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1.
Abstract

The purpose of this study was to compare measures of body size in two samples of youth baseball players with normative data from the United States National Center for Health Statistics (NCHS) growth charts. One sample of youth baseball players participated in a local little league. The second sample of youth baseball players were members of eight of the twelve teams participating in the 1995 Dixie Youth World Series. Normative data for the United States (NCHS) were used as comparative data. Two trained anthropometrists measured standing height, sitting height, lower limb height, upper limb length, arm girth, calf girth, tricep skinfold, and abdomen skinfold on all participants. In both samples, pitchers, short stops, and first basemen were a more highly skilled group and exhibited larger body size (greater standing height, sitting height, lower limb height, upper limb length) than children who played at other positions. The standing height of local little league players was similar to the median of reference data at ages 7, 8, and 9 years. The standing height and weight of skilled players in both samples approximated the 75th percentile for standing height and weight at ages 10, 11, 12, and 13 years. The results suggest that baseball players exhibit larger body size than the normal population at young ages. Body size may be an important criterion used by coaches to select and assign young players to certain positions.  相似文献   

2.
This study compared the physiological and anthropometric characteristics of specific playing positions and positional playing groups in sub-elite rugby league players. Altogether, 415 sub-elite rugby league players underwent measurements of standard anthropometry (body mass, height, sum of four skinfolds), muscular power (vertical jump), speed (10-m, 20-m, and 40-m sprint), agility ("L" run), and estimated maximal aerobic power (multi-stage fitness test). Props were significantly heavier and had a greater skinfold thickness than all other playing positions. Centres, fullbacks, and hookers were faster than props over 40 m. When the data were analysed according to positional commonality, props were taller, heavier, had a greater skinfold thickness, were less agile, and were slower over 10 m than all other positional groups. The hookers/halves and outside backs positional groups were significantly faster over 40 m than the backrowers and props positional groups. In addition, the hookers/halves and outside backs positional groups had significantly greater estimated maximal aerobic power than the props positional group. The results of this study demonstrate that few physiological and anthropometric differences exist among individual playing positions in sub-elite rugby league players, although props are taller, heavier, have greater skinfold thickness, slower 10-m and 40-m speed, less agility, and lower estimated maximal aerobic power than other positional groups. These findings provide normative data for sub-elite rugby league players competing in specific individual positions and positional playing groups.  相似文献   

3.
Abstract

This study compared the physiological and anthropometric characteristics of specific playing positions and positional playing groups in sub-elite rugby league players. Altogether, 415 sub-elite rugby league players underwent measurements of standard anthropometry (body mass, height, sum of four skinfolds), muscular power (vertical jump), speed (10-m, 20-m, and 40-m sprint), agility (“L” run), and estimated maximal aerobic power (multi-stage fitness test). Props were significantly heavier and had a greater skinfold thickness than all other playing positions. Centres, fullbacks, and hookers were faster than props over 40 m. When the data were analysed according to positional commonality, props were taller, heavier, had a greater skinfold thickness, were less agile, and were slower over 10 m than all other positional groups. The hookers/halves and outside backs positional groups were significantly faster over 40 m than the backrowers and props positional groups. In addition, the hookers/halves and outside backs positional groups had significantly greater estimated maximal aerobic power than the props positional group. The results of this study demonstrate that few physiological and anthropometric differences exist among individual playing positions in sub-elite rugby league players, although props are taller, heavier, have greater skinfold thickness, slower 10-m and 40-m speed, less agility, and lower estimated maximal aerobic power than other positional groups. These findings provide normative data for sub-elite rugby league players competing in specific individual positions and positional playing groups.  相似文献   

4.
In this study we compared the kinematic features of the throwing motion between young baseball players of different age groups. Forty-four Japanese baseball players aged 6.1 to 12.3 years who regularly played baseball, including pitchers and position players, had their throwing actions analyzed three-dimensionally using high speed videography. Of this sample, 26 players aged above 9 years of age were categorized as the senior group, while the remaining 18 were categorized as the junior group. Senior group throwers had greater height and body mass, and produced a greater ball speed than junior group throwers. The throwing arm movement of senior group throwers was similar to that of adult skilled players. However, in the junior group throwers, the shoulder horizontal adduction angle was larger during the arm acceleration phase, and the maximum angular velocities of elbow extension and shoulder internal rotation occurred later than in senior group throwers. These results indicate that players aged above 9 years can acquire a mature throwing arm movement, while players younger than that will use an immature motion. A possible reason why these differences were shown is that the official baseball is relatively heavy for junior group throwers; they would be better advised to use a lighter ball in throwing practice.  相似文献   

5.
There is limited research in talent identification in youth Australian Football (AF), especially the factors that underpin selection into higher-level development programs. Therefore, this study explored age-related differences in high-level youth AF players and investigated characteristics influencing selection into a high-level development program. Anthropometry (stature, sitting height, body mass), maturity (estimated age at peak height velocity), motor competence (Körperkoordinationstest für Kinder), fitness (change of direction speed, lower body power and upper body muscular endurance) and coach skill ratings (kicking, marking and handballing) of 277 state academy players (U13-U15) were assessed. MANOVAs identified significant age-related differences for anthropometry, fitness, and coach skill ratings. Furthermore, 90.9 and 90.0% of U15 selected and deselected players were classified correctly. Selected players were more mature, taller, heavier, more explosive, faster at changing directions, and had superior kick technique and marking results. These results demonstrate considerable age-group performance outcome differences, highlighting that high-level academies should aim to select or deselect after 15 years of age. Additionally, it appears earlier maturing players are favoured for selection into a high-level academy. While practitioners must consider the confounding effect of maturation, early maturing players may be favoured for their ability to withstand increasing demands in higher-level youth AF.  相似文献   

6.
This study addressed the question, what should baseball players focus their attention on while batting? Less-skilled and highly skilled (college) baseball players participated in four dual-task conditions in a baseball batting simulation: two that directed attention to skill execution (skill/internal [movement of the hands] and skill/external [movement of the bat]) and two that directed attention to the environment (environmental/irrelevant [auditory tones] and environmental/external [the ball leaving the bat]). Batting performance for highly skilled players was best in the environmental/external condition and worst in the skill/internal condition. Performance of less-skilled batters was significantly better in the two skill conditions than in either of the two environmental conditions. We conclude that the optimal focus of attention for highly skilled batters is one that does not disrupt proceduralized knowledge and permits attention to the perceptual effect of the action, whereas the optimal focus of attention for less-skilled batters is one that allows attention to the step-by-step execution of the swing.  相似文献   

7.
The relative age effect (RAE) is a well-established phenomenon in education and sports. Coaches have been assumed to be important social agents of RAE via biased selection decisions in favour of children with maturation advantages. In the present research, we used the Implicit Association Test to investigate automatic associations between body size and a player’s domain-specific giftedness amongst youth baseball (N = 18) and youth soccer coaches (N = 34). We found medium to strong automatic associations between body size and player giftedness (baseball: MD = 0.62; soccer: MD = 0.51). Specifically, taller players were associated with positive performance-related attributes, whereas smaller players were associated with negative attributes. The results are in line with theories of grounded cognition by showing that the abstract concept of “sport giftedness” is partly grounded in the perception of physical height amongst youth sports coaches. We argue that this grounded cognition has the potential to influence coaches’ selection decisions and in turn account for RAE as coaches are biased towards physically more matured players, even when no apparent performance advantage is evident.  相似文献   

8.
This study investigated differences in generic and soccer specific motor coordination, as well as speed and agility depending on age and maturity in elite youth soccer players (U10-U15, N = 619). Measurements included body height, body weight and sitting height to estimate age at peak height velocity (APHV); three Körperkoordinationstest für Kinder subtests (i.e. jumping sideways (JS), moving sideways (MS), balancing backwards (BB)) to assess generic motor coordination; the UGent dribbling test for soccer specific motor coordination; a 5m/30m sprint and T-test for speed and agility, respectively. Age specific z-scores of the predicted APHV identified players as earlier, on time or later maturing. (M)ANOVA analyses showed significant age by maturity interaction effects for the speed and agility test cluster, revealing maturity related differences in U14 and U15 players. Next to an overall higher performance with age for all test clusters (η2 0.080–0.468), earlier maturing players outperformed their later maturing peers in 5m/30m sprinting. The opposite was seen for JS and BB. So, players’ maturity status should be taken into account to adequately value performance in talent identification. Also, the focus on characteristics that appear to be minimally biased by an earlier maturational timing (i.e. motor coordination) should be increased.  相似文献   

9.
Abstract

In this study we compared the kinematic features of the throwing motion between young baseball players of different age groups. Forty‐four Japanese baseball players aged 6.1 to 12.3 years who regularly played baseball, including pitchers and position players, had their throwing actions analyzed three‐dimensionally using high speed videography. Of this sample, 26 players aged above 9 years of age were categorized as the senior group, while the remaining 18 were categorized as the junior group. Senior group throwers had greater height and body mass, and produced a greater ball speed than junior group throwers. The throwing arm movement of senior group throwers was similar to that of adult skilled players. However, in the junior group throwers, the shoulder horizontal adduction angle was larger during the arm acceleration phase, and the maximum angular velocities of elbow extension and shoulder internal rotation occurred later than in senior group throwers. These results indicate that players aged above 9 years can acquire a mature throwing arm movement, while players younger than that will use an immature motion. A possible reason why these differences were shown is that the official baseball is relatively heavy for junior group throwers; they would be better advised to use a lighter ball in throwing practice.  相似文献   

10.
Abstract

Nine- to 10-year-old children have difficulty playing baseball using adult rules because pitchers lack the ability to throw the ball over the plate with consistency and batters lack ability to hit erratically thrown balls. Thus a natural field experiment investigated a modification of adult baseball for 9- to 10-year-old children. Instead of one of the players on the opposing team pitching, the coach of the offensive team pitched to the batters. Teams in a league who played baseball by adult rules (traditional league) were compared with teams in a league who played the modified game (nontraditional league), and both these leagues were compared with 11- to 12-year-old teams (older league). Various offensive and defensive activities were recorded by two observers and satisfaction scores were obtained from the players after the games. More offensive and defensive activity occurred in the nontraditional league games than in the traditional and older league games.  相似文献   

11.
In this study, we investigated the relationship between physiological, anthropometric, and skill qualities and playing performance in professional rugby league players. Fifty-eight high-performance rugby league players underwent measurements for anthropometry (height, body mass, sum of seven skinfolds), physiological (speed, change of direction speed, lower body muscular power, repeated-sprint ability, prolonged high-intensity intermittent running ability, and estimated maximal aerobic power), technical skill (tackling proficiency, draw and pass proficiency), and perceptual skill (reactive agility, pattern recall, pattern prediction) qualities. National Rugby League matches were coded for attacking (e.g. line breaks, try assists, etc.) and defensive (e.g. missed tackles, tackling efficiency, etc.) statistics commonly used to assess rugby league playing performance. The number of line break assists was significantly associated (P < 0.05) with greater playing experience (r = 0.36), dual-task draw and pass proficiency (r = 0.54), reactive agility (r = 0.29), and pattern recall (r = 0.32) and prediction (r = 0.28) ability, while faster speed over 40 m (r = -0.42) was associated (P < 0.05) with a higher number of tries scored. Greater age and playing experience, better lower body muscular power, and faster 10 m and 40 m speed were significantly associated (P < 0.05) with the number of tackle attempts (positive), tackles completed (positive), and proportion of missed tackles (negative). These findings demonstrate that well-developed physical and skill qualities are associated with effective playing performance in National Rugby League players.  相似文献   

12.
The primary purpose of this study was to investigate the effect of the place of early development in a sample of Danish male elite and youth handball and football players. The sample included 366 handball and football players from the elite Danish league in the season 2011–2012 and a comparison sample of youth players under the age of 12 from 2003, including 147,221 football and 26,290 handball players. Odds ratio analysis showed that both population size and density significantly affected the proportional number of youth players per community and the odds of athletes reaching an elite level in football and handball. The odds for youth player registrations in both handball and football increased in rural in contrast to urban communities. However, elite football players primarily came from communities of high density (>1000 pop./km2), whereas elite handball players primarily came from less densely populated communities (100 to <250 pop./km2). Furthermore, there seems to be a relation between representation of elite and talent clubs in different communities and the probability of becoming an elite player in both sports. The limited number of elite players in both sports from rural communities may be due to national talent development strategies that do not incorporate development support for clubs in rural areas. Additionally, the results of the study clearly suggest the need to include the youth player population to advance research findings in birthplace effect studies.  相似文献   

13.
Abstract

The aim was to analyse the physical growth and body composition of rhythmic gymnastics athletes relative to their level of somatic maturation. This was a cross-sectional study of 136 athletes on 23 teams from Brazil. Mass, standing height and sitting height were measured. Fat-free and fat masses, body fat percentages and ages of the predicted peak height velocity (PHV) were calculated. The z scores for mass were negative during all ages according to both WHO and Brazilian references, and that for standing height were also negative for all ages according to WHO reference but only until 12 years old according to Brazilian reference. The mean age of the predicted PHV was 12.1 years. The mean mass, standing and sitting heights, body fat percentage, fat-free mass and fat mass increased significantly until 4 to 5 years after the age of the PHV. Menarche was reached in only 26% of these athletes and mean age was 13.2 years. The mass was below the national reference standards, and the standing height was below only for the international reference, but they also had late recovery of mass and standing height during puberty. In conclusion, these athletes had a potential to gain mass and standing height several years after PHV, indicating late maturation.  相似文献   

14.
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15.
The interaction of multiple influences on the path to sport success is not yet fully understood by sport scientists. In this study, we examined variation in body size, functional capacities and motivation for achievement, competitiveness and deliberate practice of youth basketball players associated with differences in biological maturity status, chronological age and years of training experience. Reflecting the importance of interactive effects, we examined the relationships between the psychological variables and functional capacities. Fifty-eight male basketball players aged 9.5 to 15.5 years were considered. Variables included chronological age, estimated age at peak height velocity, stature, body mass and sitting height by anthropometry; the Work and Family Orientation and Deliberate Practice Motivation Questionnaires were also used. Finally, the Line Drill test and Yo-Yo Intermittent Recovery level 1 (Yo-Yo IR1) tests were used as functional capacities indicators for basketball. Variance components models derived from series of multilevel linear regression models revealed a substantial variation by maturity status for body size, functional capacities indicators, mastery and will to excel. The influence of estimated maturity status on mastery and will to excel was independent of age and years of experience. In contrast, no relationships were observed between psychological variables and functional capacities indicators. We conclude that growth-related changes are relevant to understanding players´ motivations for achievement, competitiveness and deliberate practice. This should be of interest to those involved in the selection and development of youth basketball players.  相似文献   

16.
ABSTRACT

The purpose of this study was to examine the variation in accumulated basketball training experience, body size, functional performance, deliberate practice motivation, achievement and competitiveness motivation and sources of enjoyment among young female basketball players, partitioning the potential variation by individuals´ biological characteristics (menarche status) and contextual characteristics (competitive age group and competitive level). We considered 114 adolescent female basketball players aged 14.3 (1.8) years. We used multilevel regression and poststratification estimations. The adolescent female basketball players selected for state-level had more accumulated experience, were taller and with better functional performance. Conditional on the data, youth female coaches tend to value (probably overvalue) size and function when selecting/promoting players, even at early age groups, likely contributing to an overrepresentation of early maturing girls in at early age groups. Players from club- and state-level were similarly highly motivated for deliberate practice and to achievement. Only for competitiveness, state-level players had higher values than club level players. The sources of enjoyment were influenced by context (competitive levels) for self-referenced competencies and others-referenced competencies. Structured programs of training and competition in youth female basketball provide a nurturing environment for the development of players´ engagement and commitment to training and excellence attainment.  相似文献   

17.
对2013~2014赛季中国男排联赛运动员年龄、身体形态、网上高度与2013世界男排联赛运动员进行比较,结果表明:我国联赛运动员的整体年龄偏小,年龄层次结构不合理;身高无显著性差异,但我国2m以上运动员所占比例较低,体重、克托莱指数的差异非常显著,身高与体重的发展不协调;扣球高度、拦网高度指标显示我国在网上高度方面具有一定的实力。  相似文献   

18.
Abstract

This study investigated the relationship between the physical abilities of adolescent rugby league players and tackling and ball-carrying skills performed during matches, across three seasons (under-15 to under-17). The players were measured each season for acceleration (10–30 m), peak and mean speed (10–30 m), sprinting force (10–30 m), aerobic power, counter-movement jump (CMJ) height and jumping power. The matches were filmed and analysed for ball-carrying and tackling frequency per minute (successful and unsuccessful outcomes). There were strong relationships between successful carries?min–1 and 10 m force in the under-15 (R = 0.61, P < 0.001), under-16 (R = 0.69, P < 0.001) and under-17 groups (R = 0.64, P < 0.001). There were also strong and moderate relationships between predicted vertical power and successful carries?min–1 in the under-15 (R = 0.63, P = 0.011) and under-17 group (R = 0.40, P = 0.030), respectively. There were no relationships between carries or tackles and any other performance indicators. These findings suggest that acceleration, in accordance with gains in body mass, support ball-carrying but not tackling performance. Performance measurements, such as CMJ or aerobic power, do not support ball-carrying ability among youth rugby league players.  相似文献   

19.
《Sport Management Review》2020,23(3):536-547
The identification and development of players in English professional football has become an increasingly significant topic of debate given the historical perceived underperformance of the English national team at international tournaments. To enhance understanding of the challenges and barriers experienced by English youth footballers, the authors explore the developmental experiences of English professional football players from different levels of the English football pyramid. Professional players (N = 11) from football clubs in the top four professional divisions in England took part in individual semi-structured interviews, which were analysed inductively using thematic analysis. The data revealed three interrelated themes that were perceived to mediate player identification and development pathways at professional clubs. Pathways for young players to progress and experience first-team competitive football differed when the level of the league that the players operated within was considered, with significant issues also raised relating to the suitability of the under 21 league structure, the importance attached to the educational welfare of young players, and variations in the identification of player attributes. This study sheds new light on the priorities and processes of talent development and education provision in English football.  相似文献   

20.
Sean F. Brown 《Sport in Society》2018,21(10):1544-1557
Abstract

When parent relationships form within the context of a youth baseball league, they can and often do facilitate the exchange of benefits to one or more parties, a phenomenon known as social capital. Based on 18 months of fieldwork, approximately 30 interviews, and innumerable casual conversations with parents and league officials, I explore the specific types of resources that were typically shared between parents of a youth baseball league in the American Southwest. I uncovered four specific types of benefits that parents offered and accepted as a result of the relationships they cultivated during baseball seasons: emotional support, information sharing regarding goods and services about town, job information sharing, and childcare.  相似文献   

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