth Month ◽  
Chi Square Test ◽  
Selection Of

The aim of this study was to analyze the birth month distribution and anthropometric measurements of U-15 elite soccer players. The sample consisted of 400 athletes (15.4 ± 0.4 years, 171.0 ± 10.6 cm and 63.0 ± 8.8 kg) participants of the 11th edition of the Brazil U-15 Soccer Cup, who had their birth month information and height and body mass measures obtained from data available on the organization’s website. Athletes were separated according to the categorization of chronological age into four-month periods: 1st quarter (1st QDT), athletes born between January and April; 2nd quarter (2nd QDT), those born between May and August, and 3rd quarter (3rd QDT), those born between September and December. The non-parametric chi-square test (X2) was used to analyze the possible differences between observed and expected birth date distributions in the four-month periods. The significance level was P<0.05. The results show that the number of players born in 1st QDT was higher when compared to 2nd QDT and 3rd QDT (P<0.05), and higher when compared to 2nd QDT with 3rd QDT (P<0.05). For variables height and body mass, it was observed that players born in 1st QDT presented values significantly higher than those born in 2nd QDT and 3rd QDT (P<0.05). In the same way, players born in 2nd QDT presented higher values than those born in 3rd QDT (P<0.05).It could be concluded that the relative age effect exerts an influence on the selection of Brazilian U-15 soccer players because it is associated with differences in the anthropometric characteristics of these young players.

scholarly journals RELATIVE AGE EFFECT AMONG YOUNG CROATIAN TAEKWONDO COMPETITORS

2021 ◽  
pp. 86-89
Author(s):  
Matej Babić ◽  
Dražen Čular ◽  
Igor Jelaska
Keyword(s):  
Age Effect ◽  
Chi Square ◽  
Weight Category ◽  
Relative Age ◽  
Relative Age Effect ◽  
Significant Difference ◽  
Chi Square Test ◽  
Age Range ◽  
Effect Of Age ◽  
Selection Of

Aim of this research was to identify and analyse relative age effect (RAE) on sample composed of young Croatian taekwondo competitors. In order with aim of research, for medal winners (n1=72) and other competitors (n2=187) who competed at Croatian taekwondo cadet championship 2015, date of birth, weight category and sport success were extracted. By conducting of Chi-square test on all competitors (n=259) it is proven there is non-significant difference (χ2=12.28; p=0.34) between expected and observed frequencies according to month of birth. Furthermore, significant difference between observed and expected frequencies according to year of birth of medal winners (χ2=45.31; p<0.01) is confirmed. Results of this research are pointing on presence of RAE which could lead to mistakes in selection of young athletes. Authors are suggesting to minimize allowed age range for competition, or to separate competitors in more age categories, which would enable more equal competitions and reduce effect of age on sport success.

scholarly journals Efecto de la edad relativa en la élite del balonmano femenino español y su relación con aspectos antropométricos, de rendimiento y velocidad de lanzamiento.

2021 ◽  
Vol 21 (2) ◽  
pp. 213-226
Author(s):  
Carmen Ferragut ◽  
Helena Vila ◽  
Juan J. Fernández ◽  
Miguel Ángel Saavedra García
Keyword(s):  
Physical Fitness ◽  
Age Effect ◽  
Chi Square ◽  
Squat Jump ◽  
National Team ◽  
Relative Age ◽  
Relative Age Effect ◽  
Chi Square Test ◽  
The Subject

El efecto de la edad relativa es un aspecto de relevancia en el deporte en general y en balonmano en particular. Ha sido objeto de gran cantidad de estudios centrados mayoritariamente en deporte masculino. Los estudios sobre la edad relativa en balonmano femenino, no son tan numerosos, y no aclaran el efecto de la misma en esta modalidad deportiva. Por ello, el objetivo de este estudio fue determinar la existencia del efecto de la edad relativa en jugadoras de élite de balonmano, así como valorar dicho efecto en función de variables antropométricas, de condición física y técnico tácticas (velocidad de lanzamiento). Han sido evaluadas 136 jugadoras de balonmano de los ocho primeros equipos de división de honor. Se ha encontrado un efecto de la edad relativa (con la prueba de chi-cuadrado) en las jugadoras de balonmano, sustentado por aquellas que formaron parte de los equipos nacionales. No se encontraron efectos de la edad relativa en las variables antropométricas, ni en las velocidades de lanzamiento con y sin interacción. La lateralidad y el Squat Jump (SJ), presentaron un efecto de la edad relativa. El efecto de la edad relativa es importante para llegar a la selección, pero para jugar en la máxima categoría el efecto de la edad relativa no es tan importante. Son necesarios más estudios sobre el efecto de la edad relativa en el balonmano femenino. Relative age effect is an aspect of relevance in sport in general and in handball in particular. It has been the subject of a great number of studies focused largely on men's sport. Studies on relative age in female handball are not so numerous, and do not clarify the effect of female handball on this sport. Therefore, the aim of this study was to establish the effect of relative age on élite handball players, as well as to assess this effect based on anthropometric variables, physical fitness and technical and tactical skills (throwing speed). 136 handball players from the first eight honour division teams have been assessed. A relative age effect has been found (with chi-square test) in the handball players supported by those included in national teams. No effects of relative age were found on anthropometric variables, nor on throwing speed with and without interaction. Laterality and Squat Juam (SJ) presented a relative age effect. Relative age is important to reach the national team, but to play in the highest category the effect of relative age seems to lose weight Further studies on the effect of relative age on women's handball are needed. O efeito da idade relativa é um aspecto de relevância no desporto em geral e no andebol em particular. Tem sido objeto de elevado número de estudos centrados em grande parte no andebol masculino. Os estudos sobre a idade relativa no andebol feminino, não são tão numerosos, e não clarejam o efeito da mesma nesta modalidade esportiva. Por isso, o objetivo deste estudo foi determinar a existência do efeito da idade relativa em jogadoras de élite de andebol, assim como valorar este efeito em função das variáveis antropométricas, de condição física e técnico-táticas (velocidade de remate). Foram avaliadas 136 jogadoras de andebol das oito primeiras equipas da divisão de honra. Encontrou-se um efeito de idade relativa (foi usado o teste qui-quadrado) nas jogadoras de andebol sustentado pelas que participam nas seleções nacionais. Não se encontrou efeitos de idade relativa nas variáveis antropométricas, nem na velocidade de remate com e sem interação. A lateralidade e o Squat Juam (SJ) apresentaram um efeito de idade relativa. A idade relativa é importante para chegar às seleções, mas para jogar na categoria máxima o efeito da idade relativa parece perder significado. São necessários mais estudos sobre o efeito da idade relativa no andebol feminino.

scholarly journals Simulation of Virtual Reality and its Impact on Competitive State Anxiety and Level of Performance of Table Tennis Players

2015 ◽  
Vol 9 (2) ◽  
pp. 325
Author(s):  
Mervat Deeb ◽  
Tawfeeq Albakry
Keyword(s):  
Virtual Reality ◽  
Training Program ◽  
State Anxiety ◽  
Positive Impact ◽  
Sports Psychology ◽  
Table Tennis ◽  
Chi Square ◽  
Tennis Players ◽  
Chi Square Test ◽  
The Impact

This study aimed at exploring the impact of using a training program which employs simulation of virtual reality on competitive state anxiety; and the level of performance of the table tennis players in Jordan and Saudi Arabia. The sample consisted of 10 players (age 13–15 years); with five players purposefully selected from each country. The researchers administered the training program, using the immersive and nonimmersive virtual reality for 6 weeks 5 times a week. Competitive state anxiety inventory "CSAI-2" and a questionnaire for evaluating the performance in the "fore-hand drive" were used. The data were analyzed, using Mann–Whitney U test, Wilcoxon signed ranks test; and Chi square test. The results indicated that the program with simulation of virtual reality had a positive impact on the study parameters as the post measurement was significantly greater than the pre training measurement. In light of the results, the researchers recommended modern technological devices be used in sports psychology. Also, immersive simulation of virtual reality is recommended. 

scholarly journals The impact of COVID-19 related national lockdown on ophthalmic emergency in Italy: A multicenter study

2021 ◽  
pp. 112067212110280
Author(s):  
Maria L Salvetat ◽  
Carlo Salati ◽  
Patrizia Busatto ◽  
Marco Zeppieri
Keyword(s):  
Gender Bias ◽  
Tertiary Care ◽  
Lower Number ◽  
Electronic Records ◽  
Chi Square ◽  
Efficient Access ◽  
Chi Square Test ◽  
Unpaired Student ◽  
The Impact ◽  
Wet Amd

Purpose: To assess ocular pathologies admitted to Italian Emergency Eye Departments (EEDs) during the COVID-19 pandemic national lockdown in 2020 in comparison with the same period in 2019. Methods: Electronic records of all patients presenting at EEDs of two tertiary-care Eye Centers during the COVID-19 national lockdown in Italy (March 10–May 3, 2020) were compared with the equivalent period in 2019. Main outcomes were patient age, gender, and diagnoses. Statistical analysis included unpaired Student t-tests, Poisson regression, and chi-square test. Results: Overall EED visits significantly decreased by 54.1% during the 2020 lockdown compared to 2019 (851 vs 1854, p < 0.001). During lockdown, patients showed comparable mean age (52.8 years in 2020 vs 53.3 years in 2019, p = 0.52) and significant male gender bias (61.1% in 2020 vs 55.8% in 2019, p < 0.0001). The most frequent pathologies were eye inflammations, trauma-related incidents, and spontaneous acute vitreous detachment. Patients with inflammation, headache/hemicrania, and spontaneous subconjunctival hemorrhages were significantly less, whereas those with trauma-related diagnoses were significantly higher during the lockdown as compared with 2019 ( p < 0.05). The proportion of non-urgent visits decreased from 17% in 2019 to 8% in 2020 ( p < 0.001). Conclusions: During the 2020 lockdown, there was a significant reduction of accesses to EED, especially for non-urgent pathologies. Potentially visual function threatening conditions, such as trauma-related pathologies, retinal detachment or ruptures, and wet AMD, showed lower number of cases but higher or stable proportion relative to the total caseload, suggesting a correct and efficient access to ophthalmic health care during the pandemic period.

Relationship between new farming practices and chemical use and the consumption of giant cricket (Brachytrupes membranaceus Drury, 1770)

2018 ◽  
Vol 4 (4) ◽  
pp. 295-300 ◽  
Author(s):  
F.O. Miantsia ◽  
F. Meutchieye ◽  
S. Niassy
Keyword(s):  
Food Source ◽  
Farming Practices ◽  
Smallholder Farming ◽  
Chi Square ◽  
Pesticides Residues ◽  
Intensive Use ◽  
Chi Square Test ◽  
Dependence Relationship ◽  
The Impact ◽  
Persistent Pesticides

The current work is aimed at generating information on giant crickets and the impact of commonly used pesticides on the natural population of these crickets. Data was collected based on interviews and complemented with field observations. Out of 319 respondents surveyed, 290 were aware of the use of the giant cricket as a food source, and 161 were active consumers. Regarding the availability of the giant cricket, respondents reported that the crickets’ populations were diminishing because of farming practices. About 219 persons reported that commonly used herbicides harm giant crickets at different stages. This could be attributed to the scarcity of this species, as mentioned by 233 respondents. The results showed that 130 respondents were engaged in gathering giant crickets for consumption. This insect gathering is related to soil tilling. Chi-square test showed a significant dependence relationship between herbicides use and cricket scarcity. Although less than a majority (129) of respondents are making regular use of persistent pesticides (herbicides), it has been observed that intensive use of pesticides could become a popular practice in smallholder farming categories. This paper thus suggests the need for training and surveillance concerning the trade of pesticides in the region and proposes further investigations into pesticides residues or traces in collected giant crickets consumed in the study site and in all areas with similar conditions.

scholarly journals A Study on the impact of Coping Strategies over Stress Management – An Empirical Study

2021 ◽  
Vol 12 (3) ◽  
pp. 5566-5573
Author(s):  
Ch.Narahari Et. al.
Keyword(s):  
Statistical Analysis ◽  
Empirical Study ◽  
Stress Management ◽  
Emotional Support ◽  
Positive Emotion ◽  
Software Industry ◽  
Total Sample ◽  
Chi Square ◽  
Chi Square Test ◽  
The Impact

In the present study we analyze the employees’ perception towards coping measures adopted byfirms in software industry. The considered coping constructs adopted for the study in stress abatement areVenting of Emotions,Problem Focused, Seeking Information and emotional support, Positive Emotion-Focused, were, employee perception was acquired by a systematic survey.A total sample of 800 employees’perceptions have been collected through simple random technique and out of which survey respondents, irregular responses are eliminated finally 756 samples are determined for statistical analysis. Chi-square test was performed to determine the association between perceptions and model constructs. Results are reported and discussions are made as per the results and in correlation between results of previous literature.Finally, suggestions and future indication for extension of the study are proposed.

scholarly journals The Perceived Demands of Ice Hockey Goaltending Movements on the Hip and Groin Region: An Elite Coach and Player Perspective

2021 ◽  
Vol 9 (11) ◽  
pp. 232596712110556
Author(s):  
Tobias Wörner ◽  
Ryan J. Frayne ◽  
Thomas Magnusson ◽  
Frida Eek
Keyword(s):  
Injury Prevention ◽  
Study Design ◽  
Online Survey ◽  
Likert Scale ◽  
Ice Hockey ◽  
Cross Sectional Survey ◽  
Hip Joints ◽  
Chi Square ◽  
Cross Sectional ◽  
Chi Square Test

Background: Many ice hockey goaltending techniques force hip joints and groin muscles into extreme ranges of motion, which may increase the risk of hip and groin problems. Purpose: To explore how elite goaltenders and goaltending coaches perceive the demands of common goaltending techniques on the hip and groin region. We further explored differences in perception between goaltenders and their coaches as well as between junior (age <20 years) and senior (age ≥20 years) goaltenders. Study Design: Cross-sectional survey. Methods: We developed a model to categorize common ice hockey goaltending techniques into quantifiable units and invited elite goaltenders and coaches in Sweden to complete an online survey. Participants were asked to rate the perceived demands of each technique on the hip and groin using a Likert scale (not at all, slightly, somewhat, very, or extremely demanding). Using the chi-square test, the proportion of participants perceiving each technique as very or extremely demanding were compared between goaltenders and coaches as well as between senior and junior goaltenders. Results: We received responses from 132 goaltenders and 43 coaches. The stances most frequently perceived as very or extremely demanding were the reverse vertical horizontal post-play (40%) and the butterfly save (25%). Among transitions, movements into the post were most frequently rated as very or extremely demanding (11%–40%). Several techniques were perceived as demanding by a larger share of coaches than goaltenders (difference, 13%–46%; P < .001–.028) and a larger share of senior versus junior goaltenders (difference, 12%–20%; P = .13–.18). Conclusion: The post-play and the butterfly were the goaltending techniques most frequently perceived as demanding, and more coaches than goaltenders percieved these techniques demanding. The results of this study may inform injury prevention efforts for ice hockey goaltending.

Sign in / Sign up

Export Citation Format

Share Document