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1.
Abstract

The relationship between junior boys' tennis success, as measured by a top 20 International Tennis Federation's Junior Circuit (ITFJC) ranking, and subsequent ranking accomplishments in professional men's tennis is discussed. The names, countries, and birthdates of all players to achieve a top 20 ITFJC boys' year-end ranking from 1992 to 1998 were recorded. The progress of these players through the professional ranks was then tracked to the end of 2004. Results indicate that 91% of top 20-ranked boys achieved a professional men's ranking, while a stepwise regression analysis revealed junior ranking (JR) to be a predictor of future, professional ranking (β = 0.232, r 2 = 0.054, p < 0.05). A regression equation [predicted professional rank = 78.17 + 6.31?(JR)] accounted for a significant amount of variance in professional ranking. For male players, therefore, the achievement of a top 20 junior ranking appears to be a reasonable yardstick for future, professional success. The type of surface upon which junior players develop their games was also shown to influence professional ranking highs, with play on clay courts or a combination of clay and hard courts helping to produce higher, professionally ranked players than hard court play alone (p≤ 0.01).  相似文献   

2.
This study aimed to identify attributes that discriminate selected from non-selected players and predict selection into a rugby league development programme in older adolescent players. Anthropometric, performance and psychological attributes were measured in under-16 (N = 100) and under-18 (N = 60) rugby league players trialling for selection into a development programme with a professional Australian club. Sprint times (P < 0.001), predicted VO2max (P = 0.002) and push-ups1 min (P = 0.004) were superior in selected under-16 players, and sprint times (P ≤ 0.045), push-ups1 min (P < 0.001) and chin-ups1 min (P = 0.013) were superior in selected under-18 players. Further, 10-m sprint (β = ?7.706, standard error [SE] = 2.412), VO2max (β = 0.168, SE = 0.052) and body mass (β = 0.071, SE = 0.023) significantly predicted selection (R2 = 0.339) in under-16 players, while push-ups1 min (β = 0.564, SE = 0.250), 10-m sprint (β = ?68.477, SE = 28.107), body mass (β = 0.360, SE = 0.155) and chronological age (β = ?3.577, SE = 1.720) significantly predicted selection (R2 = 0.894) in under-18 players. These findings emphasise the importance of performance attributes in junior rugby league and indicate talent identification test batteries should be age-specific in older adolescent players.  相似文献   

3.
Abstract

The relationship between domestic professional tournament structure in women's tennis and the subsequent professional ranking success of a nation's female players is examined. The 2003 women's professional tennis tournament calendar provided the distribution of events in 33 countries. Criteria used to classify nations' success in women's professional tennis were as follows: number of players with Women's Tennis Association (WTA) points, number of players with Top 200 rankings, and the combined WTA ranking of a nation's Top 5 female players. Pearson product – moment correlations were performed between the number of tournaments and the three criteria. Considerable variation was observed in the number of events organized between nations (USA, n = 56; Thailand, n = 3). All countries had internationally ranked female players, and 24 nations had players ranked in the Top 200. Results revealed relationships between a nation's number of women's professional events and both that nation's number of professionally ranked players (r = 0.60; P < 0.01) and Top 200 players (r = 0.60; P < 0.01), as well as the combined ranking of their Top 5 players (r = ?0.52; P < 0.01). While a similar association was found between the number of professional events and players ranked in the men's game, there was no significant correlation between events held and the combined standing of nations' best five ranked players. Governing bodies and national associations in tennis should consider the provision of professional, domestic competition as key to the development of female tennis players.  相似文献   

4.
Tennis is an activity requiring both endurance and anaerobic components, which could have immunosuppressive effects postexercise.

Purpose

The purpose of this investigation was to determine the effect of a simulated tennis match on apoptotic and migratory markers on lymphocyte subsets.

Method

Male high school (n = 5) and college (n = 3) tennis players (M age = 18.9 ± 3.3 years) completed 10 sets of a tennis protocol including serves, forehand strokes, and backhand groundstrokes with 1-min rest periods between sets. Apoptosis antigen 1 receptor (CD95) and chemokine receptor fractalkine (CX3CR1) expression was analyzed on helper T lymphocytes (CD4+), cytotoxic T lymphocytes (CD8+), and B lymphocytes (CD19+) twice, at resting baseline and immediately after all 10 sets of the tennis protocol.

Results

An increase was observed in each lymphocyte subtype (p < .02, effect size = .41), and comparison of absolute changes revealed increases in CD4+/CD95+, CD8+/CD95+, and CD8+/CX3CR1 lymphocytes following the tennis protocol (p < .01, effect size = .43), but not in CD19+ cells.

Conclusions

A simulated tennis match has adequate intensity to induce immune modulations in terms of increased cell death and cellular migration in T lymphocyte subsets. Lymphocytopenia following tennis play is influenced by both apoptotic and migratory mechanisms.  相似文献   

5.
The aim of this cross-sectional study was to evaluate the relationships between cognitively engaging exercise (i.e., game-based and coordination exercises), executive functions (i.e., inhibitory control and working memory), and physical fitness. Forty junior tennis players (6–12 years old), who regularly participated in tennis lessons (2.55 years, SD = 1.61) prior to the study, were investigated. All participants completed evaluations of executive functions (inhibitory control and working memory) at rest. The duration of each lessons’ instructional activities, including coordination training, game-based exercise, rallying, and non-physical activity (explanations and breaks), was recorded. Physical fitness was evaluated using the Tennis Field Test. A longer duration of game-based exercise was positively correlated with inhibitory control and physical fitness. Coordination training was associated with improved working memory. Non-physical activity was inversely correlated with inhibitory control, working memory, and physical fitness. The results suggest that game-based tennis lessons have beneficial effects on inhibitory control and physical fitness levels, and a longer duration of coordination training is associated with better working memory. The present study indicates that shortened non-physical activity time within a sports setting is associated with the development of executive functions and physical fitness.  相似文献   

6.
This study examined sleep-wake habits and subjective jet-lag ratings of 55 German junior rowers (n = 30 male, 17.8 ± 0.5 years) before and during the World Rowing Junior Championships 2015 in Rio de Janeiro, Brazil. Athletes answered sleep logs every morning, and Liverpool John Moore’s University Jet-Lag Questionnaires each evening and morning. Following an 11-h westward flight with 5-h time shift, advanced bedtimes (?1 h, P < .001, ηp2 = 0.68), reduced sleep onset latency (P = .002, ηp2 = 0.53) and increased sleep duration (P < .001, ηp2 = 0.60) were reported for the first two nights. Jet-lag symptoms peaked upon arrival but were still present after 6 days. Sleep quality improved (P < .001, ηp2 = 0.31) as well as some scales of the Recovery-Stress Questionnaire for Athletes. Participation was successful as indicated by 11 of 13 top 3 placings. Overall, the initial desynchronisation did not indicate negative impacts on competition performance. As travel fatigue probably had a major effect on perceptual decrements, sleep during travel and time to recover upon arrival should be emphasised. Coaches and practitioners should consider higher sleep propensity in the early evening by scheduling training sessions and meetings until the late afternoon.  相似文献   

7.
ABSTRACT

The aim of the present study was to determine the factors affecting sports involvement in a school-based adolescent population. The cross-sectional cohort study assessed anthropometry, physical capacities and motor competence in 501 boys (aged 10–16 y), from junior (10–12 y) and senior (13–16 y) cohorts. Sports participation data was collected from junior participants. Multivariate analysis of covariance revealed moderate maturity, anthropometry, physical capacity and motor competence differences between sports in the senior cohort (F = 2.616, p < 0.001, η2 = .08), but not in the junior cohort. Furthermore, differences in physical fitness were revealed between playing levels (F = 2.616, p < 0.001, η2 = .08), with a discriminant analysis correctly classifying 73% of participants using aerobic fitness and vertical jump measures. Representative level participants engaged in more structured training and commenced organised competition at a later age (F = 4.332, p < 0.001, η2 = .21). This study’s findings are twofold: 1) physical and motor competence profiles differ more between sports with increasing age, and 2) participants at a higher level of competition report delayed engagement in their main sport. As a result, schools may be the ideal environment in which to provide children and adolescents with the opportunity to sample different sports.  相似文献   

8.
The aim of this study was to evaluate the reliability of two long jump tasks and their ability to predict 10 m sprint performance in elite adolescent female athletes. Eight junior national-level female track and field athletes completed three standing (SLJ) and reactive long jumps (RLJ) on portable force plates, followed by three 10 m sprints. Intra-class correlation coefficients (ICC) and coefficients of variation (CV) were calculated to examine reliability. Linear regression results identified the best predictor of average and best 10 m sprint time from the jump kinematic and kinetic measures. The ICCs and CVs indicated good reliability for the majority of kinetic measures however, better reliability was reported for the SLJ. The SLJ was a good predictor of best and average 10 m sprint time, with average horizontal power the best predictor of performance (best; R 2 = 0.751, p = 0.003, Standard Error of Estimate (SEE)% = 2.2 average; R 2 = 0.708, p = 0.005, SEE% = 2.5).  相似文献   

9.
This study aimed to test the effects of mental (i.e. executive) load during a dual physical-mental task on ratings of perceived exertion (RPE), affective valence, and arousal. The protocol included two dual tasks with matched physical demands but different executive demands (2-back and oddball), carried out on different days. The procedure was run twice to assess the sensitivity and stability of RPE, valence and arousal across the two trials. Linear mixed-effects analyses showed less positive valence (?0.44 points on average in a 1–9 scale; Rβ2 = 0.074 [CI90%, 0.052–0.098]), and heightened arousal (+0.13 points on average in a 1–9 scale; Rβ2 = 0.006 [CI90%, 0.001–0.015]), for the high executive load condition, but showed no effect of mental load on RPE. Separated analyses for the two task trials yielded best-fitting models that were identical across trials for RPE and valence, but not for arousal. Model fitting was improved by assuming a 1-level autoregressive covariance structure for all analyses. In conclusion, executive load during a dual physical-mental task modulates the emotional response to effort, but not RPE. The autoregressive covariance suggests that people tend to anchor estimates on prior ones, which imposes certain limits on scales' usability.  相似文献   

10.
An emerging area of research has focused on understanding how the group dynamics of a sport team influence positive youth development (PYD). The identities that youth form through their membership in sport teams (i.e., social identities) have been found to influence teammate behavior and team performance. Yet, minimal work exists on social identity and PYD in youth sport. Purpose: The purpose of this study was to investigate the relationship between social identity and PYD in sport. Method: Youth engaged in recreational sport (N = 219; Mage = 11.61 years, SD = 1.39 years) completed measures of social identity and PYD in sport. The social identity measure assessed 3 dimensions including ingroup ties (IGT; perceptions of similarity, bonding, belongingness), cognitive centrality (importance of being a team member), and ingroup affect (IGA; feelings associated with group membership). A regression analysis was performed separately for 4 PYD outcomes (personal and social skills, goal setting, initiative, negative experiences) with the 3 dimensions of social identity entered as predictors. Results: Regression analyses revealed that IGT and IGA were positively associated with personal and social skills (R2 Adj. = .29). Further, IGT predicted initiative (R2 Adj. = .16), whereas IGA was positively associated with goal setting (R2 Adj. = .17) and negatively associated with negative experiences (R2 Adj. = .08). Conclusion: The findings extend previous research highlighting the benefits of social identity on teammate behavior and team performance and demonstrate how social identity may contribute to PYD through sport.  相似文献   

11.
ABSTRACT

Purpose: The theory of planned behavior (TPB) has been criticized for not including interactions between the variables assumed to predict behavior. This study sought to test how TPB variables interact to predict physical activity (PA) in children. Method: Four hundred thirty-eight children (Mage = 8.6 years, SD = 1.6 years) completed a TPB questionnaire and a PA questionnaire at Time 1. The PA measure was repeated 2 months later. Path analyses were performed to test the hypothesized model including interaction terms between TPB variables. Simple slopes analyses were also carried out to examine the statistically significant interaction terms. Results: Path analyses confirmed the classical hypotheses of TPB (R2 for intentions = .39, R2 for PA = .12) and also demonstrated only statistically significant Attitudes × Perceived Behavioral Control and Subjective Norms × Attitudes interactions (R2 change for intentions = .01, p = .009). Simple slopes analyses revealed that the strength of the association between perceived behavioral control and intentions was only statistically significantly higher (t = 2.18, p = .05, d = 0.34, 95% CI [0.03, 0.65]) when attitudes were high compared with when attitudes were low. The link between attitudes and intentions was only statistically significant at a low level of subjective norms but not at a high level. Conclusion: The integration of interaction effects between TPB variables did not increase for the variance of PA explained by the model. More research appears to be necessary to explore how the TPB could be augmented to better predict PA in children.  相似文献   

12.
Official rankings are the most common measure of success in professional women’s tennis. Despite their importance for earning potential and tournament seeding, little is known about ranking trajectories of female players and their influence on career success. Our objective was to conduct a comprehensive study of the career progression of elite female tennis talent. The study examined the ranking trajectories of the top 250 female professionals between 1990 and 2015. Using regression modelling of yearly peak rankings, we found a strong association between the shape of the ranking trajectory and the highest career ranking earned. Players with the highest career peak ranking were the youngest when first ranked. For example, top 10 players were first ranked at age 15.5 years (99% CI = 14.8–15.9), 1.2 years (99% CI = 0.8–1.5) earlier than top 51–100 players. Top 10 players were also ranked in the top 100 longer than other players, holding a top 100 ranking until a mean age of 29.0 years (99% CI = 27.8–30.3) compared with age 24.4 years (99% CI = 23.7–25.2) for top 51–100 players. Ranking trajectories were more distinct with respect to player age than years from first ranking. The present study’s findings will be instructive for players, coaches, and administrators in setting goals and assessing athlete development in women’s tennis.  相似文献   

13.
The purpose of this study was twofold: (1) to determine the gross motor coordination performance levels of junior tennis players and (2) to analyse the effects of age and gender. Participants were junior male (n = 50) and female (n = 51) tennis players aged 6–14. Körperkoordinationstest für Kinder (KTK) was used to assess the gross motor coordination of the participants. Results revealed that none of the participants performed lower than normal level in motor coordination. Besides, 40.6% of the participants performed above normal level. No gender differences were found on all subtests of KTK and also on total motor quotient. Although older players performed better on each test than their younger counterparts for the raw scores, no significant age effect was observed on motor quotient scores among different age groups.  相似文献   

14.
To determine the effect of circadian rhythm on neuromuscular responses and kinematics related to physical tennis performance, after a standardised warm-up, 13 highly competitive male tennis players were tested twice for serve velocity/accuracy (SVA), countermovement vertical jump (CMJ), isometric handgrip strength (IS), agility T-test (AGIL) and a 10-m sprint (10-m RUN). In a randomised, counter-balance order, tennis players underwent the test battery twice, either in the morning (i.e., AM; 9:00 h) and in the afternoon (i.e., PM; 16:30 h). Paired t-tests were used to analyse differences due to time-of-day in performance variables. Comparison of morning versus afternoon testing revealed that SVA (168.5 ± 6.5 vs. 175.2 ± 6.1 km · h?1; P = 0.003; effect size [ES] = 1.07), CMJ (32.2 ± 0.9 vs. 33.7 ± 1.1 cm; P = 0.018; ES = 1.46), AGIL (10.14 ± 0.1 vs. 9.91 ± 0.2 s; P = 0.007; ES = 1.23) and 10-m RUN time (1.74 ± 0.1 vs. 1.69 ± 0.1 s; P = 0.021; ES = 0.67) were significantly blunted during the morning testing. However, IS was not affected by time-of-day (P = 0.891). Thus, tennis performance may be reduced when competing in the morning in comparison to early evening. Therefore, coaches and tennis players should focus on schedule the SVA, power, speed and agility training sessions in the afternoon.  相似文献   

15.
Assessment of movement logging devices is required to ensure suitability for the determination of court-movement variables during competitive sports performance and allow for practical recommendations to be made. Hence, the purpose was to examine wheelchair tennis speed profiles to assess data logger device applicability for court-movement quantification, with match play stratified by rank (HIGH, LOW), sex (male, female) and format (singles, doubles). Thirty-one wheelchair tennis players were monitored during competitive match play. Mixed sampling was employed (male = 23, female = 8). Friedman’s test with Wilcoxon signed-rank post hoc testing revealed a higher percentage of time below 2.5 m · s?1 [<2.5 vs. ≥2.5 m · s?1: 89.4 (5.0) vs. 1.2 (3.5)%, Z = ?4.860, P < 0.0005, r = 0.87] with the remaining time [9.0 (4.9%)] spent stationary. LOW-ranked players were stationary for longer than HIGH-ranked counterparts [12.6 (8.7) vs. 8.2 (5.1)%, U = 30.000, P = 0.011, r = 0.46] with more time at low propulsion speeds (<1.0 m · s?1). HIGH-ranked and doubles players spent more time in higher speed zones than respective counterparts. Females spent more time in the 1.0–1.49 m · s?1 zone (U = 48.000, P = 0.047, r = 0.36). Regardless of rank, sex or format, propulsion speeds during wheelchair tennis match play are consistent with data logger accuracy. Hence, data logging is appropriate for court-movement quantification.  相似文献   

16.
A motor skills assessment could be helpful in talent development by estimating essential perceptuo-motor skills of young players, which are considered requisite to develop excellent technical and tactical qualities. The Netherlands Table Tennis Association uses a motor skills assessment in their talent development programme consisting of eight items measuring perceptuo-motor skills specific to table tennis under varying conditions. This study aimed to investigate this assessment regarding its reproducibility, internal consistency, underlying dimensions and concurrent validity in 113 young table tennis players (6–10 years). Intraclass correlation coefficients of six test items met the criteria of 0.7 with coefficients of variation between 3% and 8%. Cronbach’s alpha valued 0.853 for internal consistency. The principal components analysis distinguished two conceptually meaningful factors: “ball control” and “gross motor function.” Concurrent validity analyses demonstrated moderate associations between the motor skills assessment’s results and national ranking; boys r = ?0.53 (P < 0.001) and girls r = ?0.45 (P = 0.015). In conclusion, this evaluation demonstrated six test items with acceptable reproducibility, good internal consistency and good prospects for validity. Two test items need revision to upgrade reproducibility. Since the motor skills assessment seems to be a reproducible, objective part of a talent development programme, more longitudinal studies are required to investigate its predictive validity.  相似文献   

17.
Purpose: Acute benefits of aerobic exercise on executive functioning have been reported frequently under laboratory conditions. However, to date, a beneficial effect on long-term memory has been less well supported and no data are available regarding nonlaboratory conditions in young adults. The aim of the current study was to investigate acute effects of aerobic exercise on cognitive functioning in a university classroom setting. Method: Using a cross-over design, 51 participants performed a bout of moderately intense running (RUN) and read an article while seated (CON). Afterwards, they completed free-recall tests, followed by a Flanker task and an n-back task. Results: Participants in the RUN condition compared with those in the CON condition showed shorter reaction time on the inhibition task, F(1, 50) = 5.59, p = .022, η2 = .101, and recalled more words in the immediate- and delayed-recall tests, F(1, 50) = 8.40, p = .006, η2 = .144. Conclusion: The present findings suggest that a moderately intense bout of aerobic exercise benefits verbal short-term and long-term memory as well as inhibitory control among students in a classroom setting.  相似文献   

18.
Abstract

In this study, we assessed the extent to which 2000-m rowing ergometer performance predicted final rankings at the World Junior Rowing Championship in a sample of 398 junior rowers competing in 13 events. The rowers' ergometer performance times were examined using a questionnaire, and in all 13 events they correlated (P ≤ 0.039) with the final rankings at the Championship. The strongest correlations were observed for ergometer performance times in junior women's single sculls (r = 0.92; P < 0.001), followed by junior men's single sculls (r = 0.80; P < 0.001) and junior women's double sculls (r = 0.79; P < 0.001). The observed correlations were higher for smaller boats – singles, doubles, and pairs (r = 0.64–0.92; P ≤ 0.025) – than for larger boats – quads, fours, and eights (r = 0.31–0.70; P ≤ 0.039). Linear regression analyses were used to construct regression equations to predict final rankings based on 2000-m rowing ergometer performance times for each event. Although correlations in 10 of the 13 events were above r = 0.5, the large standard errors of the estimate impaired the prediction of rankings in all of the studied events. Using these equations, the most probable rowing ergometer performance times required for a particular ranking in a given rowing event might easily be calculated.  相似文献   

19.
Research from several countries has documented a decline in physical activity (PA) levels and in participation in organized sport with increasing age, indicating that organized sport may be of importance to adolescents’ cardiorespiratory fitness (CRF). Purpose: The purpose of this study was to examine how regular participation in organized and unorganized PA affected the development of adolescents’ CRF (peak oxygen consumption [VO2peak]), when controlled for sex interaction. Method: Data on direct measures of VO2peak and participation in organized PA among adolescents organized into 3 groups (participation in organized sport, participation in unorganized PA, and no weekly PA) were collected from 76 students (39 boys and 37 girls), when they were aged 14 and 19 years old. Results: Statistically significant differences were found between VO2peak values in the 3 groups at both 14 years of age, F(2, 73) = 7.16, p < .05, ?2 = .170, and 19 years of age, F(2, 73) = 14.00, p < .05, ?2 = .300, independent of sex at both 14 and 19 years of age, F(2, 73) = 0.05, p > .05, ?2 = .02, and F(2, 73) = 0.05, p > .05, ?2 = .00. Adolescents participating in organized sport also had statistically significantly higher VO2peak values than adolescents participating in unorganized PA and those with no weekly PA, at both 14 and 19 years of age. Conclusion: From a health perspective, in terms of CRF, the findings highlight the importance of encouraging adolescents to participate in organized sport and to refrain from dropping out of organized sport programs.  相似文献   

20.
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