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Sample records for expert tennis players

  1. THE EFFECT OF MODERATE AND HIGH-INTENSITY FATIGUE ON GROUNDSTROKE ACCURACY IN EXPERT AND NON-EXPERT TENNIS PLAYERS

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    Mark Lyons

    2013-06-01

    Full Text Available Exploring the effects of fatigue on skilled performance in tennis presents a significant challenge to the researcher with respect to ecological validity. This study examined the effects of moderate and high-intensity fatigue on groundstroke accuracy in expert and non-expert tennis players. The research also explored whether the effects of fatigue are the same regardless of gender and player's achievement motivation characteristics. 13 expert (7 male, 6 female and 17 non-expert (13 male, 4 female tennis players participated in the study. Groundstroke accuracy was assessed using the modified Loughborough Tennis Skills Test. Fatigue was induced using the Loughborough Intermittent Tennis Test with moderate (70% and high-intensities (90% set as a percentage of peak heart rate (attained during a tennis-specific maximal hitting sprint test. Ratings of perceived exertion were used as an adjunct to the monitoring of heart rate. Achievement goal indicators for each player were assessed using the 2 x 2 Achievement Goals Questionnaire for Sport in an effort to examine if this personality characteristic provides insight into how players perform under moderate and high-intensity fatigue conditions. A series of mixed ANOVA's revealed significant fatigue effects on groundstroke accuracy regardless of expertise. The expert players however, maintained better groundstroke accuracy across all conditions compared to the novice players. Nevertheless, in both groups, performance following high-intensity fatigue deteriorated compared to performance at rest and performance while moderately fatigued. Groundstroke accuracy under moderate levels of fatigue was equivalent to that at rest. Fatigue effects were also similar regardless of gender. No fatigue by expertise, or fatigue by gender interactions were found. Fatigue effects were also equivalent regardless of player's achievement goal indicators. Future research is required to explore the effects of fatigue on

  2. Prediction of Tennis Performance in Junior Elite Tennis Players

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    Tamara Kramer, Barbara C.H. Huijgen, Marije T. Elferink-Gemser, Chris Visscher

    2017-03-01

    Full Text Available Predicting current and future tennis performance can lead to improving the development of junior tennis players. The aim of this study is to investigate whether age, maturation, or physical fitness in junior elite tennis players in U13 can explain current and future tennis performance. The value of current tennis performance for future tennis performance is also investigated. A total of 86 junior elite tennis players (boys, n = 44; girls, n = 42 U13 (aged: 12.5 ± 0.3 years, and followed to U16, took part in this study. All players were top-30 ranked on the Dutch national ranking list at U13, and top-50 at U16. Age, maturation, and physical fitness, were measured at U13. A principal component analysis was used to extract four physical components from eight tests (medicine ball throwing overhead and reverse, ball throwing, SJ, CMJas, Sprint 5 and 10 meter, and the spider test. The possible relationship of age, maturation, and the physical components; “upper body power”, “lower body power”, “speed”, and “agility” with tennis performance at U13 and U16 was analyzed. Tennis performance was measured by using the ranking position on the Dutch national ranking list at U13 and U16. Regression analyses were conducted based on correlations between variables and tennis performance for boys and girls, separately. In boys U13, positive correlations were found between upper body power and tennis performance (R2 is 25%. In girls, positive correlations between maturation and lower body power with tennis performance were found at U13. Early maturing players were associated with a better tennis performance (R2 is 15%. In girls U16, only maturation correlated with tennis performance (R2 is 13%; later-maturing girls at U13 had better tennis performances at U16. Measuring junior elite tennis players at U13 is important for monitoring their development. These measurements did not predict future tennis performance of junior elite tennis players three

  3. Spondylolysis in young tennis players

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    Ruiz‐Cotorro, A; Balius‐Matas, R; Estruch‐Massana, A; Angulo, J Vilaró

    2006-01-01

    The general aetiology, diagnosis, and treatment of spondylolysis, a bone defect in the pars interarticularis of the vertebra, are reviewed. A retrospective study of young tennis players diagnosed between 2000 and 2004 with spondylolysis with or without spondylolisthesis, assessed by radiography and planar bone scintigraphy, is described. If the radiographic results were negative, computed tomography was performed. Sixty six cases were evaluated: 53 L5 lesions, eight L4 lesions, two L3 lesions, and one bilateral lesion at the L2 level. Two more lesions at two levels were found (bilateral L5 and unilateral L4 and L3 on the right side). Classification, treatment, and outcome of the cases are reported. A combination of radiography, planar bone scintigraphy, and SPECT is useful for evaluating spondylolysis in tennis players and recommending treatment. Use of a brace did not appear to achieve significant results. PMID:16632576

  4. Common Injuries of Collegiate Tennis Players

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    Christian Wisdom Magtajas Valleser

    2017-09-01

    Full Text Available The purpose of this study is to determine the common injuries of Filipino collegiate tennis players; 110 varsity tennis players with a mean of 20 years old (SD ± 1.7 with an average playing experience of 12 years participated in the study. There was a 100% occurrence of at least one injury with an average rate of 5.98 injuries per person. The authors observed that the most commonly injured anatomical region is the lower extremity; ankles were recorded as the most commonly injured part. Other commonly injured areas included the shoulders and lower back. Furthermore, the most common injury type is tendinitis, sprains, and strains. The recorded injuries were mostly associated with overuse injuries, and the findings were similar to those of most other studies on tennis injuries. A larger sample size may provide more conclusive findings on tennis injuries, particularly in different levels of competition, such as recreational or professional athletes.

  5. Energy flow analysis during the tennis serve: comparison between injured and noninjured tennis players.

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    Martin, Caroline; Bideau, Benoit; Bideau, Nicolas; Nicolas, Guillaume; Delamarche, Paul; Kulpa, Richard

    2014-11-01

    Energy flow has been hypothesized to be one of the most critical biomechanical concepts related to tennis performance and overuse injuries. However, the relationships among energy flow during the tennis serve, ball velocity, and overuse injuries have not been assessed. To investigate the relationships among the quality and magnitude of energy flow, the ball velocity, and the peaks of upper limb joint kinetics and to compare the energy flow during the serve between injured and noninjured tennis players. Case-control study; Level of evidence, 3. The serves of expert tennis players were recorded with an optoelectronic motion capture system. The forces and torques of the upper limb joints were calculated from the motion captures by use of inverse dynamics. The amount of mechanical energy generated, absorbed, and transferred was determined by use of a joint power analysis. Then the players were followed during 2 seasons to identify upper limb overuse injuries with a questionnaire. Finally, players were classified into 2 groups according to the questionnaire results: injured or noninjured. Ball velocity increased and upper limb joint kinetics decreased with the quality of energy flow from the trunk to the hand + racket segment. Injured players showed a lower quality of energy flow through the upper limb kinetic chain, a lower ball velocity, and higher rates of energy absorbed by the shoulder and elbow compared with noninjured players. The findings of this study imply that improper energy flow during the tennis serve can decrease ball velocity, increase upper limb joint kinetics, and thus increase overuse injuries of the upper limb joints. © 2014 The Author(s).

  6. Does ovulation affect performance in tennis players?

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    Otaka, Machiko; Chen, Shu-Man; Zhu, Yong; Tsai, Yung-Shen; Tseng, Ching-Yu; Fogt, Donovan L; Lim, Boon-Hooi; Huang, Chih-Yang; Kuo, Chia-Hua

    2018-01-01

    Scientific data on the performance of collegiate female tennis players during the menstrual phases are scarce. Double-blind, counter-balanced, crossover trials were conducted to examine whether tennis performance was affected during menstruation, with and without dehydroepiandrosterone sulfate (DHEA-S) supplementation. Ten Division 1 collegiate tennis players (aged 18-22 years) were evenly assigned into placebo-supplemented and DHEA-supplemented (25 mg/day) trials. Treatments were exchanged among the participants after a 28-day washout. Tennis serve performance was assessed on the first day of menstrual bleeding (day 0/28) and on days 7, 14 and 21. Mood state was unaltered during the menstrual cycles in both trials. The lowest tennis serve performance score (speed times accuracy) occurred on day 14 (P=0.06 vs day 0; P=0.01 vs day 21) in both placebo and DHEA trials. Decreased performance on day 14 was explained by decreased accuracy (P=0.03 vs day 0/28; P=0.01 vs day 21), but not velocity itself. Isometric hip strength, but not quadriceps strength, was moderately lower on day 14 (P=0.08). Increasing plasma DHEA-S (by ~65%) during the DHEA-supplemented trial had no effects on mood state, sleep quality or tennis serve performance. We have shown that menses does not affect serve performance of collegiate tennis players. However, the observed decrement in the accuracy of serve speed near ovulation warrants further investigation.

  7. Effect of coach change on professional tennis players

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    Nekolová, Barbora

    2014-01-01

    Title: Effect of coach change on professional tennis players Objectives of work: The aim of the thesis is to analyze the impact of coach change on professional tennis players from the psychology perspective, social relationship and player's attitude to the sport itself. The impact of the coach change on player's approach to tennis, game results, personal life and interpersonal relationships will be examined. Method: The methods that will be used are narrative interviews - annotated transcript...

  8. Expert-novice differences in cognitive and execution skills during tennis competition.

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    Del Villar, Fernando; García González, Luis; Iglesias, Damián; Perla Moreno, M; Cervelló, Eduardo M

    2007-04-01

    This study deals with decision and execution behavior of tennis players during competition. The study is based on the expert-novice paradigm and aims to identify differences between both groups in the decision-making and execution variables in serve and shot actions in tennis. Six expert players (elite Spanish tennis players) and six novice players (grade school tennis players) took part in this study. To carry out this study, the observation protocol defined by McPherson and Thomas in 1989, in which control, decision-making and execution variables were included, was used, where it was applied to the performance of the tennis player in a real match situation. In the analysis, significant differences between experts and novices in decision-making and execution variables are found wherein it can be observed that experts display a greater ability to make the appropriate decisions, selecting the most tactical responses to put pressure on the opponent. Expert tennis players were also able to carry out forceful executions to their opponent with greater efficiency, making the opponent's response to a large extent more difficult. These findings are in accordance with those of McPherson and colleagues.

  9. Differences in Energy Capacities between Tennis Players and Runners

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    Novak, Dario; Vučetić, Vlatko; Žugaj, Sanja

    2013-01-01

    The primary purpose of this study was to determine differences between elite athletes and tennis players in order to provide a clearer picture regarding the energy demands in modern tennis. Forty-eight (48) athletes and 24 tennis players from Croatian national leagues were compared in morphological and physiological parameters of an all-out incremental treadmill test with gas exchange measurements. Tennis players’ HRmax (192.96±7.75 bpm) shows values that are most different to 400-meters spri...

  10. Differences in energy capacities between tennis players and runners.

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    Novak, Dario; Vucetić, Vlatko; Zugaj, Sanja

    2013-05-01

    The primary purpose of this study was to determine differences between elite athletes and tennis players in order to provide a clearer picture regarding the energy demands in modern tennis. Forty-eight (48) athletes and 24 tennis players from Croatian national leagues were compared in morphological and physiological parameters of an all-out incremental treadmill test with gas exchange measurements. Tennis players' HRmax (192.96+/-7.75 bpm) shows values that are most different to 400-meters sprinters (200.13+/-6.95 bpm). Maximum running speed of tennis players on the treadmill (vmax) is no different with the speed achieved by sprinters, while there are significant differences among other athletes. Values in running speed at anaerobic threshold (vAnT) show no statistically significant difference with the values for athlete sprinters and 400-m sprinters. Values of RvO2max for tennis players indicate significant similarities with athlete sprinters and 400-m sprinters while the values of RvO2AnT are nearly identical with the values for sprinters and show no statistically significant differences (psprint endurance in tennis players. Knowing these characteristics is the basis for planning and implementing training systems that will enable the increase and optimal usage of energy capacities of tennis players in possibly improving sports results.

  11. COMPARISON OF VISUAL ACUITY IN REDUCED LUMINATION AND FACILITY OF OCULAR ACCOMMODATION IN TABLE TENNIS CHAMPIONS AND NON- PLAYERS

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    Ebrahim Jafarzadehpur

    2004-03-01

    Full Text Available A table tennis player should fixate at different distances; track the objects with different speed, and in different visual environment. Their visual skills must be well developed for these capabilities. Therefore, visual acuity in reduced lumination and facility of ocular accommodation those are two criteria for visual skills have been compared in table tennis players and normal non-players. Twenty-nine young table tennis champions and 29 normal matched non-players (did not take part in any racket sports game were evaluated. Basic visual and eye examinations were done for both of them. Normal results in basic examination were fundamental requirement for all the subjects. +/-2.00 sphere lenses for accommodation facility are used. An electrical current regulator changed the output light intensity of a conventional chart projector (Topcon. Light intensity decreased to 10 cd·m-2 and visual acuity tested. In comparison of visual acuity in reduced lumination and facility of ocular accommodation in table tennis champions and non-players there are significant differences (p < 0.001. In the preliminary visual tests there was not any significant different in the two groups but the results in the top level table tennis player was very uniform and in every test and the standard deviation was lesser in tennis player group than non-players. These results show that motor and sensorial functions of expert players are well developed. That is consistent with other researchers. This result was interpreted as reflecting a better perceptual system of experts to the constraints encountered during table tennis and its use in practical settings for evaluating athletes or detecting sport talents. However some visual and perceptual training that usually used in orthoptics can be used for novice table tennis player to improve their abilities

  12. Investigating the Nutritional and Recovery Habits of Tennis Players

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    James A. Fleming

    2018-04-01

    Full Text Available In this study, the nutritional and recovery habits of tennis players pre-, during, and post-match-play were investigated. Seventy tennis players completed a bespoke nutrition and recovery habits questionnaire, with questions related to the following areas: match preparation, intra-match nutritional habits, situation dependent variables, and post-match nutrition and recovery. On match day-1, the consumption of balanced meals consisting of carbohydrate (CHO, fat and protein, with some micronutrient considerations were reported by 51% of players. On match-days, CHOs were prioritised prior to match-play with CHO dominant meals consumed by the majority of players. During matches, all players adopted a nutritional strategy, with water (94%, banana(s (86% and sports drinks (50% commonly used. Carbohydrate rich nutritional aids, including sports drinks (80% and energy gels (26% were utilised more readily during long matches (>2 h. The day after match-play, 39% of players reported the consumption of “nothing specific”. Multiple post-match recovery strategies were adopted by 80% of players, with foam rolling (77%, ice baths (40%, protein shake intake (37% and hot baths (26% most used. Findings indicate highly variable eating and recovery habits in tennis players pre-, during and post-match-play, with scope for improved practices.

  13. Investigating the Nutritional and Recovery Habits of Tennis Players.

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    Fleming, James A; Naughton, Robert J; Harper, Liam D

    2018-04-03

    In this study, the nutritional and recovery habits of tennis players pre-, during, and post-match-play were investigated. Seventy tennis players completed a bespoke nutrition and recovery habits questionnaire, with questions related to the following areas: match preparation, intra-match nutritional habits, situation dependent variables, and post-match nutrition and recovery. On match day-1, the consumption of balanced meals consisting of carbohydrate (CHO), fat and protein, with some micronutrient considerations were reported by 51% of players. On match-days, CHOs were prioritised prior to match-play with CHO dominant meals consumed by the majority of players. During matches, all players adopted a nutritional strategy, with water (94%), banana(s) (86%) and sports drinks (50%) commonly used. Carbohydrate rich nutritional aids, including sports drinks (80%) and energy gels (26%) were utilised more readily during long matches (>2 h). The day after match-play, 39% of players reported the consumption of "nothing specific". Multiple post-match recovery strategies were adopted by 80% of players, with foam rolling (77%), ice baths (40%), protein shake intake (37%) and hot baths (26%) most used. Findings indicate highly variable eating and recovery habits in tennis players pre-, during and post-match-play, with scope for improved practices.

  14. Comparison of visual acuity in reduced lumination and facility of ocular accommodation in table tennis champions and non- players.

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    Jafarzadehpur, Ebrahim; Yarigholi, Mohammad R

    2004-03-01

    A table tennis player should fixate at different distances; track the objects with different speed, and in different visual environment. Their visual skills must be well developed for these capabilities. Therefore, visual acuity in reduced lumination and facility of ocular accommodation those are two criteria for visual skills have been compared in table tennis players and normal non-players. Twenty-nine young table tennis champions and 29 normal matched non-players (did not take part in any racket sports game) were evaluated. Basic visual and eye examinations were done for both of them. Normal results in basic examination were fundamental requirement for all the subjects. +/-2.00 sphere lenses for accommodation facility are used. An electrical current regulator changed the output light intensity of a conventional chart projector (Topcon). Light intensity decreased to 10 cd·m(-2) and visual acuity tested. In comparison of visual acuity in reduced lumination and facility of ocular accommodation in table tennis champions and non-players there are significant differences (p reflecting a better perceptual system of experts to the constraints encountered during table tennis and its use in practical settings for evaluating athletes or detecting sport talents. However some visual and perceptual training that usually used in orthoptics can be used for novice table tennis player to improve their abilities. Key PointsThat the ability of a champion depends on many sensory, motor and perceptual factors.Visual factors such as facility of accommodation and visual acuity in reduced lumination should be considered in table tennis players.Visual training may be useful for novice and also for experts.

  15. Ranking benchmarks of top 100 players in men's professional tennis.

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    Reid, Machar; Morris, Craig

    2013-01-01

    In men's professional tennis, players aspire to hold the top ranking position. On the way to the top spot, reaching the top 100 can be seen as a significant career milestone. National Federations undertake extensive efforts to assist their players to reach the top 100. However, objective data considering reasonable ranking yardsticks for top 100 success in men's professional tennis are lacking. Therefore, it is difficult for National Federations and those involved in player development to give empirical programming advice to young players. By taking a closer look at the ranking history of professional male tennis players, this article tries to provide those involved in player development a more objective basis for decision-making. The 100 names, countries, birthdates and ranking histories of the top 100 players listed in the Association of Tennis Professionals (ATP) at 31 December 2009 were recorded from websites in the public domain. Descriptive statistics were reported for the ranking milestones of interest. Results confirmed the merits of the International Tennis Federation's junior tour with 91% of the top 100 professionals earning a junior ranking, the mean peak of which was 94.1, s=148.9. On average, top 100 professionals achieved their best junior rankings and earned their first ATP point at similar ages, suggesting that players compete on both the junior and professional tours during their transition. Once professionally ranked, players took an average 4.5, s=2.1 years to reach the ATP top 100 at the mean age of 21.5, s=2.6 years, which contrasts with the mean current age of the top 100 of 26.8, s=3.2. The best professional rankings of players born in 1982 or earlier were positively related to the ages at which players earned their first ATP point and then entered the top 100, suggesting that the ages associated with these ranking milestones may have some forecasting potential. Future work should focus on the change in top 100 demographics over time as well

  16. MUSCLE DAMAGE AFTER A TENNIS MATCH IN YOUNG PLAYERS

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    R.V. Gomes

    2014-07-01

    Full Text Available The present study investigated changes in indirect markers of muscle damage following a simulated tennis match play using nationally ranked young (17.6 ± 1.4 years male tennis players. Ten young athletes played a 3-hour simulated match play on outdoor red clay courts following the International Tennis Federation rules. Muscle soreness, plasma creatine kinase activity (CK, serum myoglobin concentration (Mb, one repetition maximum (1RM squat strength, and squat jump (SJ and counter movement jump (CMJ heights were assessed before, immediately after, and 24 and 48 h after the simulated match play. All parameters were also evaluated in a non-exercised group (control group. A small increase in the indirect markers of muscle damage (muscle soreness, CK and Mb was detected at 24-48 hours post-match (p<0.05. A marked acute decrement in neuromuscular performance (1RM squat strength: -35.2 ± 10.4%, SJ: -7.0 ± 6.0%, CMJ: -10.0 ± 6.3% was observed immediately post-match (p<0.05. At 24 h post-match, the 1RM strength and jump heights were not significantly different from the baseline values. However, several players showed a decrease of these measures at 24 h after the match play. The simulated tennis match play induced mild muscle damage in young players. Coaches could monitor changes in the indirect markers of muscle damage to assess athletes’ recovery status during training and competition.

  17. Utilization of cues in action anticipation in table tennis players.

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    Zhao, Qi; Lu, Yingzhi; Jaquess, Kyle J; Zhou, Chenglin

    2018-04-11

    By manipulating the congruency between body kinematics and subsequent ball trajectory, this study investigated the anticipation capabilities of regional-level, college-level, and novice table tennis players using a full video simulation occluder paradigm. Participants watched footage containing congruent, incongruent, or no ball trajectory information, to predict the landing point of the ball. They were required to choose between two potential locations to make their prediction. Percent accuracy and relevant indexes (d-prime, criterion, effect size) were calculated for each condition. Results indicated that experienced table tennis players (both regional and college players) were superior to novices in the ability to anticipate ball trajectory using kinematic information, but no difference was found between regional-level and college-level players. The findings of this study further demonstrate the superior anticipation ability of experienced table tennis players. Furthermore, the present result suggests that there may be a certain "baseline" level of motor experience in racquet sports for effective action anticipation, while the addition of further motor experience does not appear to assist direction anticipation.

  18. Sex differences in asthma in swimmers and tennis players

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    Romberg, Kerstin; Tufvesson, Ellen; Bjermer, Leif

    2017-01-01

    Background: Elite athletes, independent of sport, have increased risk of developing asthma, but little is known about sex difference among adolescent athletes. Objective: To investigate and compare sex-related differences according to symptoms and treatment of asthma, allergy, and health among elite athletes and a reference group. Methods: Adolescent elite swimmers (n = 101), tennis players (n = 86), and a reference group (n = 1,628) responded to a questionnaire about respiratory symptoms, al...

  19. Returning Serve in Tennis: A Qualitative Examination of the Interaction of Anticipatory Information Sources Used by Professional Tennis Players

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    Georgina Vernon

    2018-06-01

    Full Text Available Research has largely focused on the individual contribution of either kinematic or contextual information sources to the anticipatory skill of an expert athlete during a time-stressed situation. Very little research has considered how these two sources of information interact with each other to influence anticipation. The current study used a qualitative interview methodology to investigate this interaction. Eight former or current top 250 professional male tennis players participated in a 30–60 min interview about the interaction of kinematic and contextual information sources and their influence on anticipation. Using an open-coding analysis approach, codes were identified by each researcher from the transcribed interviews and then brought together to identify common themes. The primary themes were consciousness, tactical awareness, contextual information sources, kinematic information sources, mentality/confidence, returner technique or strategy, and build pressure on the server. Secondary themes coded from the participants were returning characteristics and practice. Consequently, a temporal model was developed which demonstrated the sequence and interaction of both kinematic and contextual information sources known to influence expert tennis player’s anticipation.

  20. Expectancy effects in tennis: the impact of opponents' pre-match non-verbal behaviour on male tennis players.

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    Buscombe, Richard; Greenlees, Iain; Holder, Tim; Thelwell, Richard; Rimmer, Matt

    2006-12-01

    In this study, we examined the impact of a male opponent's pre-match body language and clothing (general vs. sports-specific) on how his performances were judged by an observer. Forty male tennis players viewed videos of a male target tennis player warming up and then observed playing footage of the target. Each participant viewed the target player warming up displaying one of four combinations of body language and clothing (positive body language/tennis-specific clothing; positive body language/general sportswear; negative body language/tennis-specific clothing; negative body language/general sportswear). Participants rated the performance of the tennis player and gave their perceptions of the likely outcome of a tennis match with the target player. Analyses of variance indicated that clothing and body language had an interactive effect on both outcome expectations and ratings of performance. The findings support the contention that the initial impressions athletes form of their opponents can influence the way in which they judge the performances of opponents and their perceived likelihood of success against the same opponents.

  1. A Longitudinal Study of Physical Fitness in Elite Junior Tennis Players

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    Kramer, Tamara; Huijgen, Barbara C. H.; Elferink-Gemser, Marije T.; Visscher, Chris

    Purpose: To analyze how physical fitness (PF) improves in elite junior tennis players related to age, maturity, and performance level. Methods: Elite junior tennis players (n = 113 boys, n = 83 girls) divided by performance level were monitored longitudinally from U14 to U16. Maturity, upper and

  2. Comparing technical proficiency of elite table tennis players with intellectual disability: simulation testing versus game play.

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    Van Biesen, Debbie; Mactavish, Jennifer J; Vanlandewijck, Yves C

    2014-04-01

    Technical skill proficiency among elite table tennis players with intellectual disabilities (ID) was investigated in this study using two approaches: an off-court simulation testing protocol and an on-court, standardized observational framework during game play. Participants included 24 players with ID (M age = 25 yr., SD = 6; M IQ = 61, SD = 9), the top 16 performers, 13 men and 11 women, at the International Federation for sport for para-athletes with an intellectual disability (Inas) World Championships. Self-reported table tennis training experience of the players was 13 +/- 5 yr. In the Simulation Testing condition, players were instructed to play five sets of basic and five sets of advanced skills, which were subsequently assessed by experts using a standardized and validated observational protocol. The same protocol was used to assess the same skills during Game Play. Ratings of overall technical proficiency were not significantly different between Simulation Testing and Game Play conditions. There was a strong positive correlation between technical proficiency measured during Game Play vs Simulation Testing for the variables flick, topspin forehand, and topspin backhand. No correlations were found for the variables contra, block, and push. Insight into this relationship is important for future development of classification systems for ID athletes in the Paralympic Games, because comparing competition observation with the athlete's potential shown during the classification session is essential information for classifiers to confirm the athlete's competition class.

  3. BODY IMAGE AND MENTAL REPRESENTATION IN TABLE TENNIS PLAYERS WHO DO VERSUS DO NOT USE A PROSTHESIS

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    Damian Jeraj; Lisa Musculus; Babett H. Lobinger

    2017-01-01

    The prosthesis that athletes use should take over the function of the missing limb. Playing table tennis without constraints is one exemplary goal. The question arose whether table tennis players who used a prosthesis and players who did not show similar body image values and mental representation of movements. Five matched pairs of active table tennis players (n = 10) completed a body image questionnaire. Additionally, the mental representation of a forehand table tennis serve was assessed. ...

  4. Identification of the auditorium with successful tennis players

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    Dugalić Sretenka

    2015-01-01

    Full Text Available This paper presents the results of interviewing a sample of 229 respondents from Belgrade who are of a different gender, age and employment status. The study is a continuation of an earlier pilot study, with the help of identical questionnaires conducted through the Internet (Google form. The aim was to investigate the affinity of respondents concerning the business from which celebrities come, and to identify the similarities and differences in attitudes from which the promotional power of athletes may be evaluated. The study included a set of questions, some of which are presented in this paper: 1/ to what extent sport and sporting celebrities influence the decision of the respondents; 2/ assessing the similarity of equipment that respondents utilized if they play tennis (amateur, recreational or professional, with the equipment of their favorite players. During the answer to the second question, the respondents kept in mind certain players. The answers were analyzed by means of descriptive analysis. These studies show that a promotional power exists between the widest audiences of athletes. The study should encourage greater proficiency in the evaluation of sporting talent as scarce human resources, which, although burdened with costs, often remains unvalued, in terms of the declining nature of their athletic performance during their career. The research results show: 1 / respondents of different age and genders prefer sport as an activity from which celebrities come; 2 / 81.25% of those who play tennis identified using the brand of equipment as their favorite players, and the highest agreement in attitudes has been achieved with the variables of gender and employment. The study provides an answer to the question of which target group, within a promotional capacity, results in a conversion of sport results, and contributes to the strengthening of national identity through loyalty to proven sporting values.

  5. Biomechanics of the elbow joint in tennis players.

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    Eygendaal, D.; Rahussen, F.T.; Diercks, R.L.

    2007-01-01

    Elbow injuries constitute a sizeable percentage of tennis injuries. A basic understanding of biomechanics of tennis and analysis of forces, loads and motions of the elbow during tennis can will improve the understanding of the pathophysiology of these injuries. All different strokes in tennis have a

  6. Physiological responses and match characteristics in professional tennis players during a one-hour simulated tennis match

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    Kilit Bülent

    2016-06-01

    Full Text Available The purpose of this study was to investigate the effects of serve and return game situations on physiological responses and match characteristics in professional male tennis players during one hour-long simulated singles tennis matches. Ten internationally ranked tennis players (age 22.2 ± 2.8 years; body height 180.7 ± 4.4 cm; body mass 75.9 ± 8.9 kg participated in this study. Their physiological responses were measured using two portable analyzers during indoor hard court matches. Ratings of perceived exertion were also determined at the end of the game. The variables describing the characteristics of the matches determined from video recordings were: (a duration of rallies; (b rest time; (c work-to-rest ratio; (d effective playing time; and (d strokes per rally. Significant differences (p<0.05 were found between serving and returning conditions in an hour-long simulated singles tennis match in terms of oxygen uptake, a heart rate, ratings of perceived exertion, pulmonary ventilation, respiration frequency and a respiratory gas exchange ratio. In addition, both the heart rate and ratings of perceived exertion responses were moderately correlated with the duration of rallies and strokes per rally (r = 0.60 to 0.26; p<0.05. Taken together, these results indicate that the serve game situation has a significant effect on the physiological response in an hour-long simulated tennis match between professional male tennis players. These findings might be used for the physiological adaptations required for tennis-specific aerobic endurance.

  7. Characteristics of upper limb muscular strength in male wheelchair tennis players

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    Moon, Hyo-Bin; Park, Seung-Jae; Kim, Al-Chan; Jang, Jee-Hun

    2013-01-01

    The purpose of this study was to identify the characteristics of muscular strength in upper limb and to present the preliminary information for development of sports injury prevention program and exercise rehabilitation program in wheelchair tennis players. Participants were 12 male wheelchair tennis players. Muscular strength was measured in shoulder and elbow joints with isokinetic dynamometer. Ipsilateral (IR) and bilateral (BR) balance ratio were calculated with isokinetic strength at 60°/sec. As a result, extension strength (ES) was significantly higher than flexion strength (FS) (Pelbow joint FS was significantly higher than ES (Pelbow joints and lower IR and BR in elbow joints could be the characteristics in male wheelchair tennis players. It is suggested that flexor strengthening program in nondominant shoulder joint, extensor strengthening program in both elbow joint, and flexor strengthening program in non-dominant elbow joint should be introduced for male wheelchair tennis players. PMID:24278887

  8. A comparison of two conative characteristics of top basketball and recreational table tennis players.

    Science.gov (United States)

    Sindik, Josko; Missoni, Sasa

    2013-05-01

    The purpose of this study is to adapt imported instruments for measuring multidimensional perfectionism in sport situations and perceived group cohesion, in terms of construct validity and reliability, as well as from the aspect of interpretability, addressed on Croatian samples of athletes. Group Environment Questionnaire (GEQ) and Sport Multidimensional Perfectionism Scale (MSSP) are applied. The sample of 223 male Croatian athletes comprises of N1 = 107 top basketball players from nine teams in A-1 Croatian Basketball League and N2 = 116 recreational table tennis players who play in Table Tennis Organization of Clubs and Actives in Zagreb. Principal Components Analyses at both instruments showed two-component structures: combined social-task cohesion and friendship were latent dimensions of perceived group cohesion, while the internalized standards and externalized standards revealed two aspects of multidimensional perfectionism in sport situations. In perceived group cohesion, basketball players achieved higher average results than table tennis players in the friendship, while the table tennis players showed higher combined social and task orientation than basketball players. In multidimensional sport perfectionism, basketball players have higher average result than table tennis players in the dimension of internalized perfectionism, but in externalized perfectionism there is no statistical significant difference. Younger players showed higher average results than older players in the dimension of friendship, while older players showed higher combined social and task orientation than younger players. Younger players have higher average scores in internalized perfectionism. The main importance of the research is adjustment of multidimensional perfectionism in sport situations and perceived group cohesion to Croatian athletes, providing additional possibility of cross-cultural adjustment of both concepts, psychometrically and theoretically.

  9. Tennis players show a lower coactivation of the elbow antagonist muscles during isokinetic exercises.

    Science.gov (United States)

    Bazzucchi, Ilenia; Riccio, Maria Elena; Felici, Francesco

    2008-10-01

    Previous studies have suggested that muscle coactivation could be reduced by a recurrent activity (training, daily activities). If this was correct, skilled athletes should show a specific muscle activation pattern with a low level of coactivation of muscles which are typically involved in their discipline. In particular, the aim of this study was to verify the hypothesis that the amount of antagonist activation of biceps brachii (BB) and triceps brachii (TB) is different between tennis players and non-players individuals during maximal isokinetic contractions. Ten young healthy men and eight male tennis players participated in the study. The surface electromyographic signals (sEMG) were recorded from the BB and TB muscles during three maximal voluntary isometric contractions (MVC) of elbow flexors and extensors and a set of three maximal elbow flexions and extensions at 15 degrees , 30 degrees , 60 degrees , 120 degrees , 180 degrees and 240 degrees /s. Normalized root mean square (RMS) of sEMG was calculated as an index of sEMG amplitude. Antagonist activation (%RMSmax) of TB was significantly lower in tennis players (from 14.0+/-7.9% at MVC to 16.3+/-8.9% at 240 degrees /s) with respect to non-players (from 27.7+/-19.7% at MVC to 38.7+/-17.6% at 240 degrees /s) at all angular velocities. Contrary to non-players, tennis players did not show any difference in antagonist activation between BB and TB muscles. Tennis players, with a constant practice in controlling forces around the elbow joint, learn how to reduce coactivation of muscles involved in the control of this joint. This has been shown by the lower antagonist muscular activity of triceps brachii muscle during isokinetic elbow flexion found in tennis players with respect to non-players.

  10. Iliopsoas and Gluteal Muscles Are Asymmetric in Tennis Players but Not in Soccer Players

    Science.gov (United States)

    Sanchis-Moysi, Joaquin; Idoate, Fernando; Izquierdo, Mikel; Calbet, Jose A. L.; Dorado, Cecilia

    2011-01-01

    Purpose To determine the volume and degree of asymmetry of iliopsoas (IL) and gluteal muscles (GL) in tennis and soccer players. Methods IL and GL volumes were determined using magnetic resonance imaging (MRI) in male professional tennis (TP) and soccer players (SP), and in non-active control subjects (CG) (n = 8, 15 and 6, respectively). Results The dominant and non-dominant IL were hypertrophied in TP (24 and 36%, respectively, Psoccer players had similar volumes in both sides (P = 0.87). The degree of side-to-side asymmetry decreased linearly from the first lumbar disc to the pubic symphysis in TP (r = −0.97, PSoccer and CG had similar GL volumes in both sides (P = 0.11 and P = 0.19, for the dominant and contralateral GL, respectively). GL was asymmetrically hypertrophied in TP. The non-dominant GL volume was 20% greater in TP than in CG (Psoccer is associated to a symmetric hypertrophy of IL. Gluteal muscles are asymmetrically hypertrophied in TP, while SP display a similar size to that observed in controls. It remains to be determined whether the different patterns of IL and GL hypertrophy may influence the risk of injury. PMID:21829539

  11. Upper Extremity Injuries in Tennis Players: Diagnosis, Treatment, and Management.

    Science.gov (United States)

    Chung, Kevin C; Lark, Meghan E

    2017-02-01

    Upper extremity tennis injuries are most commonly characterized as overuse injuries to the wrist, elbow, and shoulder. The complex anatomy of these structures and their interaction with biomechanical properties of tennis strokes contributes to the diagnostic challenges. A thorough understanding of tennis kinetics, in combination with the current literature surrounding diagnostic and treatment methods, will improve clinical decision-making. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Dynamic ulnar impaction syndrome in tennis players: report of two cases

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    Edgard de Novaes França Bisneto

    Full Text Available ABSTRACT In this report, two tennis players with symptoms of ulnar impaction syndrome are reviewed. Both players have neutral ulnar variance. These cases represent dynamic ulnar impaction syndrome, when the impact between ulna and carpus occurs during conditions of pronated grip. The literature and the treatment of these two cases are discussed.

  13. Implementation of Motor Imagery during Specific Aerobic Training Session in Young Tennis Players.

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    Aymeric Guillot

    Full Text Available The aim of this study was to investigate the effects of implementing motor imagery (MI during specific tennis high intensity intermittent training (HIIT sessions on groundstroke performance in young elite tennis players. Stroke accuracy and ball velocity of forehand and backhand drives were evaluated in ten young tennis players, immediately before and after having randomly performed two HIIT sessions. One session included MI exercises during the recovery phases, while the other included verbal encouragements for physical efforts and served as control condition. Results revealed that similar cardiac demand was observed during both sessions, while implementing MI maintained groundstroke accuracy. Embedding MI during HIIT enabled the development of physical fitness and the preservation of stroke performance. These findings bring new insight to tennis and conditioning coaches in order to fulfil the benefits of specific playing HIIT sessions, and therefore to optimise the training time.

  14. Bone Mineral Density of Adolescent Female Tennis Players and Nontennis Players

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    Kevser Ermin

    2012-01-01

    Full Text Available The purpose of this study was to determine differences in bone mineral density (BMD among adolescent female tennis players (TPs and nontennis players (NTPs and to assess body composition as a predictor variable of BMD. Nineteen female TPs and 19 female NTPs, ages 14 to 18 years, participated in this study. Lumbar spine, total hip, femoral neck, forearms BMD, and body composition were assessed using dual-energy X-ray absorptiometry (DXA. Lumbar spine and total hip BMD measurements for TP were greater than NTP. However, these differences were not statistically significant (=0.37 and 0.12, resp.. TP had significantly greater femoral neck BMD than NTPs (=0.02. This difference might play an important role in preventing osteoporosis and decreasing the risk of fractures at the hip later in life.

  15. DIFFERENCES AMONG TENNIS PLAYERS AGED 12, 14 AND 16 YEARS IN CERTAIN MORPHOLOGICAL CHARACTERISTICS: A CROATIAN PROSPECTIVE

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    Novak, Dario; Milanović, Dragan; Barbaros-Tudor, Petar

    2015-01-01

    Primary objective of this research was to identify quantitative differences among tennis players aged 12, 14 and 16 with regards to the indicators of morphological characteristics. Sixty (60) tennis players ranked on the scale of the Croatian Tennis Association were analysed through differences in morphological characteristics which were identified by a standard laboratory diagnostic procedure in Sports-diagnostic Centre of the Faculty of Kinesiology at the University of Zagreb. Significant d...

  16. Relative Age Effect in Swedish Male and Female Tennis Players Born in 1998–2001

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    Göran Gerdin

    2018-04-01

    Full Text Available The relative age effect (RAE has been extensively debated and researched in both popular media and academic discourse. This study examined RAE in Swedish tennis players born in 1998–2001. The study was conducted in 2015–2016 and includes all ranked Swedish tennis players (n = 1835 registered in the Swedish Tennis Association database from the year 2014. The results show that when the birth dates of the corresponding Swedish population and all the ranked players are compared, they show a moderate RAE; however, the higher up they are in the ranking system, the greater the RAE becomes. Top 10 players display an average of 64.1% being born in the first half of the year. Some gender differences were also found, with a greater proportion of both higher and lower ranked females being born in the first half of the year. In our discussion of the findings we raise several issues that need to be addressed to provide more equal opportunities for all junior players regardless of birth date. Resolving ongoing problems associated with RAE in competitive sports such as tennis is important both in term of prolonged participation in the sport and increased performance. Suggestions made in this article include recognising RAE when designing the format of competitions/tournaments, not using official rankings until the juniors get older, addressing RAE in a “gender sensitive” way, and conducting further in-depth studies in which RAE is understood/examined as being associated with environmental factors. Although these findings show the RAE effect in Swedish tennis players, thus pointing at the need for further consideration in terms of ranking and selection procedures to ensure equal opportunities for player development, the study also concludes by reasserting an emphasis on a holistic approach to player development in which coaches focus on the developmentally appropriate needs and potential of each individual player regardless of their biological age.

  17. Auditory memory function in expert chess players.

    Science.gov (United States)

    Fattahi, Fariba; Geshani, Ahmad; Jafari, Zahra; Jalaie, Shohreh; Salman Mahini, Mona

    2015-01-01

    Chess is a game that involves many aspects of high level cognition such as memory, attention, focus and problem solving. Long term practice of chess can improve cognition performances and behavioral skills. Auditory memory, as a kind of memory, can be influenced by strengthening processes following long term chess playing like other behavioral skills because of common processing pathways in the brain. The purpose of this study was to evaluate the auditory memory function of expert chess players using the Persian version of dichotic auditory-verbal memory test. The Persian version of dichotic auditory-verbal memory test was performed for 30 expert chess players aged 20-35 years and 30 non chess players who were matched by different conditions; the participants in both groups were randomly selected. The performance of the two groups was compared by independent samples t-test using SPSS version 21. The mean score of dichotic auditory-verbal memory test between the two groups, expert chess players and non-chess players, revealed a significant difference (p≤ 0.001). The difference between the ears scores for expert chess players (p= 0.023) and non-chess players (p= 0.013) was significant. Gender had no effect on the test results. Auditory memory function in expert chess players was significantly better compared to non-chess players. It seems that increased auditory memory function is related to strengthening cognitive performances due to playing chess for a long time.

  18. [ANTHROPOMETRIC CHILEAN TABLE TENNIS PLAYERS OF COMPETITIVE FEATURES].

    Science.gov (United States)

    Yáñez Sepúlveda, Rodrigo; Barraza, Fernando; Rosales Soto, Giovanni; Báez, Eduardo; Tuesta, Marcelo

    2015-10-01

    The aim of the study was to characterize the anthropometric profile and somatotype of a sample of 50 players table tennis competitive with an average age 21.6 (± 3.1) years belonging to the Chilean team and institutions of higher education in the region of Valparaiso. The evaluation was conducted under the protocol marking the International Society for the Advancement of Kinanthropometry (ISAK) for the measurement procedure 25 restricted profile variables described by Drinkwater, Norton and Olds. Order to determine the body composition, fat, muscle, bone, skin and tissue residual was considered, using the equations proposed by Kerr. The body shape is characterized through somatotype method proposed by Carter. The sample was divided into 4 groups; Chilean Selection, Traditional Private Universities, State Universities and Private Universities Traditional Nontraditional. Regarding body composition; the Chilean team has the highest values of muscle tissue (45.6 ± 1.7%) and the lowest values of adipose tissue (25.2 ± 1.8%), also presenting lesser value in the Σ 6 skinfolds (mm) . The results showed no significant differences between groups in the aforementioned variables. In general somatotype compared by analyzing SANOVA no significant differences between groups (p = 0.409) was observed. The results show a biotype with such a characterization of endo-mesomorph with average values (4,1-4,9-1,8). This study provides updated data biotypological reference for this sport that can be used for decision-making. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  19. Sex differences in asthma in swimmers and tennis players.

    Science.gov (United States)

    Romberg, Kerstin; Tufvesson, Ellen; Bjermer, Leif

    2017-03-01

    Elite athletes, independent of sport, have increased risk of developing asthma, but little is known about sex difference among adolescent athletes. To investigate and compare sex-related differences according to symptoms and treatment of asthma, allergy, and health among elite athletes and a reference group. Adolescent elite swimmers (n = 101), tennis players (n = 86), and a reference group (n = 1,628) responded to a questionnaire about respiratory symptoms, allergy, health behavior, psychosomatic symptoms, self- esteem, and well-being. The athletes performed a mannitol provocation and a sport-specific exercise provocation. Atopy was assessed by skin prick tests, and fractional exhaled nitric oxide was measured. The females reported more asthma symptoms than the males in both the reference group (29.1% vs 22.3%) and the athlete group (56.4% vs 40.2%). However, no significant differences were found in physician-diagnosed asthma or treatment with inhaled corticosteroids. More female athletes had a positive mannitol provocation result (48.7% vs 35.8% in male athletes), and more female swimmers had a positive exercise provocation result (15.1% vs 7.7% in male swimmers). The females in all groups had more psychosomatic symptoms compared with the respective males, and the males in the reference group reported higher self-esteem and felt more well-being compared with the reference group females. Overall, we found a higher prevalence of asthma symptoms in the females. However, the frequency of physician-diagnosed asthma and the prescription of inhaled corticosteroids were the same in both sexes. This finding demonstrates an insufficient diagnosis of asthma in females. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  20. The Relative Age Effect and Physical Fitness Characteristics in German Male Tennis Players

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    Alexander Ulbricht, Jaime Fernandez-Fernandez, Alberto Mendez-Villanueva, Alexander Ferrauti

    2015-09-01

    Full Text Available The aims of the study were to test: 1 whether the relative age effect (RAE was prevalent in young (U12-U18 German male tennis players; 2 the potential influence of age and/or skill level on RAE and 3 whether maturity, anthropometric and fitness measures vary according to birth date distribution in elite youth tennis players. For the present study the following male populations were analysed: Overall German population (n = 3.216.811, all players affiliated to the German Tennis Federation (DTB (n = 120.851, players with DTB official ranking (n = 7165, regional (n = 381 and national (n = 57 squads (11-17 years old, as well as the top 50 German senior players were analyzed. RAEs were more prevalent at higher competitive levels with more players born in the first quarter of the year compared with the reference population for ranked (29.6%, regional (38.1% and national (42.1% players. No systematic differences were found in any of the maturity, anthropometric and fitness characteristics of the regional squad players born across different quarters. RAEs are present in the DTB competitive system and it was more pronounced at higher competitive levels. Compared with early born, late born players who were selected into elite squads did not differ in maturation, anthropometric and fitness characteristics.

  1. Isokinetic profile of elbow flexion and extension strength in elite junior tennis players.

    Science.gov (United States)

    Ellenbecker, Todd S; Roetert, E Paul

    2003-02-01

    Descriptive study. To determine whether bilateral differences exist in concentric elbow flexion and extension strength in elite junior tennis players. The repetitive nature of tennis frequently produces upper extremity overuse injuries. Prior research has identified tennis-specific strength adaptation in the dominant shoulder and distal upper extremity musculature of elite players. No previous study has addressed elbow flexion and extension strength. Thirty-eight elite junior tennis players were bilaterally tested for concentric elbow flexion and extension muscle performance on a Cybex 6000 isokinetic dynamometer at 90 degrees/s, 210 degrees/s, and 300 degrees/s. Repeated-measures ANOVAs were used to test for differences between extremities, muscle groups, and speed. Significantly greater (Pelbow extension peak torque values were measured at 90 degrees/s, 210 degrees/s, and 300 degrees/s for males. Significantly greater (Pelbow flexion muscular performance in males and for elbow flexion or extension peak torque and single-repetition work values in females. No significant difference between extremities was measured in elbow flexion/extension strength ratios in females and significant differences between extremities in this ratio were only present at 210 degrees/s in males (Pelbow in male elite junior tennis players but not females. These data have ramifications for clinicians rehabilitating upper extremity injuries in patients from this population.

  2. Arthroscopic Shoulder Surgery in Female Professional Tennis Players: Ability and Timing to Return to Play.

    Science.gov (United States)

    Young, Simon W; Dakic, Jodie; Stroia, Kathleen; Nguyen, Michael L; Safran, Marc R

    2017-07-01

    To assess the outcome and time to return to previous level of competitive play after shoulder surgery in professional tennis players. Retrospective case series. Tertiary academic centre. The records of all female tennis players on the Women's Tennis Association (WTA) professional circuit between January 2008 and June 2010 were reviewed to identify players who underwent shoulder surgery on their dominant (serving) shoulder. Primary outcomes were the ability and time to return to professional play and if they were able to return to their previous level of function as determined by singles ranking. Preoperative and postoperative singles rankings were used to determine rate and completeness of return to preoperative function. During the study period, 8 professional women tennis players from the WTA tour underwent shoulder surgery on their dominant arm. Indications included rotator cuff debridement or repair, labral reconstruction for instability or superior labral anterior posterior lesion, and neurolysis of the suprascapular nerve. Seven players (88%) returned to professional play. The mean time to return to play was 7 months after surgery. However, only 25% (2 of 8) players achieved their preinjury singles rank or better by 18 months postoperatively. In total, 4 players returned to their preinjury singles ranking, with their peak singles ranking being attained at a mean of 2.4 years postoperatively. In professional female tennis players, a high return to play rate after arthroscopic shoulder surgery is associated with a prolonged and often incomplete return to previous level of performance. Thus, counseling the patient to this fact is important to manage expectations. Level IV-Case Series.

  3. The toss of the professional and the competitive tennis player: serving from the ad-court

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    Jan Carboch

    2016-09-01

    Full Text Available We compared the serve toss of different types of serve when tennis players served from the ad-court. They used different spin on the ball and various ball placements in the opponent’s service box. Our aim was to compare the toss in different types of serve between a competitive (local tournament player and a professional player, from the point of view of the receiving player, when they served from the ad-court. One professional and one competitive tennis player (both right handed were observed while serving different types of serve to various locations of the opponent’s service box. We used a high-speed camera, which was placed opposite to the server in the position of a receiving player. The results showed that the players do not use the same toss for each type of serve. The professional player had a bigger range of racket-ball contact point on horizontal axis (32 cm of the various types of first serves, compared to the competitive player (only 24 cm. The toss of the kick serve had similar characteristics between both players (the racket-ball contact point was observed to be mostly to the right, from the view of receiver. Neither the professional nor the competitive player showed a stable profile of toss. In some cases, the receiving players could anticipate the type of the serve from the server’s toss.

  4. EFFECTS OF PLYOMETRIC TRAINING ON THE MOTOR ABILITIES OF TENNIS PLAYERS

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    Miroslav Smajić

    2015-05-01

    Full Text Available Plyometrics is a training method that uses an overload (Chu, 1983, and the main purpose of plyometric training is the development of greater reactive force (Allerheiligen & Rogers, 1995. Sports physiologists agree that plyometrics includes specific exercises that cause significant stretching of muscles located below the eccentric contraction, and followed by a strong concentric contraction, which is used for the development of a strong movement in a short period of time (LaChance, 1995. The aim of the research is to identify and analyze the transformative effects of plyometric exercise program on the manifest dimension of strength, agility and speed running experimental group of players. Methods: The sample consisted of 50 players were aged 17.5 years (± 6 months, who were divided into two groups. One group consisted of 25 tennis players TK “Gemaks” from Belgrade who represented the experimental group, while the second group included 25 tennis players TK “AS” from Belgrade who represented the control group. For evaluation of motor abilities used 4 tests. In order to determine differences between groups of respondents in the initial and final measurement was applied univariate analysis of variance. In order to determine the effect of training programs between the two tests was applied univariate analysis of covariance. Results: This research has proven that plyometric training, which was applied to a group of tennis players from Belgrade for a period of three months, youth ages contributed to improving their motor abilities, primarily explosive strength and agility. Discussion: Practice plyometric program combined with regular training for the development and improvement of techniques tennis game showed excellent results in order to improve the explosive leg strength, agility tennis players eksperimenatlne groups, and proved to be positive in working with junior tennis players ages. Research have shown that the development of explosive

  5. Effect of holding a racket on propulsion technique of wheelchair tennis players

    NARCIS (Netherlands)

    de Groot, S.; Bos, F.; Koopman, J.; Hoekstra, A. E.; Vegter, R. J. K.

    The purpose of this study was to determine possible differences in propulsion technique between propelling the wheelchair with and without a racket in the hand. Eight experienced wheelchair tennis players performed three submaximal exercise tests and six sprint tests on a wheelchair ergometer.

  6. Case report: bilateral ischial stress fractures in an elite tennis player

    International Nuclear Information System (INIS)

    Clarke, A.W.; Connell, D.A.

    2009-01-01

    A case report of bilateral ischial stress fractures in an elite tennis player initially mimicking hamstring pathology is described. This is an unusual site of stress fracture. Typical sites of stress fracture are well documented; however, awareness of less common sites of stress-related bone injury can aid early diagnosis and treatment before overt fracture occurs. (orig.)

  7. Case report: bilateral ischial stress fractures in an elite tennis player

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    Clarke, A.W.; Connell, D.A. [Royal National Orthopaedic Hospital NHS Trust, Department of Radiology, London, Middlesex (United Kingdom)

    2009-07-15

    A case report of bilateral ischial stress fractures in an elite tennis player initially mimicking hamstring pathology is described. This is an unusual site of stress fracture. Typical sites of stress fracture are well documented; however, awareness of less common sites of stress-related bone injury can aid early diagnosis and treatment before overt fracture occurs. (orig.)

  8. Evaluation of some physiological and biomotor features of young tennis players.

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    Gürkan DİKER

    2017-03-01

    Full Text Available Aim: The aim of this study is to determine some physiological and biomotor properties of 9-13 years old tennis players, and detect the effect of gender on performance. Material and Methods: 19 voluntary male tennis players, (average age: 11.21±1.08 year, average height: 1.52±0.11 cm, average weight: 44.76±7.87 kg, average sport background: 3.15±1.11 year ,17 voluntary female tennis players, (average age: 11.05±1.51 year, average height: 1.48±0.08 cm, average weight: 35.84±5.75 kg, sport background: 2.7±0.91 year who exercise at a tennis club in Ankara participated in this study. The subjects’ anthropometric measurements were taken. Then, 5 m sprint test, 10 m sprint test, flexibility test, push up test, sit up test, long jump test, medicine ball throw test, stability test were performed on the mentioned subjects. After calculating the descriptive statistics of the voluntaries, the data collected from performance tests were evaluated with Levene test and it showed normal distribution. T test was used to identify which groups had significant differences. Results: In the applied test, it has been observed that except the 10-m sprint test; there were not any significant (p<0.05 differences. Conclusion: we could state that there is no difference between gender and all parameters of 9-13 years old tennis players and the similar training models can be applied to the players regardless of their gender.

  9. Somatosensory Nerve Function, Measured by Vibration Thresholds in Asymptomatic Tennis Players: A Pilot Study

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    Sarah Harrisson

    2015-06-01

    Full Text Available Tennis players are vulnerable to injury in their upper limbs due to the repetitive exposure to racket vibrations and torsional forces during play, leading to musculoskeletal adaptations in the dominant arm including some evidence of changes in nerve function (Colak et al., 2004. Vibration is a sensitive technique for diagnosing mild pathology in clinically asymptomatic participant groups. It has been used in participants with various musculoskeletal disorders (Laursen et al., 2006 (Tucker et al., 2007 showing widespread and bilateral increases in vibration threshold. Tests of somatosensory function by vibration will be abnormal prior to changes in nerve conduction velocity. Thus vibration testing in a sub-clinical group of participants may a more sensitive measure of nerve function compared to nerve conduction by electrodiagnostic testing. The aim of this pilot study was to conduct an exploratory investigation to establish whether tennis players have a reduction in their somatosensory nerve function compared to non- tennis playing controls. It also set out to compare the somatosensory nerve function of the dominant compared to the non-dominant upper limb in tennis players. Healthy tennis players (males, n = 8, females, n = 2, mean age 22 years and control non- tennis playing volunteers (males, n = 6, females, n = 4, mean age 22 years were recruited on an opportunistic basis from a tennis centre in London UK. Participants were excluded if they had any history of neurological impairment, serious injury or fracture or any arthritic condition affecting the upper limbs, cervical or thoracic spine. Control participants were excluded if it was deemed that they played a sport where there was exposure to repetitive use of the upper body. Ethical approval was obtained from the University College London Ethics Committee and all participants gave written informed consent. A preliminary clinical examination was carried out on all participants followed by

  10. Has player development in men's tennis really changed? An historical rankings perspective.

    Science.gov (United States)

    Bane, Michael Kenneth; Reid, Machar; Morgan, Stuart

    2014-01-01

    Tennis federations are regularly faced with decisions regarding which athletes should be supported in financial terms, and for how long. The financial investments can be considerable, given the cost of competing on tour has been estimated at a minimum $121,000 per year and only the top 130 professionally ranked athletes earned enough prize money to cover this cost in 2012. This study investigates key points of progression in tennis players' careers, to determine how these have changed over time and how that evolution may inform talent development. Approximately 400,000 weekly rankings for 273 male professional tennis players between 1985 and 2010 were compiled, and historical trends in the time taken to reach career milestones were investigated by least-squares regression. The time between earning a first professional ranking point and entry into the Top 100 significantly increased over time for all considered athletes. This was at the detriment of time spent within the Top 100 for some athletes. Career peak Top 50-100 athletes have shown an increase in longevity. These results assist tennis federations in assessing the progress of developing athletes and highlight the evolving nature of the competition for top players.

  11. Investigation of game characteristics of elite tennis players on different surfaces.

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    Bülent KİLİT

    2017-03-01

    Full Text Available Aim: The purpose of this study was to investigation of game characteristics of elite tennis players on different surfaces (grass, clay and hard. Material and Methods: As a data collection tool used in the official web pages (www.rolandgarros.com, www.wimbledon.com, www.usopen.org in 2015 Grand Slam tennis tournaments. The study monitored the following game characteristics: 1st service %, aces, double faults, unforced error, winning % on 1st serve, winning % on 2nd serve, winners (including service, average 1st serve speed, average 2nd serve speed, average duration of games, average game number, total match duration, average duration of sets. One way ANOVA and Scheffe post-hoc test was performed in order to evaluate the game characteristics in this study. Results: Wimbledon had a significant more responses in terms of 1st service %, aces, winning % on 1st serve, average 1st and 2nd serve speed in male tennis players (p<0.05. For female tennis players, American open had more double faults, while Wimbledon had more aces, winning % on 1st Serve, winning % on 1st serve, average 1st and 2nd serve speed, winners responses (p<0.05. Conclusion: According to these results, serve values in fast court like Wimbledon were more than the others. Similar game characteristics were seen in French open (slow court and American open (medium court.

  12. ANAEROBIC CAPACITY MAY NOT BE DETERMINED BY CRITICAL POWER MODEL IN ELITE TABLE TENNIS PLAYERS

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    Alessandro M. Zagatto

    2008-03-01

    Full Text Available The aim of the present study was to verify the applicability of anaerobic work capacity (AWC determined from the critical power model in elite table tennis players. Eight male international level table tennis players participated in the study. The tests undertaken were: 1 A critical frequency test used to determinate the anaerobic work capacity; 2 Wingate tests were performed using leg and arm ergometers. AWC corresponded to 99.5 ± 29.1 table tennis balls. AWC was not related to peak (r = -0.25, mean (r = -0.02, relative peak (r = -0.49 or relative mean power (r = 0.01, nor fatigue index (r = -0.52 (Wingate leg ergometer. Similar correlations for peak (r = -0.34, mean (r = -0.04, relative peak (r = -0.49, relative mean power (r = -0.14 and peak blood lactate concentration (r = -0.08 were determined in the Wingate arm ergometer test. Based on these results the AWC determined by a modified critical power test was not a good index for measurement of anaerobic capacity in table tennis players

  13. Large asymmetric hypertrophy of rectus abdominis muscle in professional tennis players.

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    Joaquin Sanchis-Moysi

    Full Text Available PURPOSE: To determine the volume and degree of asymmetry of the musculus rectus abdominis (RA in professional tennis players. METHODS: The volume of the RA was determined using magnetic resonance imaging (MRI in 8 professional male tennis players and 6 non-active male control subjects. RESULTS: Tennis players had 58% greater RA volume than controls (P = 0.01, due to hypertrophy of both the dominant (34% greater volume, P = 0.02 and non-dominant (82% greater volume, P = 0.01 sides, after accounting for age, the length of the RA muscle and body mass index (BMI as covariates. In tennis players, there was a marked asymmetry in the development of the RA, which volume was 35% greater in the non-dominant compared to the dominant side (P<0.001. In contrast, no side-to-side difference in RA volume was observed in the controls (P = 0.75. The degree of side-to-side asymmetry increased linearly from the first lumbar disc to the pubic symphysis (r = 0.97, P<0.001. CONCLUSIONS: Professional tennis is associated with marked hypertrophy of the musculus rectus abdominis, which achieves a volume that is 58% greater than in non-active controls. Rectus abdominis hypertrophy is more marked in the non-dominant than in the dominant side, particularly in the more distal regions. Our study supports the concept that humans can differentially recruit both rectus abdominis but also the upper and lower regions of each muscle. It remains to be determined if this disequilibrium raises the risk of injury.

  14. Comparison of shock transmission and forearm electromyography between experienced and recreational tennis players during backhand strokes.

    Science.gov (United States)

    Wei, Shun-Hwa; Chiang, Jinn-Yen; Shiang, Tzyy-Yuang; Chang, Hsiao-Yun

    2006-03-01

    To test the hypothesis that recreational tennis players transmit more shock impact from the racket to the elbow joint than experienced tennis players during the backhand stroke. Also, to test whether recreational tennis players used higher electromyographic (EMG) activities in common wrist extensor and flexor around epicondylar region at follow-through phase. A repeated-measure, cross-sectional study. National College of Physical Education and Sports at Taipei, Taiwan. Twenty-four male tennis players with no abnormal forearm musculoskeletal injury participated in the study. According to performance level, subjects were categorized into 2 groups: experienced and recreational. Impact transmission and wrist extensor-flexor EMG for backhand acceleration, impact, and follow-through phases were recorded for each player. An independent t test with a significance level of 0.05 was used to examine mean differences of shock impact and EMG between the 2 test groups. One-way ANOVA associated with Tukey multiple comparisons was used to identify differences among different impact locations and EMG phases. Experienced athletes reduced the racket impact to the elbow joint by 89.2%, but recreational players reduced it by only 61.8%. The largest EMG differences were found in the follow-through phase (Pelbow joint and use larger wrist flexor and extensor EMG activities at follow-through phase of the backhand stroke. Follow-through control is proposed as a critical factor for reduction of shock transmission. Clinicians or trainers should instruct beginners to quickly release their grip tightness after ball-to-racket impact to reduce shock impact transmission to the wrist and elbow.

  15. BODY POSTURES AND ASYMMETRIES IN FRONTAL AND TRANSVERSE PLANES IN THE TRUNK AREA IN TABLE TENNIS PLAYERS

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    Katarzyna Barczyk-Pawelec

    2012-04-01

    Full Text Available The aim of this research was to assess the body posture within the trunk area in table tennis players and to estimate the correlations between the specific body posture types, their asymmetries and table tennis practice (training experience. To evaluate body posture the photogrammetric method based on the Moiré phenomenon with equipment by CQ Electronic was applied. Tests of significance of difference and correlation were used to estimate the correlation of the observed asymmetries with the training experience. 40 table tennis players and 43 subjects not practising sports participated in the research. The analysis of the results revealed that table tennis players, unlike non-players, are characterized by kyphotic body posture. It probably results from a specific trunk, head and limb position during table tennis matches. Thus, many asymmetries in frontal and transverse planes were observed in the examined table tennis players. Perhaps table tennis, which is characterized by intensive and one-sided trunk muscle work during its performance, is in favour of creating asymmetries. The majority of subjects did not reveal any statistically significant correlations between the observed body posture types, their asymmetries and training experience. However, it was observed that training experience is significantly related to the considerable asymmetry of the inclination angle of shoulder line (KLB. It may result from the negative influence of very intensive, one-sided work and constant work of the shoulder girdle muscles of the playing limb with negligence of exercises of the second limb.

  16. Upper limb joint muscle/tendon injury and anthropometric adaptations in French competitive tennis players.

    Science.gov (United States)

    Rogowski, Isabelle; Creveaux, Thomas; Genevois, Cyril; Klouche, Shahnaz; Rahme, Michel; Hardy, Philippe

    2016-01-01

    The purpose of this study was to examine the relationship between the upper limb anthropometric dimensions and a history of dominant upper limb injury in tennis players. Dominant and non-dominant wrist, forearm, elbow and arm circumferences, along with a history of dominant upper limb injuries, were assessed in 147 male and female players, assigned to four groups based on location of injury: wrist (n = 9), elbow (n = 25), shoulder (n = 14) and healthy players (n = 99). From anthropometric dimensions, bilateral differences in circumferences and in proportions were calculated. The wrist group presented a significant bilateral difference in arm circumference, and asymmetrical bilateral proportions between wrist and forearm, as well as between elbow and arm, compared to the healthy group (6.6 ± 3.1% vs. 4.9 ± 4.0%, P elbow group displayed asymmetrical bilateral proportions between forearm and arm compared to the healthy group (-0.4 ± 4.3% vs. 1.5 ± 4.0%, P elbow circumference, and asymmetrical bilateral proportions between forearm and elbow when compared to the healthy group (5.8 ± 4.7% vs. 3.1 ± 4.8%, P tennis injury and asymmetry in upper limb proportions using high-tech measurements in symptomatic tennis players.

  17. Medical reasons behind player departures from male and female professional tennis competitions.

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    Okholm Kryger, Katrine; Dor, Frédéric; Guillaume, Marion; Haida, Amal; Noirez, Philippe; Montalvan, Bernard; Toussaint, Jean-François

    2015-01-01

    The number of retirements, withdrawals, and "lucky losers" (the replacement of a player who withdraws before the start of the tournament by a losing player from the qualifying round) from professional tennis tournaments has increased, but the reasons behind such departures have not yet been analyzed. An official consensus statement has been conducted to allow a general categorization of injuries in tennis. To determine the reasons for departure and injury rates in professional tennis. Descriptive epidemiology study. All reasons for departures were collected from official Association of Tennis Professionals (ATP) and Women's Tennis Association (WTA) web pages. All tournaments apart from the 4 major competitions (the Australian Open, French Open, Wimbledon, and US Open) were included for the period 2001-2012 for men and women. Personal data, tournament information, surface, match setting, date, and reason were obtained for each departure scenario. Variations in departure and injury rates were seen throughout the season. Women left and were injured significantly more than men. Women mainly left because of thigh injuries, whereas men left mainly because of back injuries. Playing surface only had an influence on the risk of lower back injuries. Only women's departures were affected by the tournament round. A high number of departures from tournaments have occurred during the past 10 years on the ATP and WTA circuits. Injuries were the main reasons of these departures, regardless of the type of departure and player sex. The back and thigh were the main locations of injuries for men and women, respectively. © 2014 The Author(s).

  18. Descriptive profile of hip rotation range of motion in elite tennis players and professional baseball pitchers.

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    Ellenbecker, Todd S; Ellenbecker, Gail A; Roetert, E Paul; Silva, Rogerio Teixeira; Keuter, Greg; Sperling, Fabio

    2007-08-01

    Repetitive loading to the hip joint in athletes has been reported as a factor in the development of degenerative joint disease and intra-articular injury. Little information is available on the bilateral symmetry of hip rotational measures in unilaterally dominant upper extremity athletes. Side-to-side differences in hip joint range of motion may be present because of asymmetrical loading in the lower extremities of elite tennis players and professional baseball pitchers. Cohort (cross-sectional) study (prevalence); Level of evidence, 1. Descriptive measures of hip internal and external rotation active range of motion were taken in the prone position of 64 male and 83 female elite tennis players and 101 male professional baseball pitchers using digital photos and computerized angle calculation software. Bilateral differences in active range of motion between the dominant and nondominant hip were compared using paired t tests and Bonferroni correction for hip internal, external, and total rotation range of motion. A Pearson correlation test was used to test the relationship between years of competition and hip rotation active range of motion. No significant bilateral difference (P > .005) was measured for mean hip internal or external rotation for the elite tennis players or the professional baseball pitchers. An analysis of the number of subjects in each group with a bilateral difference in hip rotation greater than 10 degrees identified 17% of the professional baseball pitchers with internal rotation differences and 42% with external rotation differences. Differences in the elite male tennis players occurred in only 15% of the players for internal rotation and 9% in external rotation. Female subjects had differences in 8% and 12% of the players for internal and external rotation, respectively. Statistical differences were found between the mean total arc of hip range of internal and external rotation in the elite tennis players with the dominant side being greater

  19. Brachial biceps tendon injuries in young female high-level tennis players.

    Science.gov (United States)

    Tsur, A; Gillson, S

    2000-06-01

    To evaluate brachial biceps tendon lesions in four young female tennis players who complained about anterior shoulder pain on their dominant side. Medical and sport's activity history, palpation of the painful zone, Ghilchrist (palm-up) test, and brachial biceps contraction against resistance were performed. The two girls who suffered from mild tenderness in the bicipital groove and over the anterior aspect of the upper arm and the shoulder joint, had tendinitis of the long biceps head. The two girls who suffered from severe tenderness just under the groove, had a partial tear in the long head of the biceps. Ghilchrist test was positive in all girls. Tennis players can have shoulder pain without clear history of trauma. Pain occurred probably as a result of technical errors or use of inadequate equipment.

  20. A grounded theory of young tennis players use of music to manipulate emotional state.

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    Bishop, Daniel T; Karageorghis, Costas I; Loizou, Georgios

    2007-10-01

    The main objectives of this study were (a) to elucidate young tennis players' use of music to manipulate emotional states, and (b) to present a model grounded in present data to illustrate this phenomenon and to stimulate further research. Anecdotal evidence suggests that music listening is used regularly by elite athletes as a preperformance strategy, but only limited empirical evidence corroborates such use. Young tennis players (N = 14) were selected purposively for interview and diary data collection. Results indicated that participants consciously selected music to elicit various emotional states; frequently reported consequences of music listening included improved mood, increased arousal, and visual and auditory imagery. The choice of music tracks and the impact of music listening were mediated by a number of factors, including extramusical associations, inspirational lyrics, music properties, and desired emotional state. Implications for the future investigation of preperformance music are discussed.

  1. Motivational profiles in table tennis players: Relations with performance anxiety and subjective vitality.

    Science.gov (United States)

    Chu, Tsz Lun Alan; Zhang, Tao; Hung, Tsung-Min

    2018-06-27

    Research has suggested the need to use a person-centred approach to examine multidimensionality of motivation. Guided by self-determination theory (Deci & Ryan, 1985), the primary aim of the present study was to examine the motivational profiles in table tennis players and their composition by gender, country, training status, and competition levels (from recreational to international). The secondary aim was to examine the differences in performance anxiety and subjective vitality across the motivational profiles. Participants were 281 table tennis players from multiple countries, mostly the U.S. and China. Hierarchical and nonhierarchical cluster analyses were conducted and showed three motivational profiles with distinct quantity and quality: "low", "controlled", and "self-determined". Chi-square tests of independence demonstrated significant differences in their cluster membership by country, formal training with a coach, and competition levels, but not gender. MANCOVA results indicated differences in performance anxiety and subjective vitality across the motivational profiles, in which the controlled profile had the greatest anxiety symptoms. These differences are attributed to the quality over quantity of motivation, which have meaningful implications for table tennis coaches and sport psychology consultants to diagnose and intervene with players in order to reduce their performance anxiety and improve their well-being.

  2. Flexibility of internal and external glenohumeral rotation of junior female tennis players and its correlation with performance ranking.

    Science.gov (United States)

    Chiang, Ching-Cheng; Hsu, Chih-Chia; Chiang, Jinn-Yen; Chang, Weng-Cheng; Tsai, Jong-Chang

    2016-12-01

    [Purpose] The purpose of this study was to compare the internal and external rotation of the dominant and nondominant shoulders of adolescent female tennis players. The correlation between the shoulder rotation range of motion and the player's ranking was also analyzed. [Subjects and Methods] Twenty-one female junior tennis players who were 13 to 18 years old participated in this study. A standard goniometer was used to measure the internal and external rotation of both glenohumeral joints. The difference in internal and external rotation was calculated as the glenohumeral rotation deficit. The year-end ranking of each player was obtained from the Chinese Taipei Tennis Association. [Results] The internal rotation of the dominant shoulder was significantly smaller than that of the nondominant shoulder. Moreover, player ranking was significantly and negatively correlated with the internal rotation range of motion of both shoulders. On the other hand, the correlations of the internal and external rotation ranges of motion with the age, height, and weight were not significant. [Conclusion] The flexibility of the glenohumeral internal rotation is smaller in the dominant shoulder than of the nondominant shoulder in these junior female tennis players. Flexibility of the glenohumeral internal rotation may be a factor affecting performance in junior female tennis players.

  3. Characteristics and prognosis of medial epicondylar fragmentation of the humerus in male junior tennis players.

    Science.gov (United States)

    Harada, Mikio; Takahara, Masatoshi; Maruyama, Masahiro; Takagi, Michiaki

    2014-10-01

    Although medial epicondylar fragmentation of the humerus is a reported elbow injury in junior tennis players, there have been only a few studies on this entity, and none have investigated the characteristics and prognosis of medial epicondylar fragmentation. Forty-one male junior tennis players, aged 11 to 14 years (mean, 13 years), underwent elbow examination by ultrasonography. Elbow re-examination was performed in subjects with medial epicondylar fragmentation at an average of 20 months (12-30 months) after the initial examination. On examination, 9 subjects (22%) had elbow pain. Ultrasonography showed that 6 subjects (15%) had medial epicondylar fragmentation, all of whom had elbow pain. Medial epicondylar fragmentation was present in 5 (38%) of 13 subjects aged 11 to 12 years and in 1 (4%) of 28 aged 13 to 14 years. More subjects aged 11 to 12 years had medial epicondylar fragmentation (P = .0084). All 6 subjects with medial epicondylar fragmentation continued to play tennis between the initial elbow examination and the re-examination. At re-examination, although ultrasonography showed that 5 developed bone union and 1 had nonunion, 3 subjects (50%) reported elbow pain. Our results demonstrated that subjects aged 11 to 12 years had a high frequency (38%) of medial epicondylar fragmentation. Although medial epicondylar fragmentation was the main cause of elbow pain (67%) at the initial elbow examination, all 6 players with medial epicondylar fragmentation continued to play tennis between the initial elbow examination and the re-examination. At re-examination, 5 subjects presented spontaneous bone union (83%), but 3 subjects (50%) reported elbow pain. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  4. The influence of shoe drop on the kinematics and kinetics of children tennis players.

    Science.gov (United States)

    Herbaut, Alexis; Chavet, Pascale; Roux, Maxime; Guéguen, Nils; Gillet, Christophe; Barbier, Franck; Simoneau-Buessinger, Emilie

    2016-11-01

    This study investigated the immediate effects of reducing the shoe drop (i.e. the difference between the heel and the forefoot height) on the kinematics and kinetics of the lower extremities of children tennis players performing a tennis-specific movement. Thirteen children tennis players performed a series of simulated open stance forehands wearing 3 pairs of shoes differing only in the drop: 0 (D0), 6 (D6) and the control condition of 12 mm (D12). Two embedded forceplates and a motion capture system were used to analyse the ground reaction forces and ankle and knee joint angles and moments of the leading lower limb. In D6 compared with D12, the peak impact force was reduced by 24% (p = .004) and the ankle was less dorsiflexed at foot strike (p = .037). In D0 compared with D12, the peak impact force was reduced by 17% (p = .049), the ankle was less dorsiflexed at foot strike (p = .045) and the knee was more flexed at foot strike (p = .007). In addition, 4 out of 13 participants (31%) presented a forefoot strike pattern for some of the trials in D0. No difference was observed across shoe conditions for the peak knee extensor moment (p = .658) or the peak ankle plantarflexor moment (p = .071). The results provide preliminary data supporting the hypothesis that for children tennis players, using a 6-mm lower shoe drop might reduce heel impact forces and thus limit potentially impact-related injuries.

  5. Tennis Play Intensity Distribution and Relation with Aerobic Fitness in Competitive Players.

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    Ernest Baiget

    Full Text Available The aims of this study were (i to describe the relative intensity of simulated tennis play based on the cumulative time spent in three metabolic intensity zones, and (ii to determine the relationships between this play intensity distribution and the aerobic fitness of a group of competitive players. 20 male players of advanced to elite level (ITN performed an incremental on-court specific endurance tennis test to exhaustion to determine maximal oxygen uptake (VO2max and the first and second ventilatory thresholds (VT1, VT2. Ventilatory and gas exchange parameters were monitored using a telemetric portable gas analyser (K4 b2, Cosmed, Rome, Italy. Two weeks later the participants played a simulated tennis set against an opponent of similar level. Intensity zones (1: low, 2: moderate, and 3: high were delimited by the individual VO2 values corresponding to VT1 and VT2, and expressed as percentage of maximum VO2 and heart rate. When expressed relative to VO2max, percentage of playing time in zone 1 (77 ± 25% was significantly higher (p < 0.001 than in zone 2 (20 ± 21% and zone 3 (3 ± 5%. Moderate to high positive correlations were found between VT1, VT2 and VO2max, and the percentage of playing time spent in zone 1 (r = 0.68-0.75, as well as low to high inverse correlations between the metabolic variables and the percentage of time spent in zone 2 and 3 (r = -0.49-0.75. Players with better aerobic fitness play at relatively lower intensities. We conclude that players spent more than 75% of the time in their low-intensity zone, with less than 25% of the time spent at moderate to high intensities. Aerobic fitness appears to determine the metabolic intensity that players can sustain throughout the game.

  6. Construction of training proсess of tennis players aged 5-6 years, taking into account the specifics of the development and control of their coordination skills

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    A. M. Kozak

    2014-12-01

    Full Text Available Purpose: Presented results of the research to determine the features of the construction of the training process for young tennis players aged 5-6 years, in particular the specific application of pedagogical testing to test the level of development of their coordination skills. Material: The survey was attended by 30 experts. Results: Established that bigger part of coaches build the training process at the initial stage of preparation on the basis of the game approach and apply a program of the International Tennis Federation "Play and stay". About two-thirds of the coaches do not carry out a selection of tennis players aged 5-6 or make it only in individual cases. To assess the level of development of motor abilities are equally important coaches define pedagogical supervision and pedagogical testing. A significant proportion of respondents (43% previously had experience in assessing motor abilities of tennis players 5-6 years by mean of pedagogical tests. Conclusions: Overwhelming majority of coaches support the idea of having to modify the tests in accordance with the age characterristics of tennis players aged 5-6 years and expediency of complex assessment of the level of development of their coordination skills.

  7. Tactical proficiency among table tennis players with and without intellectual disabilities.

    Science.gov (United States)

    Van Biesen, Debbie; Mactavish, Jennifer; Vanlandewijck, Yves

    2014-01-01

    The effect of intellectual impairment on sports performance has received limited attention by researchers. As a contribution to closing this gap, the purpose of the present investigation was to examine the differences in tactical proficiency between table tennis players with and without intellectual disabilities (ID). These groups were matched for training-volume and experience and consisted of 41 male (age = 27±8) and 30 female (age= 28±8) elite players with ID and a reference group of 12 male (age= 24±12) and 5 female (age= 20±9) players without ID. In two different test settings - one a World Championship and the other a training camp - the players in each group performed 60 semi-standardised rallies against the same opponent. Players were told that 12 sets of five identical services would be delivered, and their goal was to return the service with the intention of 'winning the point'. The test results were validated for this study, to compute tactical proficiency scores (maximal score of eight points) for each player. A two-way Analysis of Variance (ANOVA) revealed significantly lower proficiency scores for players with ID than for those without ID. Repeated-measures ANOVA revealed that within each series of five rallies, starting with identical services, all participants were able to significantly improve their tactical proficiency gradually, but players without ID scored 4.3±0.5 from the first ball on, and while athletes with ID only 3.3±0.7 after five balls. The results of this study indicate that ID is associated with decreased tactical proficiency in table tennis.

  8. MRI findings in the lumbar spines of asymptomatic elite junior tennis players

    International Nuclear Information System (INIS)

    Rajeswaran, G.; Healy, J.C.; Turner, M.; Gissane, C.

    2014-01-01

    To evaluate the MRI findings in the lumbar spines of asymptomatic elite junior tennis players. The lumbar spine MRI studies of 98 asymptomatic junior elite tennis players (51 male, 47 female) with a mean age of 18 years (age range 11.2-26.3 years; standard deviation 3.1) was reviewed by two consultant musculoskeletal radiologists using consensus opinion. Images were assessed using accepted classification systems. Four players (4 %) had no abnormality. Facet joint arthropathy occurred in 89.7 % of the players, being mild in 84.5 % of cases. There were 41 synovial cysts in 22.4 % of the cohort all occurring in the presence of facet arthropathy. Disc degeneration was noted in 62.2 % of players, being mild in 76.2 % of those affected. Disc herniation was noted in 30.6 % of players, with 86.1 % of these being broad based and 13.9 % being focal. There was nerve root compression in 2 %. There were 41 pars interarticularis abnormalities in 29.6 % of patients, 63.4 % of these being grades 1-3. There was grade 1 spondylolisthesis in 5.1 % of players. The prevalence of facet joint arthropathy, disc degeneration, disc herniation and pars interarticularis fracture was lower in female players than in male and lower in the under 16-year-olds compared with the over 20-year-olds. There is a significant amount of underlying pathology that would normally go undetected in this group of asymptomatic elite athletes. Whilst these findings cannot be detected clinically, their relevance is in facilitating appropriate prehabilitation to prevent loss of playing time and potentially career-ending injuries. (orig.)

  9. Anger Management - Evaluation of a Cognitive-Behavioral Training Program for Table Tennis Players

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    Steffgen Georges

    2017-01-01

    Full Text Available Based on a systematic review of the literature on anger and anger management in sport, there is evidence that anger might be dysfunctional, especially in sports requiring selective attention and fine-tuned motor skills. The research literature suggests that cognitive-behavioral intervention programs can be fruitful in helping athletes to understand and control dysfunctional anger. Therefore, the main goal of the present study was to evaluate the effectiveness of a brief training program for table tennis players in cognitive-behavioral anger management that aimed at changing their noneffective anger reactions. The sample comprised 18 young competitive table tennis players (age range from 16 to 22 years divided randomly into a treatment (n = 10 and a control group (n = 8. A trained group leader instructed the treatment group. Six sessions were held over a period of two months. Cognitive-relaxation coping skills associated with social skills of subjects from the treatment group were compared to no-treatment controls. Psychological measurements (i.e., self-reports on anger were applied before, during and after treatment as well as in a follow-up session. The one-year follow-up session revealed that, in contrast to the control group, the treatment group showed a significant reduction in outwardly negative anger expression as well as anger reactions specific to table tennis. Despite limitations inherent in the research design, the training program was deemed effective.

  10. Sleep restriction and serving accuracy in performance tennis players, and effects of caffeine.

    Science.gov (United States)

    Reyner, L A; Horne, J A

    2013-08-15

    Athletes often lose sleep on the night before a competition. Whilst it is unlikely that sleep loss will impair sports mostly relying on strength and endurance, little is known about potential effects on sports involving psychomotor performance necessitating judgement and accuracy, rather than speed, as in tennis for example, and where caffeine is 'permitted'. Two studies were undertaken, on 5h sleep (33%) restriction versus normal sleep, on serving accuracy in semi-professional tennis players. Testing (14:00 h-16:00 h) comprised 40 serves into a (1.8 m×1.1 m) 'service box' diagonally, over the net. Study 1 (8 m; 8 f) was within-Ss, counterbalanced (normal versus sleep restriction). Study 2 (6m;6f -different Ss) comprised three conditions (Latin square), identical to Study 1, except for an extra sleep restriction condition with 80 mg caffeine vs placebo in a sugar-free drink, given (double blind), 30 min before testing. Both studies showed significant impairments to serving accuracy after sleep restriction. Caffeine at this dose had no beneficial effect. Study 1 also assessed gender differences, with women significantly poorer under all conditions, and non-significant indications that women were more impaired by sleep restriction (also seen in Study 2). We conclude that adequate sleep is essential for best performance of this type of skill in tennis players and that caffeine is no substitute for 'lost sleep'. 210. © 2013.

  11. The influence of tennis court surfaces on player perceptions and biomechanical response.

    Science.gov (United States)

    Starbuck, Chelsea; Damm, Loïc; Clarke, James; Carré, Matt; Capel-Davis, Jamie; Miller, Stuart; Stiles, Victoria; Dixon, Sharon

    2016-09-01

    This study aimed to examine player perceptions and biomechanical responses to tennis surfaces and to evaluate the influence of prior clay court experience. Two groups with different clay experiences (experience group, n = 5 and low-experience group, n = 5) performed a 180° turning movement. Three-dimensional ankle and knee movements (50 Hz), plantar pressure of the turning step (100 Hz) and perception data (visual analogue scale questionnaire) were collected for two tennis courts (acrylic and clay). Greater initial knee flexion (acrylic 20. 8 ± 11.2° and clay 32.5 ± 9.4°) and a more upright position were reported on the clay compared to the acrylic court (P < 0.05). This suggests adaptations to increase player stability on clay. Greater hallux pressures and lower midfoot pressures were observed on the clay court, allowing for sliding whilst providing grip at the forefoot. Players with prior clay court experience exhibited later peak knee flexion compared to those with low experience. All participants perceived the differences in surface properties between courts and thus responded appropriately to these differences. The level of previous clay court experience did not influence players' perceptions of the surfaces; however, those with greater clay court experience may reduce injury risk as a result of reduced loading through later peak knee flexion.

  12. JOINT KINETICS TO ASSESS THE INFLUENCE OF THE RACKET ON A TENNIS PLAYER'S SHOULDER

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    Thomas Creveaux

    2013-06-01

    Full Text Available This study aimed at investigating the influence of three rackets on shoulder net joint moments, power and muscle activity during the flat tennis serve under field- conditions. A 6-camera Eagle® motion analysis system, operating at 256 Hz, captured racket and dominant upper limb kinematics of the serve in five tennis players under three racket conditions (A: low mass, high balance and polar moment, B: low three moments of inertia, and C: high mass, swingweight and twistweight. The electromyographic activity of six trunk and arm muscles was simultaneously recorded. Shoulder net joint moments and power were computed by 3D inverse dynamics. The results showed that greater shoulder joint power and internal/external rotation peak moments were found to accelerate and decelerate racket A in comparison with the racket C. Moreover, serving with the racket A resulted in less activity in latissimus dorsi muscle during the acceleration phase, and biceps brachii muscle during the follow-through phase when compared with racket C. These initial findings encourage studying the biomechanical measurements to quantify the loads on the body during play in order to reduce them, and then prevent shoulder injuries. Racket specifications may be a critical point for coaches who train players suffering from shoulder pain and chronic upper limb injuries should be considered in relation to the racket specifications of the players

  13. Changes of indicators of special physical fitness of young female tennis-players at the stage of basic training

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    Oleg Shevchenko

    2014-12-01

    Full Text Available Purpose: to improve performance of special physical qualities of young tennis players at the stage of initial training. Material and Methods: analysis of scientific and methodical literature, test of physical fitness, pedagogical experiment, methods of mathematical statistics. The study involved 11 women aged 7–8 years in the group of initial training. In the training sessions of physical training of young tennis players the game has been used teaching method. Results: to investigate the changes in the indices of physical fitness of young tennis players 7–8 years. Analyzed the impact of the development on the physical qualities of assimilation techniques. Pointed out that for the qualitative development of physical qualities necessary to use outdoor games and relay races. Revealed that the results of the physical fitness of young tennis players after the pedagogical experiment and had risen significantly different to those in the beginning of the study (P<0,05, except for indicators exercises "run on 18 meters". Conclusions: it was found that the use of training sessions on physical preparation of mobile games and relays increase the interest and motivation for tennis lessons for children in the group of initial training.

  14. THE COMPARISON OF PHYSICAL ABILITIES BETWEEN ALPINE SKIING SKIERS' AND TENNIS PLAYERS

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    Giovanis Vassilis.

    2012-11-01

    Full Text Available The aim of the present research was the physical abilities diagnosis of Alpine skiing skiers and tennis players, as well the comparison of these before and after the ski period. The sample of 54 individuals emanated from two teams of different sports: skiing (N = 28 and tennis (N = 26, while the level was advancing for both. For the diagnosis and the comparison of physical abilities used four tests of Alpine skiing on dry ground the same day of December 2008 and April 2009 respectively: 30m flight start, eight continuous jumping, slalom on "folder", jumping up and down on a step with height 40cm x 40sec. The statistical analysis done with SPSS 18 program, included controls t - test, p=bilateral, for dependent samples and correlation analysis at significance level a= 0.05 with freedom degrees df = N - 1. In conclusion, in the present research the ski team (men and women presented the improvement afterwards the season in 2 of 4 tests and in the corresponding physical abilities (explosive force, t = 2,970, p < .01 and agility t = 3.533, p < .00, while also the tennis team (men and women presented improvement in 2 of 4 tests (explosive force, t = 2,397, p < .02 and anaerobic ability, t = 3.192, p < .00. Finally the common characteristic of the two teams was the performance improvement in the explosive force and their decreased attribution in speed.

  15. A PHYSIOLOGICAL CASE STUDY OF A PARALYMPIC WHEELCHAIR TENNIS PLAYER: REFLECTIVE PRACTISE

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    Nicholas J. Diaper

    2009-06-01

    Full Text Available This study was designed to examine the physiological changes caused by long-term training in a world class female tennis player in preparation for a major championship. Additionally, we aim to describe the training interventions and determine a suitable cooling strategy that was to be used at the 2004 Paralympic Games. The athlete underwent regular physiological assessment during 2003-2004. Physiological measures involved body composition, submaximal and peak oxygen uptake and key variables associated with maximal sprinting. In addition, a suitable match-play cooling intervention and hydration strategy was also explored. Body composition improved over the course of the study. Aerobic capacity fell by 21%, yet the submaximal physiological variables such as lactate profile and pushing economy improved. The trade off of aerobic capacity was perhaps noticeably counter-balanced with the maintenance of the peak sprinting speed and improvement found in the fatigue profile across ten repeated sprints. The extensive training programme was responsible for these changes and these adaptations resulted in a more confident athlete, in peak physical condition leading into the Paralympic Games. It is difficult to appreciate the extent to which this work had an impact on tennis performance given the skill requirements of wheelchair tennis and this warrants future attention

  16. A Physiological Case Study of a Paralympic Wheelchair Tennis Player: Reflective Practise

    Science.gov (United States)

    Diaper, Nicholas J.; Goosey-Tolfrey, Victoria L.

    2009-01-01

    This study was designed to examine the physiological changes caused by long-term training in a world class female tennis player in preparation for a major championship. Additionally, we aim to describe the training interventions and determine a suitable cooling strategy that was to be used at the 2004 Paralympic Games. The athlete underwent regular physiological assessment during 2003-2004. Physiological measures involved body composition, submaximal and peak oxygen uptake and key variables associated with maximal sprinting. In addition, a suitable match-play cooling intervention and hydration strategy was also explored. Body composition improved over the course of the study. Aerobic capacity fell by 21%, yet the submaximal physiological variables such as lactate profile and pushing economy improved. The trade off of aerobic capacity was perhaps noticeably counter-balanced with the maintenance of the peak sprinting speed and improvement found in the fatigue profile across ten repeated sprints. The extensive training programme was responsible for these changes and these adaptations resulted in a more confident athlete, in peak physical condition leading into the Paralympic Games. It is difficult to appreciate the extent to which this work had an impact on tennis performance given the skill requirements of wheelchair tennis and this warrants future attention. Key points Physiological adaptations were apparent over the two-year training period. The training emphasis resulted in a reduction in aerobic capacity, yet an improvement in repetitive sprint performance was seen leading into the Major competition. An effective cooling technique was identified that could be used during wheelchair tennis performance. The athlete and coaches were complimentary to the physiological support provided, which resulted in a more confident athlete at the Paralympic Games. PMID:24149542

  17. Shoe drop reduction influences the lower limb biomechanics of children tennis players during an open stance forehand: A longitudinal study.

    Science.gov (United States)

    Herbaut, Alexis; Simoneau-Buessinger, Emilie; Barbier, Franck; Gillet, Christophe; Roux, Maxime; Guéguen, Nils; Chavet, Pascale

    2017-11-01

    Compared to traditional tennis shoes, using 0-drop shoes was shown to induce an immediate switch from rear- to forefoot strike pattern to perform an open stance tennis forehand for 30% of children tennis players. The purpose of the study was to examine the long-term effects of a gradual reduction in the shoe drop on the biomechanics of children tennis players performing open stance forehands. Thirty children tennis players participated in 2 laboratory biomechanical test sessions (intermediate: +4 months and final: +8 months) after an inclusion visit where they were randomly assigned to control (CON) or experimental (EXP) group. CON received 12-mm-drop shoes twice, whereas EXP received 8 mm then 4-mm-drop shoes. Strike index indicated that all CON were rearfoot strikers in intermediate and final test sessions. All EXP were rearfoot strikers in intermediate test session, but half the group switched towards a forefoot strike pattern in final test session. This switch resulted in a decreased loading rate of the ground reaction force (-73%, p = .005) but increased peak ankle plantarflexors moment (+47%, p = .050) and peak ankle power absorption (+107%, p = .005) for these participants compared with CON. Biomechanical changes associated with the long-term use of partial minimalist shoes suggest a reduction in heel compressive forces but an increase in Achilles tendon tensile forces.

  18. Incidence of musculoskeletal sport injuries in a sample of male and female recreational paddle-tennis players.

    Science.gov (United States)

    Castillo-Lozano, Romualdo; Casuso-Holgado, Maria J

    2017-06-01

    Nowadays paddle-tennis is practiced by the Spanish population, not only in a professional or semi-professional way, but also as a recreational sport. As occurs in tennis, the repetition of specific actions and gestures in paddle-tennis could be a factor associated with one or more types of musculoskeletal injuries in this population. The aim of this research was to describe the incidence and location of musculoskeletal injuries in a sample of Spanish recreational paddle-tennis and to explore a possible causality injury model, focusing on gender contribution. The sample was composed of 113 active paddle-tennis players, of whom 47.78% were men. The participants were asked about the injuries they had suffered during their paddle participation. Other variables such as age, physical position in the game and level of ability were taken into account. 85.4% of the players reported any sport paddle injury. The elbow and the lower back have been shown as the most common regions of injury, followed by knee and shoulder injuries. Female group reported a higher injury incidence due to playing paddle-tennis (OR=0.169; P=0.008). Significant differences also existed between the genders for calf injury location (OR=0.208; P=0.020). A global injury model explaining 22.5% of the variance has been observed. Gender seems to explain 7.4% of the variance. Being a medium-aged weighty right-handed woman seems to be the profile more likely to report paddle-tennis related musculoskeletal injuries. A lack of literature regarding paddle-tennis related injuries has been observed. It could be said that our results contribute substantially in this field.

  19. MONITORING TRAINING LOADS, STRESS, IMMUNE-ENDOCRINE RESPONSES AND PERFORMANCE IN TENNIS PLAYERS

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    Rodrigo Vitasovic Gomes

    2013-06-01

    Full Text Available The study aim was to investigate the effect of a periodised pre-season training plan on internal training load and subsequent stress tolerance, immune-endocrine responses and physical performance in tennis players. Well-trained young tennis players (n = 10 were monitored across the pre-season period, which was divided into 4 weeks of progressive overloading training and a 1-week tapering period. Weekly measures of internal training load, training monotony and stress tolerance (sources and symptoms of stress were taken, along with salivary testosterone, cortisol and immunoglobulin A. One repetition maximum strength, running endurance, jump height and agility were assessed before and after training. The periodised training plan led to significant weekly changes in training loads (i.e. increasing in weeks 3 and 4, decreasing in week 5 and post-training improvements in strength, endurance and agility (P < 0.05. Cortisol concentration and the symptoms of stress also increased in weeks 3 and/or 4, before returning to baseline in week 5 (P < 0.05. Conversely, the testosterone to cortisol ratio decreased in weeks 3 and 4, before returning to baseline in week 5 (P < 0.05. In conclusion, the training plan evoked adaptive changes in stress tolerance and hormonal responses, which may have mediated the improvements in physical performance.

  20. Sling-based Exercise for External Rotator Muscles: Effects on Shoulder Profile in Young Recreational Tennis Players

    Science.gov (United States)

    Goulet, Charles; Rogowski, Isabelle

    2016-12-19

    Context: Tennis playing generates specific adaptations, particularly at the dominant shoulder. It remains to be established whether shoulder strength balance can be restored by sling-based training for adolescent recreational tennis players. Objective: We added a sling-based exercise for shoulder external rotators to investigate its effects on external rotator muscle strength, on internal rotator muscle strength, on glenohumeral range of motion and on tennis serve performance. Design: Test-retest design. Setting: Tennis training sports facilities. Participants: Twelve adolescent male players volunteered to participate in this study (age: 13.3 ± 0.5 years; height: 1.64 ± 0.07 cm, mass: 51.7 ± 5.8 kg, International Tennis Number: 8). Intervention: The procedure spanned 10 weeks. For the first five weeks, players performed their regular training (RT) twice a week. For the last five weeks, a sling-based exercise (SE) for strengthening the shoulder external rotator muscles was added to their regular training. Main Outcome Measures: Maximal isometric strength of shoulder external and internal rotator muscles and glenohumeral range of motion in external and internal rotation were assessed in both shoulders. Serve performance was also evaluated by accuracy and post-impact ball velocity, using a radar gun. Results: No change was found in any measurement after the RT period. Significant increases in external (~+5%; pexternal/internal strength ratio (~+4%; pexternal rotator muscles appears effective in restoring strength balance at the dominant shoulder, and may prevent adolescent tennis players from sustaining degenerative shoulder problems which could later impair their performance of daily and work-related tasks.

  1. Biomechanics of the elbow joint in tennis players and relation to pathology

    NARCIS (Netherlands)

    Eygendaal, Denise; Rahussen, F. T. G.; Diercks, R. L.

    Elbow injuries constitute a sizeable percentage of tennis injuries. A basic understanding of biomechanics of tennis and analysis of the forces, loads and motions of the elbow during tennis will improve the understanding of the pathophysiology of these injuries. All different strokes in tennis have a

  2. Biomechanics of the elbow joint in tennis players and relation to pathology.

    Science.gov (United States)

    Eygendaal, Denise; Rahussen, F Th G; Diercks, R L

    2007-11-01

    Elbow injuries constitute a sizeable percentage of tennis injuries. A basic understanding of biomechanics of tennis and analysis of the forces, loads and motions of the elbow during tennis will improve the understanding of the pathophysiology of these injuries. All different strokes in tennis have a different repetitive biomechanical nature that can result in tennis-related injuries. In this article, a biomechanically-based evaluation of tennis strokes is presented. This overview includes all tennis-related pathologies of the elbow joint, whereby the possible relation of biomechanics to pathology is analysed, followed by treatment recommendations.

  3. Trening sensomotoryczny w procesie szkolenia sportowego tenisistów = sensomotoric training in the process of sport training of tennis players

    Directory of Open Access Journals (Sweden)

    Ewa Waldzińska

    2015-08-01

    Abstract The purpose of the research was to portray the need of including sensomotoric trainings into the sport training process of tennis players. At present developmental tendencies and sport progress in tennis require from coaches comprehensive work with players in early phases of training. Apart from preparing technical-tactical abilities and mental training, there is a clear need to apply exercises improving stability of joints for young, adolescent competitors. Specialist trainings with the physiotherapist that improve kinesthesia and neuromuscular coordination will minimize surcharges of the layout of movement, microtraumas, or chronic injuries that may send the competitor off the game for a short time or even permanently.     In the examinations 60 tennis players of a Student Sport Club "Return" in Łomża took part. They constituted a group of children and teenagers aged 10-18, training tennis as professionals or in the form of recreation. Tennis players were divided randomly into two groups. In the examined group (A sensomotoric trainings were introduced according to the annual training program, and the control group (B wasn't embraced with the program.     In the examinations there were used three tests, that evaluate proprioception of joints of lower limbs, upper limbs and the spine. The physiotherapist conducted sensomotoric tests before starting the cycle of sensomotoric trainings with tennis players, next the same tests were repeated after the annual training cycle.     It was stated that exercises of proprioception improve functionality of joints amongst all examined players. What is more, in the group of tennis players embraced with the cycle of sensomotoric trainings neuromuscular coordination underwent some significant improvement. Conducted tests of proprioception allowed to control the effectivenesses of training introduced by a physiotherapist with tennis players. Another assumption is that sensomotoric training should been integral

  4. Celiac disease symptoms in a female collegiate tennis player: a case report.

    Science.gov (United States)

    Leone, James E; Gray, Kimberly A; Massie, John E; Rossi, Jennifer M

    2005-01-01

    To present the case of a collegiate tennis player with celiac disease symptoms. Celiac disease is a common intestinal disorder that is often confused with other conditions. It causes severe intestinal damage manifested by several uncomfortable signs and symptoms. Failure by the sports medicine staff to recognize symptoms consistent with celiac disease and treat them appropriately can have deleterious consequences for the athlete. Irritable bowel syndrome, Crohn disease, Addison disease, lupus erythematosus, juvenile rheumatoid arthritis, lactose intolerance, herpes zoster, psychogenic disorder (depression), fibromyalgia, complex regional pain syndrome, hyperthyroidism, anemia, type I diabetes. The athlete underwent a series of blood and allergen tests to confirm or refute a diagnosis of celiac disease. When celiac disease was suspected, dietary modifications were made to eliminate all wheat-based and gluten-based products from the athlete's diet. The athlete was able to fully compete in a competitive National Collegiate Athletic Association Division I tennis program while experiencing the debilitating effects associated with celiac disease. The immediacy of symptom onset was notable because the athlete had no history of similar complaints. Celiac disease is a potentially life-threatening condition that affects more people than reported. A properly educated sports medicine staff can help to identify symptoms consistent with celiac disease early, so damage to the intestine is minimized. Prompt recognition and appropriate management allow the athlete to adjust the diet accordingly, compete at a high-caliber level, and enjoy a healthier quality of life.

  5. Cognitive Predictors of Performance in Well-Trained Table Tennis Players With Intellectual Disability.

    Science.gov (United States)

    Van Biesen, Debbie; Mactavish, Jennifer; Kerremans, Janne; Vanlandewijck, Yves C

    2016-10-01

    Evidence-based classification systems in Paralympic sport require knowledge of the underlying effect of impairment in a specific sport. This study investigated the relationship between cognition and tactical proficiency in 88 well-trained table tennis players with intellectual disability (ID; 29 women, 59 men, M ± SD IQ 59.9 ± 9.6). Data were collected at 3 competitions sanctioned by the International Federation for Para-Athletes with Intellectual Disabilities (INAS). A generic cognitive test consisting of 8 neuropsychological subtests was used to assess cognitive abilities relevant to sport (reaction time, processing speed, and decision speed; spatial visualization; fluid reasoning; memory; executive functioning; and visual processing). The backward stepwise-regression analysis model revealed that 18% of the variance in tactical proficiency was attributed to spatial visualization and simple reaction time. Applications of these findings resulted in an evidence-based classification system that led to the reinclusion of athletes with ID in Paralympic table tennis and provide the basis for future research in this important area.

  6. Motivation and Anxiety in Tennis Players Motivación y ansiedad en jugadores de tenis

    Directory of Open Access Journals (Sweden)

    E. Cervelló

    2010-09-01

    Full Text Available

    This work studied the "goals achievement theory;" how dispositional goal orientation and the perception of the motivational climate are related to the different components of competitive anxiety (cognitive anxiety, somatic anxiety and self-confidence in high-level tennis players. To the accomplish this objective structural equation modelling was employed (SEM. The results show that perception of the motivational climate that tennis players perceive is related to dispositional goal orientation. Results also show positive relationships between perception of ego involving motivational climate and somatic and cognitive components of anxiety. On the other hand, results show that ego orientation is a negative predictor of cognitive anxiety. Finally, results show that task orientation is a positive and significant predictor of self-confidence.
    KEY WORDS: Goal orientation, motivational climate, competitive state anxiety, tennis

    Este estudio analiza desde la perspectiva social-cognitiva de las metas de logro como la orientación disposicional de los sujetos y la percepción del clima motivacional en los entrenamientos se relacionan con los diferentes componentes de la ansiedad estado precompetitiva (ansiedad cognitiva, ansiedad somática y autoconfianza en tenistas de alto nivel. Para ello se utilizó un análisis de ecuaciones estructurales (SEM. Los resultados muestran que el clima motivacional que los tenistas perciben en los entrenamientos se relaciona con la orientación disposicional que estos presentan, así como existe una relación directa de influencia entre el clima motivacional orientado al ego y los componentes cognitivo y somático de la ansiedad. Por otra parte, los resultados muestran como la orientación disposicional al ego se muestra como predictor significativo y negativo de la ansiedad cognitiva y la orientación disposicional a la tarea predice la autoconfianza de forma positiva. A

  7. LEVEL OF ACHIEVEMENT MOTIVATION OF YOUNG TENNIS PLAYERS AND THEIR FUTURE PROGRESS

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    Piotr Unierzyski

    2003-12-01

    Full Text Available Psychological factors influencing tennis performance have long been recognised As American champion Jimmy Connors put it in 1981: 'Tennis is 90% mental Psychological issues with respect to tennis have also been addressed in a large number of scientific studies which have examined many of the mental characteristics during competition

  8. Can a 5 Week Strength Training Program Produce Range of Motion Adaptations in Amateur Female Tennis Players?

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    Andrew L. SHIM

    2015-12-01

    Full Text Available Objective: The purpose of this study was to assess range of motion adaptations in amateur tennis players based on the effects of a five week strength training program on the dominant and non-dominant arm. Subjects: An experimental and control group of six collegiate women tennis players (Div II and NAIA participated. After initial assessment, six subjects participated in a five week, four times a week, pre-season strength training program consisting of five exercises: External Rotation 90°, Seated Row, Scaption, Chest Press, and External Shoulder Rotation (Rubber tubing. Results: Data analysis through a paired t-test showed that there were no significant changes in ROM in the experimental group when compared to the control group. In conclusion, a strength training program is highly recommended for female overhead athletes combined with a proper flexibility regimen to promote best practice.

  9. A Hard Ball for a Tennis Player: A Rare Case of Large Calcifying Sertoli Cell Testicular Tumor

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    Simone Albisinni

    2017-07-01

    Full Text Available A 46 year old tennis player was addressed to our clinic after incidental finding of right testicular calcification on plain x-ray of the spine. Urologic consultation revealed a hard non-tender testicular mass which required inguinal orchiectomy. Final histology revealed large cell calcifying Sertoli cell tumor: we herein present the case and review current physiopathology of such rare testicular disease.

  10. Mechanical, Hormonal and Psychological Effects of a Non-Failure Short-Term Strength Training Program in Young Tennis Players

    Directory of Open Access Journals (Sweden)

    Sarabia Jose Manuel

    2015-03-01

    Full Text Available This study examined the effects of a 6-week non-failure strength training program in youth tennis players. Twenty tennis players (age: 15.0 ± 1 years, body height: 170.9 ± 5.1 cm, body mass: 63.3 ± 9.1 kg were divided into experimental and control groups. Pre and post-tests included half squats, bench press, squat jumps, countermovementjumps and side-ball throws. Salivary cortisol samples were collected, and the Profile of Mood States questionnaire was used weekly during an anatomical adaptation period, a main training period and after a tapering week. The results showed that, after the main training period, the experimental group significantly improved (p<0.05 in mean and peak power output and in the total number of repetitions during the half-squat endurance test; mean force, power and velocity in the half-squat power output test; Profile of Mood States (in total mood disturbance between the last week of the mean training period and the tapering week; and in squat-jump and countermovement-jump height. Moreover, significant differences were found between the groups at the post-tests in the total number of repetitions, mean and peak power during the half-squat endurance test, mean velocity in the half-squat power output test, salivary cortisol concentration (baselines, first and third week of the mean training period and in the Profile of Mood States (in fatigue subscale: first and third week of the mean training period. In conclusion, a non-failure strength training protocol improved lower-limb performance levels and produced a moderate psychophysiological impact in youth elite tennis players, suggesting that it is a suitable program to improve strength. Such training protocols do not increase the total training load of tennis players and may be recommended to improve strength.

  11. Mechanical, Hormonal and Psychological Effects of a Non-Failure Short-Term Strength Training Program in Young Tennis Players

    Science.gov (United States)

    Sarabia, Jose Manuel; Fernandez-Fernandez, Jaime; Juan-Recio, Casto; Hernández-Davó, Hector; Urbán, Tomás; Moya, Manuel

    2015-01-01

    This study examined the effects of a 6-week non-failure strength training program in youth tennis players. Twenty tennis players (age: 15.0 ± 1 years, body height: 170.9 ± 5.1 cm, body mass: 63.3 ± 9.1 kg) were divided into experimental and control groups. Pre and post-tests included half squats, bench press, squat jumps, countermovement-jumps and side-ball throws. Salivary cortisol samples were collected, and the Profile of Mood States questionnaire was used weekly during an anatomical adaptation period, a main training period and after a tapering week. The results showed that, after the main training period, the experimental group significantly improved (pvelocity in the half-squat power output test; Profile of Mood States (in total mood disturbance between the last week of the mean training period and the tapering week); and in squat-jump and countermovement-jump height. Moreover, significant differences were found between the groups at the post-tests in the total number of repetitions, mean and peak power during the half-squat endurance test, mean velocity in the half-squat power output test, salivary cortisol concentration (baselines, first and third week of the mean training period) and in the Profile of Mood States (in fatigue subscale: first and third week of the mean training period). In conclusion, a non-failure strength training protocol improved lower-limb performance levels and produced a moderate psychophysiological impact in youth elite tennis players, suggesting that it is a suitable program to improve strength. Such training protocols do not increase the total training load of tennis players and may be recommended to improve strength. PMID:25964812

  12. Acute and Time-Course Effects of Traditional and Dynamic Warm-Up Routines in Young Elite Junior Tennis Players.

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    Francisco Ayala

    Full Text Available Despite the large number of studies that have examined the acute effects of different warm up modalities (WU on physical performance, none of them have documented the time course of potential performance recovery in tennis players. The aim of this study was twofold: (a to analyze and compare the acute effects of two different WU modalities (traditional WU [TWU] and dynamic WU [DWU] on physical performance (i.e., CMJ, sprint, serve speed and accuracy in elite junior players, as well as (b to monitor the time course of any WU-induced changes after 30 and 60 min of simulated match-play. Twelve junior elite players completed both WUs modalities (TWU and DWU in a counterbalanced order on separate days. In each experimental session, counter movement jump (CMJ, 20-m sprint, tennis serve speed and accuracy tests were performed before (immediately after TWU or DWU during (30 min and after 60 min of a simulated match play. Measures were compared via four factorial (WU intervention and time repeated measures ANOVAs. There were main effects of WU (TWU and DWU throughout the time for all the variables analysed. The results indicate that DWU routine led to significantly faster 20 m sprint times and higher CMJs as well as faster and more accurate tennis serves at both post warm-up and 30 min match-play testing moments in comparison with the scores reported by the TWU routine (p 75-99%. No significant intergroup differences were found at 60-min match-play testing moment in any variable (except for the 20 m sprint. Therefore, the findings of this study recommend for optimal performance in these elite tennis players, DWU routines should be performed prior to formal training and competition rather than TWU routines.

  13. Racquet string tension directly affects force experienced at the elbow: implications for the development of lateral epicondylitis in tennis players

    Science.gov (United States)

    Mohandhas, Badri R; Makaram, Navnit; Drew, Tim S; Wang, Weijie; Arnold, Graham P

    2016-01-01

    Background Lateral epicondylitis (LE) occurs in almost half of all tennis players. Racket-string tension is considered to be an important factor influencing the development of LE. No literature yet exists that substantiates how string-tension affects force transmission to the elbow, as implicated in LE development. We establish a quantitative relationship between string-tension and elbow loading, analyzing tennis strokes using rackets with varying string-tensions. Methods Twenty recreational tennis players simulated backhand tennis strokes using three rackets strung at tensions of 200 N, 222 N and 245 N. Accelerometers recorded accelerations at the elbow, wrist and racket handle. Average peak acceleration was determined to correlate string-tension with elbow loading. Results Statistically significant differences (p elbow at 200 N string-tension (acceleration of 5.58 m/s2) was compared with that at 222 N tension (acceleration of 6.83 m/s2) and 245 N tension (acceleration of 7.45 m/s2). The 200 N racket induced the least acceleration at the elbow. Conclusions Although parameters determining force transmission to the elbow during a tennis stroke are complex, the present study was able to control these parameters, isolating the effect of string-tension. Lower string-tensions transmit less force to the elbow in backhand strokes. Reducing string-tension should be considered favourably with respect to reducing the risk of developing LE. PMID:27583017

  14. Racquet string tension directly affects force experienced at the elbow: implications for the development of lateral epicondylitis in tennis players.

    Science.gov (United States)

    Mohandhas, Badri R; Makaram, Navnit; Drew, Tim S; Wang, Weijie; Arnold, Graham P; Abboud, Rami J

    2016-07-01

    Lateral epicondylitis (LE) occurs in almost half of all tennis players. Racket-string tension is considered to be an important factor influencing the development of LE. No literature yet exists that substantiates how string-tension affects force transmission to the elbow, as implicated in LE development. We establish a quantitative relationship between string-tension and elbow loading, analyzing tennis strokes using rackets with varying string-tensions. Twenty recreational tennis players simulated backhand tennis strokes using three rackets strung at tensions of 200 N, 222 N and 245 N. Accelerometers recorded accelerations at the elbow, wrist and racket handle. Average peak acceleration was determined to correlate string-tension with elbow loading. Statistically significant differences (p < 0.05) were observed when average peak acceleration at the elbow at 200 N string-tension (acceleration of 5.58 m/s(2)) was compared with that at 222 N tension (acceleration of 6.83 m/s(2)) and 245 N tension (acceleration of 7.45 m/s(2)). The 200 N racket induced the least acceleration at the elbow. Although parameters determining force transmission to the elbow during a tennis stroke are complex, the present study was able to control these parameters, isolating the effect of string-tension. Lower string-tensions transmit less force to the elbow in backhand strokes. Reducing string-tension should be considered favourably with respect to reducing the risk of developing LE.

  15. Goal orientation as a motivation model and self-confidence among tennis players of different levels of success

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    Lepir Duško

    2014-01-01

    Full Text Available The goal of this research was to determine differences between the successful and less successful tennis players regarding their goal orientation and self-confidence, as well as to examine the correlation between these two psychological constructs. Active male tennis players (N=40, ranked on the senior list of the Tennis Federation of Austria, age 18 to 26, filled in the TEOSQ-D1 questionnaire (Würth, Alfermann and Saborowski, 1999, and CSI questionnaire (Vealey, 1986, just before the national senior championship of Austria. After categorising a 'successful tennis player' as one ranked in top 100 (N=20, and a 'less successful' one as ranked outside top 100 (N=20, analyses of their differences concerning goal orientation and self-confidence were conducted by means of the T-test, but no statistically significant differences were found for any scale. Pearson's coefficient for the entire sample showed that task orientation correlate significantly with the sport confidence trait (r= 0,451; Sig.= 0,05, and to a certain extent with sport-confidence as a state (r= 0,387; Sig.= 0,092, but that correlation is not statistically significant at the level Sig.< 0,05. For the result/ego scale orientation, there were no significant correlations with sporting-confidence. Guidelines for future research are based on the development of a more adequate system for evaluation of success in sport, and also on increasing of sample size. This could be very helpful for making more reliable conclusions about the influence of goal orientation preference on sport-confidence and sport success, which could justify the utilization of this psychological construct for practical purposes.

  16. The Effects of Financial Incentives on Women’s Performance: The Tournament Theory Applied to Female Tennis Players

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    Matthieu LLORCA

    2017-06-01

    Full Text Available The purpose of this paper is to analyze the management model of women’s professional tennis by using the theoretical framework of the tournament theory. Indeed, this sport is particularly appropriate to study the effects of financial incentives on women’s performance in the context of competitive elimination tournament. Moreover, we take into account the direct opposition between players by building two relative performance indicators. Empirical tests are conducted, by using Ordinary Least Squares method, on the whole tournaments played by the 30 best women’s tennis players, over the 2011 season. Interesting implication found is that one tournament theory principle, the incentive effect, is confirmed. In other words, an undistributed prize structure between tournament rounds increases the player performance. However, the other consequence of the tournament theory, the participative effect, is rejected because the monetary gains distributed by the tournament’s organizer (either the premium earned or the total dollar endowment do not induce better player performance.

  17. Can Perceptuo-Motor Skills Assessment Outcomes in Young Table Tennis Players (7-11 years) Predict Future Competition Participation and Performance? An Observational Prospective Study.

    Science.gov (United States)

    Faber, Irene R; Elferink-Gemser, Marije T; Faber, Niels R; Oosterveld, Frits G J; Nijhuis-Van der Sanden, Maria W G

    2016-01-01

    Forecasting future performance in youth table tennis players based on current performance is complex due to, among other things, differences between youth players in growth, development, maturity, context and table tennis experience. Talent development programmes might benefit from an assessment of underlying perceptuo-motor skills for table tennis, which is hypothesized to determine the players' potential concerning the perceptuo-motor domain. The Dutch perceptuo-motor skills assessment intends to measure the perceptuo-motor potential for table tennis in youth players by assessing the underlying skills crucial for developing technical and tactical qualities. Untrained perceptuo-motor tasks are used as these are suggested to represent a player's future potential better than specific sport skills themselves as the latter depend on exposure to the sport itself. This study evaluated the value of the perceptuo-motor skills assessment for a talent developmental programme by evaluating its predictive validity for competition participation and performance in 48 young table tennis players (7-11 years). Players were tested on their perceptuo-motor skills once during a regional talent day, and the subsequent competition results were recorded half-yearly over a period of 2.5 years. Logistic regression analysis showed that test scores did not predict future competition participation (p >0.05). Yet, the Generalized Estimating Equations analysis, including the test items 'aiming at target', 'throwing a ball', and 'eye-hand coordination' in the best fitting model, revealed that the outcomes of the perceptuo-motor skills assessment were significant predictors for future competition results (R2 = 51%). Since the test age influences the perceptuo-motor skills assessment's outcome, another multivariable model was proposed including test age as a covariate (R2 = 53%). This evaluation demonstrates promising prospects for the perceptuo-motor skills assessment to be included in a talent

  18. Comparison and Description o f Fitness Level ، Physiological a nd Anthropometric Profiles o f Selected Versus Non Selected Iranian National Team Table Tennis Players

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    Reza BEHDARİ

    2015-08-01

    Full Text Available Objectives: The aims of this study were to comparison and describe the anthropometric characteristics physical fitness and physiological profile of the f irst 5 and the lower ranked elite male Iranian national table tennis players, who participated in table tennis championship, to compare the anthropometric data, physical fitness and physiological profile of the first 5elite tennis players on the ranking wi th the lower ranked players, and to establish an anthropometric and physiological profile chart for elite tennis players. Methods: On the direction of this aim 16 male National table tennis Players' participated in this study. According to ranked some phy sical fitness, physiological and anthropometric variables were recorded of each subject. In this research; Physical fitness was determined using the following test: 1 speed; 36m sprint, 2 shoulder, back and hamstring flexibility; sit and reach, 3 lower limb power; side jump, 4 Anaerobic power; wingate test, 5 Aerobic power; 1600 m running, 6 reaction time; visual reaction time, 7 mussel endurance; sit - ups. In addition to anthropometric analysis (height, weight, siting height, arm length, body com position and somatotype of participants have been assessed. The kolmogorof - smirnov test was applied to determine the nature of data distribution. Since a normal distribution was confirmed, a t - test for independent samples was performed to examine statisti cal differences between groups and p value < 0.05 was considered to be significant. Results: There were no significant differences in height, jump, shoulder, back and hamstring flexibility, speed, visual reaction time, anaerobic power and BMI between th e first 5 and the lower ranked table tennis players, while there were significant differences in weight, side jump, aerobic power, present body fat and somatotype component. A mesomorph – endomorph somatotype was registered for the lower ranked and somat otype of first 5 table tennis players

  19. Time distortion for expert and novice online game players.

    Science.gov (United States)

    Rau, Pei-Luen Patrick; Peng, Shu-Yun; Yang, Chin-Chow

    2006-08-01

    Online game addiction is a new mental disorder. This disorder is difficult to describe because of its comprehensive nature. Many online game players have problems controlling their playing time. They cannot stop playing a game that they enjoy. This research surveyed the past literature on "flow" and time disorder theory. A time distortion experiment was conducted. This research invited 64 children, teenagers, and young adults to investigate player skill and playing time effects on online game break-off. The playing experience and degree of time distortion were measured and analyzed. The results showed that both novice and expert online game players were subject to time distortion. The participants had difficulty breaking off from the game without intrusion by others in the real world. This research also suggests eight questions for self-evaluation for online game addiction.

  20. Recognition of tennis serve performed by a digital player: comparison among polygon, shadow, and stick-figure models.

    Directory of Open Access Journals (Sweden)

    Hirofumi Ida

    Full Text Available The objective of this study was to assess the cognitive effect of human character models on the observer's ability to extract relevant information from computer graphics animation of tennis serve motions. Three digital human models (polygon, shadow, and stick-figure were used to display the computationally simulated serve motions, which were perturbed at the racket-arm by modulating the speed (slower or faster of one of the joint rotations (wrist, elbow, or shoulder. Twenty-one experienced tennis players and 21 novices made discrimination responses about the modulated joint and also specified the perceived swing speeds on a visual analogue scale. The result showed that the discrimination accuracies of the experienced players were both above and below chance level depending on the modulated joint whereas those of the novices mostly remained at chance or guessing levels. As far as the experienced players were concerned, the polygon model decreased the discrimination accuracy as compared with the stick-figure model. This suggests that the complicated pictorial information may have a distracting effect on the recognition of the observed action. On the other hand, the perceived swing speed of the perturbed motion relative to the control was lower for the stick-figure model than for the polygon model regardless of the skill level. This result suggests that the simplified visual information can bias the perception of the motion speed toward slower. It was also shown that the increasing the joint rotation speed increased the perceived swing speed, although the resulting racket velocity had little correlation with this speed sensation. Collectively, observer's recognition of the motion pattern and perception of the motion speed can be affected by the pictorial information of the human model as well as by the perturbation processing applied to the observed motion.

  1. Recognition of tennis serve performed by a digital player: comparison among polygon, shadow, and stick-figure models.

    Science.gov (United States)

    Ida, Hirofumi; Fukuhara, Kazunobu; Ishii, Motonobu

    2012-01-01

    The objective of this study was to assess the cognitive effect of human character models on the observer's ability to extract relevant information from computer graphics animation of tennis serve motions. Three digital human models (polygon, shadow, and stick-figure) were used to display the computationally simulated serve motions, which were perturbed at the racket-arm by modulating the speed (slower or faster) of one of the joint rotations (wrist, elbow, or shoulder). Twenty-one experienced tennis players and 21 novices made discrimination responses about the modulated joint and also specified the perceived swing speeds on a visual analogue scale. The result showed that the discrimination accuracies of the experienced players were both above and below chance level depending on the modulated joint whereas those of the novices mostly remained at chance or guessing levels. As far as the experienced players were concerned, the polygon model decreased the discrimination accuracy as compared with the stick-figure model. This suggests that the complicated pictorial information may have a distracting effect on the recognition of the observed action. On the other hand, the perceived swing speed of the perturbed motion relative to the control was lower for the stick-figure model than for the polygon model regardless of the skill level. This result suggests that the simplified visual information can bias the perception of the motion speed toward slower. It was also shown that the increasing the joint rotation speed increased the perceived swing speed, although the resulting racket velocity had little correlation with this speed sensation. Collectively, observer's recognition of the motion pattern and perception of the motion speed can be affected by the pictorial information of the human model as well as by the perturbation processing applied to the observed motion.

  2. Investigating Aerobic, Anaerobic Combine Technical Trainings' Effects on Performance in Tennis Players

    Science.gov (United States)

    Suna, Gürhan; Kumartasli, Mehmet

    2017-01-01

    The aim of this study is to investigate eight-week aerobic, anaerobic combine technical trainings' effects on developments of performance. 21 athletes of tennis proficiency students from Sports Sciences Department were joined to the study voluntarily. Participated in the research athletes' ages' mean was 22,2 ± 0,3 year, lengths' mean was 177,3 ±…

  3. Examination of Anxiety Levels and Anger Expression Manners of Undergraduate Table Tennis Players

    Science.gov (United States)

    Karademir, Tamer; Türkçapar, Ünal

    2016-01-01

    This research was done for the determination of how their anxiety levels' and anger expressions' get shaped according to some variances. For this reason there were 76 female 125 male totally 201 sportsmen, who participated to the table tennis championship between universities in 2016 and ages differ from 18 to 28, were included the research group.…

  4. Can Perceptuo-Motor Skills Assessment Outcomes in Young Table Tennis Players (7-11 years Predict Future Competition Participation and Performance? An Observational Prospective Study.

    Directory of Open Access Journals (Sweden)

    Irene R Faber

    Full Text Available Forecasting future performance in youth table tennis players based on current performance is complex due to, among other things, differences between youth players in growth, development, maturity, context and table tennis experience. Talent development programmes might benefit from an assessment of underlying perceptuo-motor skills for table tennis, which is hypothesized to determine the players' potential concerning the perceptuo-motor domain. The Dutch perceptuo-motor skills assessment intends to measure the perceptuo-motor potential for table tennis in youth players by assessing the underlying skills crucial for developing technical and tactical qualities. Untrained perceptuo-motor tasks are used as these are suggested to represent a player's future potential better than specific sport skills themselves as the latter depend on exposure to the sport itself. This study evaluated the value of the perceptuo-motor skills assessment for a talent developmental programme by evaluating its predictive validity for competition participation and performance in 48 young table tennis players (7-11 years. Players were tested on their perceptuo-motor skills once during a regional talent day, and the subsequent competition results were recorded half-yearly over a period of 2.5 years. Logistic regression analysis showed that test scores did not predict future competition participation (p >0.05. Yet, the Generalized Estimating Equations analysis, including the test items 'aiming at target', 'throwing a ball', and 'eye-hand coordination' in the best fitting model, revealed that the outcomes of the perceptuo-motor skills assessment were significant predictors for future competition results (R2 = 51%. Since the test age influences the perceptuo-motor skills assessment's outcome, another multivariable model was proposed including test age as a covariate (R2 = 53%. This evaluation demonstrates promising prospects for the perceptuo-motor skills assessment to be

  5. Can Perceptuo-Motor Skills Assessment Outcomes in Young Table Tennis Players (7–11 years) Predict Future Competition Participation and Performance? An Observational Prospective Study

    Science.gov (United States)

    2016-01-01

    Forecasting future performance in youth table tennis players based on current performance is complex due to, among other things, differences between youth players in growth, development, maturity, context and table tennis experience. Talent development programmes might benefit from an assessment of underlying perceptuo-motor skills for table tennis, which is hypothesized to determine the players’ potential concerning the perceptuo-motor domain. The Dutch perceptuo-motor skills assessment intends to measure the perceptuo-motor potential for table tennis in youth players by assessing the underlying skills crucial for developing technical and tactical qualities. Untrained perceptuo-motor tasks are used as these are suggested to represent a player’s future potential better than specific sport skills themselves as the latter depend on exposure to the sport itself. This study evaluated the value of the perceptuo-motor skills assessment for a talent developmental programme by evaluating its predictive validity for competition participation and performance in 48 young table tennis players (7–11 years). Players were tested on their perceptuo-motor skills once during a regional talent day, and the subsequent competition results were recorded half-yearly over a period of 2.5 years. Logistic regression analysis showed that test scores did not predict future competition participation (p >0.05). Yet, the Generalized Estimating Equations analysis, including the test items ‘aiming at target’, ‘throwing a ball’, and ‘eye-hand coordination’ in the best fitting model, revealed that the outcomes of the perceptuo-motor skills assessment were significant predictors for future competition results (R2 = 51%). Since the test age influences the perceptuo-motor skills assessment’s outcome, another multivariable model was proposed including test age as a covariate (R2 = 53%). This evaluation demonstrates promising prospects for the perceptuo-motor skills assessment to be

  6. Naturalistic decision-making in expert badminton players.

    Science.gov (United States)

    Macquet, A C; Fleurance, P

    2007-09-01

    This paper reports on a study of naturalistic decision-making in expert badminton players. These decisions are frequently taken under time-pressured conditions, yet normally lead to successful performance. Two male badminton teams participated in this study. Self-confrontation interviews were used to collect data. Inductive data analysis revealed three types of intentions during a rally: to maintain the rally; to take the advantage; and to finish the point. It also revealed eight types of decision taken in this situation: to ensure an action; to observe the opponent's response to an action; to realize a limited choice; to influence the opponent's decision; to put pressure on an opponent; to surprise the opponent; to reproduce an efficient action; and to play wide. A frequent decision was to put pressure on the opponent. Different information and knowledge was linked to specific decisions. The results are discussed in relation to research that has considered naturalistic decision-making.

  7. ISOKINETIC COMPARISON OF THE ROTATOR CUFF BETWEEN WATERPOLO AND TENNIS PLAYERS/ COMPARAREA ISOKINETICĂ A COIFULUI ROTATORILOR ÎNTRE JUCĂTORII DE POLLO ŞI CEI DE TENIS

    Directory of Open Access Journals (Sweden)

    Linde FJ

    Full Text Available Isokinetic evaluation is an objective method that allows rapid and reliable comparison of the relationship between the muscle groups of the rotator cuff, during dynamic exercise. At shoulder level, balance between the rotator cuff muscle groups is essential for keeping joint stability. The purpose of this study is to detect significant differences in muscular performance strength values of the muscles of the rotator cuff by isokinetic tests, in two overhead sport specialities: water polo and tennis. Comparison could be realized analyzing various parameters derivate of the test. Material and methods. We undertook an isokinetic study in a group of 36 high-level athletes: 30 water polo players (12 women and 18 men and 6 tennis players (2 women and 4 men. The parameters analyzed were: peak torque (PT, maximal repetition work (MRW, muscle asymmetry between dominant and no dominant shoulder, and ratio between external and internal rotators. Results. For all tested values of PT, the dominant limb has always been stronger than the no dominant in both sports, but differences in tennis players were much higher in favor of the dominant than water polo players with specific reference to IR. With regard to MRW, water polo players had values higher than tennis players in ER of both sides, but the IR of the dominant limb is greater in tennis players. Conclusions. In water polo players, due to the environment in which specific work is developed and the symmetrical content of simming, the ratios in both extremities were very symmetrical (related to PT; in tennis players, the dominant limb had more normal ratio values but this doesn’t happen in the no dominant possibly because it comes into play shortly.

  8. MOVEMENT CHARACTERISTICS OF ELITE TENNIS PLAYERS ON HARD COURTS WITH RESPECT TO THE DIRECTION OF GROUND STROKES

    Directory of Open Access Journals (Sweden)

    Rafael Martínez-Gallego

    2013-06-01

    Full Text Available Previous studies of movement characteristics in tennis have considered the effect of playing surface but have assumed that playing strategies are simply determined by the surface as opposed to being under an individual's control. This study considered the selection of cross court or down the line ground strokes as being indicative of playing strategy and measured the outcome of playing these shots in terms of the opponent's movements. Matches (N = 8 at the 2011 ATP tournament 500 Valencia were recorded and analysed using SAGIT, a computer vision tracking system that allowed both players' movements to be tracked automatically, albeit with operator supervision. The data was split into (N = 188 games for analysis purposes and these lasted a median 174.24 seconds with active time (ball in play a median proportion of 34.89% (IQR = 10.64% of total time. During the active time losers of games tended to cover less distance (median = 80.17 m, move quicker (median = 1.38 m·s-1, spend more time in the defensive zones (median = 14.24 s and less in the offensive zones (median = 44.74 s. These results suggested that game winners tended to dominate game losers, forcing them to exhibit behaviors typically associated with a defensive strategy. Defensive and offensive strategy are not well defined currently and future investigations should consider movements in relation to individual shots, in particular their velocities, at the rally level and by different individuals to better understand successful performance

  9. Sonic Tennis

    DEFF Research Database (Denmark)

    Baldan, Stefano; Götzen, Amalia De; Serafin, Stefania

    2013-01-01

    their movements in order to keep the ball into play. The device can be swung freely and act as a full-fledged motion- based controller, as the game does not rely at all on visual feedback and the device display can thus be ignored. The game aims to be entertaining but also effective for educa- tional purposes......This paper presents an audio-based tennis simulation game for mobile devices, which uses motion input and non-verbal audio feedback as exclusive means of interaction. Players have to listen carefully to the provided auditory clues, like racquet hits and ball bounces, rhythmically synchronizing...

  10. Individualization of psychological training and its importance at different stages of many years’ perfection in tennis

    Directory of Open Access Journals (Sweden)

    N.L. Vysochina

    2015-08-01

    Full Text Available Purpose: to determine significance of individualized approach during psychological training at different stages of many years’ perfection in tennis. The tasks of the research were studying of place and role of psychological component in general system of tennis players’ sport training as well as determination of specificities of individualized approach during 14-15 years old and elite tennis players’ psychological training. Material: In the research 24 experts, coaches of combined teams and clubs, elite tennis players took part. Results: Role of psychological training in general system of many years’ perfection has been determined. We also found out that individualization of psychological training in modern tennis is not paid sufficient attention to at present. Most of the questioned respondents pointed, that such training is conducted mainly with elite sportsmen (42%. Only 14% noted that individual psychological training is carried out at basic stages of many years’ perfection. Conclusions: Principle of individualization is a determining one in the course of sportsmen’s training at stages of many years’ perfection. About 86% of experts stressed on significance of application of individualized approach in work with tennis players. Consideration of tennis players’ individual features during psychological training is a compulsory matter in increasing of effectiveness of sportsmen’s training and competition functioning.

  11. A COMPARATIVE STUDY OF PASSIVE SHOULDER ROTATION RANGE OF MOTION, ISOMETRIC ROTATION STRENGTH AND SERVE SPEED BETWEEN ELITE TENNIS PLAYERS WITH AND WITHOUT HISTORY OF SHOULDER PAIN.

    Science.gov (United States)

    Moreno-Pérez, V; Elvira, Jll; Fernandez-Fernandez, J; Vera-Garcia, F J

    2018-02-01

    Glenohumeral internal rotation deficit and external rotation strength have been associated with the development of shoulder pain in overhead athletes. To examine the bilateral passive shoulder rotational range of motion (ROM), the isometric rotational strength and unilateral serve speed in elite tennis players with and without shoulder pain history (PH and NPH, respectively) and compare between dominant and non-dominant limbs and between groups. Cohort study. Fifty-eight elite tennis players were distributed into the PH group (n = 20) and the NPH group (n = 38). Serve velocity, dominant and non-dominant passive shoulder external and internal rotation (ER and IR) ROM, total arc of motion (TAM: the sum of IR and ER ROM), ER and IR isometric strength, bilateral deficits and ER/IR strength ratio were measured in both groups. Questionnaires were administered in order to classify characteristics of shoulder pain. The dominant shoulder showed significantly reduced IR ROM and TAM, and increased ER ROM compared to the non-dominant shoulder in both groups. Isometric ER strength and ER/IR strength ratio were significantly lower in the dominant shoulder in the PH group when compared with the NPH group. No significant differences between groups were found for serve speed. These data show specific adaptations in the IR, TAM and ER ROM in the dominant shoulder in both groups. Isometric ER muscle weakness and ER/IR strength ratio deficit appear to be associated with history of shoulder injuries in elite tennis players. It would be advisable for clinicians to use the present information to design injury prevention programs. 2.

  12. Tennis elbow

    Science.gov (United States)

    Epitrochlear bursitis; Lateral epicondylitis; Epicondylitis - lateral; Tendonitis - elbow ... tennis or other racket sports, hence the name "tennis elbow." Backhand is the most common stroke to cause ...

  13. Biomechanics and tennis.

    Science.gov (United States)

    Elliott, B

    2006-05-01

    Success in tennis requires a mix of player talent, good coaching, appropriate equipment, and an understanding of those aspects of sport science pertinent to the game. This paper outlines the role that biomechanics plays in player development from sport science and sport medicine perspectives. Biomechanics is a key area in player development because all strokes have a fundamental mechanical structure and sports injuries primarily have a mechanical cause.

  14. The effects of creatine supplementation on selected factors of tennis specific training

    NARCIS (Netherlands)

    Pluim, B.M.; Ferrauti, A.; Broekhof, F.; Deutekom, M.; Gotzmann, A.; Kuipers, H.; Weber, K.

    2006-01-01

    BACKGROUND: Creatine supplementation is popular among tennis players but it is not clear whether it actually enhances tennis performance. OBJECTIVES: To examine the effects of creatine supplementation on tennis specific performance indices. METHODS: In a randomised, double blind design, 36

  15. A case study of virilizing adrenal tumor in an adolescent female elite tennis player--insight into the use of anabolic steroids in young athletes.

    Science.gov (United States)

    Eliakim, Alon; Cale-Benzoor, Mia; Klinger-Cantor, Beatrice; Freud, Enrique; Nemet, Dan; Feigin, Elad; Weintrob, Neomi

    2011-01-01

    A 14-year-old Caucasian girl was referred to the endocrine clinic for evaluation of voice deepening, facial hirsutism, and acne starting 2 years previously. She had been a competitive tennis player since age 7 years, practicing for 4-6 hours daily. On physical examination she was noticed to have a masculine appearance with mild facial acne and moderate hirsutism. Tanner stage was 1 for breast tissue and 5 for pubic hair. Her androgen levels (testosterone, androstenedione, dehydroepiandrosterone sulfate) were extremely elevated. Adrenal ultrasonography revealed a round left 4.6 × 5.3-cm adrenal mass. Laparoscopic left adrenalectomy was performed. The histologic findings were compatible with a benign adrenocortical tumor. Postoperatively, androgen levels dropped to within the normal range. Breast development proceeded normally, menarche occurred 2 months after tumor resection, and menses has been regular since then. Muscle strength of the dominant and nondominant upper and lower extremities was measured 1 month before surgery and 1 year later, using an isokinetic dynamometer (Biodex Systems II, Biodex, Shirley, NY, USA). There was no significant decrease in overall muscle strength after removal of the virilizing tumor and the marked drop in circulating androgens. In addition, the patient maintained her age category, number 1, national tennis ranking. The results suggest that even extremely high levels of tumor-related circulating androgens had no evident effect on muscle strength and competitive performance in a female adolescent tennis player. The lack of beneficial effect on performance in adolescents, combined with the potentially hazardous side effects of anabolic steroids, suggests that teenage athletes should avoid their use.

  16. Women's Lib and Professional Tennis

    Science.gov (United States)

    Geist, Harold; And Others

    1971-01-01

    The purpose of the study was to assess the psyche of the people who watch and pay to see female tennis players. It was concluded that women are breaking through the cultural constraints of this sport. (Author/BY)

  17. The Snapping Elbow Syndrome as a Reason for Chronic Elbow Neuralgia in a Tennis Player - MR, US and Sonoelastography Evaluation.

    Science.gov (United States)

    Łasecki, Mateusz; Olchowy, Cyprian; Pawluś, Aleksander; Zaleska-Dorobisz, Urszula

    2014-01-01

    Ulnar neuropathy is the second most common peripheral nerve neuropathy after median neuropathy, with an incidence of 25 cases per 100 000 men and 19 cases per 100 000 women each year. Skipping (snapping) elbow syndrome is an uncommon cause of pain in the posterior-medial elbow area, sometimes complicated by injury of the ulnar nerve. One of the reason is the dislocation of the abnormal insertion of the medial triceps head over the medial epicondyle during flexion and extension movements. Others are: lack of the Osboune fascia leading to ulnar nerve instability and focal soft tissue tumors (fibromas, lipomas, etc). Recurrent subluxation of the nerve at the elbow results in a tractional and frictional neuritis with classical symptoms of peripheral neuralgia. As far as we know snapping triceps syndrome had never been evaluated in sonoelastography. A 28yo semi-professional left handed tennis player was complaining about pain in posterior-medial elbow area. Initial US examination suggest golfers elbow syndrome which occurs quite commonly and has a prevalence of 0.3-0.6% in males and 0-3-1.1% in women and may be associated (approx. 50% of cases) with ulnar neuropathy. However subsequently made MRI revealed unusual distal triceps anatomy, moderate ulnar nerve swelling and lack of medial epicondylitis symptoms. Followed (second) US examination and sonoelastography have detected slipping of the both ulnar nerve and the additional band of the medial triceps head. Snapping elbow syndrome is a poorly known medical condition, sometimes misdiagnosed as the medial epicondylitis. It describes a broad range of pathologies and anatomical abnormalities. One of the most often reasons is the slipping of the ulnar nerve as the result of the Osborne fascia/anconeus epitrochlearis muscle absence. Simultaneously presence of two or more "snapping reasons" is rare but should be always taken under consideration. There are no sonoelastography studies describing golfers elbow syndrome

  18. TENNIS: HISTORY AND THE PRESENT

    Directory of Open Access Journals (Sweden)

    Borisova O. V.

    2012-12-01

    Full Text Available Purpose - a substantiation of ways of development of professional sports in Ukraine (on a tennis material. The primary information is received by the analysis of the scientifically-methodical literature and the documentary sources, official sites of organizational structures of tennis (АТР, WТА, ITF, continental and national federations, organising committees of tennis tournaments, tennis academies etc. (more than 450 sources; the method of expert estimations (the qualified experts, judges, trainers, science officers - 26 people was applied. In article possibility of use of tennis as by one of effective models of development of Olympic kinds of sports in conditions of commercialization and professionalization is theoretically proved; the history-theoretical analyzes of development of professional tennis in the world (3 periods is carried out; the analyzes of its organizational-legal and economic forms at the international and national levels.

  19. The effects of creatine supplementation on selected factors of tennis specific training

    NARCIS (Netherlands)

    Pluim, B. M.; Ferrauti, A.; Broekhof, F.; Deutekom, M.; Gotzmann, A.; Kuipers, H.; Weber, K.

    2006-01-01

    Creatine supplementation is popular among tennis players but it is not clear whether it actually enhances tennis performance. To examine the effects of creatine supplementation on tennis specific performance indices. In a randomised, double blind design, 36 competitive male tennis players (24

  20. Case report 355: Delayed closure of the right olecranon epiphysis in a right-handed, tournament-class tennis player (post-traumatic)

    Energy Technology Data Exchange (ETDEWEB)

    Retrum, R.K.; Wepfer, J.F.; Olen, D.W.; Laney, W.H.

    1986-02-01

    In summary, two cases of delayed union of the ossification center of the ulnar olecranon in the dominant elbow of competitive sibling male tennis players are reported. Pain in the elbow, exaggerated by the serving motion, was the presenting complaint in each patient, and painful, limited, terminal extension of the forearm was the major finding in both patients on physical examination. Radiological studied on the two brothers were virtually identical. In two previously reported cases in the literature, the patients were treated by operative intervention, whereas both young men reported in this manuscript, were treated non-surgically, with subsequent spontaneous fusion of the ossification center of the olecranon in each patient. Thus, such conservative therapy may very well be the treatment of choice. (orig./SHA).

  1. Case report 355: Delayed closure of the right olecranon epiphysis in a right-handed, tournament-class tennis player (post-traumatic)

    International Nuclear Information System (INIS)

    Retrum, R.K.; Wepfer, J.F.; Olen, D.W.; Laney, W.H.

    1986-01-01

    In summary, two cases of delayed union of the ossification center of the ulnar olecranon in the dominant elbow of competitive sibling male tennis players are reported. Pain in the elbow, exaggerated by the serving motion, was the presenting complaint in each patient, and painful, limited, terminal extension of the forearm was the major finding in both patients on physical examination. Radiological studied on the two brothers were virtually identical. In two previously reported cases in the literature, the patients were treated by operative intervention, whereas both young men reported in this manuscript, were treated non-surgically, with subsequent spontaneous fusion of the ossification center of the olecranon in each patient. Thus, such conservative therapy may very well be the treatment of choice. (orig./SHA)

  2. Exploring Self-regulation of More or Less Expert College-Age Video Game Players: A Sequential Explanatory Design.

    Science.gov (United States)

    Yilmaz Soylu, Meryem; Bruning, Roger H

    2016-01-01

    This study examined differences in self-regulation among college-age expert, moderately expert, and non-expert video game players in playing video games for fun. Winne's model of self-regulation (Winne, 2001) guided the study. The main assumption of this study was that expert video game players used more processes of self-regulation than the less-expert players. We surveyed 143 college students about their game playing frequency, habits, and use of self-regulation. Data analysis indicated that while playing recreational video games, expert gamers self-regulated more than moderately expert and non-expert players and moderately expert players used more processes of self-regulation than non-experts. Semi-structured interviews also were conducted with selected participants at each of the expertise levels. Qualitative follow-up analyses revealed five themes: (1) characteristics of expert video gamers, (2) conditions for playing a video game, (3) figuring out a game, (4) how gamers act and, (5) game context. Overall, findings indicated that playing a video game is a highly self-regulated activity and that becoming an expert video game player mobilizes multiple sets of self-regulation related skills and processes. These findings are seen as promising for educators desiring to encourage student self-regulation, because they indicate the possibility of supporting students via recreational video games by recognizing that their play includes processes of self-regulation.

  3. Exploring Self-regulation of More or Less Expert College-Age Video Game Players: A Sequential Explanatory Design

    Science.gov (United States)

    Yilmaz Soylu, Meryem; Bruning, Roger H.

    2016-01-01

    This study examined differences in self-regulation among college-age expert, moderately expert, and non-expert video game players in playing video games for fun. Winne's model of self-regulation (Winne, 2001) guided the study. The main assumption of this study was that expert video game players used more processes of self-regulation than the less-expert players. We surveyed 143 college students about their game playing frequency, habits, and use of self-regulation. Data analysis indicated that while playing recreational video games, expert gamers self-regulated more than moderately expert and non-expert players and moderately expert players used more processes of self-regulation than non-experts. Semi-structured interviews also were conducted with selected participants at each of the expertise levels. Qualitative follow-up analyses revealed five themes: (1) characteristics of expert video gamers, (2) conditions for playing a video game, (3) figuring out a game, (4) how gamers act and, (5) game context. Overall, findings indicated that playing a video game is a highly self-regulated activity and that becoming an expert video game player mobilizes multiple sets of self-regulation related skills and processes. These findings are seen as promising for educators desiring to encourage student self-regulation, because they indicate the possibility of supporting students via recreational video games by recognizing that their play includes processes of self-regulation. PMID:27729881

  4. Exploring Self-Regulation of More or Less Expert College-Age Video Game Players: A Sequential Explanatory Design

    Directory of Open Access Journals (Sweden)

    Meryem YILMAZ SOYLU

    2016-09-01

    Full Text Available This study examined differences in self-regulation among college-age expert, moderately expert, and non-expert video game players in playing video games for fun. Winne’s model of self-regulation (Winne, 2001 guided the study. Main assumption of this study was that expert video game players used more processes of self-regulation than the less-expert players. We surveyed 143 college students about their game playing frequency, habits, and use of self-regulation. Data analysis indicated that while playing recreational video games, expert gamers self-regulated more than moderately expert and non-expert players and moderately expert players used more processes of self-regulation than non-experts. Semi-structured interviews also were conducted with selected participants at each of the expertise levels. Qualitative follow-up analyses revealed five themes: 1 characteristics of expert video gamers, 2 conditions for playing a video game, 3 figuring out a game, 4 how gamers act and, 5 game context. Overall, findings indicated that playing a video game is a highly self-regulated activity and that becoming an expert video game player mobilizes multiple sets of self-regulation related skills and processes. These findings are seen as promising for educators desiring to encourage student self-regulation, because they indicate the possibility of supporting students via recreational video games by recognizing that their play includes processes of self-regulation.

  5. Tennis injuries: prevention and treatment. A review.

    Science.gov (United States)

    Kulund, D N; McCue, F C; Rockwell, D A; Gieck, J H

    1979-01-01

    When players are engaged in the sport of tennis, injuries may occur to the eyes, in the neck, to the shoulder and back, arm and elbow, wrist and hand, and feet. The key to prevention and treatment of these injuries is good coaching and a formal stretching and strengthening program. The drooped "tennis shoulder" of professionals and senior tennis players is a natural response to heavy use. Shoulder elevating exercises are useful when soreness is associated. The treatment of tennis elbow includes wrist extensor stretching, isometrics, and light weightlifting. When a player follows this program, injections or counterforce braces are rarely needed. It is important for the player to bring his racket to the examination so that his stroke mechanics and grip can be checked. Wrist soreness in a tennis player may denote a hamate hook fracture. Special radiographic views are needed to discern the fracture and it is treated with a short arm cast and little finger extension splint. Nonunion of a hamate hook requires excision. The calf pain prodrome of "tennis leg" requires rest and then a stretching program. Tennis shoes should have rolled heels and large toe boxes with reinforced toe bumpers. The physician may have to fashion soft inserts for the tennis shoes; arch supports may be insufficient.

  6. Stroke performance in high-level Spanish wheelchair tennis players. [Rendimiento del golpeo en jugadores españoles de tenis en silla de ruedas de alto nivel].

    Directory of Open Access Journals (Sweden)

    Gema Torres-Luque

    2017-04-01

    Full Text Available The aim of this study was to analyse shot selection in a wheelchair tennis (WT tournament, comparing winning and losing players and evaluating the outcome of strokes. Sixteen men’s singles WT matches (comprising a total of 5,720 strokes were analysed. Each match was recorded and the following variables were analysed: services, returns, groundstrokes and net shots. Additionally, all strokes were coded according to type of point (non-game point opportunity, NGO; game point opportunity, GO, outcome (error; rally; winner and set outcome (winner; loser. A Z-test was used to assess differences between winning and losing players and between NGOs and GOs. The results showed that WT players make more errors (19% than winning strokes (10.6%. Service and return shots make up about 55% of shots played during a point and volleys and smashes are infrequent (2.1%. Winning players hit more winners on service, return and groundstrokes than losing players. At the net losing players hit more winners than winning players, although they also made more errors. The critical situation (GO could be not affect on game actions of WT points. These results and the differences between performances should be taken into consideration by wheelchair tennis coaches. Resumen El objetivo de este estudio fue conocer los tipos de golpeo en un torneo de tenis en silla de ruedas (WT, observar las diferencias entre ganadores y perdedores, y evaluar su resultado. Se analizaron 16 partidos individuales, con un total de 5720 golpes. Cada partido fue grabado y analizado en base a las siguientes variables: saques, restos, golpes de fondo y golpes de red. Además, cada golpeo fue codificado con el tipo de punto (sin oportunidad de ganar el juego –NGO-, o con oportunidad de ganar el juego -GO, con el resultado del golpeo (error, peloteo, o golpe ganador, y el resultado del set (ganador y perdedor. Se utilizó el test Z para comparar las diferencias entre ganadores y perdedores, así como

  7. Inhibition of irrelevant information is not necessary to performance of expert chess players.

    Science.gov (United States)

    Postal, Virginie

    2012-08-01

    Some studies on expertise have demonstrated that the difference between novices and experts can be partly due to a lack of knowledge about which information is relevant for a given situation. This lack of knowledge seems to be associated with the selection of correct information and with inhibitory processes. However, while the efficiency of inhibitory processes can lead to better performance in the normal population, it seems that experts in chess do not base their performance on this process but rather on an automatic and parallel encoding of information. Two experiments investigated the processes involved in a check detection task. The congruence of the information was manipulated in a Stroop situation similar to Reingold, Charness, Scheltetus, & Stampe (2001). The results showed that the experts did not benefit from cuing with a congruent cue and that they did not show any interference effect by the incongruent cue, contrary to less skilled chess players who benefited from cuing (Exp. 1). An attentional priming procedure confirmed the automatic encoding of chess relations in the more skilled chess players by showing no advantage from the prime in this group (Exp. 2). Taken together, the results indicate that the processing was serial for the less skilled chess players and that it was automatic and parallel for the more expert chess players. The inhibition of irrelevant information does not seem necessary to process information rapidly and efficiently.

  8. Different intensities of basketball drills affect jump shot accuracy of expert and junior players

    Directory of Open Access Journals (Sweden)

    Giuseppe Marcolin

    2018-02-01

    Full Text Available Background In basketball a maximum accuracy at every game intensity is required while shooting. The aim of the present study was to investigate the acute effect of three different drill intensity simulation protocols on jump shot accuracy in expert and junior basketball players. Materials & Methods Eleven expert players (age 26 ± 6 yrs, weight 86 ± 11 kg, height 192 ± 8 cm and ten junior players (age 18 ± 1 yrs, weight 75 ± 12 kg, height 184 ± 9 cm completed three series of twenty jump shots at three different levels of exertion. Counter Movement Jump (CMJ height was also measured after each series of jump shots. Exertion’s intensity was induced manipulating the basketball drills. Heart rate was measured for the whole duration of the tests while the rating of perceived exertion (RPE was collected at the end of each series of shots. Results Heart rate and rating of perceived exertion (RPE were statistically different in the three conditions for both expert and junior players. CMJ height remained almost unchanged in both groups. Jump shot accuracy decreased with increasing drills intensity both in experts and junior players. Expert players showed higher accuracy than junior players for all the three levels of exertion (83% vs 64%, p < 0.001; 75% vs 57%, p < 0.05; 76% vs 60%, p < 0.01. Moreover, for the most demanding level of exertion, experts showed a higher accuracy in the last ten shots compared to the first ten shots (82% vs 70%, p < 0.05. Discussion Experts coped better with the different exertion’s intensities, thus maintaining a higher level of performance. The introduction of technical short bouts of high-intensity sport-specific exercises into skill sessions should be proposed to improve jump shot accuracy during matches.

  9. Neural Correlates of Expert Visuomotor Performance in Badminton Players.

    Science.gov (United States)

    Hülsdünker, Thorben; Strüder, Heiko K; Mierau, Andreas

    2016-11-01

    Elite/skilled athletes participating in sports that require the initiation of targeted movements in response to visual cues under critical time pressure typically outperform nonathletes in a visuomotor reaction task. However, the exact physiological mechanisms of this advantage remain unclear. Therefore, this study aimed to determine the neurophysiological processes contributing to superior visuomotor performance in athletes using visual evoked potential (VEP). Central and peripheral determinants of visuomotor reaction time were investigated in 15 skilled badminton players and 28 age-matched nonathletic controls. To determine the speed of visual signal perception in the cortex, chromatic and achromatic pattern reversal stimuli were presented, and VEP values were recorded with a 64-channel EEG system. Further, a simple visuomotor reaction task was performed to investigate the transformation of the visual into a motor signal in the brain as well as the timing of muscular activation. Amplitude and latency of VEP (N75, P100, and N145) revealed that the athletes did not significantly differ from the nonathletes. However, visuomotor reaction time was significantly reduced in the athletes compared with nonathletes (athletes = 234.9 ms, nonathletes = 260.3 ms, P = 0.015). This was accompanied by an earlier activation of the premotor and supplementary motor areas (athletes = 163.9 ms, nonathletes = 199.1 ms, P = 0.015) as well as an earlier EMG onset (athletes = 167.5 ms, nonathletes = 206.5 ms, P < 0.001). The latency of premotor and supplementary motor area activation was correlated with EMG onset (r = 0.41) and visuomotor reaction time (r = 0.43). The results of this study indicate that superior visuomotor performance in athletes originates from faster visuomotor transformation in the premotor and supplementary motor cortical regions rather than from earlier perception of visual signals in the visual cortex.

  10. Intrateam Communication and Performance in Doubles Tennis

    Science.gov (United States)

    Lausic, Domagoj; Tennebaum, Gershon; Eccles, David; Jeong, Allan; Johnson, Tristan

    2009-01-01

    Verbal and nonverbal communication is a critical mediator of performance in team sports and yet there is little extant research in sports that involves direct measures of communication. Our study explored communication within NCAA Division I female tennis doubles teams. Video and audio recordings of players during doubles tennis matches captured…

  11. Comparative Analysis of Return of Serve Comparative Analysis of Return of Serve as Counter- as Counter-attack in Modern Tennis attack in Modern Tennis attack in Modern Tennis

    OpenAIRE

    Petru Eugen MERGHEŞ; Beatris SIMION; Adrian NAGEL

    2017-01-01

    High performance modern tennis is characterised by high dynamism, speed in thinking and action, precision and high technical and tactical skills. In this study, we used direct observation and statistical recording of nine matches during two competition years in the tennis players Roger Federer, Rafael Nadal and Andre Agassi. In these tennis players, we studied mainly the return of serve, one of the most important shots in tennis, together with serve, as first shots in a point. We ...

  12. A reciprocal effects model of the temporal ordering of motivation and burnout among youth table tennis players in intensive training settings.

    Science.gov (United States)

    Martinent, Guillaume; Decret, Jean-Claude; Guillet-Descas, Emma; Isoard-Gautheur, Sandrine

    2014-01-01

    Using self-determination theory (SDT) (Deci, E.L., & Ryan, R.M. (1985). Intrinsic motivation and self-determination in human behavior. New York, NY: Plenum) as the theoretical framework, we conducted a longitudinal investigation of the temporal ordering between motivation and burnout among youth athletes in intensive training setting. Data were collected from 145 table tennis players in intensive training centres at three time points during a 2-month period characterised by a simultaneous increase in social, physical and psychological demands for these athletes. Structural equation modelling of cross-lagged panel models was used to test the hypotheses. Results showed significant paths leading from athlete burnout - especially sport devaluation and reduced sense of accomplishment - at time 1 to amotivation, intrinsic and extrinsic motivations at times 2 and 3. Only two significant paths leading from motivation (introjected regulation at time 1) to burnout (emotional/physical exhaustion at time 2 and reduced sense of accomplishment at time 3) were identified. Overall, our results suggest that athlete burnout predicts motivation over time but motivation did not predict athlete burnout over time. Results are discussed in terms of current research findings on SDT.

  13. Fuzzy controller for better tennis ball robot | Nguyen | Journal of ...

    African Journals Online (AJOL)

    This paper aims at designing a tennis ball robot as a training facility for tennis players. The robot is built with fuzzy controller which provides proper techniques for the players to gain practical experience as well as technical skills; thus, it can effectively serve the community and train athletes in the high-performance sport.

  14. "Strategic" and "tactical" chess differentiate in their hippocampal and precuneus requirements in expert chess players

    DEFF Research Database (Denmark)

    Wallentin, Mikkel; Roepstorff, Andreas; Vestergaard-Poulsen, Peter

    Introduction Expert chess players have been a popular population for research in acquired expertise. The putative cognitive underpinnings of chess-expertise (eg. IQ and memory) have been sought for with mixed results. We suggest that this may be partly due to a lack of detail in the analysis...... of the game itself. We investigated whether different types of chess positions, known as "tactical" and "strategic", activates different neurocognitive structures. In a tactical position the choice of move determines the game, whereas strategic moves are based on long term considerations and do not imply...... an immediate determination. We therefore hypothesised that tactical considerations rely more on working memory (WM) brain structures, such as the precuneus , while strategic rely on long term memory (LTM), i.e. hippocampus. Methods 22 chess-players participated, 9 during fMRI scanning in a 3T scanner while...

  15. THE IMPACT OF MODERATE AND HIGH INTENSITY TOTAL BODY FATIGUE ON PASSING ACCURACY IN EXPERT AND NOVICE BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Mark Lyons

    2006-06-01

    Full Text Available Despite the acknowledged importance of fatigue on performance in sport, ecologically sound studies investigating fatigue and its effects on sport-specific skills are surprisingly rare. The aim of this study was to investigate the effect of moderate and high intensity total body fatigue on passing accuracy in expert and novice basketball players. Ten novice basketball players (age: 23.30 ± 1.05 yrs and ten expert basketball players (age: 22.50 ± 0.41 yrs volunteered to participate in the study. Both groups performed the modified AAHPERD Basketball Passing Test under three different testing conditions: rest, moderate intensity and high intensity total body fatigue. Fatigue intensity was established using a percentage of the maximal number of squat thrusts performed by the participant in one minute. ANOVA with repeated measures revealed a significant (F 2,36 = 5.252, p = 0.01 level of fatigue by level of skill interaction. On examination of the mean scores it is clear that following high intensity total body fatigue there is a significant detriment in the passing performance of both novice and expert basketball players when compared to their resting scores. Fundamentally however, the detrimental impact of fatigue on passing performance is not as steep in the expert players compared to the novice players. The results suggest that expert or skilled players are better able to cope with both moderate and high intensity fatigue conditions and maintain a higher level of performance when compared to novice players. The findings of this research therefore, suggest the need for trainers and conditioning coaches in basketball to include moderate, but particularly high intensity exercise into their skills sessions. This specific training may enable players at all levels of the game to better cope with the demands of the game on court and maintain a higher standard of play

  16. Expert-novice differences in brain function of field hockey players.

    Science.gov (United States)

    Wimshurst, Z L; Sowden, P T; Wright, M

    2016-02-19

    The aims of this study were to use functional magnetic resonance imaging to examine the neural bases for perceptual-cognitive superiority in a hockey anticipation task. Thirty participants (15 hockey players, 15 non-hockey players) lay in an MRI scanner while performing a video-based task in which they predicted the direction of an oncoming shot in either a hockey or a badminton scenario. Video clips were temporally occluded either 160 ms before the shot was made or 60 ms after the ball/shuttle left the stick/racquet. Behavioral data showed a significant hockey expertise×video-type interaction in which hockey experts were superior to novices with hockey clips but there were no significant differences with badminton clips. The imaging data on the other hand showed a significant main effect of hockey expertise and of video type (hockey vs. badminton), but the expertise×video-type interaction did not survive either a whole-brain or a small-volume correction for multiple comparisons. Further analysis of the expertise main effect revealed that when watching hockey clips, experts showed greater activation in the rostral inferior parietal lobule, which has been associated with an action observation network, and greater activation than novices in Brodmann areas 17 and 18 and middle frontal gyrus when watching badminton videos. The results provide partial support both for domain-specific and domain-general expertise effects in an action anticipation task. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Estudio de la relación entre conocimiento y toma de decisiones en jugadores de tenis, y su influencia en la pericia deportiva. (Relation between knowledge and decision making in tennis players and its influence in sport expertise.

    Directory of Open Access Journals (Sweden)

    Luis García González

    2009-10-01

    Full Text Available Resumen Este trabajo pretende estudiar no solo algunos de los factores cognitivos implicados dentro del tenis, sino establecer las relaciones existentes entre distintos factores cognitivos fundamentales como el conocimiento y la toma de decisiones. De esta forma, se han evaluado 12 tenistas de distinto nivel de pericia en variables como el conocimiento declarativo y procedimental general de juego (medidos a través de cuestionarios, toma de decisiones y ejecución (evaluados a través de observación sistemática. Podemos destacar fundamentalmente la relación observada entre el conocimiento, tanto declarativo como procedimental, y la toma de decisiones, destacando en mayor medida la que se produce entre el conocimiento procedimental general y la toma de decisiones tanto en el servicio como en el resto de golpeos, que plantean la importancia del conocimiento sobre los aspectos tácticos y decisionales que los jugadores de tenis desarrollan durante el juego. Abastract This work tries to study nonsingle some of the cognitive factors implied in tennis, but to establish the existing relations between different fundamental cognitive factors as the knowledge and the decision making. Of this form, 12 tennis players of different skill level in variables like declarative and procedural knowledge (measured through questionnaires, decision making and execution (evaluated through systematic observation have evaluated themselves. We can emphasize the relation observed between the knowledge (declarative and procedural, and decision making, emphasizing in greater measurement the one takes place between the procedural knowledge and decision making in service as in the game play, that raise the importance of the knowledge on the tactical and decisional aspects that tennis players develop during the game.

  18. The Snapping Elbow Syndrome as a Reason for Chronic Elbow Neuralgia in a Tennis Player – MR, US and Sonoelastography Evaluation

    International Nuclear Information System (INIS)

    Łasecki, Mateusz; Olchowy, Cyprian; Pawluś, Aleksander; Zaleska-Dorobisz, Urszula

    2014-01-01

    Ulnar neuropathy is the second most common peripheral nerve neuropathy after median neuropathy, with an incidence of 25 cases per 100 000 men and 19 cases per 100 000 women each year. Skipping (snapping) elbow syndrome is an uncommon cause of pain in the posterior-medial elbow area, sometimes complicated by injury of the ulnar nerve. One of the reason is the dislocation of the abnormal insertion of the medial triceps head over the medial epicondyle during flexion and extension movements. Others are: lack of the Osboune fascia leading to ulnar nerve instability and focal soft tissue tumors (fibromas, lipomas, etc). Recurrent subluxation of the nerve at the elbow results in a tractional and frictional neuritis with classical symptoms of peripheral neuralgia. As far as we know snapping triceps syndrome had never been evaluated in sonoelastography. A 28yo semi-professional left handed tennis player was complaining about pain in posterior-medial elbow area. Initial US examination suggest golfers elbow syndrome which occurs quite commonly and has a prevalence of 0.3–0.6% in males and 0–3–1.1% in women and may be associated (approx. 50% of cases) with ulnar neuropathy. However subsequently made MRI revealed unusual distal triceps anatomy, moderate ulnar nerve swelling and lack of medial epicondylitis symptoms. Followed (second) US examination and sonoelastography have detected slipping of the both ulnar nerve and the additional band of the medial triceps head. Snapping elbow syndrome is a poorly known medical condition, sometimes misdiagnosed as the medial epicondylitis. It describes a broad range of pathologies and anatomical abnormalities. One of the most often reasons is the slipping of the ulnar nerve as the result of the Osborne fascia/anconeus epitrochlearis muscle absence. Simultaneously presence of two or more “snapping reasons” is rare but should be always taken under consideration. There are no sonoelastography studies describing golfers elbow syndrome

  19. ON THE GENDER EFFECTS OF HANDEDNESS IN PROFESSIONAL TENNIS

    Directory of Open Access Journals (Sweden)

    Kristijan Breznik

    2013-06-01

    Full Text Available ABSTRACT The aim of this study was to explore the effects of the gender variable in relation to other player and match characteristics on the advantage possessed by left-handed professional tennis players over their right-handed rivals. The data include 16 732 male tennis players and 16 432 female tennis players who played 438 937 and 415 346 matches, respectively, in the period from 1968 to the end of 2011. The results revealed that the advantage of left-handed professional tennis players is higher in males compared to females. The inverse impact of player and match quality on the left- handers' advantage was clearly confirmed. On the contrary, it seems that the type of court surface does not directly imply this advantage. To obtain an overview on the individual level, directed and weighted networks of tennis matches in both gender categories were constructed. Applying network analytic methods and the PageRank algorithm, the best left and right-handed players in the Open Era of tennis were identified. The top three ranked left-handed players in the male and female categories were found to be far more consistent in their ranks achieved against left and right-handed opponents compared to their right-handed counterparts

  20. Constitutional aspects of sports mastery in tennis.

    Directory of Open Access Journals (Sweden)

    Jagiello Marina

    2009-02-01

    Full Text Available The aim of the study was to determine somatic indices of highly-qualified tennis players (men and women correlate at the highest level of connections with the level of sports mastery and training experience, to settle the question whether these connections are of dimorphic character. The study involved Polish national team tennis representatives. The female players' age (n=10 oscillated between 16-20 (18.1±1.4, and the training experience - 8-12 years (10.5±1.8. The male players' age, on the other hand, between 16-22 (18.5±2.17, and the training experience - 8-15 years (10.5±2.66. 20 basic somatic features were measured. It was found that the connection of the studied somatic features with the level of sports mastery and the training experience of Polish tennis representatives are of heterogeneous and dimorphic character.

  1. UPPER EXTREMITY KINEMATICS OF FLAT SERVE IN TENNIS ...

    African Journals Online (AJOL)

    Brian McAllister

    kinematics on the ball velocity at the impact phase of a tennis flat serve. 15 elite male tennis players were recruited to participate in this study (mean age 18.4±3.3 .... For field calibration, a Direct Linear Transformation technique, developed by ...

  2. Tennis elbow: a biomechanical and therapeutic approach.

    Science.gov (United States)

    Schnatz, P; Steiner, C

    1993-07-01

    Lateral epicondylitis, one of the most common lesions of the arm, affects some 50% of tennis players. This condition poses a problem in clinical management because treatment is dependent not only on proper medical therapy but also on correction of the improper on-court biomechanics. The most common flaw is a late contact on the backhand groundstroke, forcing the player to extend the wrist with the extensor muscles. This action predisposes to trauma of the tendon fibers at the lateral epicondyle. Understanding the biomechanics will better prepare the physician to advise the patient and to communicate with a tennis teaching professional to facilitate long-term relief.

  3. The impact of periodized core training program on accurate service velocity of male tennis players aged 11-1311-13 yaş arası erkek tenisçilerde periyotlanmış core antrenman programının isabetli servis hızına etkisi

    OpenAIRE

    Sever, Ozan; Kır, Rıdvan; Yaman, Metin

    2017-01-01

    The purpose of this study is to examine the effect of periodized core training program on the serve velocity in male tennis players aged 11-13 years. 24 male nationally ranged (age 11.9±1.63, height 154.4±11.32, weight 43±8.76) participated to the study from a professional tennis club. Pre-post-training - control group design was applied and subjects were randomly assigned to Control Group and Training Group. Training Group participated to the core training program consisted of isometric and ...

  4. Annual change in the rate of participation in breast cancer screening through active encouragement of sports participation. A survey of women participants at the annual meetings of the Pink Ribbon Ladies' Tennis Tournament organized by the Japan Women's Tennis Players' League

    International Nuclear Information System (INIS)

    Shimada, Naoko; Nozue; Etsuko; Fukuda, Mamoru; Sawai, Kiyoshi; Kasumi, Fujio

    2007-01-01

    In March 2002, an initial attempt was made to decrease breast cancer mortality by the Japan Society of Breast Health, by means of encouraging participation in sports. This was followed by other similar events. The present study was designed to examine whether these kinds of sport-associated events are actually effective for increasing the screening participation rate. We hoped that the results would reveal practical ways of organizing such programs. One of these activities, the All Japan Women's Tennis Players' League, has called for amateur players to participate in an annual meeting of the Pink Ribbon Ladies' Tennis Tournament since 2003. A survey of their knowledge about breast cancer and their will to participate in breast cancer screening has been carried out annually in 2003, 2004 and 2005, by asking the participants to respond to our questionnaires. As a result, the number of participants has increased: from 7,201 women in 2003, to 7,846 in 2004 and to 8,572 in 2005. The questionnaires included items about participation in breast cancer screening, performance of self-examination, and participation in mammography screening. The participation rate increased year by year. The participation rate at mammography screening was 21% in 2003, and this increased to 26% in 2005. Thus this kind of sports event appears to promote knowledge about breast cancer screening and to increase the participation rate. On the other hand, it was found that the rate of self-examination decreased from 53% to 22%. Therefore problems that need to be addressed in the future include not only increasing women's motivation to undergo screening, but also the selection of appropriate screening methods, their combination, and distribution of accurate information. (author)

  5. The Dutch Technical-Tactical Tennis Test (D4T) for Talent Identification and Development : Psychometric Characteristics

    NARCIS (Netherlands)

    Kolman, Nikki; Huijgen, Barbara; Kramer, Tamara; Elferink-Gemser, Marije; Visscher, Chris

    2017-01-01

    This study examined the test-retest reliability, validity and feasibility of the newly developed Dutch Technical Tactical Tennis Test (D4T). This new test is relevant for talent identification and development in tennis. Thirty-two youth male tennis players (age 13.4 +/- 0.5) were classified as elite

  6. The effect of motor imagery with specific implement in expert badminton player.

    Science.gov (United States)

    Wang, Z; Wang, S; Shi, F-Y; Guan, Y; Wu, Y; Zhang, L-L; Shen, C; Zeng, Y-W; Wang, D-H; Zhang, J

    2014-09-05

    Motor skill can be improved with mental simulation. Implements are widely used in daily life and in various sports. However, it is unclear whether the utilization of implements enhances the effect of mental simulation. The present study was designed to investigate the different effects of motor imagery in athletes and novices when they handled a specific implement. We hypothesize that athletes have better motor imagery ability than novices when they hold a specific implement for the sport. This is manifested as higher motor cortical excitability in athletes than novices during motor imagery with the specific implement. Sixteen expert badminton players and 16 novices were compared when they held a specific implement such as a badminton racket and a non-specific implement such as a a plastic bar. Motor imagery ability was measured with a self-evaluation questionnaire. Transcranial magnetic stimulation was used to test the motor cortical excitability during motor imagery. Motor-evoked potentials (MEPs) in the first dorsal interosseous (FDI) and extensor carpi radialis muscles were recorded. Athletes reported better motor imagery than novices when they held a specific implement. Athletes exhibited more MEP facilitation than novices in the FDI muscle with the specific implement applied during motor imagery. The MEP facilitation is correlated with motor imagery ability in athletes. We conclude that the effects of motor imagery with a specific implement are enhanced in athletes compared to novices and the difference between two groups is caused by long-term physical training of athletes with the specific implement. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. Tennis elbow surgery

    Science.gov (United States)

    Lateral epicondylitis - surgery; Lateral tendinosis - surgery; Lateral tennis elbow - surgery ... Surgery to repair tennis elbow is often an outpatient surgery. This means you will not stay in the hospital overnight. You will be given ...

  8. Tennis elbow surgery - discharge

    Science.gov (United States)

    ... epicondylitis surgery - discharge; Lateral tendinosis surgery - discharge; Lateral tennis elbow surgery - discharge ... long as you are told. This helps ensure tennis elbow will not return. You may be prescribed a ...

  9. Hydration and temperature in tennis - a practical review.

    Science.gov (United States)

    Kovacs, Mark S

    2006-03-01

    Competitive tennis is typically played in warm and hot environments. Because hypohydration will impair tennis performance and increases the risk of heat injury, consumption of appropriate fluid levels is necessary to prevent dehydration and enhance performance. The majority of research in this area has focused on continuous aerobic activity - unlike tennis, which has average points lasting less than ten seconds with rest periods dispersed between each work period. For this reason, hydration and temperature regulation methods need to be specific to the activity. Tennis players can sweat more than 2.5 L·h(-1) and replace fluids at a slower rate during matches than in practice. Latter stages of matches and tournaments are when tennis players are more susceptible to temperature and hydration related problems. Sodium (Na(+)) depletion, not potassium (K(+)), is a key electrolyte in tennis related muscle cramps. However, psychological and competitive factors also contribute. CHO drinks have been shown to promote fluid absorption to a greater degree than water alone, but no performance benefits have been shown in tennis players in short matches. It is advisable to consume a CHO beverage if practice or matches are scheduled longer than 90-120 minutes. Key PointsAlthough substantial research has been performed on temperature and hydration concerns in aerobic activities, there is little information with regard to tennis performance and safetyTennis athletes should be on an individualized hydration schedule, consuming greater than 200ml of fluid every changeover (approximately 15 minutes).Optimum hydration and temperature regulation will reduce the chance of tennis related muscle cramps and performance decrements.

  10. HYDRATION AND TEMPERATURE IN TENNIS - A PRACTICAL REVIEW

    Directory of Open Access Journals (Sweden)

    Mark S. Kovacs

    2006-03-01

    Full Text Available Competitive tennis is typically played in warm and hot environments. Because hypohydration will impair tennis performance and increases the risk of heat injury, consumption of appropriate fluid levels is necessary to prevent dehydration and enhance performance. The majority of research in this area has focused on continuous aerobic activity - unlike tennis, which has average points lasting less than ten seconds with rest periods dispersed between each work period. For this reason, hydration and temperature regulation methods need to be specific to the activity. Tennis players can sweat more than 2.5 L·h-1 and replace fluids at a slower rate during matches than in practice. Latter stages of matches and tournaments are when tennis players are more susceptible to temperature and hydration related problems. Sodium (Na+ depletion, not potassium (K+, is a key electrolyte in tennis related muscle cramps. However, psychological and competitive factors also contribute. CHO drinks have been shown to promote fluid absorption to a greater degree than water alone, but no performance benefits have been shown in tennis players in short matches. It is advisable to consume a CHO beverage if practice or matches are scheduled longer than 90-120 minutes.

  11. Epidemiological analysis of doping offences in the professional tennis circuit

    Directory of Open Access Journals (Sweden)

    Maquirriain Javier

    2010-12-01

    Full Text Available Abstract Introduction Tennis is a professional sport under a strict anti-doping control. However, since the first violation of the code, the positive cases have not been statistically studied. The objective of this study was to analyze doping offences in the international professional tennis circuit. Methods All offences to the Doping Code committed by tennis players during 2003-2009 were collected from the ITF official webpage, registered and analyzed. Results An average of 1905.7 (±174.5 samples was obtained per year. Fifty-two doping offences were reported and the overall incidence of positive doping samples accounted for 0.38% and 7.4 (±4.1 cases/year. Male players showed higher incidence doping offences than females (p = 0.0004. The incidence in wheelchair players was higher than in non-handicapped subjects (p = 0.0001 Banned substance distribution showed: stimulants 32.69%, cannabis 23.07%; anabolic 11.53%, diuretics and masking agents 11.53, β2-agonists 9.61%; corticosteroids 3.84%, others 3.84%. The overall incidence of 'social drugs' (cocaine, cannabis was 36.53%. All EPO and blood samples were normal, while the incidence of 'out-of-competition' offences was 0.12%. The lower incidence of doping was found in Grand Slams tournaments. Conclusions The incidence of positive doping samples among professional tennis players is quite low supporting the assumption that there is no evidence of systematic doping in Tennis. "Social drugs" misuse constitutes the main problem of doping in tennis. Male and wheelchair tennis players showed higher risk of infringing the doping code than their females and non-handicapped counterparts. Findings of this study should help to determine the direction of the ongoing strategy in the fight against doping in Tennis.

  12. Neural Correlates of Expert Behavior During a Domain-Specific Attentional Cueing Task in Badminton Players.

    Science.gov (United States)

    Wang, Chun-Hao; Tu, Kuo-Cheng

    2017-06-01

    The present study aimed to investigate the neural correlates associated with sports expertise during a domain-specific task in badminton players. We compared event-related potentials activity from collegiate male badminton players and a set of matched athletic controls when they performed a badminton-specific attentional cueing task in which the uncertainty and validity were manipulated. The data showed that, regardless of cue type, the badminton players had faster responses along with greater P3 amplitudes than the athletic controls on the task. Specifically, the contingent negative variation amplitude was smaller for the players than for the controls in the condition involving higher uncertainty. Such an effect, however, was absent in the condition with lower uncertainty. We conclude that expertise in sports is associated with proficient modulation of brain activity during cognitive and motor preparation, as well as response execution, when performing a task related to an individual's specific sport domain.

  13. Manufacturing, Testing of Polymer Nanocomposite and Analysis of Tennis Racket Frame

    Directory of Open Access Journals (Sweden)

    P. K. Chidambaram

    2014-01-01

    Full Text Available The modern days, the game of tennis expects high levels of performance from every international tennis players. The performance of every tennis player based on the tennis racket and playing conditions. The evolution of the tennis racket, with respect to both design and materials (tennis racket strings and grips developed lots of new tennis racket frames. The tennis racket required to change in recent years as a result of lightweight, stiffer rackets for better performance. The paper discusses the manufacturing, testing, structural and modal analysis of four ratios of Nylon6,6/MWNT new polymer nanocomposite material replacing excising composite materials to a tennis racket frame for better mechanical properties to enhanced performance of the tennis racket. Using universal testing machine test and calculate the various mechanical properties strength, modulus, impact, hardness, stiffness, toughness of the polymer nanocomposite. In the design, the tennis racket frame was designed of the shape, dimensions. After design part created the 3D model using by PRO/ENGINEER software. The 3D racket model can be export to ANSYS analysis software and incorporated with new polymer nanocomposite properties. The structural and model analysis was done.

  14. An Intervention Based on Video Feedback and Questioning to Improve Tactical Knowledge in Expert Female Volleyball Players.

    Science.gov (United States)

    Moreno, M Perla; Moreno, Alberto; García-González, Luis; Ureña, Aurelio; Hernández, César; Del Villar, Fernando

    2016-06-01

    This study applied an intervention program, based on video feedback and questioning, to expert female volleyball players to improve their tactical knowledge. The sample consisted of eight female attackers (26 ± 2.6 years old) from the Spanish National Volleyball Team, who were divided into an experimental group (n = 4) and a control group (n = 4). The video feedback and questioning program applied in the study was developed over eight reflective sessions and consisted of three phases: viewing of the selected actions, self-analysis and reflection by the attacker, and joint player-coach analysis. The attackers were videotaped in an actual game and four clips (situations) of each of the attackers were chosen for each reflective session. Two of the clips showed a correct action by the attacker, and two showed an incorrect decision. Tactical knowledge was measured by problem representation with a verbal protocol. The members of the experimental group showed adaptations in long-term memory, significantly improving their tactical knowledge. With respect to conceptual content, there was an increase in the total number of conditions verbalized by the players; with respect to conceptual sophistication, there was an increase in the indication of appropriate conditions with two or more details; and finally, with respect to conceptual structure, there was an increase in the use of double or triple conceptual structures. The intervention program, based on video feedback and questioning, in addition to on-court training sessions of expert volleyball players, appears to improve the athletes' tactical knowledge. © The Author(s) 2016.

  15. TABLE TENNIS CLUB

    CERN Document Server

    TABLE TENNIS CLUB

    2010-01-01

    2010 CERN Table Tennis Tournament The CERN Table Tennis Club organizes its traditional CERN Table Tennis Tournament, at the Meyrin club, 2 rue de livron, in Meyrin, Saturday August 21st, in the afternoon. The tournament is open to all CERN staff, users, visitors and families, including of course summer students. See below for details. In order to register, simply send an E-mail to Jean-Pierre Revol (jean-pierre.revol@cern.ch). You can also download the registration form from the Club Web page (http://www.cern.ch/tabletennis), and send it via internal mail. Photo taken on August 22, 2009 showing some of the participants in the 2nd CERN Table Tennis tournament. INFORMATION ON CERN TABLE TENNIS CLUB CERN used to have a tradition of table tennis activities at CERN. For some reason, at the beginning of the 1980’s, the CERN Table Tennis club merged with the Meyrin Table Tennis club, a member of the Association Genevoise de Tennis de Table (AGTT). Therefore, if you want to practice table tennis, you...

  16. Determining Mechanical Parameters for Spin in Tennis Strings

    DEFF Research Database (Denmark)

    Bendtsen, Kaare; Rasmussen, Kasper; Hansen, Martin B.

    2015-01-01

    The ability to generate spin is a key element for any tennis player. However, the mechanical parameters of tennis strings which contribute to producing spin are poorly understood. This study attempted to determine some of these parameters through a spin test and a tensile test. Nine different...... string types with different gauges, geometry, price and user ratings were tested. The main finding of the study was that the three gauges of MSV Co Focus were able to generate significantly (p

  17. Earlier visual N1 latencies in expert video-game players: a temporal basis of enhanced visuospatial performance?

    Directory of Open Access Journals (Sweden)

    Andrew J Latham

    Full Text Available Increasing behavioural evidence suggests that expert video game players (VGPs show enhanced visual attention and visuospatial abilities, but what underlies these enhancements remains unclear. We administered the Poffenberger paradigm with concurrent electroencephalogram (EEG recording to assess occipital N1 latencies and interhemispheric transfer time (IHTT in expert VGPs. Participants comprised 15 right-handed male expert VGPs and 16 non-VGP controls matched for age, handedness, IQ and years of education. Expert VGPs began playing before age 10, had a minimum 8 years experience, and maintained playtime of at least 20 hours per week over the last 6 months. Non-VGPs had little-to-no game play experience (maximum 1.5 years. Participants responded to checkerboard stimuli presented to the left and right visual fields while 128-channel EEG was recorded. Expert VGPs responded significantly more quickly than non-VGPs. Expert VGPs also had significantly earlier occipital N1s in direct visual pathways (the hemisphere contralateral to the visual field in which the stimulus was presented. IHTT was calculated by comparing the latencies of occipital N1 components between hemispheres. No significant between-group differences in electrophysiological estimates of IHTT were found. Shorter N1 latencies may enable expert VGPs to discriminate attended visual stimuli significantly earlier than non-VGPs and contribute to faster responding in visual tasks. As successful video-game play requires precise, time pressured, bimanual motor movements in response to complex visual stimuli, which in this sample began during early childhood, these differences may reflect the experience and training involved during the development of video-game expertise, but training studies are needed to test this prediction.

  18. Earlier visual N1 latencies in expert video-game players: a temporal basis of enhanced visuospatial performance?

    Science.gov (United States)

    Latham, Andrew J; Patston, Lucy L M; Westermann, Christine; Kirk, Ian J; Tippett, Lynette J

    2013-01-01

    Increasing behavioural evidence suggests that expert video game players (VGPs) show enhanced visual attention and visuospatial abilities, but what underlies these enhancements remains unclear. We administered the Poffenberger paradigm with concurrent electroencephalogram (EEG) recording to assess occipital N1 latencies and interhemispheric transfer time (IHTT) in expert VGPs. Participants comprised 15 right-handed male expert VGPs and 16 non-VGP controls matched for age, handedness, IQ and years of education. Expert VGPs began playing before age 10, had a minimum 8 years experience, and maintained playtime of at least 20 hours per week over the last 6 months. Non-VGPs had little-to-no game play experience (maximum 1.5 years). Participants responded to checkerboard stimuli presented to the left and right visual fields while 128-channel EEG was recorded. Expert VGPs responded significantly more quickly than non-VGPs. Expert VGPs also had significantly earlier occipital N1s in direct visual pathways (the hemisphere contralateral to the visual field in which the stimulus was presented). IHTT was calculated by comparing the latencies of occipital N1 components between hemispheres. No significant between-group differences in electrophysiological estimates of IHTT were found. Shorter N1 latencies may enable expert VGPs to discriminate attended visual stimuli significantly earlier than non-VGPs and contribute to faster responding in visual tasks. As successful video-game play requires precise, time pressured, bimanual motor movements in response to complex visual stimuli, which in this sample began during early childhood, these differences may reflect the experience and training involved during the development of video-game expertise, but training studies are needed to test this prediction.

  19. Good maintenance of exercise-induced bone gain with decreased training of female tennis and squash players: a prospective 5-year follow-up study of young and old starters and controls.

    Science.gov (United States)

    Kontulainen, S; Kannus, P; Haapasalo, H; Sievänen, H; Pasanen, M; Heinonen, A; Oja, P; Vuori, I

    2001-02-01

    This prospective 5-year follow-up study of 64 adult female racquet sports players and 27 controls assessed the changes in the playing-to-nonplaying arm bone mineral content (BMC) differences to answer three questions: (1) Are training-induced bone gains lost with decreased training? (2) Is the bone response to decreased training different if the playing career has been started before or at puberty rather than after it? (3) Are the possible bone changes related to the changes in training? The players were divided into two groups according to the starting age of their tennis or squash playing. The mean starting age was 10.5 years (SD, 2.2) among the players who had started training before or at menarche (young starters; n = 36) while 26.4 years (SD, 8.0) among those players who had begun training a minimum of 1 year after menarche (old starters; n = 28). At baseline of the 5-year follow-up, the mean age of the young starters was 21.6 years (SD, 7.6) and that of old starters was 39.4 years (SD, 10.5). During the follow-up, the young starters had reduced the average training frequency from 4.7 times a week (2.7) to 1.4 times a week (1.3) and the old starters from 4.0 times a week (1.4) to 2.0 times a week (1.4), respectively. The 5-year follow-up revealed that despite reduced training the exercise-induced bone gain was well maintained in both groups of players regardless of their clearly different starting age of activity and different amount of exercise-induced bone gain. The gain was still 1.3-2.2 times greater in favor of the young starters (at the follow-up, the dominant-to-nondominant arm BMC difference was 22% [8.4] in the humeral shaft of the young starters versus 10% [3.8] in the old starters, and 3.5% [2.4] in controls). In the players, changes in training were only weakly related to changes in the side-to-side BMC difference (r(s) = 0.05-0.34, all NS), and this was true even among the players who had stopped training completely a minimum 1 year before the

  20. Table Tennis Club

    CERN Multimedia

    Table Tennis Club

    2013-01-01

    Apparently table tennis plays an important role in physics, not so much because physicists are interested in the theory of table tennis ball scattering, but probably because it provides useful breaks from their deep intellectual occupation. It seems that many of the greatest physicists took table tennis very seriously. For instance, Heisenberg could not even bear to lose a game of table tennis, Otto Frisch played a lot of table tennis, and had a table set up in his library, and Niels Bohr apparently beat everybody at table tennis. Therefore, as the CERN Table Tennis Club advertises on a poster for the next CERN Table Tennis Tournament: “if you want to be a great physicist, perhaps you should play table tennis”. Outdoor table at restaurant n° 1 For this reason, and also as part of the campaign launched by the CERN medical service “Move! & Eat better”, to encourage everyone at CERN to take regular exercise, the CERN Table Tennis Club, with the supp...

  1. CERN Table Tennis Club

    CERN Multimedia

    CERN Table Tennis Club

    2014-01-01

    CERN Table Tennis Club Announcing CERN 60th Anniversary Table Tennis Tournament to take place at CERN, from July 1 to July 15, 2014   The CERN Table Tennis Club, reborn in 2008, is encouraging people at CERN to take more regular exercise. This is why the Club, thanks to the strong support of the CERN Staff Association, installed last season a first outdoor table on the terrace of restaurant # 1, and will install another one this season on the terrace of Restaurant # 2. Table tennis provides both physical exercise and friendly social interactions. The CERN Table Tennis club is happy to use the unique opportunity of the 60th CERN anniversary to promote table tennis at CERN, as it is a game that everybody can easily play, regardless of level. Table tennis is particularly well suited for CERN, as many great physicists play table tennis, as you might already know: “Heisenberg could not even bear to lose a game of table tennis”; “Otto Frisch played a lot of table tennis;...

  2. Understanding the traction of tennis surfaces

    OpenAIRE

    Clarke, James; Carré, Matt; Richardson, Andrea; Yang, Zhijun; Damm, Loic; Dixon, Sharon

    2011-01-01

    The traction provided by a footwear-surface interaction can have an impact on player safety, performance and overall enjoyment of sport. Mechanical test methods used for the testing and categorisation of safe playing surfaces do not tend to simulate loads occurring during participation on the surface, and thus are unlikely to predict human response to the surface. For example, the pendulum system routinely employed by the International Tennis Federation (I.T.F.) utilises a standard rubber ‘fo...

  3. THE PHYSIOLOGICAL DEMANDS OF TABLE TENNIS: A REVIEW

    Directory of Open Access Journals (Sweden)

    Miran Kondric

    2013-09-01

    Full Text Available Although table tennis has a tradition lasting more than 100 years, relatively little is known about players' physiological requirements - especially during competition. In this review we discuss research studies that have led to our current understanding of how the body functions during table tennis training and competition and how this is altered by training. Match and practice analysis of the table tennis game indicates that during intense practice and competition it is predominantly the anaerobic alactic system that is called into play, while the endurance system is relied on to recovery the anaerobic stores used during such effort. It is thus important for coaches to keep in mind that, while the anaerobic alactic system is the most energetic system used during periods of exertion in a table tennis game, a strong capacity for endurance is what helps a player recover quicker for the following match and the next day of competition. This paper provides a review of specific studies that relate to competitive table tennis, and highlights the need for training and research programs tailored to table tennis

  4. Comparative Analysis of Return of Serve Comparative Analysis of Return of Serve as Counter- as Counter-attack in Modern Tennis attack in Modern Tennis attack in Modern Tennis

    Directory of Open Access Journals (Sweden)

    Petru Eugen MERGHEŞ

    2017-02-01

    Full Text Available High performance modern tennis is characterised by high dynamism, speed in thinking and action, precision and high technical and tactical skills. In this study, we used direct observation and statistical recording of nine matches during two competition years in the tennis players Roger Federer, Rafael Nadal and Andre Agassi. In these tennis players, we studied mainly the return of serve, one of the most important shots in tennis, together with serve, as first shots in a point. We have chosen the three tennis players because they are the best example of return of serve as shown by the matches recorded and interpreted. The study we have carried out shows that return of serve makes Agassi a winner in most matches. The high percentage in Federer’s serves makes his adversaries have a lower percentage in return of serve, which prevents them to win against his serve. High percentage in return of serve results in more points on the adversary’s serve and an opportunity to start the offensive point. After comparing the three tennis players mentioned above, we can see that the highest percentage of points won on return of serve belongs to Agassi, which ranks him among the best return of serve tennis players in the world. The tennis player with the highest percentage in return of service is the one who wins the match, which shows, once again, the importance of the return of serve. Return of serve can be a strong counter-attack weapon if used at its highest level.

  5. Effects of A 6-Week Junior Tennis Conditioning Program on Service Velocity

    OpenAIRE

    Fernandez-Fernandez, Jaime; Ellenbecker, Todd; Sanz-Rivas, david; Ulbricht, Alexander; Ferrautia, lexander

    2013-01-01

    This study examined the effects of a 6-week strength-training program on serve velocity in youth tennis players. Thirty competitive healthy and nationally ranked male junior tennis players (13 years of age) were randomly and equally divided into control and training groups. The training group performed 3 sessions (60-70 min) weekly for 6 weeks, comprising core strength, elastic resistance and medicine ball exercises. Both groups (control and training) also performed a supervised stretching ro...

  6. Playing vs. Nonplaying Aerobic Training in Tennis: Physiological and Performance Outcomes

    OpenAIRE

    Pialoux, Vincent; Genevois, Cyril; Capoen, Arnaud; Forbes, Scott C.; Thomas, Jordan; Rogowski, Isabelle

    2015-01-01

    This study compared the effects of playing and nonplaying high intensity intermittent training (HIIT) on physiological demands and tennis stroke performance in young tennis players. Eleven competitive male players (13.4 ± 1.3 years) completed both a playing and nonplaying HIIT session of equal distance, in random order. During each HIIT session, heart rate (HR), blood lactate, and ratings of perceived exertion (RPE) were monitored. Before and after each HIIT session, the velocity and accuracy...

  7. Expert model of decision-making system for efficient orientation of basketball players to positions and roles in the game--empirical verification.

    Science.gov (United States)

    Dezman, B; Trninić, S; Dizdar, D

    2001-06-01

    The purpose of the research was to empirically verify the expert model system designed for more efficient orientation of basketball players to particular positions and /or roles in the game (specialization). Participants were 60 randomly chosen male basketball players (12 players per each position) from the 12 Croatian 1st league teams in season 1998/99. Data were gathered from 10 basketball coaches who estimated overall performance (actual quality) of players on defense (7 variables) and on offense (12 variables). Variables were established by Trninić, Perica and Dizdar. A measure of body height was added to the aforementioned group of variables. The results obtained suggest that the proposed decision-making system can be used as an auxiliary instrument in orienting players to the positions and roles in the game. It has been established that the players have attained the highest grades of overall performance exactly at their primary playing positions in the game. The largest differences were determined between point guards (position 1) and centers (position 5). The greatest difficulties have occurred in determining optimal position for small forwards (position 3), then for shooting guards (position 2) and, last, for power forwards (position 4), because all these basketball players are the most versatile ones. Therefore, reliability of the system is the lowest when it is applied for selecting and orientating players to these positions. Convenient body height significantly contributes to aptitude of these players to play multiple positions and to assume multiple roles in the game. This research has reinforced the thesis that body height is a variable with the greatest influence on orientation of players to particular positions and roles in the game.

  8. Effectiveness of 14-15 years old tennis players’ competition functioning considering correction of their psychological fitness

    Directory of Open Access Journals (Sweden)

    T.B. Makuts

    2015-10-01

    Full Text Available Purpose: to determination influence of individualized psychological training on effectiveness of 14-15 years old tennis players’ competition functioning. Material: in the research 24 tennis players of 14-15 years’ age participated. Individualized psychological training consisted of 15 sessions of total duration of 1.5 months. Results: We substantiated necessity of individualized approach to tennis players’ psychological training. Individual psychological profiles for tennis players, which determined content of psychological training and their selection, were worked out. Informative indicators for assessment of 14-15 years old tennis players’ competition functioning were determined: 1 percentage of won and lost scores at the account of own actions; 2 integral criteria of tennis players’ competition functioning assessment (coefficient of stability and effectiveness; complex indicator of efficiency. Conclusions: it is recommended to consider individual potentials and bents of sportsmen in the course of psychological training.

  9. Srovnání herních charakteristik tenistů a tenistek na Roland Garros 2005 Comparison of game characteristics of male and female tennis players at Roland Garros 2005

    Directory of Open Access Journals (Sweden)

    Tomaž Berendijaš

    2008-04-01

    Full Text Available Herní charakteristiky elitních tenistů a tenistek na French Open 2005 (Roland Garros byly analyzovány na rozsáhlém základě 894 setů v kategorii mužů a 592 setů v kategorii žen. Navíc se srovnávaly herní charakteristiky jednotlivého setu mezi vítězi a poraženými. Bylo potvrzeno, že u většiny proměnných existují statisticky významné rozdíly mezi vítězi a poraženými, a to jak v kategorii mužů, tak i žen. V kategorii mužů jsou statisticky významné rozdíly u všech proměnných, s výjimkou využití brejkbolu. U žen byly shledány statisticky významné rozdíly u všech proměnných s výjimkou počtu vyhraných es. Na základě těchto zjištění lze učinit závěr, že statisticky významné rozdíly u většiny proměnných určujících herní charakteristiky naznačují existenci určitých měřitelných ukazatelů ve statistice tenisu, kterými se odlišují vítězové od poražených. The game characteristics of elite male and female tennis players at the French Open 2005 (Roland Garros have been analyzed based on a large number of sets, a total of 894 in the category of men and 592 sets in the category of women. In addition, a comparison of game characteristics in an individual set between winners and losers has been made. It was ascertained that there are statistically characteristic differences in most variables between the winners and loser in the category of men as well as in the category of women. In the category of men, there are statistically characteristic differences in all variables except in the break point conversions. In women however, there are statistically characteristic differences in all variables except in the number of won aces. Based on these findings it can be concluded that statistically characteristic differences in the majority of variables, which define game characteristics, indicate that there are certain measurable indicators of tennis statistics, which distinguish

  10. Winning in straight sets helps in Grand Slam tennis

    NARCIS (Netherlands)

    Goossens, Dries R.; Kempeneers, Jurgen; Koning, Ruud H.; Spieksma, Frits C. R.

    2015-01-01

    In this contribution, we study whether fatigue resulting from the previous match affects a player's chances of winning his (or her) next match in Grand Slum tennis. We measure relative fatigue levels of two opponents by looking at the difference in number of sets played in their previous match. We

  11. Tennis: Applied Examples of a Game-Based Teaching Approach

    Science.gov (United States)

    Crespo, Miguel; Reid, Machar M.; Miley, Dave

    2004-01-01

    In this article, the authors reveal that tennis has been increasingly taught with a tactical model or game-based approach, which emphasizes learning through practice in match-like drills and actual play, rather than in practicing strokes for exact technical execution. Its goal is to facilitate the player's understanding of the tactical, physical…

  12. Competition Field Perceptions of Table-tennis Athletes and their Performance

    Directory of Open Access Journals (Sweden)

    Liu Ying-Chieh

    2018-03-01

    Full Text Available The distinction between positive and negative perceptions is fundamental in perception models. The purpose of this study was to investigate the correlation between field perceptions of table tennis players and the outcome (net result during the matches in a competition. Experimental data were collected from 10 elite table tennis players and analysed. The results addressed the following three competition field perceptions: (1 before the service, the player’s positive perceptions had significant effect on the positive outcome (winning rate of that service; (2 the perception after the net result of the previous service increased the positive outcome of the next service, and (3 the player’s positive/negative perception during the matches affected the win/loss outcome of that competition. In conclusion, the player’s positive perceptions enhanced their winning rate during table tennis competitions. Therefore, during the training program, coaches need to develop positive perceptions and strengthen the psychological quality of table tennis players.

  13. LOW COMPRESSION TENNIS BALLS AND SKILL DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    John Hammond

    2006-12-01

    Full Text Available Coaching aims to improve player performance and coaches have a number of coaching methods and strategies they use to enhance this process. If new methods and ideas can be determined to improve player performance they will change coaching practices and processes. This study investigated the effects of using low compression balls (LCBs during coaching sessions with beginning tennis players. In order to assess the effectiveness of LCBs on skill learning the study employed a quasi-experimental design supported by qualitative and descriptive data. Beginner tennis players took part in coaching sessions, one group using the LCBs while the other group used standard tennis balls. Both groups were administered a skills at the beginning of a series of coaching sessions and again at the end. A statistical investigation of the difference between pre and post-test results was carried out to determine the effect of LCBs on skill learning. Additional qualitative data was obtained through interviews, video capture and the use of performance analysis of typical coaching sessions for each group. The skill test results indicated no difference in skill learning when comparing beginners using the LCBs to those using the standard balls. Coaches reported that the LCBs appeared to have a positive effect on technique development, including aspects of technique that are related to improving power of the shot. Additional benefits were that rallies went on longer and more opportunity for positive reinforcement. In order to provide a more conclusive answer to the effects of LCBs on skill learning and technique development recommendations for future research were established including a more controlled experimental environment and larger sample sizes across a longer period of time

  14. Influence of a Prolonged Tennis Match Play on Serve Biomechanics.

    Directory of Open Access Journals (Sweden)

    Caroline Martin

    Full Text Available The aim of this study was to quantify kinematic, kinetic and performance changes that occur in the serve throughout a prolonged tennis match play. Serves of eight male advanced tennis players were recorded with a motion capture system before, at mid-match, and after a 3-hour tennis match. Before and after each match, electromyographic data of 8 upper limb muscles obtained during isometric maximal voluntary contraction were compared to determine the presence of muscular fatigue. Vertical ground reaction forces, rating of perceived exertion, ball speed, and ball impact height were measured. Kinematic and upper limb kinetic variables were computed. The results show decrease in mean power frequency values for several upper limb muscles that is an indicator of local muscular fatigue. Decreases in serve ball speed, ball impact height, maximal angular velocities and an increase in rating of perceived exertion were also observed between the beginning and the end of the match. With fatigue, the majority of the upper limb joint kinetics decreases at the end of the match. No change in timing of maximal angular velocities was observed between the beginning and the end of the match. A prolonged tennis match play may induce fatigue in upper limb muscles, which decrease performance and cause changes in serve maximal angular velocities and joint kinetics. The consistency in timing of maximal angular velocities suggests that advanced tennis players are able to maintain the temporal pattern of their serve technique, in spite of the muscular fatigue development.

  15. Table Tennis Club

    CERN Multimedia

    Table Tennis Club

    2012-01-01

    The CERN Table Tennis club and the Meyrin CTT are organizing two Table Tennis workshops from 2 to 6 July and from 20 to 24 August 2012 inclusive in Meyrin. A professional would be with your children from 14.00 pm to 18.00 pm: an instructor J + S category A. Training courses with specific themes, individual courses would be given depending on the level of the child’s game, “discoveries –table tennis games” courses and games with the robot. Other activities (stretching, relaxation). Afternoons (from 18 to 20 children): 40 CHF per workshop and per child. Evenings (from 18 to 20 adults): 60 CHF per workshop and per adult. For further information, please contact Mr. Monteil : Mobile: (+33) 06 61 31 70 47 E-mail: wilfried.monteil@free.fr.

  16. Análisis de la condición física en jugadores y jugadoras de tenis de mesa y su relación con el rendimiento deportivo. [Physical fitness analysis in male and female table tennis players and their relationship to competition performance].

    Directory of Open Access Journals (Sweden)

    Jon Mikel Picabea

    2017-01-01

    Full Text Available Los objetivos de este estudio fueron analizar el perfil físico de jugadores de tenis de mesa, observar si existían diferencias en función del género en las pruebas realizadas y determinar si existía alguna relación entre las pruebas de condición física y el rendimiento deportivo. Veinte jugadores de tenis de mesa, de los cuales 10 eran jugadores de categoría masculina (17,61 ± 7,56 años, 1,63 ± 0,11 m, 60,62 ± 20,03 kg, 22,07 ± 5,87 kg/m2 y 10 jugadoras de categoría femenina (17,35 ± 7,12 años, 1,61 ± 0,07 m, 48,89 ± 7,66 kg, 19,33 ± 2,26 kg/m2 fueron evaluados en la capacidad de sprint, fuerza isométrica de antebrazo, salto vertical con contra movimiento, salto horizontal con contra movimiento, capacidad de cambiar de dirección y flexibilidad. Los resultados mostraron mejores resultados en el grupo de jugadores masculinos en comparación con el grupo femenino en el test de capacidad de cambio de dirección (MAT, p 0,05 entre el resultado obtenido en las pruebas de condición física y el rendimiento deportivo en competición ni en jugadores masculinos ni femeninos. Este aspecto pone de manifiesto que la condición física puede no ser uno de los factores relevantes en el rendimiento deportivo de los jugadores de tenis de mesa de este estudio. Abstract The aims of this study were to analyze the physical profile of table tennis players, look at differences between genders in the different tests and to determinate the relationships between the physical fitness test and sport performance. 20 table tennis players, 10 male players (17.61 ± 7.56 years, 1.63 ± 0.11 m, 60.62 ± 20.03 kg, 22.07 ± 5.87 kg/m2 and 10 female players (17.35 ± 7.12 years, 1.61 ± 0.07 m, 48.89 ± 7.66 kg, 19.33 ± 2.26 kg/m2, performed a sprint test, forearm isometric strength, countermovement vertical test, countermovement horizontal test, change of direction ability test and flexibility. The male players obtained better results than the female

  17. Vliv motorických schopností a antropometrických měr na úspěšnost v závodech u 11 a 12letých hráček tenisu The influence of tennis motor abilities and anthropometric measures on the competition successfulness of 11 and 12 year-old female tennis players

    Directory of Open Access Journals (Sweden)

    Tjaša Filipčič

    2005-02-01

    Full Text Available Soubor 75 mladých hráček tenisu ve věku 11 a 12 let byl zahrnut do výzkumného projektu s cílem zjistit vliv vybraných antropometrických údajů a tenisových motorických dovedností na úspěšnost v soutěžích mladých tenisových hráčů. Vybrané tenisové motorické proměnné zahrnují: sílu svalů paží a ramen, sílu nohou, opakovanou sílu trupu, rychlost pohybu, rychlost střídavého pohybu rukou, ohebnost zad, hbitost a koordinaci ruka – oko. Výsledky regresní analýzy antropometrických měr odhalují statisticky významné spojení s kritérii proměnných (0,36. Skupina predikčních proměnných může vysvětlit 13% rozdílnost kritérií proměnných. To stejné se aplikuje na tenisové motorické proměnné, u kterých je důležitá hodnota poněkud bližší, dosahuje 0,64, zatímco systém prediktorů vysvětluje 41% rozdílnost kritérií proměnných. Tři proměnné z antropometrických měr (obvod lýtka, tělesná váha, břišní kožní řasa vysvětlují kritérium proměnné se statistickou významností. Mezi již výše zmíněné tenisové motorické proměnné patří běh na 2 400 metrů, který se používá pro měření vytrvalosti v běhu, a běh na 5 metrů, který se používá pro meření rychlosti pohybu. A sample of 75 young female tennis players, aged 11 and 12, was included in a research project aimed at establishing the influence of selected anthropometric measures and tennis motor abilities on the competition successfulness of young tennis players. The selected tennis motor variables include: the muscular power of arms and shoulders, elastic power of the legs, repetitive strength of the trunk, speed of movement, speed of alternative movements with the arm, flexibility of the back, agility, and hand-eye coordination. The results of regression analysis of anthropometric measures reveal a statistically significant connection with the criterion variable (0.36. The system of

  18. 基于时间序列情境的网球专家预判优势——来自ERP的证据%The Advantage Anticipation of Tennis Experts Based on Time Series Scenarios——An ERP Study

    Institute of Scientific and Technical Information of China (English)

    王小春; 周成林

    2012-01-01

    The ability of perceptual prediction played a crucial role in competitive sports. This study around this clues,by means of time series occlusion, with event-related potentials technologies (ERP) .investigated the characteristics of perceptual processing of tennis experts. The results showed that: (l)The accuracy and speed of response had significant advantages of tennis experts,the accuracy increase gradually as the time point of series occlusion delayed. (2)In the early epoch of stimulus onset,tennis experts induced N1 amplitude were significantly greater than the experience and the novice group,and be affected significantly by time series occlusion;In the late epoch of stimulus onset,the experts group induced the maximum amplitude of P3b at Pz.and the latencies were earlier;PSW component was induced only in the group of experts and experiences,and the appearance time was significantly early in experts than experiences group. Results indicated that tennis experts had advantages of perceptual processing speed and accuracy because of professional training and competition,and they had a high degree activation of the early attention. Tennis expert had a professional context memory,the representation of working memory was activated during the prediction,take the top-down processing,more efficient about the memory retrieval.%知觉预判能力在竞技运动比赛中发挥着关键性的作用.本研究围绕知觉预判这一线索,以时间序列遮蔽为手段,借助事件相关电位技术(ERP),寻找网球专家预判优势的知觉加工特征.结果发现:(1)网球专家的预判准确性与反应速度具有显著优势,随着时间序列遮蔽点的推迟,准确性逐渐递增.(2)刺激呈现早期,网球专家诱发的N1波幅显著大于经验组和新手组被试,且受时间序列遮蔽影响显著;刺激呈现晚期,专家组在Pz点诱发的P3b波幅达到最大值,且潜伏期较早;PSW仅在专家与经验组中被发现,并且专家诱发时间显

  19. THE EFFICIENCY OF TENNIS DOUBLES SCORING SYSTEMS

    Directory of Open Access Journals (Sweden)

    Geoff Pollard

    2010-09-01

    Full Text Available In this paper a family of scoring systems for tennis doubles for testing the hypothesis that pair A is better than pair B versus the alternative hypothesis that pair B is better than A, is established. This family or benchmark of scoring systems can be used as a benchmark against which the efficiency of any doubles scoring system can be assessed. Thus, the formula for the efficiency of any doubles scoring system is derived. As in tennis singles, one scoring system based on the play-the-loser structure is shown to be more efficient than the benchmark systems. An expression for the relative efficiency of two doubles scoring systems is derived. Thus, the relative efficiency of the various scoring systems presently used in doubles can be assessed. The methods of this paper can be extended to a match between two teams of 2, 4, 8, …doubles pairs, so that it is possible to establish a measure for the relative efficiency of the various systems used for tennis contests between teams of players.

  20. Srovnání hodnocení chování rodičů a trenérů u tenistů a tenistek různých věkových skupin Comparison of assessments of parents' and coaches' behaviour by male and female tennis players of different ages

    Directory of Open Access Journals (Sweden)

    Tjaša Filipčič

    2006-02-01

    Full Text Available Tenis je určitě jednou z těch sportovních her, v nichž je úspěch ovlivňován psychologickými schopnostmi. Během celé své sportovní dráhy jsou obvykle tenisoví hráči vystaveni psychologickému tlaku. Cílem této studie bylo zjistit, jak mladí tenisoví hráči hodnotí chování (psychologický tlak a aktivitu své matky, otce a tenisového trenéra. Vzorek zahrnoval 96 tenistů a 96 tenistek náležejících do třech věkových kategorií, kteří vyplňovali tři dotazníky uzavřeného typu. Údaje byly zpracovávány v souladu s výzkumnými cíly. Pro všechny proměnné byly podle pohlaví vypočítávány popisné statistické parametry: střední hodnota, standardní odchylka, minimum, maximum, šikmost, špičatost a Kolmogorovův-Smirnovův test normality. Pro srovnávání hodnocení chování hráčova otce, matky a trenéra podle pohlaví a posléze pro srovnávání tří věkových kategorií (U12, U14, U16 byla použita analýza variance (ANOVA. Srovnávání hodnocení chování otce, matky a trenéra podle pohlaví odhalilo statisticky významné rozdíly pouze u hodnocení otce. Při srovnávání hodnocení chování obou rodičů a trenéra podle věkových kategorií byly statisticky významné rozdíly stanoveny opět pouze u hodnocení otce. Tennis is clearly one of those sports games where success is influenced by one's psychological abilities. Throughout their sports careers tennis players are usually exposed to psychological pressure. The aim of the study was to investigate how young tennis players assess the behaviour (psychological pressure and activity of their mother, father and tennis coach. The sample included 96 male and 96 female players distributed in three age categories who filled in three questionnaires of the closed type. Data were processed in accordance with the research goals. Descriptive statistics parameters were calculated for all variables by gender: mean value, standard deviation

  1. Joint Kinetics to Assess the Influence of the Racket on a Tennis Player’s Shoulder

    OpenAIRE

    Creveaux, Thomas; Dumas, Raphaël; Hautier, Christophe; Macé, Pierre; Chèze, Laurence; Rogowski, Isabelle

    2013-01-01

    This study aimed at investigating the influence of three rackets on shoulder net joint moments, power and muscle activity during the flat tennis serve under field- conditions. A 6-camera Eagle® motion analysis system, operating at 256 Hz, captured racket and dominant upper limb kinematics of the serve in five tennis players under three racket conditions (A: low mass, high balance and polar moment, B: low three moments of inertia, and C: high mass, swingweight and twistweight). The electromyog...

  2. Aerobic Exercise Combined with Techniques Programe Can Be Increased Groundstroke Skill of Tennis Athlet

    OpenAIRE

    Nasrulloh, Ahmad

    2012-01-01

    Professional tennis athletes should be able to master all the basic techniques of playing tennis and having physical fitness. Therefore, it is necessary to get an exercise that can give meaning to the skills and physical fitness. One of the proper exercises is with aerobic exercise combined with the technique.Aerobic exercise program combined with techniques is: (1) a number of players consisting of six to seven people with backward sequential formation techniques performing forehand and back...

  3. Proprioceptive Ability of Fencing and Table Tennis Practioners

    Directory of Open Access Journals (Sweden)

    Bańkosz Ziemowit

    2014-09-01

    Full Text Available Purpose. The aim of the study was to compare the spatial component of proprioceptive ability by reproducing a upper limb movement typical in table tennis and fencing. Methods. The research comprised 41 young males of which 12 were table tennis players, 14 fencers, and 15 not involved in any competitive sports as a control. The experiment was based on assessing the precision of pronation and supination of the forearm at the elbow joint in recreating a set movement range by use of a goniometer. Results and conclusions. The results point to a higher level of proprioceptive ability in fencers and table tennis players than the control group but only in respect to the tasks executed with the dominant limb. This is inferred to be the result from the specific character of both sports (i.e. the intensive use of one limb and the consequent laterality of that limb causing higher sensitivity and proprioception. This may provide a link between swordplay, table tennis, and the level of proprioception. The research methodology used herein may be useful in monitoring fencing training. Although not unequivocally statistically significant, the results indicate the potential for further research in this area.

  4. Mental Toughness in Competitive Tennis: Relationships with Resilience and Stress

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    Richard Gregory Cowden

    2016-03-01

    Full Text Available The present study investigated the relationships between mental toughness (MT, resilience, and stress among competitive South African tennis players. A total of 351 tennis players participating at various competitive standards completed the Sport Mental Toughness Questionnaire, the Resilience Scale for Adults, and a modified version of the Recovery-Stress Questionnaire for Athletes. The results indicated that total MT was positively associated with total resilience (r = .59, but negatively associated with total stress (r = -.44. The resilience subscales of perception of self, perception of future, social competence, and social resources, but not family cohesion, significantly predicted total MT (R2 = .35. Both total resilience and total MT significantly predicted total stress (R2 = .21. Based on the findings, interrelations between MT and resilience are explored, implications outlined, and additional research is suggested to ascertain the contextual relevance and outcomes associated with each construct in sport.

  5. Mental Toughness in Competitive Tennis: Relationships with Resilience and Stress.

    Science.gov (United States)

    Cowden, Richard G; Meyer-Weitz, Anna; Oppong Asante, Kwaku

    2016-01-01

    The present study investigated the relationships between mental toughness (MT), resilience, and stress among competitive South African tennis players. A total of 351 tennis players participating at various competitive standards completed the Sports Mental Toughness Questionnaire, the Resilience Scale for Adults, and a modified version of the Recovery-Stress Questionnaire for Athletes. The results indicated that total MT was positively associated with total resilience (r = 0.59), but negatively associated with total stress (r = -0.44). The resilience subscales of perception of self, perception of future, social competence, and social resources, but not family cohesion, significantly predicted total MT (R (2) = 0.35). Both total resilience and total MT significantly predicted total stress (R (2) = 0.21). Based on the findings, interrelations between MT and resilience are explored, implications outlined, and additional research is suggested to ascertain the contextual relevance and outcomes associated with each construct in sport.

  6. Table Tennis Club

    CERN Document Server

    Table Tennis Club

    2012-01-01

    2012 CERN Table Tennis Tournament As the campaign launched by the CERN medical service “Move! & Eat better” is designed in particular to encourage people at CERN to take more regular exercise, the CERN Table Tennis Club, with its traditional CERN Table Tennis Tournament is providing an excellent opportunity to practice moving. The tournament will take place at the Meyrin CTT, 2 rue de Livron, Saturday August 25, 2012, in the afternoon (starting at 13:30). It is open to all CERN staff, users, visitors and families, including of course summer students, who are strongly encouraged to participate. In order to register, simply send an E-mail to Jean-Pierre Revol (jean-pierre.revol@cern.ch). You may also find useful information on the Club Web page http://www.cern.ch/tabletennis CERN 2011 champion Savitha Flaecher, between the finalist Bertrand Mouches on her left, the winner of the consolation draw on her right (Sudarshan Paramesvaran), and far left, Denis Moriaud (semi-finalist a...

  7. Management of tennis elbow

    Directory of Open Access Journals (Sweden)

    Chesterton LS

    2011-06-01

    Full Text Available Linda S Chesterton, Christian D Mallen, Elaine M HayArthritis Research UK Primary Care Centre, Primary Care Sciences, Keele University, Keele, Staffordshire, UKDate of preparation: April 21, 2011Conflict of interest: None declaredClinical question: What is the best treatment for tennis elbow?Results: Despite a wealth of research, there is no true consensus on the most efficacious management of tennis elbow especially for effective long-term outcomes. Corticosteroid injections do show large pain-relieving effects in the short term but are associated with risks of adverse events and long-term reoccurrence. Advice with a “wait and see” approach is recommended as the first-line treatment in primary care for most cases. In the medium term physiotherapy and or low-level laser therapy may be effective.Implementation: Rule out alternative diagnosis. Onward referral may be indicated if the condition does not resolve after 12 months.Keywords: tennis elbow, corticosteroids, physiotherapy, laser therapy

  8. Why bigger may in fact be better... in the context of table tennis

    Science.gov (United States)

    Truscott, Tadd; Pan, Zhao; Belden, Jesse

    2014-11-01

    We submit that table tennis is too fast. Because of the high ball velocities relative to the small table size, players are required to act extremely quickly, often exceeding the limits of human reaction time. Additionally, the Magnus effect resulting from large rotation rates introduces dramatically curved paths and causes rapid direction changes after striking the table or paddle, which effectively reduces reaction time further. Moreover, watching a professional game is often uninteresting and even tiring because the ball is moving too quickly to follow with the naked eye and the action of the players is too subtle to resolve from a distance. These facts isolate table tennis from our quantitatively defined ``fun game club,'' and make it less widely appealing than sports like baseball and soccer. Over the past 100 years, the rules of table tennis have changed several times in an effort to make the game more attractive to players and spectators alike, but the game continues to lose popularity. Here, we experimentally quantify the historic landmark equipment changes of table tennis from a fluid dynamics perspective. Based on theory and observation, we suggest a larger diameter ball for table tennis to make the game more appealing to both spectators and amateur players.

  9. The issue of scientific thesaurus differentiation of table tennis sportsmen's psychomotor abilities

    Directory of Open Access Journals (Sweden)

    Kushnir V.V.

    2010-02-01

    Full Text Available Essence of psychomotor capabilities opens up for tennis sportsmen-players. Clear differentiation of the most essential psychomotor capabilities is conducted. They will present the constituent of competent training process and successful competition period. It is necessary to take to the group of general psychomotor qualities of tennis players: spatial orientation, kinesthetic sensitiveness, exactness of motions. The special attention is deserved by the group of psychomotor capabilities: difficult visile-motor reaction, functional mobility and force of nervous processes. Determination of level of their development on the initial stage of long-term preparation is the prerogative of forming of skilled sportsman high level trades.

  10. Coordination and variability in the elite female tennis serve.

    Science.gov (United States)

    Whiteside, David; Elliott, Bruce Clifford; Lay, Brendan; Reid, Machar

    2015-01-01

    Enhancing the understanding of coordination and variability in the tennis serve may be of interest to coaches as they work with players to improve performance. The current study examined coordinated joint rotations and variability in the lower limbs, trunk, serving arm and ball location in the elite female tennis serve. Pre-pubescent, pubescent and adult players performed maximal effort flat serves while a 22-camera 500 Hz motion analysis system captured three-dimensional body kinematics. Coordinated joint rotations in the lower limbs and trunk appeared most consistent at the time players left the ground, suggesting that they coordinate the proximal elements of the kinematic chain to ensure that they leave the ground at a consistent time, in a consistent posture. Variability in the two degrees of freedom at the elbow became significantly greater closer to impact in adults, possibly illustrating the mechanical adjustments (compensation) these players employed to manage the changing impact location from serve to serve. Despite the variable ball toss, the temporal composition of the serve was highly consistent and supports previous assertions that players use the location of the ball to regulate their movement. Future work should consider these associations in other populations, while coaches may use the current findings to improve female serve performance.

  11. Biomechanical Analysis of Abdominal Injury in Tennis Serves. A Case Report

    Directory of Open Access Journals (Sweden)

    François Tubez, Bénédicte Forthomme, Jean-Louis Croisier, Caroline Cordonnier, Olivier Brüls, Vincent Denoël, Gilles Berwart, Maurice Joris, Stéphanie Grosdent, Cédric Schwartz

    2015-06-01

    Full Text Available The serve is an important stroke in any high level tennis game. A well-mastered serve is a substantial advantage for players. However, because of its repeatability and its intensity, this stroke is potentially deleterious for upper limbs, lower limbs and trunk. The trunk is a vital link in the production and transfer of energy from the lower limbs to the upper limbs; therefore, kinematic disorder could be a potential source of risk for trunk injury in tennis. This research studies the case of a professional tennis player who has suffered from a medical tear on the left rectus abdominis muscle after tennis serve. The goal of the study is to understand whether the injury could be explained by an inappropriate technique. For this purpose, we analyzed in three dimensions the kinematic and kinetic aspects of the serve. We also performed isokinetic tests of the player’s knees. We then compared the player to five other professional players as reference. We observed a possible deficit of energy transfer because of an important anterior pelvis tilt. Some compensation made by the player during the serve could be a possible higher abdominal contraction and a larger shoulder external rotation. These particularities could induce an abdominal overwork that could explain the first injury and may provoke further injuries.

  12. Biomechanical analysis of abdominal injury in tennis serves. A case report.

    Science.gov (United States)

    Tubez, François; Forthomme, Bénédicte; Croisier, Jean-Louis; Cordonnier, Caroline; Brüls, Olivier; Denoël, Vincent; Berwart, Gilles; Joris, Maurice; Grosdent, Stéphanie; Schwartz, Cédric

    2015-06-01

    The serve is an important stroke in any high level tennis game. A well-mastered serve is a substantial advantage for players. However, because of its repeatability and its intensity, this stroke is potentially deleterious for upper limbs, lower limbs and trunk. The trunk is a vital link in the production and transfer of energy from the lower limbs to the upper limbs; therefore, kinematic disorder could be a potential source of risk for trunk injury in tennis. This research studies the case of a professional tennis player who has suffered from a medical tear on the left rectus abdominis muscle after tennis serve. The goal of the study is to understand whether the injury could be explained by an inappropriate technique. For this purpose, we analyzed in three dimensions the kinematic and kinetic aspects of the serve. We also performed isokinetic tests of the player's knees. We then compared the player to five other professional players as reference. We observed a possible deficit of energy transfer because of an important anterior pelvis tilt. Some compensation made by the player during the serve could be a possible higher abdominal contraction and a larger shoulder external rotation. These particularities could induce an abdominal overwork that could explain the first injury and may provoke further injuries. Key pointsIn the proximal-distal sequence, energy is transmitted from lower limbs to upper limps via trunk.The 3D analysis tool is an indispensable test for an objective evaluation of the kinematic in the tennis serve.Multiple evaluations techniques are useful for fuller comprehension of the kinematics and contribute to the awareness of the player's staff concerning pathologies and performance.

  13. Efectos de un entrenamiento pliométrico en extremidades superiores e inferiores en el rendimiento físico en jóvenes tenistas. [Effects of upper and lower body plyometric training on physical performance in young tennis players].

    Directory of Open Access Journals (Sweden)

    Elena Pardos-Mainer

    2017-07-01

    Full Text Available El objetivo del presente estudio fue evaluar el efecto de un entrenamiento pliométrico (ejercicios en extremidades superiores e inferiores en acciones físicas explosivas específicas en jóvenes tenistas. Veintiún jóvenes tenistas (11 chicos, 10 chicas; media de edad 14.33 ± 1.77 años participaron en el presente estudio y fueron divididos de forma no aleatoria en grupo control, el cual continuó con su entrenamiento habitual de preparación física y en experimental, al que se le sustituyó su entrenamiento de preparación física habitual por un programa de entrenamiento pliométrico dos veces por semana durante un período de 8 semanas. Las variables de rendimiento fueron analizadas a través de diferentes valoraciones: un sprint de 20 metros (tiempos parciales 5m, 10m y 15m, un sprint de 5 + 5 metros con un cambio de dirección de 180º, un test de salto con contramovimiento bilateral (CMJ y unilateral, un test de lanzamiento de balón medicinal a la máxima distancia (BM, un test de velocidad de servicio y un test de salto horizontal bilateral (SH y unilateral (SHU. El efecto producido por el entrenamiento fue calculado en base al tamaño del efecto. Todas las variables de rendimiento fueron mejoradas en ambos grupos en comparación con los valores del pre-test. Además, el grupo experimental obtuvo mejoras sustanciales con respecto al grupo control en el SH, SHU, CMJ Y BM. Por lo tanto, el programa de entrenamiento pliométrico podría considerarse como un estímulo efectivo en la mejora de las acciones explosivas en jóvenes tenistas. Abstract The aim of the current study was to assess the effect of plyometric training (upper and lower body exercises in explosive actions in young tennis players. Twenty-one young tennis players (11 males, 10 females, age 14.33 ± 1.77 years old participated in the present study and were divided, in a non-randomized manner, into a control group which continued with a regular physical training and in a

  14. Reducing the likelihood of long tennis matches.

    Science.gov (United States)

    Barnett, Tristan; Alan, Brown; Pollard, Graham

    2006-01-01

    Long matches can cause problems for tournaments. For example, the starting times of subsequent matches can be substantially delayed causing inconvenience to players, spectators, officials and television scheduling. They can even be seen as unfair in the tournament setting when the winner of a very long match, who may have negative aftereffects from such a match, plays the winner of an average or shorter length match in the next round. Long matches can also lead to injuries to the participating players. One factor that can lead to long matches is the use of the advantage set as the fifth set, as in the Australian Open, the French Open and Wimbledon. Another factor is long rallies and a greater than average number of points per game. This tends to occur more frequently on the slower surfaces such as at the French Open. The mathematical method of generating functions is used to show that the likelihood of long matches can be substantially reduced by using the tiebreak game in the fifth set, or more effectively by using a new type of game, the 50-40 game, throughout the match. Key PointsThe cumulant generating function has nice properties for calculating the parameters of distributions in a tennis matchA final tiebreaker set reduces the length of matches as currently being used in the US OpenA new 50-40 game reduces the length of matches whilst maintaining comparable probabilities for the better player to win the match.

  15. Glenohumeral contact force during flat and topspin tennis forehand drives.

    Science.gov (United States)

    Blache, Yoann; Creveaux, Thomas; Dumas, Raphaël; Chèze, Laurence; Rogowski, Isabelle

    2017-03-01

    The primary role of the shoulder joint in tennis forehand drive is at the expense of the loadings undergone by this joint. Nevertheless, few studies investigated glenohumeral (GH) contact forces during forehand drives. The aim of this study was to investigate GH compressive and shearing forces during the flat and topspin forehand drives in advanced tennis players. 3D kinematics of flat and topspin forehand drives of 11 advanced tennis players were recorded. The Delft Shoulder and Elbow musculoskeletal model was implemented to assess the magnitude and orientation of GH contact forces during the forehand drives. The results showed no differences in magnitude and orientation of GH contact forces between the flat and topspin forehand drives. The estimated maximal GH contact force during the forward swing phase was 3573 ± 1383 N, which was on average 1.25 times greater than during the follow-through phase, and 5.8 times greater than during the backswing phase. Regardless the phase of the forehand drive, GH contact forces pointed towards the anterior-superior part of the glenoid therefore standing for shearing forces. Knowledge of GH contact forces during real sport tasks performed at high velocity may improve the understanding of various sport-specific adaptations and causative factors for shoulder problems.

  16. A Shot Number Based Approach to Performance Analysis in Table Tennis

    Directory of Open Access Journals (Sweden)

    Tamaki Sho

    2017-01-01

    Full Text Available The current study proposes a novel approach that improves the conventional performance analysis in table tennis by introducing the concept of frequency, or the number of shots, of each shot number. The improvements over the conventional method are as follows: better accuracy of the evaluation of skills and tactics of players, additional insights into scoring and returning skills and ease of understanding the results with a single criterion. The performance analysis of matches played at the 2012 Summer Olympics in London was conducted using the proposed method. The results showed some effects of the shot number and gender differences in table tennis. Furthermore, comparisons were made between Chinese players and players from other countries, what threw light on the skills and tactics of the Chinese players. The present findings demonstrate that the proposed method provides useful information and has some advantages over the conventional method.

  17. Does a perceptuomotor skills assessment have added value to detect talent for table tennis in primary school children?

    Science.gov (United States)

    Faber, Irene R; Pion, Johan; Munivrana, Goran; Faber, Niels R; Nijhuis-Van der Sanden, Maria W G

    2017-04-18

    Talent detection intends to support lifelong sports participation, reduce dropouts and stimulate sports at the elite level. For this purpose it is important to reveal the specific profile which directs children to the sports that connect to their strengths and preferences. This study evaluated a perceptuomotor skills assessment as part of talent detection for table tennis, a sport in which perceptuomotor skills are considered essential to cope with the difficult technical aspects. Primary school children (n = 121) and gifted young table tennis players (n = 146) were assessed using the Dutch perceptuomotor skills assessment measuring "ball control" and "gross motor function". A discriminant function analysis confirmed the added value by identifying primary school children fitting the table tennis perceptuomotor profile of the young gifted table tennis players (28%). General linear model analyses for the assessment's individual test items showed that the table tennis players outperformed their primary school peers on all "ball control" items (P talent detection in table tennis at this young age. Longitudinal studies need to reveal the predictive value for sports participation and elite sports.

  18. A preliminary investigation regarding the effect of tennis grunting: does white noise during a tennis shot have a negative impact on shot perception?

    Science.gov (United States)

    Sinnett, Scott; Kingstone, Alan

    2010-10-01

    There is a growing chorus of critics who complain that many of the top-ranked professional tennis players who grunt when they hit the ball gain an unfair advantage because the sound of the grunt interferes with their opponent's game. However, there is no scientific evidence to support this claim. We explored this potential detrimental effect of grunting by presenting videos of a tennis player hitting a ball to either side of a tennis court; the shot either did, or did not, contain a brief sound that occurred at the same time as contact. The participants' task was to respond as quickly as possible, indicating whether the ball was being hit to the left- or right-side of the court. The results were unequivocal: The presence of an extraneous sound interfered with a participants' performance, making their responses both slower and less accurate. Our data suggest that a grunting player has a competitive edge on the professional tennis tour. The mechanism that underlies this effect is a topic for future investigation. Viable alternatives are discussed. For example, the possibility that the interfering auditory stimulus masks the sound of the ball being struck by the racket or it distracts an opponent's attention away from the sound of the ball.

  19. A preliminary investigation regarding the effect of tennis grunting: does white noise during a tennis shot have a negative impact on shot perception?

    Directory of Open Access Journals (Sweden)

    Scott Sinnett

    Full Text Available BACKGROUND: There is a growing chorus of critics who complain that many of the top-ranked professional tennis players who grunt when they hit the ball gain an unfair advantage because the sound of the grunt interferes with their opponent's game. However, there is no scientific evidence to support this claim. METHODOLOGY/PRINCIPAL FINDINGS: We explored this potential detrimental effect of grunting by presenting videos of a tennis player hitting a ball to either side of a tennis court; the shot either did, or did not, contain a brief sound that occurred at the same time as contact. The participants' task was to respond as quickly as possible, indicating whether the ball was being hit to the left- or right-side of the court. The results were unequivocal: The presence of an extraneous sound interfered with a participants' performance, making their responses both slower and less accurate. CONCLUSIONS/SIGNIFICANCE: Our data suggest that a grunting player has a competitive edge on the professional tennis tour. The mechanism that underlies this effect is a topic for future investigation. Viable alternatives are discussed. For example, the possibility that the interfering auditory stimulus masks the sound of the ball being struck by the racket or it distracts an opponent's attention away from the sound of the ball.

  20. Relation of Knowledge and Performance in Boys' Tennis: Age and Expertise.

    Science.gov (United States)

    McPherson, Sue L.; Thomas, Jerry R.

    1989-01-01

    Examined 10- to 13-year-old boys' development of knowledge structure and sport performance in tennis by comparing skills and knowledge of experts and novices. Experts focused on higher concepts and exhibited greater decision-making ability because of their more highly developed knowledge structure. (SAK)

  1. Motor adaptation in complex sports - the influence of visual context information on the adaptation of the three-point shot to altered task demands in expert basketball players.

    Science.gov (United States)

    Stöckel, Tino; Fries, Udo

    2013-01-01

    We examined the influence of visual context information on skilled motor behaviour and motor adaptation in basketball. The rules of basketball in Europe have recently changed, such that that the distance for three-point shots increased from 6.25 m to 6.75 m. As such, we tested the extent to which basketball experts can adapt to the longer distance when a) only the unfamiliar, new three-point line was provided as floor markings (NL group), or b) the familiar, old three-point line was provided in addition to the new floor markings (OL group). In the present study 20 expert basketball players performed 40 three-point shots from 6.25 m and 40 shots from 6.75 m. We assessed the percentage of hits and analysed the landing position of the ball. Results showed better adaptation of throwing performance to the longer distance when the old three-point line was provided as a visual landmark, compared to when only the new three-point line was provided. We hypothesise that the three-point line delivered relevant information needed to successfully adapt to the greater distance in the OL group, whereas it disturbed performance and ability to adapt in the NL group. The importance of visual landmarks on motor adaptation in basketball throwing is discussed relative to the influence of other information sources (i.e. angle of elevation relative to the basket) and sport practice.

  2. Effects of a 6-week junior tennis conditioning program on service velocity.

    Science.gov (United States)

    Fernandez-Fernandez, Jaime; Ellenbecker, Todd; Sanz-Rivas, David; Ulbricht, Alexander; Ferrautia, Alexander

    2013-01-01

    This study examined the effects of a 6-week strength-training program on serve velocity in youth tennis players. Thirty competitive healthy and nationally ranked male junior tennis players (13 years of age) were randomly and equally divided into control and training groups. The training group performed 3 sessions (60-70 min) weekly for 6 weeks, comprising core strength, elastic resistance and medicine ball exercises. Both groups (control and training) also performed a supervised stretching routine at the end of each training session, during the 6 week intervention. Service velocity, service accuracy and shoulder internal/external rotation were assessed initially and at the end of the 6-week conditioning program for both, control and training groups. There was a significant improvement in the serve velocity for the training group (p = 0. 0001) after the intervention, whereas in the control group there were no differences between pre and post-tests (p = 0.29). Serve accuracy was not affected in the training group (p = 0.10), nor in the control group (p = 0.15). Shoulder internal/external rotation ROM significantly improved in both groups, training (p = 0.001) and control (p = 0.0001). The present results showed that a short- term training program for young tennis players, using minimum equipment and effort, can result in improved tennis performance (i.e., serve velocity) and a reduction in the risk of a possible overuse injury, reflected by an improvement in shoulder external/internal range of motion. Key PointsA short-term training program for young tennis players, using minimum equipment and effort, can result in improved tennis performance and a reduction in the risk of a possible overuse injury, reflected by an improvement in shoulder external/internal range of motionA combination of core stabilization, elastic resistance exercises, and upper body plyometric exercises (i.e., medicine ball throws), focussing on the primary muscle groups and stabilizers involved in

  3. Getting to the top: an analysis of 25 years of career rankings trajectories for professional women's tennis.

    Science.gov (United States)

    Kovalchik, Stephanie A; Bane, Michael K; Reid, Machar

    2017-10-01

    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.

  4. Biomechanical Analysis of Abdominal Injury in Tennis Serves. A Case Report

    Science.gov (United States)

    Tubez, François; Forthomme, Bénédicte; Croisier, Jean-Louis; Cordonnier, Caroline; Brüls, Olivier; Denoël, Vincent; Berwart, Gilles; Joris, Maurice; Grosdent, Stéphanie; Schwartz, Cédric

    2015-01-01

    The serve is an important stroke in any high level tennis game. A well-mastered serve is a substantial advantage for players. However, because of its repeatability and its intensity, this stroke is potentially deleterious for upper limbs, lower limbs and trunk. The trunk is a vital link in the production and transfer of energy from the lower limbs to the upper limbs; therefore, kinematic disorder could be a potential source of risk for trunk injury in tennis. This research studies the case of a professional tennis player who has suffered from a medical tear on the left rectus abdominis muscle after tennis serve. The goal of the study is to understand whether the injury could be explained by an inappropriate technique. For this purpose, we analyzed in three dimensions the kinematic and kinetic aspects of the serve. We also performed isokinetic tests of the player’s knees. We then compared the player to five other professional players as reference. We observed a possible deficit of energy transfer because of an important anterior pelvis tilt. Some compensation made by the player during the serve could be a possible higher abdominal contraction and a larger shoulder external rotation. These particularities could induce an abdominal overwork that could explain the first injury and may provoke further injuries. Key points In the proximal-distal sequence, energy is transmitted from lower limbs to upper limps via trunk. The 3D analysis tool is an indispensable test for an objective evaluation of the kinematic in the tennis serve. Multiple evaluations techniques are useful for fuller comprehension of the kinematics and contribute to the awareness of the player’s staff concerning pathologies and performance. PMID:25983591

  5. Tennis elbow: associated psychological factors.

    Science.gov (United States)

    Aben, Aurelie; De Wilde, Lieven; Hollevoet, Nadine; Henriquez, Carlos; Vandeweerdt, Marc; Ponnet, Koen; Van Tongel, Alexander

    2018-03-01

    The etiology of tennis elbow is multifactorial. Overuse of the wrist extensors along with anatomic factors, such as flexibility problems, aging, and poor blood circulation, may play a role. This study investigated whether patients with tennis elbow have a different psychological profile compared with healthy controls. Patients with clinical signs of tennis elbow, consulting at the Ghent University Hospital between September 2015 and January 2017, were offered a paper-and-pencil questionnaire about Big Five personality traits, perfectionism, anxiety, depression, work satisfaction, and working conditions. Healthy controls in the same risk group were offered the same questionnaires. We recruited 69 patients (35 men, 34 women) and 100 controls (44 men, 56 women). Tennis elbow patients scored significantly lower on the personality traits extraversion and agreeableness. Men, in particular, scored significantly higher on perfectionism and were more likely to develop an anxiety disorder or a depression. Concerning work, patients indicated a significantly higher workload (especially men) and a significantly lower autonomy (especially women). Female patients also indicated less contact with colleagues. However, work satisfaction was relatively high in both groups. The results suggest that there is a relationship between complaints related to tennis elbow and psychological characteristics. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  6. The role of proximal body information on anticipatory judgment in tennis using graphical information richness.

    Directory of Open Access Journals (Sweden)

    Kazunobu Fukuhara

    Full Text Available Recent studies have reported that skilled tennis players are likely to use proximal body information for anticipating the direction of their opponent's forehand shot. However, in these studies, the visual stimuli did not include visual information about the ball. Skilled players may have used proximal information owing to the lack of distal information. To address this issue, we developed a novel methodological approach using computer graphics (CG images in which the entire body was presented by a combination of point-light display (i.e., poor graphical information, PLD and polygons (i.e., rich graphical information. Using our novel methodological approach, we examined whether skilled tennis players use proximal body information when anticipating shot directions.Fifteen skilled tennis players and fifteen novice players tried to anticipate shot directions by observing four CG forehand strokes (ALPOL: all body parts were represented with polygon; RAPLD: racket and arm were represented with PLD; BOPLD: body parts without racket and arm were represented with PLD; and ALPLD: all body parts were represented with PLD. Our intention in creating CG models with such combinations (i.e., RAPLD and BOPLD was that because of the richer graphical information provided by polygons compared to PLD, the participant's anticipatory judgment would be influenced more by body parts expressed with polygons. The results showed that for skilled players, anticipatory judgment was more accurate when they observed RAPLD than when they observed BOPLD and ALPLD. In contrast, for novice players, there were no differences in the accuracy of anticipatory judgments with the four CG models.Only skilled players made more accurate anticipatory judgments when body regions were expressed with rich graphical information, and the racket and arm were expressed with poor graphical information. These suggest that skilled players used proximal information to effectively anticipate shot

  7. Application of an automated protocol for the analysis of the temporal parameters of the response of reaction tennis players during the execution of split-step and volley Aplicación de un protocolo automatizado para el análisis de los parámetros temporales de la respuesta de reacción en jugadores de tenis durante la ejecución de split-step y volea

    Directory of Open Access Journals (Sweden)

    V. Luis

    2010-09-01

    Full Text Available

    This study is aimed to show the design and application process of an automated system to recording in real time the temporary parameters of tennis players reaction response during the execution of the technical-tactical movement called “split-step and second volley”. The knowledge about temporary characteristics of the action will be make used of identify the variables to cause in that and also to design an investigation to permit an improvement of the tennis players efficiency in this sequence of the play. In this way, the use of the technological system will allow a precise analysis of player’s motor response and the eminent information about the defined action
    KEY WORDS: Tennis, split-step and volley, automated system of measure, reaction response

    El propósito de este trabajo consiste en mostrar el proceso de diseño y la aplicación de un sistema automatizado de medida para el registro en tiempo real de los parámetros temporales de la respuesta de reacción en jugadores de tenis durante la ejecución de una acción técnico-táctica denominada “split-step y segunda volea”. El conocimiento generado en cuanto a las características temporales de la acción se empleará para identificar las variables que determinan la eficacia en la misma y diseñar una investigación que permita optimizar el rendimiento de los tenistas en esta secuencia del juego. Así, el empleo de este sistema tecnológico permitirá un análisis preciso de la respuesta motriz de los jugadores y la extracción de información relevante acerca de la acción definida.
    PALABRAS CLAVE: Tenis, split-step y volea, sistema automatizado de medida, respuesta de reacción.

  8. The relationship between performance and flow state in tennis competition.

    Science.gov (United States)

    Koehn, S; Morris, T

    2012-08-01

    The study aimed to examine 1) the validity of the nine-factor flow model in tennis competition; 2) differences in flow state between athletes who won or lost their competition match; 3) the link between flow and subjective performance; and 4) flow dimensions as predictors of performance outcome The sample consisted of 188 junior tennis players (115 male, 73 female) between 12 and 18 years of age. Participants' performance was recorded during junior ranking-list tournaments. Following the completion of a tennis competition match, participants completed the Flow State Scale-2 and a subjective performance outcome measure. Acceptable flow model fit indices of CFI, TLI, SRMR, and RMSEA were only found for winning athletes. The group of winning athletes scored significantly higher on all nine flow dimensions, except time transformation, than losing athletes, showing statistically significant differences for challenge-skills balance, clear goals, sense of control, and autotelic experience. Significant correlation coefficients were found between flow state and subjective performance assessments. The binary logistic regression revealed concentration on the task and sense of control to be significant predictors of performance outcome. The predictor variables explained 13% of the variance in games won. The study showed that athletes who win or lose perceived flow state differently. Studies using retrospective assessments need to be aware that subjective experience could be biased by performance outcomes. Pinpointing psychological variables and their impact on ecologically valid measures, such as performance results, would support the development of effective intervention studies to increase performance in sport competition.

  9. Orthotic devices for tennis elbow

    NARCIS (Netherlands)

    Struijs, P. A.; Smidt, N.; Arola, H.; van Dijk, C. N.; Buchbinder, R.; Assendelft, W. J.

    2001-01-01

    BACKGROUND: Lateral epicondylitis (tennis elbow) is a frequently reported condition. A wide variety of treatment strategies has been described. As of yet, no optimal strategy has been identified. OBJECTIVES: The objective of this review was to assess the effectiveness of orthotic devices for

  10. Concepções de treinadores "experts" Brasileiros sobre o processo de formação desportiva do jogador de voleibol Expert coaches conceptions concerning the sport development of the volleyball player

    Directory of Open Access Journals (Sweden)

    Michel Milistetd

    2010-03-01

    ção desportiva a longo prazo do jogador de Voleibol.The aim of the present study was to examine the conceptions of expert coaches concerning the volleyball player's long term sport development. The participants were 10 expert coaches. The sample presented 45 ± 13.8 years old and 24.8 ± 12.1 years of coaching experience in the Brazilian volleyball. Data collection was accomplished through structured open answer interviews based on Fernandes' protocol (2004. Its content adaptation to sociocultural and sportive Brazilian reality was accomplished through expert validation. The treatment of the information was accomplished through content analysis, with logic-semantic procedures of the prevalent ideas in the corpus of interviews. The reliability of codification was assured by percentage accord of the same encoder and the different encoders, registering values between 95% and 100%. The present study evidences that no participant knows about the existence of a national long term sport development model for a volleyball player. Moreover, coaches confirmed that the Volleyball is a sport of late specialization, being a widespread consensus that the age of initiation of systematic practice is in the beginning of adolescence, around the age of 13 years old. The components of sport development throughout the stages highlight the practice of the deliberate play in the first stage, where diversified motor experiences prevail. From the second stage, the deliberate practice increases with the acquisition of specific competences and commitment with the modality. The absence of specification of the training contents along the stages, as well as the scanty reference to the psychosocial competences along the stages, can be due, in great measure, to the inexistence of a national model of long term sport development.

  11. Does an eye-hand coordination test have added value as part of talent identification in table tennis? A validity and reproducibility study.

    Science.gov (United States)

    Faber, Irene R; Oosterveld, Frits G J; Nijhuis-Van der Sanden, Maria W G

    2014-01-01

    This study investigated the added value, i.e. discriminative and concurrent validity and reproducibility, of an eye-hand coordination test relevant to table tennis as part of talent identification. Forty-three table tennis players (7-12 years) from national (n = 13), regional (n = 11) and local training centres (n = 19) participated. During the eye-hand coordination test, children needed to throw a ball against a vertical positioned table tennis table with one hand and to catch the ball correctly with the other hand as frequently as possible in 30 seconds. Four different test versions were assessed varying the distance to the table (1 or 2 meter) and using a tennis or table tennis ball. 'Within session' reproducibility was estimated for the two attempts of the initial tests and ten youngsters were retested after 4 weeks to estimate 'between sessions' reproducibility. Validity analyses using age as covariate showed that players from the national and regional centres scored significantly higher than players from the local centre in all test versions (ptalent identification appears to be the version with a table tennis ball at 1 meter regarding the psychometric characteristics evaluated. Longitudinal studies are necessary to evaluate the predictive value of this test.

  12. The Relationship Between Stress and Coping in Table Tennis

    Directory of Open Access Journals (Sweden)

    Kurimay Dora

    2017-01-01

    Full Text Available The aim of this study was to examine the relationship between cognitive competitive anxiety intensity and coping strategies in table tennis players. One hundred and two (102 US competitive table tennis players of age range from 10 to 60 filled out a Revised Competitive State Anxiety Inventory-2 (CSAI-2R, Cox et al., 2003 at least 30 minutes before the start of their tournament match and a Modified Cope questionnaire (MCOPE; Crocker and Graham, 1995 15 minutes after they finished their match. Our study found significant differences between low and high cognitive competitive anxiety groups with regard to the use of coping strategies. The high cognitive competitive anxiety intensity group used significantly more behavioral disengagement (avoidance coping, p ≤ 0.05, denial coping strategies (emotion focused coping, p ≤ 0.01 compared to the low cognitive anxiety intensity group. Our results suggest that there is some connection between anxiety intensity and coping strategies. If the cognitive anxiety intensity (for example, intensity from worrying is very high, an athlete might be more likely to use avoidance coping (such as behavioral disengagement and emotion-focused coping (such as denial and venting of emotions compared to athletes who have low cognitive competitive anxiety. Furthermore, gender differences in cognitive anxiety and direction were found. Confidence management techniques such as positive self-talk, breathing techniques and visualization should be taught to athletes to assist them in coping with their competitive anxiety better and to enhance their performance.

  13. The Dutch motor skills assessment as tool for talent development in table tennis : a reproducibility and validity study

    NARCIS (Netherlands)

    Faber, Irene R.; Nijhuis-Van der Sanden, Maria W. G.; Elferink-Gemser, Marije T.; Oosterveld, Frits G. J.

    2015-01-01

    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

  14. The Dutch motor skills assessment as tool for talent development in table tennis: a reproducibility and validity study

    NARCIS (Netherlands)

    Faber, I.R.; Nijhuis-Van der Sanden, M.W.G.; Elferink-Gemser, M.T.; Oosterveld, F.G.

    2015-01-01

    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

  15. The Dutch motor skills assessment as tool for talent development in table tennis: a reproducibility and validity study

    NARCIS (Netherlands)

    Faber, I.R.; Nijhuis-Van der Sanden, M.W.; Elferink-Gemser, M.T.; Oosterveld, F.G.J.

    2014-01-01

    Abstract 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

  16. History and development of the tennis equipment

    OpenAIRE

    Horáková, Kateřina

    2007-01-01

    Title: History and development of the tennis equipment. Aim of the work: Process an integral, tabular and synoptic historical development overview of the tennis equipment. This owerview will cover the period since the early beginnings of the game to present days. Methods: Advance work has historical charakter therefore used methods are historiogaphical methods such as chronological method and historical method. Results: Produce tabular description of the tennis equipment by means of reading a...

  17. Subject-specific computer simulation model for determining elbow loading in one-handed tennis backhand groundstrokes.

    Science.gov (United States)

    King, Mark A; Glynn, Jonathan A; Mitchell, Sean R

    2011-11-01

    A subject-specific angle-driven computer model of a tennis player, combined with a forward dynamics, equipment-specific computer model of tennis ball-racket impacts, was developed to determine the effect of ball-racket impacts on loading at the elbow for one-handed backhand groundstrokes. Matching subject-specific computer simulations of a typical topspin/slice one-handed backhand groundstroke performed by an elite tennis player were done with root mean square differences between performance and matching simulations of elbow loading for a topspin and slice one-handed backhand groundstroke is relatively small. In this study, the relatively small differences in elbow loading may be due to comparable angle-time histories at the wrist and elbow joints with the major kinematic differences occurring at the shoulder. Using a subject-specific angle-driven computer model combined with a forward dynamics, equipment-specific computer model of tennis ball-racket impacts allows peak internal loading, net impulse, and shock due to ball-racket impact to be calculated which would not otherwise be possible without impractical invasive techniques. This study provides a basis for further investigation of the factors that may increase elbow loading during tennis strokes.

  18. ACUTE EFFECTS OF STATIC STRETCHING, DYNAMIC EXERCISES, AND HIGH VOLUME UPPER EXTREMITY PLYOMETRIC ACTIVITY ON TENNIS SERVE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Ertugrul Gelen

    2012-12-01

    Full Text Available The purpose of this study was to compare the acute effects of static stretching; dynamic exercises and high volume upper extremity plyometric activity on tennis serve performance. Twenty-six elite young tennis players (15.1 ± 4.2 years, 167.9 ± 5.8 cm and 61.6 ± 8.1 kg performed 4 different warm-up (WU routines in a random order on non-consecutive days. The WU methods consisted of traditional WU (jogging, rally and serve practice (TRAD; traditional WU and static stretching (TRSS; traditional WU and dynamic exercise (TRDE; and traditional WU and high volume upper extremity plyometric activity (TRPLYP. Following each WU session, subjects were tested on a tennis serve ball speed test. TRAD, TRSS, TRDE and TRPLYO were compared by repeated measurement analyses of variance and post-hoc comparisons. In this study a 1 to 3 percent increase in tennis serve ball speed was recorded in TRDE and TRPLYO when compared to TRAD (p 0.05. ICCs for ball speed showed strong reliability (0.82 to 0.93 for the ball speed measurements.The results of this study indicate that dynamic and high volume upper extremity plyometric WU activities are likely beneficial to serve speed of elite junior tennis players.

  19. Does an eye-hand coordination test have added value as part of talent identification in table tennis? A validity and reproducibility study.

    Directory of Open Access Journals (Sweden)

    Irene R Faber

    Full Text Available This study investigated the added value, i.e. discriminative and concurrent validity and reproducibility, of an eye-hand coordination test relevant to table tennis as part of talent identification. Forty-three table tennis players (7-12 years from national (n = 13, regional (n = 11 and local training centres (n = 19 participated. During the eye-hand coordination test, children needed to throw a ball against a vertical positioned table tennis table with one hand and to catch the ball correctly with the other hand as frequently as possible in 30 seconds. Four different test versions were assessed varying the distance to the table (1 or 2 meter and using a tennis or table tennis ball. 'Within session' reproducibility was estimated for the two attempts of the initial tests and ten youngsters were retested after 4 weeks to estimate 'between sessions' reproducibility. Validity analyses using age as covariate showed that players from the national and regional centres scored significantly higher than players from the local centre in all test versions (p<0.05. The tests at 1 meter demonstrated better discriminative ability than those at 2 meter. While all tests but one had a positive significant association with competition outcome, which were corrected for age influences, the version with a table tennis ball at 1 meter showed the highest association (r = 0.54; p = 0.001. Differences between the first and second attempts were comparable for all test versions (between -8 and +7 repetitions with ICC's ranging from 0.72 to 0.87. The smallest differences were found for the test with a table tennis ball at 1 meter (between -3 and +3 repetitions. Best test version as part of talent identification appears to be the version with a table tennis ball at 1 meter regarding the psychometric characteristics evaluated. Longitudinal studies are necessary to evaluate the predictive value of this test.

  20. Playing vs. nonplaying aerobic training in tennis: physiological and performance outcomes.

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    Vincent Pialoux

    Full Text Available This study compared the effects of playing and nonplaying high intensity intermittent training (HIIT on physiological demands and tennis stroke performance in young tennis players. Eleven competitive male players (13.4 ± 1.3 years completed both a playing and nonplaying HIIT session of equal distance, in random order. During each HIIT session, heart rate (HR, blood lactate, and ratings of perceived exertion (RPE were monitored. Before and after each HIIT session, the velocity and accuracy of the serve, and forehand and backhand strokes were evaluated. The results demonstrated that both HIIT sessions achieved an average HR greater than 90% HRmax. The physiological demands (average HR were greater during the playing session compared to the nonplaying session, despite similar lactate concentrations and a lower RPE. The results also indicate a reduction in shot velocity after both HIIT sessions; however, the playing HIIT session had a more deleterious effect on stroke accuracy. These findings suggest that 1 both HIIT sessions may be sufficient to develop maximal aerobic power, 2 playing HIIT sessions provide a greater physiological demand with a lower RPE, and 3 playing HIIT has a greater deleterious effect on stroke performance, and in particular on the accuracy component of the ground stroke performance, and should be incorporated appropriately into a periodization program in young male tennis players.

  1. Playing vs. Nonplaying Aerobic Training in Tennis: Physiological and Performance Outcomes

    Science.gov (United States)

    Pialoux, Vincent; Genevois, Cyril; Capoen, Arnaud; Forbes, Scott C.; Thomas, Jordan; Rogowski, Isabelle

    2015-01-01

    This study compared the effects of playing and nonplaying high intensity intermittent training (HIIT) on physiological demands and tennis stroke performance in young tennis players. Eleven competitive male players (13.4 ± 1.3 years) completed both a playing and nonplaying HIIT session of equal distance, in random order. During each HIIT session, heart rate (HR), blood lactate, and ratings of perceived exertion (RPE) were monitored. Before and after each HIIT session, the velocity and accuracy of the serve, and forehand and backhand strokes were evaluated. The results demonstrated that both HIIT sessions achieved an average HR greater than 90% HRmax. The physiological demands (average HR) were greater during the playing session compared to the nonplaying session, despite similar lactate concentrations and a lower RPE. The results also indicate a reduction in shot velocity after both HIIT sessions; however, the playing HIIT session had a more deleterious effect on stroke accuracy. These findings suggest that 1) both HIIT sessions may be sufficient to develop maximal aerobic power, 2) playing HIIT sessions provide a greater physiological demand with a lower RPE, and 3) playing HIIT has a greater deleterious effect on stroke performance, and in particular on the accuracy component of the ground stroke performance, and should be incorporated appropriately into a periodization program in young male tennis players. PMID:25816346

  2. Posterolateral Rotatory Apprehension Test in Tennis Elbow.

    Science.gov (United States)

    Chanlalit, Cholawish; Phorkhar, Termphong

    2015-11-01

    Tennis elbow is a syndrome that commonly diagnosed in patient who comes with lateral elbow pain. Instability pain in tennis elbow patient was observed and reported in many previous literatures. Posterolateral rotatory apprehension test was proposed for diagnosis of posterolateral rotatory instability of elbow. However, no review literatures that studied about posterolateral rotatory apprehensions test in tennis elbow. To find out the relationship between posterolateral rotatory apprehension test and tennis elbow. There were 44 patients that were recruited in this study. We examined the posterolateral rotatory apprehension test in tennis elbow patients. The examination was done in our outpatient clinic from March 2012 to April 2012. The data was collected to find out the ratio of negative test in tennis elbow patient. The results from the posterolateral rotatory apprehension test were negative in 43 patients. The ratio of the negative test result was 98%. A result from posterolateral rotatory apprehension test should be negative in general tennis elbow patients. If this test is used in a tennis elbow patients who are suspected with hidden instability and the result is positive, further evaluation is strongly suggested.

  3. Comparing Matchplay Characteristics and Physical Demands of Junior and Professional Tennis Athletes in the Era of Big Data

    Directory of Open Access Journals (Sweden)

    Stephanie A. Kovalchik, Machar Reid

    2017-12-01

    Full Text Available Differences in the competitive performance characteristics of junior and professional tennis players are not well understood. The present study provides a comprehensive comparative analysis of junior and professional matchplay. The study utilized multiple large-scale datasets covering match, point, and shot outcomes over multiple years of competition. Regression analysis was used to identify differences between junior and professional matchplay. Top professional men and women were found to play significantly more matches, sets, and games compared to junior players of an equivalent ranking. Professional players had a greater serve advantage, men winning 4 and women winning 2 additional percentage points on serve compared to juniors. Clutch ability in break point conversion was 6 to 8 percentage points greater for junior players. In general, shots were more powerful and more accurate at the professional level with the largest differences observed for male players on serve. Serving to the center of the court was more than two times more common for junior players on first serve. While male professionals performed 50% more total work in a Grand Slam match than juniors, junior girls performed 50% more work than professional women. Understanding how competitiveness, play demands, and the physical characteristics of shots differ between junior and professional tennis players can help set realistic expectations and developmentally appropriate training for transitioning players.

  4. Comparing Matchplay Characteristics and Physical Demands of Junior and Professional Tennis Athletes in the Era of Big Data.

    Science.gov (United States)

    Kovalchik, Stephanie A; Reid, Machar

    2017-12-01

    Differences in the competitive performance characteristics of junior and professional tennis players are not well understood. The present study provides a comprehensive comparative analysis of junior and professional matchplay. The study utilized multiple large-scale datasets covering match, point, and shot outcomes over multiple years of competition. Regression analysis was used to identify differences between junior and professional matchplay. Top professional men and women were found to play significantly more matches, sets, and games compared to junior players of an equivalent ranking. Professional players had a greater serve advantage, men winning 4 and women winning 2 additional percentage points on serve compared to juniors. Clutch ability in break point conversion was 6 to 8 percentage points greater for junior players. In general, shots were more powerful and more accurate at the professional level with the largest differences observed for male players on serve. Serving to the center of the court was more than two times more common for junior players on first serve. While male professionals performed 50% more total work in a Grand Slam match than juniors, junior girls performed 50% more work than professional women. Understanding how competitiveness, play demands, and the physical characteristics of shots differ between junior and professional tennis players can help set realistic expectations and developmentally appropriate training for transitioning players.

  5. The prognostic relevance of psychological factors with regard to participation and success in table-tennis.

    Science.gov (United States)

    Martinent, Guillaume; Cece, Valérian; Elferink-Gemser, Marije Titia; Faber, Irene Renate; Decret, Jean-Claude

    2018-05-15

    This study examined the prognostic relevance of self-determined motivation, coping, burnout, perceived stress and recovery experienced by 159 youth table-tennis players involved in intensive training centers with regard to their participation and success six years later. Results of ANCOVAs showed that players who still practiced at time 2 (T2; six years later; n = 130) reported lower time 1 (T1; while they were involved in intensive training centers) amotivation (large effect), disengagement-oriented coping, sport devaluation and reduced accomplishment (moderate effects) than their counterparts who dropped out at T2 (n = 29). Results of ANCOVAs also showed that international (n = 18) and/or national players (n = 86) at T2 reported significantly lower T1 amotivation (large effect), disengagement-oriented coping and sport devaluation (moderate effects) in comparison to regional (n = 26) players at T2. Finally results of correlational analyses showed that T2 performance and/or six-year performance progress were significantly and weakly correlated with introjected and external regulations, perceived stress and perceived recovery, and significantly and moderately correlated with amotivation, disengagement-oriented coping, sport devaluation, and reduced accomplishment. Overall, this study provided insights into the role played by self-determined motivation, coping, burnout, perceived stress and recovery in the table-tennis players' dropout and performance level six years later.

  6. Toss differences between the slice serve and the kick serve in tennis

    Directory of Open Access Journals (Sweden)

    Jan Carboch

    2015-06-01

    Full Text Available Background: Pre-contact information of servers' motion is important for receiving players in tennis. Objective: The aim of this study is to examine whether serving players use the same ball toss for kick serve (KS and slice serve (SS at two different directions of serves, from the receiver's view. Methods: 10 male right-handed professional tennis players with an average ATP ranking of 533 were videotaped from the receiver's view using a high-speed video camera (200 Hz. Firstly, they served SS and then KS from deuce court. After reaching 3 successful SS and 3 KS to the correct location, the same procedure followed from the ad court. Kinematic analysis was used to obtain the point of ball release, vertical toss peak and racquet-ball contact. Results: Even though the release point was found nearly in the same location, the vertical toss peak of KS was horizontally to the right compared to SS and the point of racquet ball-contact of KS was even more to the right by approximately 30 cm from the receiver's view. Similar findings were obtained from deuce court and ad court. Conclusions: We found differences in the ball toss execution between KS and SS. The serve toss can provide useful information for receiving players. Serving players should use the same toss for each type of serve to hide their intention.

  7. EFFECTS OF A 6-WEEK JUNIOR TENNIS CONDITIONING PROGRAM ON SERVICE VELOCITY

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    Jaime Fernandez-Fernandez

    2013-06-01

    Full Text Available This study examined the effects of a 6-week strength-training program on serve velocity in youth tennis players. Thirty competitive healthy and nationally ranked male junior tennis players (13 years of age were randomly and equally divided into control and training groups. The training group performed 3 sessions (60-70 min weekly for 6 weeks, comprising core strength, elastic resistance and medicine ball exercises. Both groups (control and training also performed a supervised stretching routine at the end of each training session, during the 6 week intervention. Service velocity, service accuracy and shoulder internal/external rotation were assessed initially and at the end of the 6-week conditioning program for both, control and training groups. There was a significant improvement in the serve velocity for the training group (p = 0. 0001 after the intervention, whereas in the control group there were no differences between pre and post-tests (p = 0.29. Serve accuracy was not affected in the training group (p = 0.10, nor in the control group (p = 0.15. Shoulder internal/external rotation ROM significantly improved in both groups, training (p = 0.001 and control (p = 0.0001. The present results showed that a short- term training program for young tennis players, using minimum equipment and effort, can result in improved tennis performance (i.e., serve velocity and a reduction in the risk of a possible overuse injury, reflected by an improvement in shoulder external/internal range of motion

  8. SPORT NUTRITION AND DOPING IN TENNIS: AN ANALYSIS OF ATHLETES' ATTITUDES AND KNOWLEDGE

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    Miran Kondric

    2013-06-01

    Full Text Available Nutrition and doping issues are rarely studied in the sport of tennis. The aims of this investigation were to determine knowledge on doping (KD and knowledge on sport nutrition (KSN, and corresponding socio-demographic-, sport-, and sport-nutrition- and doping-factors among an international sample of high-level tennis players of both sexes (43 females; 22 years old on average. In the first phase of the investigation, the KSN and KD questionnaires were studied for their reliability and validity. The consumption of NS is found to be very high, with almost of all the females and 80% of the males using NS at least occasionally. The athletes showed a low tendency regarding future doping usage, although most of them are convinced that doping does exist in tennis. Since athletes declared that their coaches are their main source of information about NS and doping, future studies should investigate what coaches actually know about such problems. KSN has been found to be protective against potential doping behavior in the future. Males are found to be more prone to doping than females. Therefore, in order to prevent doping behavior in tennis we strongly suggest intensive educational programs on sports nutrition and doping-related problems

  9. The Player, the Controller and the amazing Avatar

    DEFF Research Database (Denmark)

    Sandvik, Kjetil

    Playing computer games consists of an interplay between the player's body movements in the physical world and the agency of game characters in the game's virtual environment with the controller as a mediator remediating the movements of the player in physical space into the actions of the avatar ...... both the avatars bodily movements, it also represents the very tool which the avatar is using when performing its actions, e.g. a sword or a tennis catcher....

  10. A Multidisciplinary Investigation of the Effects of Competitive State Anxiety on Serve Kinematics in Table Tennis

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    Ngo Vuong

    2017-01-01

    Full Text Available Displays of anxiety in table tennis were assessed through subjective (a self-report questionnaire, physiological (heart-rate variability and kinematic variables. Using a within-group crossover design, 9 university-level table tennis players completed a series of serves under low- and high-anxiety conditions. Anxiety manipulation was achieved through the introduction of a national standard table tennis player, known to the participants, to receive serves in the high-anxiety condition, whilst serves were received by no opponent in the low-anxiety condition. Automated motion capture systems consisting of high-speed 3D motion cameras and analytical software (QUALISYS determined the subject’s movement kinematics: bat face angle (degrees and serve routine duration (s. Self-reported state anxiety (MRF-Likert and heart rate measurements were collected to examine changes between conditions. Contrary to the hypothesis, bat face angles did not change significantly between anxiety conditions (F (1.8 = 2.791, p = 0.133 and movement times were faster in the high-anxiety condition. In light of these findings, research into other facets of movement behaviour must be analysed to gain further understanding of the effects of anxiety on performance, which remain unclear.

  11. A stochastic Markov chain approach for tennis: Monte Carlo simulation and modeling

    Science.gov (United States)

    Aslam, Kamran

    This dissertation describes the computational formulation of probability density functions (pdfs) that facilitate head-to-head match simulations in tennis along with ranking systems developed from their use. A background on the statistical method used to develop the pdfs , the Monte Carlo method, and the resulting rankings are included along with a discussion on ranking methods currently being used both in professional sports and in other applications. Using an analytical theory developed by Newton and Keller in [34] that defines a tennis player's probability of winning a game, set, match and single elimination tournament, a computational simulation has been developed in Matlab that allows further modeling not previously possible with the analytical theory alone. Such experimentation consists of the exploration of non-iid effects, considers the concept the varying importance of points in a match and allows an unlimited number of matches to be simulated between unlikely opponents. The results of these studies have provided pdfs that accurately model an individual tennis player's ability along with a realistic, fair and mathematically sound platform for ranking them.

  12. PELVIC ROTATION AND LOWER EXTREMITY MOTION WITH TWO DIFFERENT FRONT FOOT DIRECTIONS IN THE TENNIS BACKHAND GROUNDSTROKE

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    Sayumi Iwamoto

    2013-06-01

    Full Text Available When a tennis player steps forward to hit a backhand groundstroke in closed stance, modifying the direction of the front foot relative to the net may reduce the risk of ankle injury and increase performance. This study evaluated the relationship between pelvic rotation and lower extremity movement during the backhand groundstroke when players stepped with toes parallel to the net (Level or with toes pointed towards the net (Net. High school competitive tennis players (eleven males and seven females, 16.8 ± 0.8 years, all right- handed performed tennis court tests comprising five maximum speed directional runs to the court intersection line to hit an imaginary ball with forehand or backhand swings. The final backhand groundstroke for each player at the backcourt baseline was analyzed. Pelvic rotation and lower extremity motion were quantified using 3D video analysis from frontal and sagittal plane camera views reconstructed to 3D using DLT methods. Plantar flexion of ankle and supination of the front foot were displayed for both Net and Level groups during the late phase of the front foot step. The timings of the peak pelvis rotational velocity and peak pelvis rotational acceleration showed different pattern for Net and Level groups. The peak timing of the pelvis rotational velocity of the Level group occurred during the late phase of the step, suggesting an increase in the risk of inversion ankle sprain and a decrease in stroke power compared to the Net group

  13. Effects of the racket polar moment of inertia on dominant upper limb joint moments during tennis serve.

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    Isabelle Rogowski

    Full Text Available This study examined the effect of the polar moment of inertia of a tennis racket on upper limb loading in the serve. Eight amateur competition tennis players performed two sets of 10 serves using two rackets identical in mass, position of center of mass and moments of inertia other than the polar moment of inertia (0.00152 vs 0.00197 kg.m2. An eight-camera motion analysis system collected the 3D trajectories of 16 markers, located on the thorax, upper limbs and racket, from which shoulder, elbow and wrist net joint moments and powers were computed using inverse dynamics. During the cocking phase, increased racket polar moment of inertia was associated with significant increases in the peak shoulder extension and abduction moments, as well the peak elbow extension, valgus and supination moments. During the forward swing phase, peak wrist extension and radial deviation moments significantly increased with polar moment of inertia. During the follow-through phase, the peak shoulder adduction, elbow pronation and wrist external rotation moments displayed a significant inverse relationship with polar moment of inertia. During the forward swing, the magnitudes of negative joint power at the elbow and wrist were significantly larger when players served using the racket with a higher polar moment of inertia. Although a larger polar of inertia allows players to better tolerate off-center impacts, it also appears to place additional loads on the upper extremity when serving and may therefore increase injury risk in tennis players.

  14. Effects of the racket polar moment of inertia on dominant upper limb joint moments during tennis serve.

    Science.gov (United States)

    Rogowski, Isabelle; Creveaux, Thomas; Chèze, Laurence; Macé, Pierre; Dumas, Raphaël

    2014-01-01

    This study examined the effect of the polar moment of inertia of a tennis racket on upper limb loading in the serve. Eight amateur competition tennis players performed two sets of 10 serves using two rackets identical in mass, position of center of mass and moments of inertia other than the polar moment of inertia (0.00152 vs 0.00197 kg.m2). An eight-camera motion analysis system collected the 3D trajectories of 16 markers, located on the thorax, upper limbs and racket, from which shoulder, elbow and wrist net joint moments and powers were computed using inverse dynamics. During the cocking phase, increased racket polar moment of inertia was associated with significant increases in the peak shoulder extension and abduction moments, as well the peak elbow extension, valgus and supination moments. During the forward swing phase, peak wrist extension and radial deviation moments significantly increased with polar moment of inertia. During the follow-through phase, the peak shoulder adduction, elbow pronation and wrist external rotation moments displayed a significant inverse relationship with polar moment of inertia. During the forward swing, the magnitudes of negative joint power at the elbow and wrist were significantly larger when players served using the racket with a higher polar moment of inertia. Although a larger polar of inertia allows players to better tolerate off-center impacts, it also appears to place additional loads on the upper extremity when serving and may therefore increase injury risk in tennis players.

  15. The Dutch Technical-Tactical Tennis Test (D4T for Talent Identification and Development: Psychometric Characteristics

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    Kolman Nikki

    2017-01-01

    Full Text Available This study examined the test-retest reliability, validity and feasibility of the newly developed Dutch Technical-Tactical Tennis Test (D4T. This new test is relevant for talent identification and development in tennis. Thirty-two youth male tennis players (age 13.4 ± 0.5 were classified as elite (n = 15 or sub-elite (n = 17 according to their position on the national youth ranking list under 15 years (cut-off rank 50 in the Netherlands. Games, rallies and different tactical situations (i.e. offensive, neutral and defensive were simulated with a ball machine. Players had to return 72 balls to predetermined target areas. Stroke quality was recorded based on ball velocity and accuracy (VA-index, as well as percentage errors. Test-retest reliability was assessed by comparing differences between the first and second test-session (n = 10. An intraclass-correlation coefficient of .78 for the VA-index was found (p < .05, indicating excellent test-retest reliability. Independent t-tests revealed that elite players outscored sub-elite players for the VA-index, ball velocity, accuracy and percentage errors (p < .05, supporting good validity. Furthermore, a high correlation was found between the VA-index and individual positions on the youth ranking list (p = -.75; p < .001. The assessment of feasibility indicated that the D4T was applicable for instructors and coaches. In conclusion, the D4T was shown to be a reliable, valid and feasible test to measure technical-tactical characteristics of tennis performance in youth players.

  16. The effect of ball impact location on racket and forearm joint angle changes for one-handed tennis backhand groundstrokes.

    Science.gov (United States)

    King, Mark; Hau, Agnes; Blenkinsop, Glen

    2017-07-01

    Recreational tennis players tend to have higher incidence of tennis elbow, and this has been hypothesised to be related to one-handed backhand technique and off-centre ball impacts on the racket face. This study aimed to investigate for a range of participants the effect of off-longitudinal axis and off-lateral axis ball-racket impact locations on racket and forearm joint angle changes immediately following impact in one-handed tennis backhand groundstrokes. Three-dimensional racket and wrist angular kinematic data were recorded for 14 university tennis players each performing 30 "flat" one-handed backhand groundstrokes. Off-longitudinal axis ball-racket impact locations explained over 70% of the variation in racket rotation about the longitudinal axis and wrist flexion/extension angles during the 30 ms immediately following impact. Off-lateral axis ball-racket impact locations had a less clear cut influence on racket and forearm rotations. Specifically off-longitudinal impacts below the longitudinal axis forced the wrist into flexion for all participants with there being between 11° and 32° of forced wrist flexion for an off-longitudinal axis impact that was 1 ball diameter away from the midline. This study has confirmed that off-longitudinal impacts below the longitudinal axis contribute to forced wrist flexion and eccentric stretch of the wrist extensors and there can be large differences in the amount of forced wrist flexion from individual to individual and between strokes with different impact locations.

  17. Leadership and satisfaction in tennis: examination of congruence, gender, and ability.

    Science.gov (United States)

    Riemer, H A; Toon, K

    2001-09-01

    The study investigated: (a) the congruency hypothesis, and (b) the member characteristics hypotheses relating to ability and gender, of Chelladurai's (1978) Multidimensional Model of Leadership. One hundred forty-eight tennis players (77 women) competing at the NCAA Division I and II Tennis Championship level participated in the study. Results indicated athlete satisfaction (Athlete Satisfaction Scale; Riemer & Chelladurai, 1998) was not dependent on the congruence between preferred and perceived leadership behavior. Other results indicated that an athlete's level of ability did affect preferences for leadership behavior. Further, while athlete gender was responsible for some variance in preferences for autocratic behavior and positive feedback behavior, the gender of the athlete's coach had a significant effect on the athlete's preferences for social support behavior.

  18. Intention Understanding over T: A neuroimaging study on shared representations and tennis return predictions

    Directory of Open Access Journals (Sweden)

    Stephanie eCacioppo

    2014-10-01

    Full Text Available Studying the way athletes predict actions of their peers during fast-ball sports, such as a tennis, has proved to be a valuable tool for increasing our knowledge of intention understanding. The working model in this area is that the anticipatory representations of others’ behaviors require internal predictive models of actions formed from pre-established and shared representations between the observer and the actor. This model also predicts that observers would not be able to read accurately the intentions of a competitor if the competitor were to perform the action without prior knowledge of their intention until moments before the action. To test this hypothesis, we recorded brain activity from 25 male tennis players while they performed a novel behavioral tennis intention inference task, which included two conditions: i one condition in which they viewed video clips of a tennis athlete who knew in advance where he was about to act/serve (initially intended serves and ii one condition in which they viewed video clips of that same athlete when he did not know where he was to act/serve until the target was specified after he had tossed the ball into the air to complete his serve (non-initially intended serves. Our results demonstrated that i tennis expertise is related to the accuracy in predicting where another server intends to serve when that server knows where he intends to serve before (but not after he tosses the ball in the air; and ii accurate predictions are characterized by the recruitment of both cortical areas within the human mirror neuron system (that is known to be involved in higher-order (top-down processes of embodied cognition and shared representation and subcortical areas within brain regions involved in procedural memory (caudate nucleus. Interestingly, inaccurate predictions instead recruit areas known to be involved in low-level (bottom-up computational processes associated with the sense of agency and self

  19. A naturalistic study of the directional interpretation process of discrete emotions during high-stakes table tennis matches.

    Science.gov (United States)

    Martinent, Guillaume; Ferrand, Claude

    2009-06-01

    The purpose of this study was to explore the directional interpretation process of discrete emotions experienced by table tennis players during competitive matches by adopting a naturalistic qualitative video-assisted approach. Thirty self-confrontation interviews were conducted with 11 national table tennis players (2 or 3 matches per participants). Nine discrete emotions were identified through the inductive analyses of the participants' transcriptions: anger, anxiety, discouragement, disappointment, disgust, joy, serenity, relief, and hope. Inductive analyses revealed the emergence of 4 categories and 13 themes among the 9 discrete emotions: positive direction (increased concentration, increased motivation, increased confidence, positive sensations, and adaptive behaviors), negative direction (decreased concentration, decreased motivation, too confident, decreased confidence, negative sensations, and maladaptive behaviors), neutral direction (take more risk and take less risk), and no perceived influence on own performance. Results are discussed in terms of current research on directional interpretation and emotions in sport.

  20. Upper limb joint kinetic analysis during tennis serve: Assessment of competitive level on efficiency and injury risks.

    Science.gov (United States)

    Martin, C; Bideau, B; Ropars, M; Delamarche, P; Kulpa, R

    2014-08-01

    The aim of this work was to compare the joint kinetics and stroke production efficiency for the shoulder, elbow, and wrist during the serve between professionals and advanced tennis players and to discuss their potential relationship with given overuse injuries. Eleven professional and seven advanced tennis players were studied with an optoelectronic motion analysis system while performing serves. Normalized peak kinetic values of the shoulder, elbow, and wrist joints were calculated using inverse dynamics. To measure serve efficiency, all normalized peak kinetic values were divided by ball velocity. t-tests were used to determine significant differences between the resultant joint kinetics and efficiency values in both groups (advanced vs professional). Shoulder inferior force, shoulder anterior force, shoulder horizontal abduction torque, and elbow medial force were significantly higher in advanced players. Professional players were more efficient than advanced players, as they maximize ball velocity with lower joint kinetics. Since advanced players are subjected to higher joint kinetics, the results suggest that they appeared more susceptible to high risk of shoulder and elbow injuries than professionals, especially during the cocking and deceleration phases of the serve. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. A kinematic comparison of successful and unsuccessful tennis serves across the elite development pathway.

    Science.gov (United States)

    Whiteside, David; Elliott, Bruce; Lay, Brendan; Reid, Machar

    2013-08-01

    While velocity generation is an obvious prerequisite to proficient tennis serve performance, it is also the only stroke where players are obliged to negotiate a unique target constraint. Therefore, the dearth of research attending to the accuracy component of the serve is surprising. This study compared the body, racquet and ball kinematics characterising successful serves and service faults, missed into the net, in two groups of elite junior female players and one professional female tennis player. Three-dimensional body, racquet and ball kinematics were recorded using a 22-camera VICON motion analysis system. There were no differences in body kinematics between successful serves and service faults, suggesting that service faults cannot be attributed to a single source of biomechanical error. However, service faults missing into the net are characterized by projection angles significantly further below the horizontal, implying that consistency in this end-point parameter is critical to successful performance. Regulation of this parameter appears dependent on compensatory adjustments in the distal elbow and wrist joints immediately prior to impact and also perceptual feedback. Accordingly, coordination of the distal degrees of freedom and a refined perception-action coupling appear more important to success than any isolated mechanical component of the service action. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Management of tennis elbow by Agnikarma

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    Vyasadeva Mahanta

    2013-01-01

    Full Text Available Tennis elbow is a painful condition and causes restricted movement of forearm which requires treatment for long period. Till date only symptomatic treatments are available like use of anti-inflammatory analgesic drugs, steroids injection, physiotherapy, exercise etc. But none of these provide satisfactory result. Long term use of anti-inflammatory, analgesic drugs and steroids injection is also not free from the adverse effects. Usually, ′wait-and-see policy′ of treatment guideline is recommended in most of medical texts. According to Ayurveda, snayugata vata can be correlated with the condition of tennis elbow. Sushruta has advised Agnikarma for disorders of snayu (ligaments and tendons, asthi (bone, siddhi (joints etc. Hence, in this study a case of tennis elbow (snayugata vata was treated by Agnikarma, along with administration of powder of Ashwagandha and Navajivana Rasa orally, for a period of 03 weeks. This combination therapy provided considerable relief in pain and movement of the elbow joint.

  3. Management of tennis elbow by Agnikarma.

    Science.gov (United States)

    Mahanta, Vyasadeva; Dudhamal, Tukaram S; Gupta, Sanjay Kumar

    2013-01-01

    Tennis elbow is a painful condition and causes restricted movement of forearm which requires treatment for long period. Till date only symptomatic treatments are available like use of anti-inflammatory analgesic drugs, steroids injection, physiotherapy, exercise etc. But none of these provide satisfactory result. Long term use of anti-inflammatory, analgesic drugs and steroids injection is also not free from the adverse effects. Usually, 'wait-and-see policy' of treatment guideline is recommended in most of medical texts. According to Ayurveda, snayugata vata can be correlated with the condition of tennis elbow. Sushruta has advised Agnikarma for disorders of snayu (ligaments and tendons), asthi (bone), siddhi (joints) etc. Hence, in this study a case of tennis elbow (snayugata vata) was treated by Agnikarma, along with administration of powder of Ashwagandha and Navajivana Rasa orally, for a period of 03 weeks. This combination therapy provided considerable relief in pain and movement of the elbow joint.

  4. Recommendations for Measuring Tennis Racket Parameters

    Directory of Open Access Journals (Sweden)

    Tom Allen

    2018-02-01

    Full Text Available Tennis rackets have advanced significantly since the invention of the game in 1874, including innovations in both shape and materials. Advances in these design parameters have implications for racket performance, especially swing speed. This study tested one hundred rackets, spanning brands and eras, using simple, portable instruments in order to pilot protocols and make recommendations for streamlining testing procedures for tennis rackets. A wide range of properties were measured and documented for each racket. We suggest that since Transverse and Lateral Moment of Inertia are well correlated, measuring both is not necessary when processing a large number of rackets. In addition, it is also possible to predict the Transverse Moment of Inertia well from models that use simple dimension and mass measurements, which may be preferable in larger studies. Exploring the use of more complex modelling will allow us to better understand the impact of tennis racket design on performance in the future.

  5. Methodology of education used in the education of the tennis during the stage of initiation

    Directory of Open Access Journals (Sweden)

    José Carlos Carreras Duaigües

    2010-07-01

    Full Text Available The main objective of this study is to define the methodological model used in the introduction to tennis in Huelva, as well as emphasize teaching resources employed in the teaching of this sport.The method that has been used is video recording 16 sessions initiating to tennis (2 for each of the 8 monitors. Then proceed to analyze the instructor-trainer from the educational point: position on the track, chosen tasks (with or without opposition, material used, adaptation to the level that imparts and kinds of feedbacks.The most outstanding results have been: the predominant position for the teacher is central, he also elects mainly unopposed tasks, few questions are made but there are incentives and positive reinforcement for correction.We also point out the inadequate training of the instructors, most former players without qualification, different styles of teaching tennis in clubs (less pupils and increased importance of the techniques or municipal schools (more pupils and more games.This research concludes affirming the consolidation of a technical modified model, with better attitude in teachers when correcting and the presence of more games, a little different from what was used to do in the 80’s but showing a lack of draught of the constructivist methodology in those who are responsible initiating sports outside the school environment in the province of Huelva.

  6. Structural Analysis of Technical-Tactical Elements in Table Tennis and their Role in Different Playing Zones.

    Science.gov (United States)

    Munivrana, Goran; Petrinović, Lidija Zekan; Kondrič, Miran

    2015-09-29

    For the purpose of determining the overall structure of technical-tactical elements in table tennis and evaluating their role in different playing zones around the table, a new measuring instrument (a questionnaire) was formulated that took advantage of the expert knowledge of top, world class table tennis coaches. The results of the hierarchical taxonomic (cluster) analysis showed that the overall structure of the technical-tactical elements forming the table tennis technique could be divided into three basic groups; a group of technical-tactical elements (A) used in the phase of preparing one's own and disabling the opponent's attack; a group of technical-tactical elements (B) used in the phase of attack and counterattack; and a group of technical-tactical elements (C) used in the phase of defense. The differences among the obtained groups of table tennis elements were determined by applying the Kruskal-Wallis test, while relations between the groups and their role in different playing zones around the table were analyzed by comparing the average values of the experts' scores.

  7. Fractal Aggregates in Tennis Ball Systems

    Science.gov (United States)

    Sabin, J.; Bandin, M.; Prieto, G.; Sarmiento, F.

    2009-01-01

    We present a new practical exercise to explain the mechanisms of aggregation of some colloids which are otherwise not easy to understand. We have used tennis balls to simulate, in a visual way, the aggregation of colloids under reaction-limited colloid aggregation (RLCA) and diffusion-limited colloid aggregation (DLCA) regimes. We have used the…

  8. The Dutch motor skills assessment as tool for talent development in table tennis: a reproducibility and validity study.

    Science.gov (United States)

    Faber, Irene R; Nijhuis-Van Der Sanden, Maria W G; Elferink-Gemser, Marije T; Oosterveld, Frits G J

    2015-01-01

    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 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.

  9. Biomechanical analysis of three tennis serve types using a markerless system.

    Science.gov (United States)

    Abrams, Geoffrey D; Harris, Alex H S; Andriacchi, Thomas P; Safran, Marc R

    2014-02-01

    The tennis serve is commonly associated with musculoskeletal injury. Advanced players are able to hit multiple serve types with different types of spin. No investigation has characterised the kinematics of all three serve types for the upper extremity and back. Seven NCAA Division I male tennis players performed three successful flat, kick and slice serves. Serves were recorded using an eight camera markerless motion capture system. Laser scanning was utilised to accurately collect body dimensions and data were computed using inverse kinematic methods. There was no significant difference in maximum back extension angle for the flat, kick or slice serves. The kick serve had a higher force magnitude at the back than the flat and slice as well as larger posteriorly directed shoulder forces. The flat serve had significantly greater maximum shoulder internal rotation velocity versus the slice serve. Force and torque magnitudes at the elbow and wrist were not significantly different between the serves. The kick serve places higher physical demands on the back and shoulder while the slice serve demonstrated lower overall kinetic forces. This information may have injury prevention and rehabilitation implications.

  10. The Relationship Between Maximum Isometric Strength and Ball Velocity in the Tennis Serve

    Directory of Open Access Journals (Sweden)

    Baiget Ernest

    2016-12-01

    Full Text Available The aims of this study were to analyze the relationship between maximum isometric strength levels in different upper and lower limb joints and serve velocity in competitive tennis players as well as to develop a prediction model based on this information. Twelve male competitive tennis players (mean ± SD; age: 17.2 ± 1.0 years; body height: 180.1 ± 6.2 cm; body mass: 71.9 ± 5.6 kg were tested using maximum isometric strength levels (i.e., wrist, elbow and shoulder flexion and extension; leg and back extension; shoulder external and internal rotation. Serve velocity was measured using a radar gun. Results showed a strong positive relationship between serve velocity and shoulder internal rotation (r = 0.67; p < 0.05. Low to moderate correlations were also found between serve velocity and wrist, elbow and shoulder flexion – extension, leg and back extension and shoulder external rotation (r = 0.36 – 0.53; p = 0.377 – 0.054. Bivariate and multivariate models for predicting serve velocity were developed, with shoulder flexion and internal rotation explaining 55% of the variance in serve velocity (r = 0.74; p < 0.001. The maximum isometric strength level in shoulder internal rotation was strongly related to serve velocity, and a large part of the variability in serve velocity was explained by the maximum isometric strength levels in shoulder internal rotation and shoulder flexion.

  11. Technical and tactical skills related to performance levels in tennis: A systematic review.

    Science.gov (United States)

    Kolman, Nikki S; Kramer, Tamara; Elferink-Gemser, Marije T; Huijgen, Barbara C H; Visscher, Chris

    2018-06-11

    The aim of this systematic review is to provide an overview of outcome measures and instruments identified in the literature for examining technical and tactical skills in tennis related to performance levels. Such instruments can be used to identify talent or the specific skill development training needs of particular players. Searches for this review were conducted using the PubMed, Web of Science, and PsycInfo databases. Out of 733 publications identified through these searches, 40 articles were considered relevant and included in this study. They were divided into three categories: (1) technical skills, (2) tactical skills and (3) integrated technical and tactical skills. There was strong evidence that technical skills (ball velocity and to a lesser extent ball accuracy) and tactical skills (decision making, anticipation, tactical knowledge and visual search strategies) differed among players according to their performance levels. However, integrated measurement of these skills is required, because winning a point largely hinges on a tactical decision to perform a particular stroke (i.e., technical execution). Therefore, future research should focus on examining the relationship between these skills and tennis performance and on the development of integrated methods for measuring these skills.

  12. The Relationship Between Maximum Isometric Strength and Ball Velocity in the Tennis Serve.

    Science.gov (United States)

    Baiget, Ernest; Corbi, Francisco; Fuentes, Juan Pedro; Fernández-Fernández, Jaime

    2016-12-01

    The aims of this study were to analyze the relationship between maximum isometric strength levels in different upper and lower limb joints and serve velocity in competitive tennis players as well as to develop a prediction model based on this information. Twelve male competitive tennis players (mean ± SD; age: 17.2 ± 1.0 years; body height: 180.1 ± 6.2 cm; body mass: 71.9 ± 5.6 kg) were tested using maximum isometric strength levels (i.e., wrist, elbow and shoulder flexion and extension; leg and back extension; shoulder external and internal rotation). Serve velocity was measured using a radar gun. Results showed a strong positive relationship between serve velocity and shoulder internal rotation (r = 0.67; p isometric strength level in shoulder internal rotation was strongly related to serve velocity, and a large part of the variability in serve velocity was explained by the maximum isometric strength levels in shoulder internal rotation and shoulder flexion.

  13. Hip joint kinetics in the table tennis topspin forehand: relationship to racket velocity.

    Science.gov (United States)

    Iino, Yoichi

    2018-04-01

    The purpose of this study was to determine hip joint kinetics during a table tennis topspin forehand, and to investigate the relationship between the relevant kinematic and kinetic variables and the racket horizontal and vertical velocities at ball impact. Eighteen male advanced table tennis players hit cross-court topspin forehands against backspin balls. The hip joint torque and force components around the pelvis coordinate system were determined using inverse dynamics. Furthermore, the work done on the pelvis by these components was also determined. The peak pelvis axial rotation velocity and the work done by the playing side hip pelvis axial rotation torque were positively related to the racket horizontal velocity at impact. The sum of the work done on the pelvis by the backward tilt torques and the upward joint forces was positively related to the racket vertical velocity at impact. The results suggest that the playing side hip pelvis axial rotation torque exertion is important for acquiring a high racket horizontal velocity at impact. The pelvis backward tilt torques and upward joint forces at both hip joints collectively contribute to the generation of the racket vertical velocity, and the mechanism for acquiring the vertical velocity may vary among players.

  14. Joint Kinetics to Assess the Influence of the Racket on a Tennis Player’s Shoulder

    Science.gov (United States)

    Creveaux, Thomas; Dumas, Raphaël; Hautier, Christophe; Macé, Pierre; Chèze, Laurence; Rogowski, Isabelle

    2013-01-01

    This study aimed at investigating the influence of three rackets on shoulder net joint moments, power and muscle activity during the flat tennis serve under field- conditions. A 6-camera Eagle® motion analysis system, operating at 256 Hz, captured racket and dominant upper limb kinematics of the serve in five tennis players under three racket conditions (A: low mass, high balance and polar moment, B: low three moments of inertia, and C: high mass, swingweight and twistweight). The electromyographic activity of six trunk and arm muscles was simultaneously recorded. Shoulder net joint moments and power were computed by 3D inverse dynamics. The results showed that greater shoulder joint power and internal/external rotation peak moments were found to accelerate and decelerate racket A in comparison with the racket C. Moreover, serving with the racket A resulted in less activity in latissimus dorsi muscle during the acceleration phase, and biceps brachii muscle during the follow-through phase when compared with racket C. These initial findings encourage studying the biomechanical measurements to quantify the loads on the body during play in order to reduce them, and then prevent shoulder injuries. Racket specifications may be a critical point for coaches who train players suffering from shoulder pain and chronic upper limb injuries should be considered in relation to the racket specifications of the players. Key Points Light racket required more joint power than heavy one to achieve similar post impact ball velocity. Serving with a light racket resulted in higher shoulder internal and external rotation moments than using a heavy one for similar performance. Chronic shoulder pain should encourage coaches to check for potentially inappropriate racket specifications of their players. PMID:24149804

  15. Natural course in tennis elbow--lateral epicondylitis after all?

    Science.gov (United States)

    Zeisig, Eva

    2012-12-01

    Tennis elbow is a common and difficult-to-treat condition largely because of lack of evidence. The natural history is unknown, but the condition is described as self-limiting. The objective of this case report is to describe the natural course of two control participants (pain free), who later developed tennis elbow, patient history, clinical findings, and ultrasound and colour Doppler examination before, during and after a period of tennis elbow.

  16. HYDRATION AND TEMPERATURE IN TENNIS - A PRACTICAL REVIEW

    OpenAIRE

    Mark S. Kovacs

    2006-01-01

    Competitive tennis is typically played in warm and hot environments. Because hypohydration will impair tennis performance and increases the risk of heat injury, consumption of appropriate fluid levels is necessary to prevent dehydration and enhance performance. The majority of research in this area has focused on continuous aerobic activity - unlike tennis, which has average points lasting less than ten seconds with rest periods dispersed between each work period. For this reason, hydration a...

  17. Pictorial essay: Ultrasonography in 'tennis leg'.

    Science.gov (United States)

    Shah, Jeshil R; Shah, Bipin R; Shah, Ankit B

    2010-11-01

    Tennis leg is caused by a rupture of the medial head of the gastrocnemius muscle, usually at its distal musculotendinous junction region. However, tears in this muscle and its tendon are also included under the term 'tennis leg'. It is seen regularly in practice and is an important cause of a painful calf. The common USG findings include: disruption of the pinnate pattern of the distal medial gastrocnemius, usually near the junction of the triceps surae (which is the echogenic line between the gastrocnemius, the soleus, and the plantaris muscles), fluid tracking along the fascia, adjacent hematoma, and intramuscular tears as well as hematomas. USG is useful for confirming the diagnosis, excluding other causes of a painful calf, for assessing the severity of the disease, and in follow-up.

  18. Sodium bicarbonate supplementation prevents skilled tennis performance decline after a simulated match

    Directory of Open Access Journals (Sweden)

    Huang Ming-Hsiang

    2010-10-01

    Full Text Available Abstract The supplementation of sodium bicarbonate (NaHCO3 could increase performance or delay fatigue in intermittent high-intensity exercise. Prolonged tennis matches result in fatigue, which impairs skilled performance. The aim of this study was to investigate the effect of NaHCO3 supplementation on skilled tennis performance after a simulated match. Nine male college tennis players were recruited for this randomized cross-over, placebo-controlled, double-blind study. The participants consumed NaHCO3 (0.3 g. kg-1 or NaCl (0.209 g. kg-1 before the trial. An additional supplementation of 0.1 g. kg-1 NaHCO3 or 0.07 g. kg-1 NaCl was ingested after the third game in the simulated match. The Loughborough Tennis Skill Test was performed before and after the simulated match. Post-match [HCO3-] and base excess were significantly higher in the bicarbonate trial than those in the placebo trial. Blood [lactate] was significantly increased in the placebo (pre: 1.22 ± 0.54; post: 2.17 ± 1.46 mM and bicarbonate (pre: 1.23 ± 0.41; post: 3.21 ± 1.89 mM trials. The match-induced change in blood [lactate] was significantly higher in the bicarbonate trial. Blood pH remained unchanged in the placebo trial (pre: 7.37 ± 0.32; post: 7.37 ± 0.14 but was significantly increased in the bicarbonate trial (pre: 7.37 ± 0.26; post: 7.45 ± 0.63, indicating a more alkaline environment. The service and forehand ground stroke consistency scores were declined significantly after the simulated match in the placebo trial, while they were maintained in the bicarbonate trial. The match-induced declines in the consistency scores were significantly larger in the placebo trial than those in the bicarbonate trial. This study suggested that NaHCO3 supplementation could prevent the decline in skilled tennis performance after a simulated match.

  19. Structural Analysis of Technical-Tactical Elements in Table Tennis and their Role in Different Playing Zones

    Directory of Open Access Journals (Sweden)

    Munivrana Goran

    2015-09-01

    Full Text Available For the purpose of determining the overall structure of technical-tactical elements in table tennis and evaluating their role in different playing zones around the table, a new measuring instrument (a questionnaire was formulated that took advantage of the expert knowledge of top, world class table tennis coaches. The results of the hierarchical taxonomic (cluster analysis showed that the overall structure of the technical-tactical elements forming the table tennis technique could be divided into three basic groups; a group of technical-tactical elements (A used in the phase of preparing one’s own and disabling the opponent’s attack; a group of technical-tactical elements (B used in the phase of attack and counterattack; and a group of technical-tactical elements (C used in the phase of defense. The differences among the obtained groups of table tennis elements were determined by applying the Kruskal-Wallis test, while relations between the groups and their role in different playing zones around the table were analyzed by comparing the average values of the experts’ scores.

  20. Veto players

    NARCIS (Netherlands)

    Warntjen, Andreas; Dowding, Keith

    2010-01-01

    Veto players are political actors whose consent is necessary to adopt a new policy. Put otherwise, they have veto power which allows them to prevent a change to the status quo. The concept is crucial to the influential veto player theory developed by George Tsebelis. Building on earlier work in

  1. Orthotic devices for the treatment of tennis elbow

    NARCIS (Netherlands)

    Struijs, P. A. A.; Smidt, N.; Arola, H.; Dijk, van C. N.; Buchbinder, R.; Assendelft, W. J. J.

    2002-01-01

    BACKGROUND: Lateral epicondylitis (tennis elbow) is a frequently reported condition. A wide variety of treatment strategies has been described. As of yet, no optimal strategy has been identified. OBJECTIVES: To assess the effectiveness of orthotic devices for the treatment of tennis elbow. SEARCH

  2. Orthotic devices for tennis elbow: a systematic review

    NARCIS (Netherlands)

    Struijs, P. A.; Smidt, N.; Arola, H.; van Dijk, C. N.; Buchbinder, R.; Assendelft, W. J.

    2001-01-01

    Lateral epicondylitis (tennis elbow) is af requently reported condition. A wide variety of treatment strategies has been described. Asy et, no optimal strategy has been identified. The aim of this review was to assess the effectiveness of orthotic devices for treatment of tennis elbow. An electronic

  3. USTC & TBA Guidelines for Tennis Court & Running Track Construction.

    Science.gov (United States)

    United States Tennis Court & Track Builders Association.

    Guidelines are presented on tennis court and track and field construction that reflect the latest developments in construction technology, methodology, and practice. Based on contributions from experienced certified tennis court and track builders, material suppliers and design professionals, this manual examines each of the critical areas of…

  4. Modifying Equipment in Early Skill Development: A Tennis Perspective

    Science.gov (United States)

    Buszard, Tim; Farrow, Damian; Reid, Machar; Masters, Rich S. W.

    2014-01-01

    Purpose: The International Tennis Federation recently launched a worldwide campaign advocating the use of equipment scaling for children learning to play tennis. The aim of this study was to investigate the influence that varying racquet sizes and ball compressions had on children's ability to play a forehand groundstroke. Method: This was a…

  5. Differentiating Experts' Anticipatory Skills in Beach Volleyball

    Science.gov (United States)

    Canal-Bruland, Rouwen; Mooren, Merel; Savelsbergh, Geert J. P.

    2011-01-01

    In this study, we examined how perceptual-motor expertise and watching experience contribute to anticipating the outcome of opponents' attacking actions in beach volleyball. To this end, we invited 8 expert beach volleyball players, 8 expert coaches, 8 expert referees, and 8 control participants with no beach volleyball experience to watch videos…

  6. Analysis of the tennis racket vibrations during forehand drives: Selection of the mother wavelet.

    Science.gov (United States)

    Blache, Y; Hautier, C; Lefebvre, F; Djordjevic, A; Creveaux, T; Rogowski, I

    2017-08-16

    The time-frequency analysis of the tennis racket and hand vibrations is of great interest for discomfort and pathology prevention. This study aimed to (i) to assess the stationarity of the vibratory signal of the racket and hand and (ii) to identify the best mother wavelet to perform future time-frequency analysis, (iii) to determine if the stroke spin, racket characteristics and impact zone can influence the selection of the best mother wavelet. A total of 2364 topspin and flat forehand drives were performed by fourteen male competitive tennis players with six different rackets. One tri-axial and one mono-axial accelerometer were taped on the racket throat and dominant hand respectively. The signal stationarity was tested through the wavelet spectrum test. Eighty-nine mother wavelet were tested to select the best mother wavelet based on continuous and discrete transforms. On average only 25±17%, 2±5%, 5±7% and 27±27% of the signal tested respected the hypothesis of stationarity for the three axes of the racket and the hand respectively. Regarding the two methods for the detection of the best mother wavelet, the Daubechy 45 wavelet presented the highest average ranking. No effect of the stroke spin, racket characteristics and impact zone was observed for the selection of the best mother wavelet. It was concluded that alternative approach to Fast Fourier Transform should be used to interpret tennis vibration signals. In the case where wavelet transform is chosen, the Daubechy 45 mother wavelet appeared to be the most suitable. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Le genre en jeu. De la construction du genre dans les interactions en tennis de table

    Directory of Open Access Journals (Sweden)

    Rémi Richard

    2012-05-01

    Full Text Available À travers le cas d’un groupe de pongistes, cet article s’attache à mettre au jour les processus de construction du genre dans une pratique sportive mixte. À partir des propositions américaines des gender studies et plus particulièrement la notion de performativité qui replace l’individu au centre du processus de construction sociale de la réalité, nous allons tenter de saisir les procédés mis en œuvre par ces sportifs pour produire des normes de genre. Les observations et les entretiens réalisés montrent que tous les éléments de la situation sportive constituent une occasion de « faire » le genre : l’espace, les temps sportifs, la logique de l’activité et, bien sûr, les discours des sportifs sont mis au service d’une masculinisation du tennis de table.Gender game. About the construction of gender in the interactions in table tennisThrough the case of a group of table tennis players, this article attempts to bring to light the processes of gender construction in a mixed sports practice. From the American propositions of gender studies, and more particularly the concept of performativity which replaces the individual in the center of the process of social construction of the reality, we are going to try to seize the strategies implemented by these table tennis players to produce norms of gender. The observations and interviews realized show that all the elements of the sport situation are an opportunity "to do" gender: space, time, logic of the activity and of course speeches of the players service a masculinizing of table tennis.El género en juego. La construcción del género en las interacciones en el tenis de mesaA través el caso de un grupo de tenistas de mesa, este artículo tiene como objeto el poner en evidencia los procesos de construcción de género en una actividad deportiva mixta. A partir de las proposiciones americanas de los gender studies y en particular la noción de «performatividad» que

  8. The impact of match-play tennis in a hot environment on indirect markers of oxidative stress and antioxidant status

    Science.gov (United States)

    Knez, Wade L; Périard, JP

    2014-01-01

    Objectives The purpose of this study was to determine the impact of changes in oxidative stress and antioxidant status in response to playing tennis in HOT (∼36°C and 35% relative humidity (RH)) and COOL (∼22°C and 70% RH) conditions. Methods 10 male tennis players undertook two matches for an effective playing time (ie, ball in play) of 20 min, corresponding to ∼122 and ∼107 min of total play in HOT and COOL conditions, respectively. Core body temperature, body mass and indirect markers of oxidative stress (diacrons reactive oxygen metabolic test) and antioxidant status (biological antioxidant potential test) were assessed immediately prematch, midmatch and postmatch, and 24 and 48 h into recovery. Results Regardless of the condition, oxidative stress remained similar throughout play and into recovery. Likewise, match-play tennis in the COOL had no impact on antioxidant status. However, antioxidants status increased significantly in the HOT compared with COOL environment (pantioxidant status. These data suggest that the heat stress observed in the HOT environment may provide a necessary signal for the upregulation of antioxidant defence, dampening cellular damage. PMID:24668382

  9. Comparison of athlete-coach perceptions of internal and external load markers for elite junior tennis training.

    Science.gov (United States)

    Murphy, Alistair P; Duffield, Rob; Kellett, Aaron; Reid, Machar

    2014-09-01

    To investigate the discrepancy between coach and athlete perceptions of internal load and notational analysis of external load in elite junior tennis. Fourteen elite junior tennis players and 6 international coaches were recruited. Ratings of perceived exertion (RPEs) were recorded for individual drills and whole sessions, along with a rating of mental exertion, coach rating of intended session exertion, and athlete heart rate (HR). Furthermore, total stroke count and unforced-error count were notated using video coding after each session, alongside coach and athlete estimations of shots and errors made. Finally, regression analyses explained the variance in the criterion variables of athlete and coach RPE. Repeated-measures analyses of variance and interclass correlation coefficients revealed that coaches significantly (P coach and athlete. However, athlete drill RPE (P = .14; r = .71) and mental exertion (P = .44; r = .68) were comparable and substantially correlated. No significant differences in estimated stroke count were evident between athlete and coach (P = .21), athlete notational analysis (P = .06), or coach notational analysis (P = .49). Coaches estimated significantly greater unforced errors than either athletes or notational analysis (P coach RPE was explained by intended session exertion and coach drill RPE, while drill RPE and peak HR explained 45.3% of the variance in athlete session RPE. Coaches misinterpreted session RPE but not drill RPE, while inaccurately monitoring error counts. Improved understanding of external- and internal-load monitoring may help coach-athlete relationships in individual sports like tennis avoid maladaptive training.

  10. A study of kinematic cues and anticipatory performance in tennis using computational manipulation and computer graphics.

    Science.gov (United States)

    Ida, Hirofumi; Fukuhara, Kazunobu; Kusubori, Seiji; Ishii, Motonobu

    2011-09-01

    Computer graphics of digital human models can be used to display human motions as visual stimuli. This study presents our technique for manipulating human motion with a forward kinematics calculation without violating anatomical constraints. A motion modulation of the upper extremity was conducted by proportionally modulating the anatomical joint angular velocity calculated by motion analysis. The effect of this manipulation was examined in a tennis situation--that is, the receiver's performance of predicting ball direction when viewing a digital model of the server's motion derived by modulating the angular velocities of the forearm or that of the elbow during the forward swing. The results showed that the faster the server's forearm pronated, the more the receiver's anticipation of the ball direction tended to the left side of the serve box. In contrast, the faster the server's elbow extended, the more the receiver's anticipation of the ball direction tended to the right. This suggests that tennis players are sensitive to the motion modulation of their opponent's racket-arm.

  11. Kinematics analysis of ankle inversion ligamentous sprain injuries in sports: five cases from televised tennis competitions.

    Science.gov (United States)

    Fong, Daniel Tik-Pui; Ha, Sophia Chui-Wai; Mok, Kam-Ming; Chan, Christie Wing-Long; Chan, Kai-Ming

    2012-11-01

    Ankle ligamentous sprain is common in sports. The most direct way to study the mechanism quantitatively is to study real injury cases; however, it is unethical and impractical to produce an injury in the laboratory. A recently developed, model-based image-matching motion analysis technique allows quantitative analysis of real injury incidents captured in televised events and gives important knowledge for the development of injury prevention protocols and equipment. To date, there have been only 4 reported cases, and there is a need to conduct more studies for a better understanding of the mechanism of ankle ligamentous sprain injury. This study presents 5 cases in tennis and a comparison with 4 previous cases for a better understanding of the mechanism of ankle ligamentous sprain injury. Case series; level of evidence, 4. Five sets of videos showing ankle sprain injuries in televised tennis competition with 2 camera views were collected. The videos were transformed, synchronized, and rendered to a 3-dimensional animation software. The dimensions of the tennis court in each case were obtained to build a virtual environment, and a skeleton model scaled to the injured athlete's height was used for the skeleton matching. Foot strike was determined visually, and the profiles of the ankle joint kinematics were individually presented. There was a pattern of sudden inversion and internal rotation at the ankle joint, with the peak values ranging from 48°-126° and 35°-99°, respectively. In the sagittal plane, the ankle joint fluctuated between plantar flexion and dorsiflexion within the first 0.50 seconds after foot strike. The peak inversion velocity ranged from 509 to 1488 deg/sec. Internal rotation at the ankle joint could be one of the causes of ankle inversion sprain injury, with a slightly inverted ankle joint orientation at landing as the inciting event. To prevent the foot from rolling over the edge to cause a sprain injury, tennis players who do lots of sideward

  12. ASSESMENT OF A NEW METHOD HIGHLIGHTING COGNITIVE ATTRIBUTES WITH TABLE TENNIS ATHLETES

    Directory of Open Access Journals (Sweden)

    Senay Sahin

    2015-05-01

    Full Text Available Table tennis is among sports that are difficult to learn and perform. The athlete has to perceive the ball within a small space, in various rotations, aiming at different points on the table in various speeds, and perform the correct action. Thus, assessing and improving the athletes’ attention, perception, fast learning and adaptation skills are of significant importance in training top-tier athletes. This study evaluates fast learning, visual perception and adaptation skills of national athletes using Selective Action Array, developed recently for the study. Out of 2014 Balkan Youth Table Tennis Championship athletes, 11 male and 11 females participated in the study. For the Selective Action Array, a table tennis robot was utilized. Robot was set up to send a total of 26 balls in 3 different colors (6 whites, 10 yellows, 10 pinks to different areas of the table, in random colors and at the rate of 90 balls per minute. The participants were asked to ignore the white balls, to touch the yellow balls and to grab the pink balls using their dominant hands. Pursuant to explaining the task to the participants, two consecutive trials were executed and recorded using a camera. Every action performed/not performed by the participants was transformed into points in the scoring system. First trial total points in the Selective Action Array were 124±15 for males and 108±13 for females, whereas on the second trial the total points were 136±15 and 119±8, respectively. The higher scores obtained in the second trial were significant. Success rates for males were higher than females in both trials based on the percentage of correct actions executed in relation with the ball. The most significant difference between males and females was observed in white ball success rates. The highest increase in the rate of success in the second trial as compared to the first was observed in yellow balls for females and in pink balls for males. Table tennis players

  13. Developing an intelligent assistant for table tennis umpires

    OpenAIRE

    Wong, Patrick K. C.

    2007-01-01

    This paper outlines the idea and plan of developing an intelligent assistant for table tennis umpire in evaluating services. Table tennis is a fast sport. A service usually takes a few second to complete but there are many observations an umpire needs to take and makes a judgment before or soon after the service is complete. This is a complex task and the author believes the employment of videography, image processing and artificial intelligence (AI) technologies could help evaluating the ser...

  14. Tennis elbow: role of local steroid injection.

    Science.gov (United States)

    Ahmed, Gulzar Saeed; Ali, Muhammad; Trago, Imtiaz Ahmed

    2012-01-01

    Tennis elbow is a condition, characterised by pain and tenderness over the lateral epicondyle of the humerus, and pain on resisted dorsiflexion of the wrist, middle finger, or both. The aim of this randomised controlled trial was to investigate the short term efficacy of local steroid injection compared with oral and topical NSAIDs. Sixty patients (45 male and 15 female) were included in the study. The mean age was 42 years for men and 40 years for women. They were placed in group A and B (30 cases each). Group A received local steroid injection (triamcinolone 20 mg mixed with lignocaine 2% 1 cc) and topical NSAID cream application (diclofenac diethylammonium) twice a day, tab. diclofenac sodium 50 mg twice a day for 3 weeks. Group B received tab diclofenac 50 mg twice a day and, topical NSAID cream application twice a day for 3 weeks. Assessment of patients was made 3 times; first at the start of the study, 2nd time after 6 weeks, and 3rd time after 12 weeks. A blinded assessor rated the elbow complaints of the patients at resisted dorsiflexion of wrist using VAS (0 = no severity, 1-3 mild, 4-6 moderate, 7-9 sever, 10 = maximum severity). At six weeks, 22 (73.33%) patient in group A had no pain as compared to 7 (23.33%) patients in group B who were pain free (p < 0.0001, chi2 = 38.75). At 12 weeks 27 (90%) patients in group A were pain free compared to group B in which 7 (23.33%) patients were pain free (p < 0.0001, chi2 = 27.56). In patients with tennis elbow, the use of local steroid injection in combination with topical and oral NSAIDs is superior to the use of combination of topical and oral NSAIDs. Better results with combination therapy using local steroid injection may be limited to the short term.

  15. The impact of development o f the special coordination abilities on the general skill ability for table tennis juniors under 12 years old

    Directory of Open Access Journals (Sweden)

    Shawkat Gaber Radwan

    2014-06-01

    Full Text Available Indicates each of Muhama d Allawi (2002, Essam Abdul Khaliq (2003, and Walf Droge (2002 that the coordination abilities are closely related to the development of technical motor skills, and that pra ctitioner athletic activity which determines the quality of this abilities should be developed, where the player can not master the technical skills in the special activity in case lack of special coordination abilities for this activity. Both Manf red Must er (1986, Jürgen Schmicker (2000, Wolfgang and others (2000 and Wohlgefahrt, Karlheinz (2004 refers that the special coordination abilities for table tennis include each of: 1 - The motor adaptation and adjustment ability, 2 - The ability to differentiat e , 3 - reaction speed ability, 4 - orientation ability, 5 - balance ability, 6 - coupling ability, 7 - The ability to sense the rhythm. The aim of this study is design training program to development the special coordination abilities of table tennis and identi fies the impact of this program on the general skill ability for table tennis juniors under 12 years old. The researcher used the experimental method into two groups one experimental and the other control group the strength of each of them is 8 of table te nnis juniors in Ismailia city in Egypt. The duration of the program is three months, three training units a week the duration of each training unit is 90 minutes. The most important results of this study was the training program led to improvement the spec ial coordination abilities of table tennis for the experimental group, which led to high level of the general skill ability in table tennis for the experimental group more than the control group .

  16. Expert systems

    International Nuclear Information System (INIS)

    Haldy, P.A.

    1988-01-01

    The definitions of the terms 'artificial intelligence' and 'expert systems', the methodology, areas of employment and limits of expert systems are discussed. The operation of an expert system is described, especially the presentation and organization of knowledge as well as interference and control. Methods and tools for expert system development are presented and their application in nuclear energy are briefly addressed. 7 figs., 2 tabs., 6 refs

  17. Expert Systems

    OpenAIRE

    Lucas, P.J.F.

    2005-01-01

    Expert systems mimic the problem-solving activity of human experts in specialized domains by capturing and representing expert knowledge. Expert systems include a knowledge base, an inference engine that derives conclusions from the knowledge, and a user interface. Knowledge may be stored as if-then rules, orusing other formalisms such as frames and predicate logic. Uncertain knowledge may be represented using certainty factors, Bayesian networks, Dempster-Shafer belief functions, or fuzzy se...

  18. Assessment of Specificity of the Badcamp Agility Test for Badminton Players

    Directory of Open Access Journals (Sweden)

    de França Bahia Loureiro Luiz

    2017-06-01

    Full Text Available The Badcamp agility test was created to evaluate agility of badminton players. The Badcamp is a valid and reliable test, however, a doubt about the need for the use of this test exists as simpler tests could provide similar information about agility in badminton players. Thus, the aim of this study was to examine the specificity of the Badcamp, comparing the performance of badminton players and athletes from other sports in the Badcamp and the shuttle run agility test (SRAT. Sixty-four young male and female athletes aged between 14 and 16 years participated in the study. They were divided into 4 groups of 16 according to their sport practices: badminton, tennis, team sport (basketball and volleyball, and track and field. We compared the groups in both tests, the Badcamp and SRAT. The results revealed that the group of badminton players was faster compared to all other groups in the Badcamp. However, in the SRAT there were no differences among groups composed of athletes from open skill sports (e.g., badminton, tennis, and team sports, and a considerable reduction of the difference between badminton players and track and field athletes. Thus, we concluded that the Badcamp test is a specific agility test for badminton players and should be considered in evaluating athletes of this sport modality.

  19. Assessment of Specificity of the Badcamp Agility test for Badminton Players.

    Science.gov (United States)

    de França Bahia Loureiro, Luiz; Costa Dias, Mário Oliveira; Cremasco, Felipe Couto; da Silva, Maicon Guimarães; de Freitas, Paulo Barbosa

    2017-06-01

    The Badcamp agility test was created to evaluate agility of badminton players. The Badcamp is a valid and reliable test, however, a doubt about the need for the use of this test exists as simpler tests could provide similar information about agility in badminton players. Thus, the aim of this study was to examine the specificity of the Badcamp, comparing the performance of badminton players and athletes from other sports in the Badcamp and the shuttle run agility test (SRAT). Sixty-four young male and female athletes aged between 14 and 16 years participated in the study. They were divided into 4 groups of 16 according to their sport practices: badminton, tennis, team sport (basketball and volleyball), and track and field. We compared the groups in both tests, the Badcamp and SRAT. The results revealed that the group of badminton players was faster compared to all other groups in the Badcamp. However, in the SRAT there were no differences among groups composed of athletes from open skill sports (e.g., badminton, tennis, and team sports), and a considerable reduction of the difference between badminton players and track and field athletes. Thus, we concluded that the Badcamp test is a specific agility test for badminton players and should be considered in evaluating athletes of this sport modality.

  20. iTTVis: Interactive Visualization of Table Tennis Data.

    Science.gov (United States)

    Wu, Yingcai; Lan, Ji; Shu, Xinhuan; Ji, Chenyang; Zhao, Kejian; Wang, Jiachen; Zhang, Hui

    2018-01-01

    The rapid development of information technology paved the way for the recording of fine-grained data, such as stroke techniques and stroke placements, during a table tennis match. This data recording creates opportunities to analyze and evaluate matches from new perspectives. Nevertheless, the increasingly complex data poses a significant challenge to make sense of and gain insights into. Analysts usually employ tedious and cumbersome methods which are limited to watching videos and reading statistical tables. However, existing sports visualization methods cannot be applied to visualizing table tennis competitions due to different competition rules and particular data attributes. In this work, we collaborate with data analysts to understand and characterize the sophisticated domain problem of analysis of table tennis data. We propose iTTVis, a novel interactive table tennis visualization system, which to our knowledge, is the first visual analysis system for analyzing and exploring table tennis data. iTTVis provides a holistic visualization of an entire match from three main perspectives, namely, time-oriented, statistical, and tactical analyses. The proposed system with several well-coordinated views not only supports correlation identification through statistics and pattern detection of tactics with a score timeline but also allows cross analysis to gain insights. Data analysts have obtained several new insights by using iTTVis. The effectiveness and usability of the proposed system are demonstrated with four case studies.

  1. EXPERT SYSTEMS

    OpenAIRE

    Georgiana Marin; Mihai Catalin Andrei

    2011-01-01

    In recent decades IT and computer systems have evolved rapidly in economic informatics field. The goal is to create user friendly information systems that respond promptly and accurately to requests. Informatics systems evolved into decision assisted systems, and such systems are converted, based on gained experience, in expert systems for creative problem solving that an organization is facing. Expert systems are aimed at rebuilding human reasoning on the expertise obtained from experts, sto...

  2. Expert System

    DEFF Research Database (Denmark)

    Hildebrandt, Thomas Troels; Cattani, Gian Luca

    2016-01-01

    An expert system is a computer system for inferring knowledge from a knowledge base, typically by using a set of inference rules. When the concept of expert systems was introduced at Stanford University in the early 1970s, the knowledge base was an unstructured set of facts. Today the knowledge b...... for the application of expert systems, but also raises issues regarding privacy and legal liability....

  3. The influence of expertise on brain activation of the action observation network during anticipation of tennis and volleyball serves

    Science.gov (United States)

    Balser, Nils; Lorey, Britta; Pilgramm, Sebastian; Naumann, Tim; Kindermann, Stefan; Stark, Rudolf; Zentgraf, Karen; Williams, A. Mark; Munzert, Jörn

    2014-01-01

    In many daily activities, and especially in sport, it is necessary to predict the effects of others' actions in order to initiate appropriate responses. Recently, researchers have suggested that the action–observation network (AON) including the cerebellum plays an essential role during such anticipation, particularly in sport expert performers. In the present study, we examined the influence of task-specific expertise on the AON by investigating differences between two expert groups trained in different sports while anticipating action effects. Altogether, 15 tennis and 16 volleyball experts anticipated the direction of observed tennis and volleyball serves while undergoing functional magnetic resonance imaging (fMRI). The expert group in each sport acted as novice controls in the other sport with which they had only little experience. When contrasting anticipation in both expertise conditions with the corresponding untrained sport, a stronger activation of AON areas (SPL, SMA), and particularly of cerebellar structures, was observed. Furthermore, the neural activation within the cerebellum and the SPL was linearly correlated with participant's anticipation performance, irrespective of the specific expertise. For the SPL, this relationship also holds when an expert performs a domain-specific anticipation task. Notably, the stronger activation of the cerebellum as well as of the SMA and the SPL in the expertise conditions suggests that experts rely on their more fine-tuned perceptual-motor representations that have improved during years of training when anticipating the effects of others' actions in their preferred sport. The association of activation within the SPL and the cerebellum with the task achievement suggests that these areas are the predominant brain sites involved in fast motor predictions. The SPL reflects the processing of domain-specific contextual information and the cerebellum the usage of a predictive internal model to solve the anticipation

  4. The influence of expertise on brain activation of the action observation network during anticipation of tennis and volleyball serves.

    Science.gov (United States)

    Balser, Nils; Lorey, Britta; Pilgramm, Sebastian; Naumann, Tim; Kindermann, Stefan; Stark, Rudolf; Zentgraf, Karen; Williams, A Mark; Munzert, Jörn

    2014-01-01

    In many daily activities, and especially in sport, it is necessary to predict the effects of others' actions in order to initiate appropriate responses. Recently, researchers have suggested that the action-observation network (AON) including the cerebellum plays an essential role during such anticipation, particularly in sport expert performers. In the present study, we examined the influence of task-specific expertise on the AON by investigating differences between two expert groups trained in different sports while anticipating action effects. Altogether, 15 tennis and 16 volleyball experts anticipated the direction of observed tennis and volleyball serves while undergoing functional magnetic resonance imaging (fMRI). The expert group in each sport acted as novice controls in the other sport with which they had only little experience. When contrasting anticipation in both expertise conditions with the corresponding untrained sport, a stronger activation of AON areas (SPL, SMA), and particularly of cerebellar structures, was observed. Furthermore, the neural activation within the cerebellum and the SPL was linearly correlated with participant's anticipation performance, irrespective of the specific expertise. For the SPL, this relationship also holds when an expert performs a domain-specific anticipation task. Notably, the stronger activation of the cerebellum as well as of the SMA and the SPL in the expertise conditions suggests that experts rely on their more fine-tuned perceptual-motor representations that have improved during years of training when anticipating the effects of others' actions in their preferred sport. The association of activation within the SPL and the cerebellum with the task achievement suggests that these areas are the predominant brain sites involved in fast motor predictions. The SPL reflects the processing of domain-specific contextual information and the cerebellum the usage of a predictive internal model to solve the anticipation task.

  5. The influence of expertise on brain activation of the Action Observation Network during anticipation of tennis and volleyball serves

    Directory of Open Access Journals (Sweden)

    Nils eBalser

    2014-08-01

    Full Text Available In many daily activities, and especially in sport, it is necessary to predict the effects of others’ actions in order to initiate appropriate responses. Recently, researchers have suggested that the action–observation network (AON including the cerebellum plays an essential role during such anticipation, particularly in sport expert performers. In the present study, we examined the influence of task-specific expertise on the AON by investigating differences between two expert groups trained in different sports while anticipating action effects. Altogether, 15 tennis and 16 volleyball experts anticipated the direction of observed tennis and volleyball serves while undergoing functional magnetic resonance imaging (fMRI. The expert group in each sport acted as novice controls in the other sport with which they had only little experience. When contrasting anticipation in both expertise conditions with the corresponding untrained sport, a stronger activation of AON areas (SPL, SMA, and particularly of cerebellar structures, was observed. Furthermore, the neural activation within the cerebellum and the SPL was linearly correlated with participant’s anticipation performance, irrespective of the specific expertise. For the SPL, this relationship also holds when an expert performs a domain-specific anticipation task. Notably, the stronger activation of the cerebellum as well as of the SMA and the SPL in the expertise conditions suggests that experts rely on their more fine-tuned perceptual-motor representations that have improved during years of training when anticipating the effects of others’ actions in their preferred sport. The association of activation within the SPL and the cerebellum with the task achievement suggests that these areas are the predominant brain sites involved in fast motor predictions. The SPL reflects the processing of domain-specific contextual information and the cerebellum the usage of a predictive internal model to

  6. Influence of Tennis Racquet Kinematics on Ball Topspin Angular Velocity and Accuracy during the Forehand Groundstroke.

    Science.gov (United States)

    Kwon, Sunku; Pfister, Robin; Hager, Ronald L; Hunter, Iain; Seeley, Matthew K

    2017-12-01

    Forehand groundstroke effectiveness is important for tennis success. Ball topspin angular velocity (TAV) and accuracy are important for forehand groundstroke effectiveness, and have been extensively studied, previously; despite previous, quality studies, it was unclear whether certain racquet kinematics relate to ball TAV and shot accuracy during the forehand groundstroke. This study evaluated potential relationships between (1) ball TAV and (2) forehand accuracy, and five measures of racquet kinematics: racquet head impact angle (i.e., closed or open face), horizontal and vertical racquet head velocity before impact, racquet head trajectory (resultant velocity direction, relative to horizontal) before impact, and hitting zone length (quasi-linear displacement, immediately before and after impact). Thirteen collegiate-level tennis players hit forehand groundstrokes in a biomechanics laboratory, where racquet kinematics and ball TAV were measured, and on a tennis court, to assess accuracy. Correlational statistics were used to evaluate potential relationships between racquet kinematics, and ball TAV (mixed model) and forehand accuracy (between-subjects model; α = 0.05). We observed an average (1) racquet head impact angle, (2) racquet head trajectory before impact, relative to horizontal, (3) racquet head horizontal velocity before impact, (4) racquet head vertical velocity before impact, and (5) hitting zone length of 80.4 ± 3.6˚, 18.6 ± 4.3˚, 15.4 ± 1.4 m·s -1 , 6.6 ± 2.2 m·s -1 , and 79.8 ± 8.6 mm, respectively; and an average ball TAV of 969 ± 375 revolutions per minute. Only racquet head impact angle and racquet head vertical velocity, before impact, significantly correlated with ball TAV (p < 0.01). None of the observed racquet kinematics significantly correlated to the measures of forehand accuracy. These results confirmed mechanical logic and indicate that increased ball TAV is associated with a more closed racquet head impact angle (ranging from

  7. Influence of Tennis Racquet Kinematics on Ball Topspin Angular Velocity and Accuracy during the Forehand Groundstroke

    Directory of Open Access Journals (Sweden)

    Sunku Kwon, Robin Pfister, Ronald L. Hager, Iain Hunter, Matthew K. Seeley

    2017-12-01

    Full Text Available Forehand groundstroke effectiveness is important for tennis success. Ball topspin angular velocity (TAV and accuracy are important for forehand groundstroke effectiveness, and have been extensively studied, previously; despite previous, quality studies, it was unclear whether certain racquet kinematics relate to ball TAV and shot accuracy during the forehand groundstroke. This study evaluated potential relationships between (1 ball TAV and (2 forehand accuracy, and five measures of racquet kinematics: racquet head impact angle (i.e., closed or open face, horizontal and vertical racquet head velocity before impact, racquet head trajectory (resultant velocity direction, relative to horizontal before impact, and hitting zone length (quasi-linear displacement, immediately before and after impact. Thirteen collegiate-level tennis players hit forehand groundstrokes in a biomechanics laboratory, where racquet kinematics and ball TAV were measured, and on a tennis court, to assess accuracy. Correlational statistics were used to evaluate potential relationships between racquet kinematics, and ball TAV (mixed model and forehand accuracy (between-subjects model; α = 0.05. We observed an average (1 racquet head impact angle, (2 racquet head trajectory before impact, relative to horizontal, (3 racquet head horizontal velocity before impact, (4 racquet head vertical velocity before impact, and (5 hitting zone length of 80.4 ± 3.6˚, 18.6 ± 4.3˚, 15.4 ± 1.4 m·s-1, 6.6 ± 2.2 m·s-1, and 79.8 ± 8.6 mm, respectively; and an average ball TAV of 969 ± 375 revolutions per minute. Only racquet head impact angle and racquet head vertical velocity, before impact, significantly correlated with ball TAV (p < 0.01. None of the observed racquet kinematics significantly correlated to the measures of forehand accuracy. These results confirmed mechanical logic and indicate that increased ball TAV is associated with a more closed racquet head impact angle (ranging

  8. Measurement issues in the sonographic assessment of tennis elbow.

    Science.gov (United States)

    Poltawski, Leon; Jayaram, Vijay; Watson, Tim

    2010-05-01

    Sonography is increasingly being used for assessment in tennis elbow research and clinical practice, but there are a lack of data regarding its validity, reliability, and responsiveness to change for this application. Studies using the modality were reviewed to establish current levels of evidence for these measurement properties. There is reasonable evidence regarding its validity for identifying tennis elbow tendinopathy, but a lack of data addressing its reliability and responsiveness. Practical issues affecting image quality are discussed, and recommendations for further investigation are suggested, to enhance the credible use of sonography with this debilitating condition.

  9. Expert ease

    Energy Technology Data Exchange (ETDEWEB)

    1984-04-01

    Expert-ease allows the most inexperienced of computer users to build an expert system in a matter of hours. It is nothing more or less than a computer based problem-solving system. It allows the expert to preserve his or her knowledge in the form of rules, which can be applied to problems put to the system by the non-expert. The crucial piece of software at the heart of Expert-Ease extracts rules from data, and is called the analogue concept learning system. It was developed by Intelligent Terminals Ltd. and supplied to Export Software International to be incorporated into a commercially attractive package for business users. The resulting product runs on the Act Sirius and the IBM PC and compatibles. It is a well conceived and polished product with a popular appeal that should ensure widespread acceptance even at a cost of >1500 plus vat.

  10. Tennis in hot and cool conditions decreases the rapid muscle torque production capacity of the knee extensors but not of the plantar flexors

    Science.gov (United States)

    Girard, Olivier; Racinais, Sébastien; Périard, Julien D

    2014-01-01

    Objectives To assess the time course of changes in rapid muscle force/torque production capacity and neuromuscular activity of lower limb muscles in response to prolonged (∼2 h) match-play tennis under heat stress. Methods The rates of torque development (RTD) and electromyographic activity (EMG; ie, root mean square) rise were recorded from 0 to 30, –50, –100 and –200 ms during brief (3–5 s) explosive maximal isometric voluntary contractions (MVC) of the knee extensors (KE) and plantar flexors (PF), along with the peak RTD within the entirety of the torque-time curve. These values were recorded in 12 male tennis players before (prematch) and after (postmatch, 24 and 48 h) match-play in HOT (∼37°C) and COOL (∼22°C) conditions. Results The postmatch core temperature was greater in the HOT (∼39.4°C) vs COOL (∼38.7°C) condition (ptorque. Furthermore, the rate of KE EMG activity rise remained unchanged. Conversely, the PF contractile RTD and rate of EMG activity rise were unaffected by the exercise or environmental conditions. Conclusions In the KE, a reduction in maximal torque production capacity following prolonged match-play tennis appears to account for the decrease in the rate of torque development, independent of environmental conditions, while remaining unchanged in the PF. PMID:24668381

  11. Scapular Resting Position and Gleno-Humeral Movement Dysfunction in Asymptomatic Racquet Players: A Case-Control Study.

    Science.gov (United States)

    Shimpi, Apurv P; Bhakti, Shah; Roshni, Karnik; Rairikar, Savita A; Shyam, Ashok; Sancheti, Parag K

    2015-12-01

    Racquet sports, especially lawn tennis and badminton have been gaining popularity in Asian countries like India. With this increase in popularity, the injury rate in the sport has also increased. The study will help detect the presence of gleno-humeral movement dysfunction and scapular resting position abnormality in asymptomatic racquet players, thus providing basis for screening the players and allow the clinician to determine if the asymmetry is a normal adaptation in the player or an abnormal change associated with injury. 46 asymptomatic professional players were divided into a study group of 23 players (16 tennis and 7 badminton) and control group of 23 football players. Assessment of passive gleno-humeral range of motion and distance of spine and inferior angle of scapula from corresponding spinous process were measured bilaterally and between groups. There was statistically significant reduction in range of internal rotation (62.17 ± 8.09), extension (39.78 ± 4.12) and an increase in the external rotation (106.95 ± 7.49) of dominant compared to non-dominant arm of racquet players and a statistically significant decrease in internal rotation (78.69 ± 10.24), extension (44.78 ± 3.19), adduction (37.39 ± 6.54) and an increase in external rotation (102.6 ± 5.19) of dominant arm of racquet players compared to football players. Study also showed statistically significant increase in the spino-scapular distance at the level of inferior angle of scapula (10.23 ± 1.43) on dominant side compared to non-dominant. The dominant side scapula of asymptomatic racquet players showed increased external rotation and elevation as compared to the non-dominant side. Also, reduced shoulder internal rotation, extension and adduction and gain in shoulder external rotation was observed on the dominant side of racquet players when compared to the control group.

  12. Standoffish perhaps, but successful as well: evidence that avoidant attachment can be beneficial in professional tennis and computer science.

    Science.gov (United States)

    Ein-Dor, Tsachi; Reizer, Abira; Shaver, Phillip R; Dotan, Eyal

    2012-06-01

    Attachment-related avoidance and anxiety have repeatedly been associated with poorer adjustment in various social, emotional, and behavioral domains. We examined 2 domains in which avoidant individuals might be better equipped than their less avoidant peers to succeed and be satisfied--professional singles tennis and computer science. These fields may reward self-reliance, independence, and the ability to work without proximal social support from loved ones. In study 1, we followed 58 professional singles tennis players for 16 months and found that scores on attachment-related avoidance predicted a higher ranking, above and beyond the contributions of training and coping resources. In study 2, we sampled 100 students and found that those who scored higher on avoidance were happier with their choice of computer science as a career than those who scored lower on avoidance. Results are discussed in relation to the possible adaptive functions of certain personality characteristics often viewed as undesirable. © 2011 The Authors. Journal of Personality © 2011, Wiley Periodicals, Inc.

  13. Effect of the racket mass and the rate of strokes on kinematics and kinetics in the table tennis topspin backhand.

    Science.gov (United States)

    Iino, Yoichi; Kojima, Takeji

    2016-01-01

    The purpose of this study was to investigate the effect of the racket mass and the rate of strokes on the kinematics and kinetics of the trunk and the racket arm in the table tennis topspin backhand. Eight male Division I collegiate table tennis players hit topspin backhands against topspin balls projected at 75 balls · min(-1) and 35 balls · min(-1) using three rackets varying in mass of 153.5, 176 and 201.5 g. A motion capture system was used to obtain trunk and racket arm motion data. The joint torques of the racket arm were determined using inverse dynamics. The racket mass did not significantly affect all the trunk and racket arm kinematics and kinetics examined except for the wrist dorsiflexion torque, which was significantly larger for the large mass racket than for the small mass racket. The racket speed at impact was significantly lower for the high ball frequency than for the low ball frequency. This was probably because pelvis and upper trunk axial rotations tended to be more restricted for the high ball frequency. The result highlights one of the advantages of playing close to the table and making the rally speed fast.

  14. Expert Witness

    African Journals Online (AJOL)

    Adele

    formal rules of evidence apply) to help it understand the issues of a case and ... statements on medical expert witness by professional representative bodies in .... determining the size of the financial settlement that may have to be made to the.

  15. Relative age effect on success in tennis competition in the older age-school children

    Directory of Open Access Journals (Sweden)

    Adrián Agricola

    2015-06-01

    Full Text Available BACKGROUND: The theory of relative age effect assumes that children and adolescents - athletes born at the beginning of the calendar year in sports competitions are more successful than those who were born in the later months of the same year. This percentage is based on advantage of fitness, morphological and psychological assumptions of the older athletes. AIM: The research objective of the present study was to verify the assumption of competitive success of older players in the elite boys and girls tennis groups in the older school age. METHODOLOGY: The data from groups of 13 year old boys and girls (13 years and 0 months to 13 years and 11 months were included into the analysis. These players were registered in the first one hundred ranking of International Tennis Federation (ITF according to the total number of ranking points in each year during the period 2007-2011 (500 boys, 500 girls. An ANOVA was used for analysis with a total ranking score as an indicator of competitive success with the age factor (12 levels = 12 months of birth (α = .05. The same analysis was used in sub-groups of boys, respectively girls, registered in ITF separately for each year of the period 2007-2011. Dates of birth of children were obtained from official sources of ITF. In the event of the significance factor of age we performed a simple regression analysis depending on the number of ITF points on the month of birth (p < .05. Analyses were processed in SPSS 21 software (IBM, USA. RESULTS: The analysis showed no significance of age, respective of the month of birth on the total number of points in a boys group (n = 500 (p = .624 and girls group (n = 500 (p = .152 from ITF ranking during five-year period. No significance was found in the boys' groups (n = 100, respective girls' groups (n = 100 registered in ITF ranking in each year of the five-year period. The exception was found only in a boys group in 2007 (p = .021, and significant regression relationship

  16. The Table Tennis Triathlon: An Integrated Sport Education Season

    Science.gov (United States)

    Buchanan, Alice M.; Barrow, Brook

    2016-01-01

    This article describes an integrated, 10-day unit that was designed using the sport education model in physical education. English language arts and social responsibility were integrated into a unit of table tennis in fifth-grade physical education. The student roles were adapted to best fit the needs of the unit. Through the integration of three…

  17. Tennis-Badminton-Squash Guide. June 1974-June 1976.

    Science.gov (United States)

    Sherman, Patricia, Ed.; And Others

    This guide is a collection of essays by various authors on tennis, badminton, and squash. The document is divided into three sections, one for each sport. The topics covered include general teaching methods, methods to employ for teaching specific skills such as the lob or the backhand, the use of visual aids, conditioning drills, study questions,…

  18. START TO PLAY TENNIS LIKE INCETIVE TO DEVELOPMENT SPORTS IN MONTENEGRO

    Directory of Open Access Journals (Sweden)

    Dimitrije Rašović

    2006-06-01

    Full Text Available At the end of 19 centuries tenis like popular game has srarted to play in Vojvodina. At 1880 tennis grassy courts was built in Senta and from that year it started to play in Vojvodina. Austrohungarion officers propageted tennis who were built tennis courts in their barracks but they was built courts in city parks. At 1892 the first tennis competition organised which mean that the first clubs probably had establishment befor thet year. Later at 1894 tennis started to play at palace of greand duke Nikola in Cetinje. Later tennis started to play in srbia at 1900. At that year people organised the first tennis tournament in vrsac. Momcilo Tapavica the first sout slovenion who was montegrion descent who was participat at first modern olimpic’s games in atina at 1896 he gave great countrabucsion developeted tennis sport in Montenegro. Momcilo Tapavica come to palase of graund duke’s Nikola at 1902 and ofter thet date his all family moved to Herceg-Novi and they spent all time to secound world war. At first olimpic’s games Momcilo Tapavica took parr in these sports/tennis, life weights, wrestling. Certain thet like talented sportman he gave great contabution not only in tennis than he gave contribution in the other sports in Montenegro.

  19. Influence of a mentoring through reflection program on the verbal behavior of tennis coach in a wheelchair high competition Influencia de un programa de supervisión reflexiva sobre la conducta verbal del entrenador de tenis en silla de ruedas de alta competición

    Directory of Open Access Journals (Sweden)

    D. Iglesias

    2010-09-01

    Full Text Available

    Our study deal with the teaching coaches process, applied to the adapted sport field, concretely to the wheelchair tennis of top level. From the literature revision and the collect of the expert opinion, we have designed a formative program in order to optimize the verbal behaviour coach during the training sessions. Concretely, we focus our research about the first information that the coach sends previously to each skill, and about the feedback gave after the execution by the player. The research design had three phases, the first one without the participation of the researcher, the second one where the researcher had a meeting with the coach to analyze everything succeded into the training session, and the third phase where the researcher recorded, only, the training session. Our research has been developed as a study of cases, with three coaches of players integrated into the national wheelchair tennis team, and related to the results we have contrasted the efficacy of the program about the coach verbal behaviour, increasing the number of first information with higher quality, and also the number of feedback, suggested by the experts as the most quality.
    KEY WORDS: Coaches formation, verbal behaviour; formative program, wheelchair tennis.

     

    Nuestro estudio se centra en los procesos formativos del entrenador deportivo, aplicándolo al ámbito del deporte adaptado, concretamente al tenis en silla de ruedas de alta competición. A partir de la revisión bibliográfica y la recogida de información de las opiniones de los expertos en el área, hemos diseñado un programa formativo para intentar optimizar la conducta verbal del entrenador durante las sesiones de entrenamiento. Concretamente, nos hemos centrado en la información inicial que el entrenador emite previa a cada tarea y en el feedback administrado tras la ejecución del deportista. El diseño de la

  20. A Comparison of the Perceptual and Technical Demands of Tennis Training, Simulated Match Play, and Competitive Tournaments.

    Science.gov (United States)

    Murphy, Alistair P; Duffield, Rob; Kellett, Aaron; Reid, Machar

    2016-01-01

    High-performance tennis environments aim to prepare athletes for competitive demands through simulated-match scenarios and drills. With a dearth of direct comparisons between training and tournament demands, the current investigation compared the perceptual and technical characteristics of training drills, simulated match play, and tournament matches. Data were collected from 18 high-performance junior tennis players (gender: 10 male, 8 female; age 16 ± 1.1 y) during 6 ± 2 drill-based training sessions, 5 ± 2 simulated match-play sessions, and 5 ± 3 tournament matches from each participant. Tournament matches were further distinguished by win or loss and against seeded or nonseeded opponents. Notational analysis of stroke and error rates, winners, and serves, along with rating of perceived physical exertion (RPE) and mental exertion was measured postsession. Repeated-measures analyses of variance and effect-size analysis revealed that training sessions were significantly shorter in duration than tournament matches (P training and simulated match-play sessions were lower than in tournaments (P > .05; d = 1.26, d = 1.05, respectively). Mental exertion in training was lower than in both simulated match play and tournaments (P > .05; d = 1.10, d = 0.86, respectively). Stroke rates during tournaments exceeded those observed in training (P .05, d Training in the form of drills or simulated match play appeared to inadequately replicate tournament demands in this cohort of players. Coaches should be mindful of match demands to best prescribe sessions of relevant duration, as well as internal (RPE) and technical (stroke rate) load, to aid tournament preparation.

  1. The Effects of External Focus of Attention on Shoulder Muscle Activities during Forehand Drive in Table Tennis

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Hatami

    2016-06-01

    Full Text Available Objective: The aim of this study was to evaluate the impact of the external focus of attention on the rotator cuff muscle activity for the timely hit forehand drive by table tennis players. Methods: Twelve professional table tennis players with mean age of 26.5 years voluntarily participated in this study. The electrical activities of the muscles of the shoulder girdle using M.A 300 machine and bipolar electrodes surface under two conditions .First with external focus of attention and then without such attention were recorded, first without any guidance blows forehand drive was carried out by subjects (without focus. Then such subject was asked to focus their attention on the area marked for the ball landing (external focus of attention.      Muscle activities in both preparation and tapping phases were analyzed the three –dimensional (200 Hz, Vicon, with four camera series T motion analysis system was used to obtain the data. Data was analyzed by running reported measures ANOVA at a significance level of p0.05 but the different between the intensity of muscle activity was meaningful. This suggests that there is a mutual influence between the two attention factors and muscles (p=0.03, that is, orientation can have a significant effect on the severity of muscle contraction. Intensities of muscle contraction in the preparation and tapping were different (p<0.05. Conclusion: On the forehand drive technique, the anterior deltoid muscle has the most activity. The type of focus and attention had a significant impact on the change of activity of muscles relative to each other, and the greatest impact is on the reduction of activity of the infraspinatus muscle. This type of focus delays fatigue and results in an increase in the efficiency of neuromuscular in the activities of skills.

  2. 3D technology of Sony Bloggie has no advantage in decision-making of tennis serve direction: A randomized placebo-controlled study.

    Science.gov (United States)

    Liu, Sicong; Ritchie, Jason; Sáenz-Moncaleano, Camilo; Ward, Savanna K; Paulsen, Cody; Klein, Tyler; Gutierrez, Oscar; Tenenbaum, Gershon

    2017-06-01

    This study aimed at exploring whether 3D technology enhances tennis decision-making under the conceptual framework of human performance model. A 3 (skill-level: varsity, club, recreational) × 3 (experimental condition: placebo, weak 3D [W3D], strong 3D [S3D]) between-participant design was used. Allocated to experimental conditions by a skill-level stratified randomization, 105 tennis players judged tennis serve direction from video scenarios and rated their perceptions of enjoyment, flow, and presence during task performance. Results showed that varsity players made more accurate decisions than less skilled ones. Additionally, applying 3D technology to typical video displays reduced tennis players' decision-making accuracy, although wearing the 3D glasses led to a placebo effect that shortened the decision-making reaction time. The unexpected negative effect of 3D technology on decision-making was possibly due to participants being more familiar to W3D than to S3D, and relatedly, a suboptimal task-technology match. Future directions for advancing this area of research are offered. Highlights 3D technology augments binocular depth cues to tradition video displays, and thus results in the attainment of more authentic visual representation. This process enhances task fidelity in researching perceptual-cognitive skills in sports. The paper clarified both conceptual and methodological difficulties in testing 3D technology in sports settings. Namely, the nomenclature of video footage (with/without 3D technology) and the possible placebo effect (arising from wearing glasses of 3D technology) merit researchers' attention. Participants varying in level of domain-specific expertise were randomized into viewing conditions using a placebo-controlled design. Measurement consisted of both participants' subjective experience (i.e., presence, flow, and enjoyment) and objective performance (i.e., accuracy and reaction time) in a decision-making task. Findings revealed that

  3. Personality of Elite Male and Female Chess Players and Its Relation to Chess Skill

    Science.gov (United States)

    Vollstadt-Klein, Sabine; Grimm, Oliver; Kirsch, Peter; Bilalic, Merim

    2010-01-01

    Whereas a lot of studies examine cognitive processes in chess players, personality profiles of elite chess players are still not described well. The aim of this study was to examine personality of strong chess experts and its influence on chess skill. We tested elite male and female chess players with Freiburg Personality Inventory Revised…

  4. The development of a methodology to determine the relationship in grip size and pressure to racket head speed in a tennis forehand stroke

    DEFF Research Database (Denmark)

    Christensen, Jonas; Rasmussen, John; Halkon, Ben

    2016-01-01

    and kinematic contribution of the body segments in the upper trunk translational and angular velocities. Two Babolat Pure Storm GT rackets, with grip sizes 2 and 4 respectively, were used with Tekscan 9811E pressure sensors applied to the handles to examine pressure distribution during the stroke. Upper body...... kinematic data taken from the racket arm and trunk were obtained by means of a Vicon motion capture system. One elite male tennis player was recruited. Fifty topspin forehand strokes per grip at two nominal grip pressures were performed in a laboratory environment with balls being tossed towards the player...... joint and wrist joint in KCAV across grip conditions. Grip pressure for grip size 2 showed the same pattern across gripping conditions. From 50-75% of completion in forward swing, the pressure difference due to grip firmness decreased. This feasibility study managed to quantify the KCAV while performing...

  5. Expert Baseball Batters Have Greater Sensitivity in Making Swing Decisions

    Science.gov (United States)

    Gray, Rob

    2010-01-01

    This study used signal detection theory to conceptualize the problem a baseball batter faces when deciding whether or not to swing at a pitch. It examined the launch angle (LA) criteria used by expert (college players) and less experienced (recreational league players) batters using a baseball batting simulation. This study showed that, although…

  6. Information encryption in the expert management of strategic uncertainty

    OpenAIRE

    Frey, Seth; Williams, Paul L.; Albino, Dominic K.

    2016-01-01

    Strategic agents in incomplete-information environments have a conflicted relationship with uncertainty: it can keep them unpredictable to their opponents, but it must also be overcome to predict the actions of those opponents. We use a multivariate generalization of information theory to characterize the information processing behavior of strategic reasoning experts. We compare expert and novice poker players --- "sharks" and "fish" --- over 1.75 million hands of online two-player No-Limit T...

  7. The Perception of Leader Behaviors upon the Satisfaction of College Tennis Players

    Science.gov (United States)

    Adams, Orville Moses

    2009-01-01

    During the past 30 years, the discipline of Leadership Studies has pervaded several academic domains including business management. Recently, leadership theory has been applied to sports management. The current study sought to inform this line of inquiry and was based on Chelladurai (1979), multidimensional model of leadership. The purpose of the…

  8. The state of emotional tension of tennis sportswomen-players of high qualification

    Directory of Open Access Journals (Sweden)

    Uliz'ko V.M.

    2010-06-01

    Full Text Available An analysis and distributing of sportswomen is presented to on by the degree of expressed a personality and situation anxiety. 40 sportswomen took part in research. The psychophysiological functional state of man is studied in the conditions of high psychoemotional tension. The features of psychological mood are examined taking into account personality descriptions of every sportsman. Sporting achievement is the result of cooperation of external (financial, material and internal (attitude toward trainings, presence of genetic preconditions factors. External factors are mediated influence on success and cause for a sportsman the subjective states with the proper conduct.

  9. Expert Systems: What Is an Expert System?

    Science.gov (United States)

    Duval, Beverly K.; Main, Linda

    1994-01-01

    Describes expert systems and discusses their use in libraries. Highlights include parts of an expert system; expert system shells; an example of how to build an expert system; a bibliography of 34 sources of information on expert systems in libraries; and a list of 10 expert system shells used in libraries. (Contains five references.) (LRW)

  10. Pictorial essay: Ultrasonography in ′tennis leg′

    Directory of Open Access Journals (Sweden)

    Shah Jeshil

    2010-01-01

    Full Text Available Tennis leg is caused by a rupture of the medial head of the gastrocnemius muscle, usually at its distal musculotendinous junction region. However, tears in this muscle and its tendon are also included under the term ′tennis leg′. It is seen regularly in practice and is an important cause of a painful calf. The common USG findings include: disruption of the pinnate pattern of the distal medial gastrocnemius, usually near the junction of the triceps surae (which is the echogenic line between the gastrocnemius, the soleus, and the plantaris muscles, fluid tracking along the fascia, adjacent hematoma, and intramuscular tears as well as hematomas. USG is useful for confirming the diagnosis, excluding other causes of a painful calf, for assessing the severity of the disease, and in follow-up.

  11. Pictorial essay: Ultrasonography in ‘tennis leg’

    Science.gov (United States)

    Shah, Jeshil R; Shah, Bipin R; Shah, Ankit B

    2010-01-01

    Tennis leg is caused by a rupture of the medial head of the gastrocnemius muscle, usually at its distal musculotendinous junction region. However, tears in this muscle and its tendon are also included under the term ‘tennis leg’. It is seen regularly in practice and is an important cause of a painful calf. The common USG findings include: disruption of the pinnate pattern of the distal medial gastrocnemius, usually near the junction of the triceps surae (which is the echogenic line between the gastrocnemius, the soleus, and the plantaris muscles), fluid tracking along the fascia, adjacent hematoma, and intramuscular tears as well as hematomas. USG is useful for confirming the diagnosis, excluding other causes of a painful calf, for assessing the severity of the disease, and in follow-up. PMID:21577246

  12. Internal and External Imagery Effects on Tennis Skills Among Novices.

    Science.gov (United States)

    Dana, Amir; Gozalzadeh, Elmira

    2017-10-01

    The purpose of this study was to determine the effects of internal and external visual imagery perspectives on performance accuracy of open and closed tennis skills (i.e., serve, forehand, and backhand) among novices. Thirty-six young male novices, aged 15-18 years, from a summer tennis program participated. Following initial skill acquisition (12 sessions), baseline assessments of imagery ability and imagery perspective preference were used to assign participants to one of three groups: internal imagery ( n = 12), external imagery ( n = 12), or a no-imagery (mental math exercise) control group ( n = 12). The experimental interventions of 15 minutes of mental imagery (internal or external) or mental math exercises followed by 15 minutes of physical practice were held three times a week for six weeks. The performance accuracy of the groups on the serve, forehand, and backhand strokes was measured at pre- and post-test using videotaping. Results showed significant increases in the performance accuracy of all three tennis strokes in all three groups, but serve accuracy in the internal imagery group and forehand accuracy in the external imagery group showed greater improvements, while backhand accuracy was similarly improved in all three groups. These findings highlight differential efficacy of internal and external visual imagery for performance improvement on complex sport skills in early stage motor learning.

  13. Cost effectiveness of brace, physiotherapy, or both for treatment of tennis elbow

    NARCIS (Netherlands)

    Struijs, P. A. A.; Korthals-de Bos, I. B. C.; van Tulder, M. W.; van Dijk, C. N.; Bouter, L. M.; Assendelft, W. J. J.

    2006-01-01

    BACKGROUND: The annual incidence of tennis elbow in the general population is high (1-3%). Tennis elbow often leads to limitation of activities of daily living and work absenteeism. Physiotherapy and braces are the most common treatments. OBJECTIVES: The hypothesis of the trial was that no

  14. The predictive value of the extensor grip test for the effectiveness of bracing for tennis elbow

    NARCIS (Netherlands)

    Struijs, Peter A. A.; Assendelft, Willem J. J.; Kerkhoffs, Gino M. M. J.; Souer, Sebastiaan; van Dijk, C. Niek

    2005-01-01

    Background: Tennis elbow is a common complaint. Several treatment strategies, such as corticosteroid injections and physical therapy and braces, have been described. Hypothesis: The extensor grip test has predictive value in assessing the effectiveness of bracing in tennis elbow. Study Design:

  15. Corticosteroid injection for tennis elbow or lateral epicondylitis: a review of the literature

    OpenAIRE

    Saccomanni, Bernardino

    2010-01-01

    Lateral epicondylitis or tennis elbow is a painful and functionally limiting entity affecting the upperextremity and is frequently treated by hand surgeons. Corticosteroid injection is one of the most common interventions for lateral epicondylitis or tennis elbow. Here, a review of the medical literature on this treatment is presented.

  16. Tennis-Badminton-Squash Guide with Official Rules. June 1972 - June 1974.

    Science.gov (United States)

    Knight, Martha, Ed.; And Others

    Rules in tennis, badminton, and squash for girls and women from June 1972 - June 1974 are discussed. Standards in the sports are detailed along with the Division for Girls and Women's Sports (DGWS) statement of beliefs. Specific articles dealing with teaching techniques, officiating techniques, and rules for tennis and badminton are presented.…

  17. Assessing personal talent determinants in young racquet sport players: a systematic review.

    Science.gov (United States)

    Faber, Irene R; Bustin, Paul M J; Oosterveld, Frits G J; Elferink-Gemser, Marije T; Nijhuis-Van der Sanden, Maria W G

    2016-01-01

    Since junior performances have little predictive value for future success, other solutions are sought to assess a young player's potential. The objectives of this systematic review are (1) to provide an overview of instruments measuring personal talent determinants of young players in racquet sports, and (2) to evaluate these instruments regarding their validity for talent development. Electronic searches were conducted in PubMed, PsychINFO, Web of Knowledge, ScienceDirect and SPORTDiscus (1990 to 31 March 2014). Search terms represented tennis, table tennis, badminton and squash, the concept of talent, methods of testing and children. Thirty articles with information regarding over 100 instruments were included. Validity evaluation showed that instruments focusing on intellectual and perceptual abilities, and coordinative skills discriminate elite from non-elite players and/or are related to current performance, but their predictive validity is not confirmed. There is moderate evidence that the assessments of mental and goal management skills predict future performance. Data on instruments measuring physical characteristics prohibit a conclusion due to conflicting findings. This systematic review yielded an ambiguous end point. The lack of longitudinal studies precludes verification of the instrument's capacity to forecast future performance. Future research should focus on instruments assessing multidimensional talent determinants and their predictive value in longitudinal designs.

  18. Cross-cultural adaptation and validation of the Patient-Rated Tennis Elbow Evaluation Questionnaire on lateral elbow tendinopathy for French-speaking patients.

    Science.gov (United States)

    Kaux, Jean-François; Delvaux, François; Schaus, Jean; Demoulin, Christophe; Locquet, Médéa; Buckinx, Fanny; Beaudart, Charlotte; Dardenne, Nadia; Van Beveren, Julien; Croisier, Jean-Louis; Forthomme, Bénédicte; Bruyère, Olivier

    Translation and validation of algo-functional questionnaire. The lateral elbow tendinopathy is a common injury in tennis players and physical workers. The Patient-Rated Tennis Elbow Evaluation (PRTEE) Questionnaire was specifically designed to measure pain and functional limitations in patients with lateral epicondylitis (tennis elbow). First developed in English, this questionnaire has since been translated into several languages. The aims of the study were to translate and cross-culturally adapt the PRTEE questionnaire into French and to evaluate the reliability and validity of this translated version of the questionnaire (PRTEE-F). The PRTEE was translated and cross-culturally adapted into French according to international guidelines. To assess the reliability and validity of the PRTEE-F, 115 participants were asked twice to fill in the PRTEE-F, and once the Disabilities of Arm, Shoulder and Hand Questionnaire (DASH) and the Short Form Health Survey (SF-36). Internal consistency (using Cronbach's alpha), test-retest reliability (using intraclass correlation coefficient (ICC), standard error of measurement and minimal detectable change), and convergent and divergent validity (using the Spearman's correlation coefficients respectively with the DASH and with some subscales of the SF-36) were assessed. The PRTEE was translated into French without any problems. PRTEE-F showed a good test-retest reliability for the overall score (ICC 0.86) and for each item (ICC 0.8-0.96) and a high internal consistency (Cronbach's alpha = 0.98). The correlation analyses revealed high correlation coefficients between PRTEE-F and DASH (convergent validity) and, as expected, a low or moderate correlation with the divergent subscales of the SF-36 (discriminant validity). There was no floor or ceiling effect. The PRTEE questionnaire was successfully cross-culturally adapted into French. The PRTEE-F is reliable and valid for evaluating French-speaking patients with lateral elbow

  19. Le tennis dans le monde: état et prospective

    Directory of Open Access Journals (Sweden)

    Pierre DUMOLARD

    1989-06-01

    Full Text Available Le tennis est peu ou prou pratiqué dans tous les pays du monde, mais avec de considérables variations d'intensité. Actuellement, ses points d'ancrage se situent dans les pays développés occidentaux et dans l'ancienne sphère d'influence britannique. En tenant compte de l'évolution démographique et économique possible des nations, des projections de pénétration de ce sport sont établies pour l'horizon 2000.

  20. Investigation on Suitability of Natural Fibre as Replacement Material for Table Tennis Blade

    Science.gov (United States)

    Arifin, A. M. T.; Fahrul Hassan, M.; Ismail, A. E.; Zulafif Rahim, M.; Rasidi Ibrahim, M.; Haq, R. H. Abdul; Rahman, M. N. A.; Yunos, M. Z.; Amin, M. H. M.

    2017-08-01

    This paper presents an investigation of suitability natural fibre as replacement material for table tennis blade, due to low cost, lightweight and apparently environmentally. Nowadays, natural fibre are one of the materials often used in replaced the main material on manufacturing sector, such as automotive, and construction. The objective of this study is to investigate and evaluate the suitability natural fiber materials to replace wood as a structure on table tennis blade. The mechanical properties of the different natural fibre material were examined, and correlated with characteristic of table tennis blade. The natural fibre selected for the study are kenaf (Hibiscus Cannabinus), jute, hemp, sisal (Agave Sisalana) and ramie. A further comparison was made with the corresponding properties of each type of natural fiber using Quality Function Deployment (QFD) and Theory of Inventive Problem Solving (TRIZ). TRIZ has been used to determine the most appropriate solution in producing table tennis blade. The results showed the most appropriate solution in producing table tennis blade using natural fibre is kenaf natural fibre. The selected on suitability natural fibre used as main structure on table tennis blade are based on the characteristics need for good performance of table tennis blade, such as energy absorption, lightweight, strength and hardness. Therefore, it shows an opportunity for replacing existing materials with a higher strength, lower cost alternative that is environmentally friendly.

  1. The Sport Expert's Attention Superiority on Skill-related Scene Dynamic by the Activation of left Medial Frontal Gyrus: An ERP and LORETA Study.

    Science.gov (United States)

    He, Mengyang; Qi, Changzhu; Lu, Yang; Song, Amanda; Hayat, Saba Z; Xu, Xia

    2018-05-21

    Extensive studies have shown that a sports expert is superior to a sports novice in visually perceptual-cognitive processes of sports scene information, however the attentional and neural basis of it has not been thoroughly explored. The present study examined whether a sport expert has the attentional superiority on scene information relevant to his/her sport skill, and explored what factor drives this superiority. To address this problem, EEGs were recorded as participants passively viewed sport scenes (tennis vs. non-tennis) and negative emotional faces in the context of a visual attention task, where the pictures of sport scenes or of negative emotional faces randomly followed the pictures with overlapping sport scenes and negative emotional faces. ERP results showed that for experts, the evoked potential of attentional competition elicited by the overlap of tennis scene was significantly larger than that evoked by the overlap of non-tennis scene, while this effect was absent for novices. The LORETA showed that the experts' left medial frontal gyrus (MFG) cortex was significantly more active as compared to the right MFG when processing the overlap of tennis scene, but the lateralization effect was not significant in novices. Those results indicate that experts have attentional superiority on skill-related scene information, despite intruding the scene through negative emotional faces that are prone to cause negativity bias toward their visual field as a strong distractor. This superiority is actuated by the activation of left MFG cortex and probably due to self-reference. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Analysis of Experts’ Quantitative Assessment of Adolescent Basketball Players and the Role of Anthropometric and Physiological Attributes

    Directory of Open Access Journals (Sweden)

    Štrumbelj Erik

    2014-10-01

    Full Text Available In this paper, we investigated two questions: (1 can measurements of anthropometric and physiological attributes substitute for expert assessment of adolescent basketball players, and (2 how much does the quantitative assessment of a player vary among experts? The first question is relevant to the potential simplification of the player selection process. The second question pertains directly to the validity of expert quantitative assessment. Our research was based on data from 148 U14 female and male basketball players. For each player, an array of anthropometric and physiological attributes was recorded, including body height, body mass, BMI, and several motor skill tests. Furthermore, each player's current ability and potential ability were quantitatively evaluated by two different experts from a group of seven experts. Analysis of the recorded data showed that the anthropometric and physiological attributes explained between 15% and 40% of the variance in experts’ scores. The primary predictive attributes were speed and agility (for predicting current ability and body height and growth potential (for predicting potential ability. We concluded that these attributes were not sufficiently informative to act as a substitute for expert assessment of the players’ current or potential ability. There is substantial variability in different experts' scores of the same player’s ability. However, the differences between experts are mostly in scale, and the relationships between experts’ scores are monotonic. That is, different experts rank players on ability very similarly, but their scores are not well calibrated.

  3. Long term results in refractory tennis elbow using autologous blood.

    Science.gov (United States)

    Gani, Naseem Ul; Khan, Hayat Ahmad; Kamal, Younis; Farooq, Munir; Jeelani, Hina; Shah, Adil Bashir

    2014-10-27

    Tennis elbow (TE) is one of the commonest myotendinosis. Different treatment options are available and autologous blood injection has emerged as the one of the acceptable modalities of treatment. Long term studies over a larger group of patients are however lacking. The purpose of this study was to evaluate these patients on longer durations. One-hundred and twenty patients of TE, who failed to respond to conventional treatment including local steroid injections were taken up for this prospective study over the period from year 2005 to 2011 and were followed up for the minimum of 3 years (range 3-9 years). Two mL of autologous blood was taken from the ipsilateral limb and injected into the lateral epicondyle. The effectiveness of the procedure was assessed by Pain Rating Sscale and Nirschl Staging, which was monitored before the procedure, at first week, monthly for first three months, at 6 months and then 3 monthly for first year, six monthly for next 2 years and then yearly. Statistical analysis was done and a P value of tennis elbow should be made as there is lot of controversy regarding the treatment.

  4. A Newly Designed Tennis Elbow Orthosis With a Traditional Tennis Elbow Strap in Patients With Lateral Epicondylitis

    Science.gov (United States)

    Saremi, Hossein; Chamani, Vahid; Vahab-Kashani, Reza

    2016-01-01

    Background Lateral epicondylitis is a common cause of pain and upper limb dysfunction. The use of counterforce straps for treatment of lateral epicondylitis is widespread. This kind of orthosis can be modified to have a greater effect on relieving pain by reducing tension on the origin of the extensor pronator muscles. Objectives To determine the immediate effects of a newly designed orthosis on pain and grip strength in patients with lateral epicondylitis. Materials and Methods Twelve participants (six men and six women) were recruited (mean age = 41 ± 6.7 years) and evaluated for pain and grip strength in three sessions. A 48-hour break was taken between each session. The first session was without any orthosis, the second session was with the new modified tennis elbow orthosis, and the third session was with a conventional tennis elbow strap. Results Both counterforce straps were effective. However, significantly more improvement was observed in pain and grip strength after using the newly modified orthosis (P < 0.05). Conclusions The newly designed strap reduces pain more effectively and improves grip strength by causing greater localized pressure on two regions with different force applications (two component vectors versus one). PMID:28180116

  5. A Newly Designed Tennis Elbow Orthosis With a Traditional Tennis Elbow Strap in Patients With Lateral Epicondylitis.

    Science.gov (United States)

    Saremi, Hossein; Chamani, Vahid; Vahab-Kashani, Reza

    2016-07-01

    Lateral epicondylitis is a common cause of pain and upper limb dysfunction. The use of counterforce straps for treatment of lateral epicondylitis is widespread. This kind of orthosis can be modified to have a greater effect on relieving pain by reducing tension on the origin of the extensor pronator muscles. To determine the immediate effects of a newly designed orthosis on pain and grip strength in patients with lateral epicondylitis. Twelve participants (six men and six women) were recruited (mean age = 41 ± 6.7 years) and evaluated for pain and grip strength in three sessions. A 48-hour break was taken between each session. The first session was without any orthosis, the second session was with the new modified tennis elbow orthosis, and the third session was with a conventional tennis elbow strap. Both counterforce straps were effective. However, significantly more improvement was observed in pain and grip strength after using the newly modified orthosis (P < 0.05). The newly designed strap reduces pain more effectively and improves grip strength by causing greater localized pressure on two regions with different force applications (two component vectors versus one).

  6. The architecture of the chess player's brain.

    Science.gov (United States)

    Hänggi, Jürgen; Brütsch, Karin; Siegel, Adrian M; Jäncke, Lutz

    2014-09-01

    The game of chess can be seen as a typical example for an expertise task requiring domain-specific training and experience. Despite intensive behavioural studies the neural underpinnings of chess performance and expertise are not entirely understood. A few functional neuroimaging studies have shown that expert chess players recruit different psychological functions and activate different brain areas while they are engaged in chess-related activities. Based on this functional literature, we predicted to find morphological differences in a network comprised by parietal and frontal areas and especially the occipito-temporal junction (OTJ), fusiform gyrus, and caudate nucleus. Twenty expert chess players and 20 control subjects were investigated using voxel-based and surface-based morphometry as well as diffusion tensor imaging. Grey matter volume and cortical thickness were reduced in chess players compared with those of control men in the OTJ and precunei. The volumes of both caudate nuclei were not different between groups, but correlated inversely with the years of chess playing experience. Mean diffusivity was increased in chess players compared with that of controls in the left superior longitudinal fasciculus and the Elo score (a chess tournament ranking) was inversely related to mean diffusivity within the right superior longitudinal fasciculus. To the best of our knowledge we showed for the first time that there are specific differences in grey and white matter morphology between chess players and control subjects in brain regions associated with cognitive functions important for playing chess. Whether these anatomical alterations are the cause or consequence of the intensive and long-term chess training and practice remains to be shown in future studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. AN IMPLEMENTATION OF VIBRATION-BASED AUTOMATIC SCORE-KEEPING SYSTEM FOR TABLE TENNIS GAME

    Directory of Open Access Journals (Sweden)

    Erdem YAVUZ

    2014-01-01

    Full Text Available In sport tournaments human factor plays an important role to evaluate the game. Table tennis is an example of this kind of sports. In order to avoid erroneous human decisions and to enhance referees’ decisions an automatic score-keeping system for table tennis game is designed and implemented with low cost vibration sensors attached underside of the tennis table. The purpose of using vibration sensors is to detect ball colliding with the surface. An additional vibration sensor is also used to detect ball touching the net, determining let state in the game. Petri net scheme is used to model the operation of the system, making it easy to visualize its operation. We believe that the proposed system will contribute much to better evaluate the various phases of table tennis games and to aid the referees to make better decisions.

  8. Key players must help shatter the glass ceiling, say experts.

    Science.gov (United States)

    Eubanks, P

    1991-10-05

    Women are continuing to move up through the management pipeline in hospitals across the country; but is top management prepared? Although many women are aiming for the highest levels in management, a recent survey of female and male health care executives indicates that critical changes must be made by top management and boards of hospitals before those women can continue to advance accordingly. Meanwhile, women's experience as senior executives has been quite different from men's, the survey also shows.

  9. Video Game Player Profiles: Bridging Industry, Game Studies and Social Science Perspectives

    Science.gov (United States)

    Frye, Jonathan M.

    2013-01-01

    For decades, game designers and game studies experts have largely sought to understand video game players through a lens of experience and observation. Meanwhile, social science research has focused on the empirical understanding of video game players using a variety of psychological constructs. This study focuses on the creation and evaluation of…

  10. Computational intelligence for qualitative coaching diagnostics: Automated assessment of tennis swings to improve performance and safety

    OpenAIRE

    Bačić, Boris; Hume, Patria

    2017-01-01

    Coaching technology, wearables and exergames can provide quantitative feedback based on measured activity, but there is little evidence of qualitative feedback to aid technique improvement. To achieve personalised qualitative feedback, we demonstrated a proof-of-concept prototype combining kinesiology and computational intelligence that could help improving tennis swing technique. Three-dimensional tennis motion data were acquired from multi-camera video (22 backhands and 21 forehands, includ...

  11. Rectus abdominis muscle injuries in elite handball players: management and rehabilitation

    Science.gov (United States)

    Balius, Ramon; Pedret, Carles; Pacheco, Laura; Gutierrez, Josep Antoni; Vives, Joan; Escoda, Jaume

    2011-01-01

    Muscle injuries generally occur in two-joint muscles with a high percentage of type II fibers during the performance of eccentric activity. Some muscle injuries, such as those located in the adductor longus, a monoarticular muscle, as well as rectus abdominis do not fully comply with these requirements. This study examines five cases of elite handball players with ruptured rectus abdominals. Sonographically, lesions in rectus abdominis are shown as a disruption of the fibrillar pattern with a hematic suffusion that invades the entire lesion. In some of the cases, the ultrasound study was complemented with a MRI. A unified rehabilitation protocol was applied and the return to play time of each handball player ranged between 16 and 22 days, with an average of 18.2 days. Follow-up at 15 months showed no evidence of re-injury or residual discomfort and all of them are playing at their highest level. The aim of this study was to illustrate a feature of handball injury that, as in tennis and volleyball, is uncommon and so far has not been specifically reported. The phenomenon of contralateral abdominal hypertrophy in handball appears in the dominant arm as in tennis and volleyball. PMID:24198573

  12. Reliability of sonographic assessment of tendinopathy in tennis elbow.

    Science.gov (United States)

    Poltawski, Leon; Ali, Syed; Jayaram, Vijay; Watson, Tim

    2012-01-01

    To assess the reliability and compute the minimum detectable change using sonographic scales to quantify the extent of pathology and hyperaemia in the common extensor tendon in people with tennis elbow. The lateral elbows of 19 people with tennis elbow were assessed sonographically twice, 1-2 weeks apart. Greyscale and power Doppler images were recorded for subsequent rating of abnormalities. Tendon thickening, hypoechogenicity, fibrillar disruption and calcification were each rated on four-point scales, and scores were summed to provide an overall rating of structural abnormality; hyperaemia was scored on a five point scale. Inter-rater reliability was established using the intraclass correlation coefficient (ICC) to compare scores assigned independently to the same set of images by a radiologist and a physiotherapist with training in musculoskeletal imaging. Test-retest reliability was assessed by comparing scores assigned by the physiotherapist to images recorded at the two sessions. The minimum detectable change (MDC) was calculated from the test-retest reliability data. ICC values for inter-rater reliability ranged from 0.35 (95% CI: 0.05, 0.60) for fibrillar disruption to 0.77 (0.55, 0.88) for overall greyscale score, and 0.89 (0.79, 0.95) for hyperaemia. Test-retest reliability ranged from 0.70 (0.48, 0.84) for tendon thickening to 0.82 (0.66, 0.90) for overall greyscale score and 0.86 (0.73, 0.93) for calcification. The MDC for the greyscale total score was 2.0/12 and for the hyperaemia score was 1.1/5. The sonographic scoring system used in this study may be used reliably to quantify tendon abnormalities and change over time. A relatively inexperienced imager can conduct the assessment and use the rating scales reliably.

  13. Decreased Brain Neurokinin-1 Receptor Availability in Chronic Tennis Elbow.

    Science.gov (United States)

    Linnman, Clas; Catana, Ciprian; Svärdsudd, Kurt; Appel, Lieuwe; Engler, Henry; Långström, Bengt; Sörensen, Jens; Furmark, Tomas; Fredrikson, Mats; Borsook, David; Peterson, Magnus

    Substance P is released in painful and inflammatory conditions, affecting both peripheral processes and the central nervous system neurokinin 1 (NK1) receptor. There is a paucity of data on human brain alterations in NK1 expression, how this system may be affected by treatment, and interactions between central and peripheral tissue alterations. Ten subjects with chronic tennis elbow (lateral epicondylosis) were selected out of a larger (n = 120) randomized controlled trial evaluating graded exercise as a treatment for chronic tennis elbow (lateral epicondylosis). These ten subjects were examined by positron emission tomography (PET) with the NK1-specific radioligand 11C-GR205171 before, and eight patients were followed up after treatment with graded exercise. Brain binding in the ten patients before treatment, reflecting NK1-receptor availability (NK1-RA), was compared to that of 18 healthy subjects and, longitudinally, to the eight of the original ten patients that agreed to a second PET examination after treatment. Before treatment, patients had significantly lower NK1-RA in the insula, vmPFC, postcentral gyrus, anterior cingulate, caudate, putamen, amygdala and the midbrain but not the thalamus and cerebellum, with the largest difference in the insula contralateral to the injured elbow. No significant correlations between brain NK1-RA and pain, functional severity, or peripheral NK1-RA in the affected limb were observed. In the eight patients examined after treatment, pain ratings decreased in everyone, but there were no significant changes in NK1-RA. These findings indicate a role for the substance P (SP) / NK1 receptor system in musculoskeletal pain and tissue healing. As neither clinical parameters nor successful treatment response was reflected in brain NK1-RA after treatment, this may reflect the diverse function of the SP/NK1 system in CNS and peripheral tissue, or a change too small or slow to capture over the three-month treatment.

  14. Management of Tennis Elbow with sodium hyaluronate periarticular injections

    Directory of Open Access Journals (Sweden)

    Petrella Robert J

    2010-02-01

    Full Text Available Abstract Objectives To determine the efficacy and safety of peri-articular hyaluronic acid injections in chronic lateral epicondylosis (tennis elbow. Design Prospective randomized clinical trial in primary care sport medicine. Patients Three hundred and thirty one consecutive competitive racquette sport athletes with chronic (>3 months lateral epicondylosis were administered 2 injections (first injection at baseline into the subcutaneous tissue and muscle 1 cm. from the lateral epicondyle toward the primary point of pain using a two-dimensional fanning technique. A second injection was administered 1 week later. Outcomes measures Assessments were done at baseline, days 7, 14, 30, 90 and 356. Efficacy measures included patient's visual analogue scale (VAS of pain at rest (0-100 mm and following assessment of grip strength (0-100 mm. Grip strength was determined using a jamar hydraulic hand dynamometer. Other assessments included patients' global assessment of elbow injury (5 point categorical scale; 1 = no disability, 5 = maximal disability, patients' assessment of normal function/activity (5 point categorical scale, patients/physician satisfaction assessment (10 point categorical scale, time to return to pain-free and disability-free sport and adverse events as per WHO definition. Differences between groups were determined using an intent-to-treat ANOVA. Results Average age of the study population was 49 years (± 12 years. One hundred and sixty-five patients were randomized to the HA and 166 were randomized to the control groups. The change in VAS pain was -6.7 (± 2.0 for HA vs -1.3 (± 1.5 for control (p Conclusion Peri-articular HA treatment for tennis elbow was significantly better than control in improving pain at rest and after maximal grip testing. Further, HA treatment was highly satisfactory by patients and physicians and resulted in better return to pain free sport compared to control.

  15. Decreased Brain Neurokinin-1 Receptor Availability in Chronic Tennis Elbow.

    Directory of Open Access Journals (Sweden)

    Clas Linnman

    Full Text Available Substance P is released in painful and inflammatory conditions, affecting both peripheral processes and the central nervous system neurokinin 1 (NK1 receptor. There is a paucity of data on human brain alterations in NK1 expression, how this system may be affected by treatment, and interactions between central and peripheral tissue alterations. Ten subjects with chronic tennis elbow (lateral epicondylosis were selected out of a larger (n = 120 randomized controlled trial evaluating graded exercise as a treatment for chronic tennis elbow (lateral epicondylosis. These ten subjects were examined by positron emission tomography (PET with the NK1-specific radioligand 11C-GR205171 before, and eight patients were followed up after treatment with graded exercise. Brain binding in the ten patients before treatment, reflecting NK1-receptor availability (NK1-RA, was compared to that of 18 healthy subjects and, longitudinally, to the eight of the original ten patients that agreed to a second PET examination after treatment. Before treatment, patients had significantly lower NK1-RA in the insula, vmPFC, postcentral gyrus, anterior cingulate, caudate, putamen, amygdala and the midbrain but not the thalamus and cerebellum, with the largest difference in the insula contralateral to the injured elbow. No significant correlations between brain NK1-RA and pain, functional severity, or peripheral NK1-RA in the affected limb were observed. In the eight patients examined after treatment, pain ratings decreased in everyone, but there were no significant changes in NK1-RA. These findings indicate a role for the substance P (SP / NK1 receptor system in musculoskeletal pain and tissue healing. As neither clinical parameters nor successful treatment response was reflected in brain NK1-RA after treatment, this may reflect the diverse function of the SP/NK1 system in CNS and peripheral tissue, or a change too small or slow to capture over the three-month treatment.

  16. Rotation sequence to report humerothoracic kinematics during 3D motion involving large horizontal component: application to the tennis forehand drive.

    Science.gov (United States)

    Creveaux, Thomas; Sevrez, Violaine; Dumas, Raphaël; Chèze, Laurence; Rogowski, Isabelle

    2018-03-01

    The aim of this study was to examine the respective aptitudes of three rotation sequences (Y t X f 'Y h '', Z t X f 'Y h '', and X t Z f 'Y h '') to effectively describe the orientation of the humerus relative to the thorax during a movement involving a large horizontal abduction/adduction component: the tennis forehand drive. An optoelectronic system was used to record the movements of eight elite male players, each performing ten forehand drives. The occurrences of gimbal lock, phase angle discontinuity and incoherency in the time course of the three angles defining humerothoracic rotation were examined for each rotation sequence. Our results demonstrated that no single sequence effectively describes humerothoracic motion without discontinuities throughout the forehand motion. The humerothoracic joint angles can nevertheless be described without singularities when considering the backswing/forward-swing and the follow-through phases separately. Our findings stress that the sequence choice may have implications for the report and interpretation of 3D joint kinematics during large shoulder range of motion. Consequently, the use of Euler/Cardan angles to represent 3D orientation of the humerothoracic joint in sport tasks requires the evaluation of the rotation sequence regarding singularity occurrence before analysing the kinematic data, especially when the task involves a large shoulder range of motion in the horizontal plane.

  17. Social dimensions of expertise in World of Warcraft players

    Directory of Open Access Journals (Sweden)

    Mark Chen

    2009-03-01

    Full Text Available Expertise development in the massively multiplayer online game World of Warcraft (Blizzard Entertainment, 2004 depends greatly on a player's use of social skills to gain access to expert player groups and accrue social and cultural capital. Drawn from ethnographic research, this paper maps out various forms of expert practice and highlights the social aspects of game play that often eclipse the importance of game-mechanics knowledge. At the time of this research, playing World of Warcraft and developing expertise in the game happened roughly within a two-stage process: (1 leveling up, or advancing one's character or avatar while learning the mechanics of the game, and (2 drawing on social capital gained during the first stage to join a group of up to 40 players to partake in high-end or endgame content.

  18. Experts Appear to Use Angle of Elevation Information in Basketball Shooting

    Science.gov (United States)

    de Oliveira, Rita Ferraz; Oudejans, Raoul R. D.; Beek, Peter J.

    2009-01-01

    For successful basketball shooting, players must use information about the location of the basket relative to themselves. In this study, the authors examined to what extent shooting performance depends on the absolute distance to the basket ("m") and the angle of elevation (alpha). In Experiment 1, expert players took jump shots under different…

  19. Influence of a mentoring through reflection program on the verbal behavior of tennis coach in a wheelchair high competition Influencia de un programa de supervisión reflexiva sobre la conducta verbal del entrenador de tenis en silla de ruedas de alta competición

    OpenAIRE

    D. Iglesias; M. P. Moreno; J. P. Fuentes; D. Sanz; F. Del Villar

    2010-01-01

    Our study deal with the teaching coaches process, applied to the adapted sport field, concretely to the wheelchair tennis of top level. From the literature revision and the collect of the expert opinion, we have designed a formative program in order to optimize the verbal behaviour coach during the training sessions. Concretely, we focus our research about the first information that the coach sends previously to each skill, and about the feedback gave...

  20. CUE USAGE IN VOLLEYBALL: A TIME COURSE COMPARISON OF ELITE, INTERMEDIATE AND NOVICE FEMALE PLAYERS

    Science.gov (United States)

    Vaeyens, R; Zeuwts, L; Philippaerts, R; Lenoir, M

    2014-01-01

    This study compared visual search strategies in adult female volleyball players of three levels. Video clips of the attack of the opponent team were presented on a large screen and participants reacted to the final pass before the spike. Reaction time, response accuracy and eye movement patterns were measured. Elite players had the highest response accuracy (97.50 ± 3.5%) compared to the intermediate (91.50 ± 4.7%) and novice players (83.50 ± 17.6%; pvolleyball and suggests that expert players extract more information from parafoveal regions. PMID:25609887

  1. Medical Expert Systems Survey

    OpenAIRE

    Abu-Nasser, Bassem S.

    2017-01-01

    International audience; There is an increased interest in the area of Artificial Intelligence in general and expert systems in particular. Expert systems are rapidly growing technology. Expert systems are a branch of Artificial Intelligence which is having a great impact on many fields of human life. Expert systems use human expert knowledge to solve complex problems in many fields such as Health, science, engineering, business, and weather forecasting. Organizations employing the technology ...

  2. Long term results in refractory tennis elbow using autologous blood

    Directory of Open Access Journals (Sweden)

    Naseem ul Gani

    2014-11-01

    Full Text Available Tennis elbow (TE is one of the commonest myotendinosis. Different treatment options are available and autologous blood injection has emerged as the one of the acceptable modalities of treatment. Long term studies over a larger group of patients are however lacking. The purpose of this study was to evaluate these patients on longer durations. One-hundred and twenty patients of TE, who failed to respond to conventional treatment including local steroid injections were taken up for this prospective study over the period from year 2005 to 2011 and were followed up for the minimum of 3 years (range 3-9 years. Two mL of autologous blood was taken from the ipsilateral limb and injected into the lateral epicondyle. The effectiveness of the procedure was assessed by Pain Rating Sscale and Nirschl Staging, which was monitored before the procedure, at first week, monthly for first three months, at 6 months and then 3 monthly for first year, six monthly for next 2 years and then yearly. Statistical analysis was done and a P value of <0.05 was taken as significant. The patients (76 females and 44 males were evaluated after procedure. The mean age group was 40.67±8.21. The mean follow up was 5.7±1.72 (range 3 to 9 years. The mean pain score and Nirschl stage before the procedure was 3.3±0.9 and 6.2±0.82 respectively. At final follow up the pain score and Nirschl were 1.1±0.9 and 1.5±0.91 respectively. Autologous blood injection was found to be one of the modalities for treatment of TE. Being cheap, available and easy method of treatment, it should be considered as a treatment modality before opting for the surgery. Universal guidelines for the management of tennis elbow should be made as there is lot of controversy regarding the treatment.

  3. Player-Character Dynamics in Multi- Player Role Playing Games

    DEFF Research Database (Denmark)

    Tychsen, Anders; McIlwain, D.; Brolund, T.

    2007-01-01

    This paper presents the results of a comprehensive empirical study of the impact of integrating complex game characters in multi-player Role Playing Games across tabletop and digital formats. Players were provided with characters that had detailed background history, personality and goals. Player...

  4. The Influence of Training Strategy and Physical Condition toward Forehand Drive Ability in Table Tennis

    Science.gov (United States)

    Langitan, F. W.

    2018-02-01

    The objective of this research is to find out the influence of training strategy and physical condition toward forehand drive ability in table tennis of student in faculty of sport in university of Manado, department of health and recreation education. The method used in this research was factorial 2x2 design method. The population was taken from the student of Faculty of Sport at Manado State University, Indonesia, in 2017 of 76 students for sample research. The result of this research shows that: In general, this training strategy of wall bounce gives better influence toward forehand drive ability compare with the strategy of pair training in table tennis. For the students who have strong forehand muscle, the wall bounce training strategy give better influence to their ability of forehand drive in table tennis. For the student who have weak forehand muscle, pair training strategy give better influence than wall bound training toward forehand drive ability in table tennis. There is an interaction between training using hand muscle strength to the training result in table tennis using forehand drive.

  5. The Relation between Self Esteem Levels and Life Quality Levels of Disabled and Non-Disabled Tennis Sportsmen

    Science.gov (United States)

    Civan, Adem

    2015-01-01

    This research was carried out to determine the self-esteem and life quality levels of disabled and non-disabled tennis sportsmen; and also to set forth the relation between their self-esteem and life quality levels. The research group consists of total 44 sportsmen including 22 disabled tennis sportsmen (n[subscript (female)]=9, n[subscript…

  6. Key attributes of expert NRL referees.

    Science.gov (United States)

    Morris, Gavin; O'Connor, Donna

    2017-05-01

    Experiential knowledge of elite National Rugby League (NRL) referees was investigated to determine the key attributes contributing to expert officiating performance. Fourteen current first-grade NRL referees were asked to identify the key attributes they believed contributed to their expert refereeing performance. The modified Delphi method involved a 3-round process of an initial semi-structured interview followed by 2 questionnaires to reach consensus of opinion. The data revealed 25 attributes that were rated as most important that underpin expert NRL refereeing performance. Results illustrate the significance of the cognitive category, with the top 6 ranked attributes all cognitive skills. Of these, the referees ranked decision-making accuracy as the most important attribute, followed by reading the game, communication, game understanding, game management and knowledge of the rules. Player rapport, positioning and teamwork were the top ranked game skill attributes underpinning performance excellence. Expert referees also highlighted a number of psychological attributes (e.g., concentration, composure and mental toughness) that were significant to performance. There were only 2 physiological attributes (fitness, aerobic endurance) that were identified as significant to elite officiating performance. In summary, expert consensus was attained which successfully provided a hierarchy of the most significant attributes of expert NRL refereeing performance.

  7. The Player Engagement Process

    DEFF Research Database (Denmark)

    Schoenau-Fog, Henrik

    2011-01-01

    , categories and triggers involved in this process. By applying grounded theory to the analysis of the responses, a process-oriented player engagement framework was developed and four main components consisting of objectives, activities, accomplishments and affects as well as the corresponding categories...

  8. Teaching Beginning Trombone Players.

    Science.gov (United States)

    Fallis, Todd L.

    2001-01-01

    Discusses the process of introducing the trombone to beginning students and addresses the issue of warming-up. Provides resources for beginning trombone methods, band methods, and daily warm-up studies. Includes resources for scale studies and etudes for beginning to intermediate trombone players. (CMK)

  9. Comparação entre a utilização de saliva e sangue para determinação do lactato mínimo em cicloergômetro e ergômetro de braço em mesa-tenistas Comparacion entre la utilizacion de saliva y sangre para la determinacion del lactato mínimo en cicloergómetro y ergómetro de brazo en tenistas de mesa Comparison between the use of saliva and blood for the minimum lactate determination in arm ergometer and cycle ergometer in table tennis players

    Directory of Open Access Journals (Sweden)

    Alessandro Moura Zagatto

    2004-12-01

    al test de correlación de Pearson con niveles de significancia de 5%. Los LACmin determinados con muestras de sangre y de saliva tanto para el ergômetro de brazo (LACmin brazo 91,71 ± 12,43; Na+min brazo-saliva 71,99 ± 23,42; K+min brazo-saliva 79,67 ± 17,72, como para el cicloergómetro (LACmin ciclo 157,68 ± 13,48; LACmin ciclo-saliva 135,49 ± 33,2; Na+min ciclo-saliva 121,81 ± 51,31; K+min ciclo-saliva 135,49 ± 33,21 no fueron diferentes significativamente. Con todo, estas intensidades no presentaron correlaciones significativas. Se puede entónces concluir que la utilización de los metabólitos en la saliva para la determinación de la del TLM no parece ser posible para este protocolo cuando los ergómetros utilizados son el ergómetro de brazo isocinético y el cicloergómetro.The aim of this study was to verify if it is possible to determine the lactate minimum test (LMT by saliva sodium (Na+, potassium (K+ and lactate (LAC concentrations in arm ergometer and cycle ergometers. Eight male international-level table tennis players participated in this study. To induce increases of lactate concentration in both ergometers, 30 seconds maximal tests were used with maximal force application in constant 102 rpm in isokinetic arm ergometer (Cybex UBE 2432, and loads of 7.5% of body weight (Kp in cycle ergometer (mechanical Monark. After the anaerobic stimulus in arm ergometer, the incremental test was applied at constant 60 rpm, started at 49 watts and increment loads of 16 watts each three minutes. The LMT intensity was determined with the analysis of the blood lactate (LACmin arm and the saliva concentrations of sodium (Na+min arm-saliva and potassium (K+min arm-saliva. For the cycle ergometer, the incremental test started with an intensity of 85 watts and increments of 17 watts at constant speed of 70 rpm. The stages were also of three minutes. The LACmin was determined using blood and saliva samples (LACmin cycle; Na+min cycle-saliva, K+min cycle

  10. Expert auditors’ services classification

    OpenAIRE

    Jolanta Wisniewska

    2013-01-01

    The profession of an expert auditor is a public trust occupation with a distinctive feature of taking responsibility for actions in the public interest. The main responsibility of expert auditors is performing financial auditing; however, expert auditors are prepared to carry out different tasks which encompass a wide plethora of financial and auditing services for different kinds of institutions and companies. The aim of the article is first of all the description of expert auditors’ service...

  11. Efficiently detecting outlying behavior in video-game players.

    Science.gov (United States)

    Kim, Young Bin; Kang, Shin Jin; Lee, Sang Hyeok; Jung, Jang Young; Kam, Hyeong Ryeol; Lee, Jung; Kim, Young Sun; Lee, Joonsoo; Kim, Chang Hun

    2015-01-01

    In this paper, we propose a method for automatically detecting the times during which game players exhibit specific behavior, such as when players commonly show excitement, concentration, immersion, and surprise. The proposed method detects such outlying behavior based on the game players' characteristics. These characteristics are captured non-invasively in a general game environment. In this paper, cameras were used to analyze observed data such as facial expressions and player movements. Moreover, multimodal data from the game players (i.e., data regarding adjustments to the volume and the use of the keyboard and mouse) was used to analyze high-dimensional game-player data. A support vector machine was used to efficiently detect outlying behaviors. We verified the effectiveness of the proposed method using games from several genres. The recall rate of the outlying behavior pre-identified by industry experts was approximately 70%. The proposed method can also be used for feedback analysis of various interactive content provided in PC environments.

  12. Delegating Decisions to Experts

    Science.gov (United States)

    Li, Hao; Suen, Wing

    2004-01-01

    We present a model of delegation with self-interested and privately informed experts. A team of experts with extreme but opposite biases is acceptable to a wide range of decision makers with diverse preferences, but the value of expertise from such a team is low. A decision maker wants to appoint experts who are less partisan than he is in order…

  13. Methodology for the motor coordination through the adapted table tennis in boys and girl with Down´s Syndrome

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Govea Macía

    2014-12-01

    Full Text Available The present research approaches the application of a pre experiment with the objective of elaborating a methodology that stimulates the development of the motor coordination, adapting the table tennis to the necessities and characteristics of the boys and girls with Downs Syndrome diagnose. To elaborate it was started from the deficiencies and contradictions found in the adapted sport for patients with Down’s Syndrome, as well as the potentialities and deficiencies in their motor coordination; there are used methods and techniques of theoretical character (analysis, synthesis, induction, deduction, hypothetical, deductive, systemic structural functional and modeling; of empiric-experimental character (observation, measurement, documental analysis, experts' approach, pre pedagogic experiment, study case; and as techniques: the survey and instruments; and of mathematical-statistical character, descriptive statistic and inferential. The use of the experts’ criterion is used to verify the theoretical validity elements of the designed methodology. The results analysis allows accepting the proposal as valid after having obtained the theoretical and practical results validation with a case study implementation.

  14. Training with anxiety has a positive effect on expert perceptual-motor performance under pressure

    NARCIS (Netherlands)

    Oudejans, R.R.D.; Pijpers, J.R.

    2009-01-01

    In two experiments, we examined whether training with anxiety can prevent choking in experts performing perceptual-motor tasks. In Experiment 1, 17 expert basketball players practised free throws over a 5-week period with or without induced anxiety. Only after training with anxiety did performance

  15. Expert status and performance.

    Directory of Open Access Journals (Sweden)

    Mark A Burgman

    Full Text Available Expert judgements are essential when time and resources are stretched or we face novel dilemmas requiring fast solutions. Good advice can save lives and large sums of money. Typically, experts are defined by their qualifications, track record and experience. The social expectation hypothesis argues that more highly regarded and more experienced experts will give better advice. We asked experts to predict how they will perform, and how their peers will perform, on sets of questions. The results indicate that the way experts regard each other is consistent, but unfortunately, ranks are a poor guide to actual performance. Expert advice will be more accurate if technical decisions routinely use broadly-defined expert groups, structured question protocols and feedback.

  16. Managing player load in professional rugby union: a review of current knowledge and practices.

    Science.gov (United States)

    Quarrie, Kenneth L; Raftery, Martin; Blackie, Josh; Cook, Christian J; Fuller, Colin W; Gabbett, Tim J; Gray, Andrew J; Gill, Nicholas; Hennessy, Liam; Kemp, Simon; Lambert, Mike; Nichol, Rob; Mellalieu, Stephen D; Piscione, Julien; Stadelmann, Jörg; Tucker, Ross

    2017-03-01

    The loads to which professional rugby players are subjected has been identified as a concern by coaches, players and administrators. In November 2014, World Rugby commissioned an expert group to identify the physical demands and non-physical load issues associated with participation in professional rugby. To describe the current state of knowledge about the loads encountered by professional rugby players and the implications for their physical and mental health. The group defined 'load' as it relates to professional rugby players as the total stressors and demands applied to the players. In the 2013-2014 seasons, 40% of professional players appeared in 20 matches or more, and 5% of players appeared in 30 matches or more. Matches account for ∼5-11% of exposure to rugby-related activities (matches, team and individual training sessions) during professional competitions. The match injury rate is about 27 times higher than that in training. The working group surmised that players entering a new level of play, players with unresolved previous injuries, players who are relatively older and players who are subjected to rapid increases in load are probably at increased risk of injury. A mix of 'objective' and 'subjective' measures in conjunction with effective communication among team staff and between staff and players was held to be the best approach to monitoring and managing player loads. While comprehensive monitoring holds promise for individually addressing player loads, it brings with it ethical and legal responsibilities that rugby organisations need to address to ensure that players' personal information is adequately protected. Administrators, broadcasters, team owners, team staff and the players themselves have important roles in balancing the desire to have the 'best players' on the field with the ongoing health of players. In contrast, the coaching, fitness and medical staff exert significant control over the activities, duration and intensity of training

  17. Kinematic Analysis on the Serve Technique of Elite Tennis Player Grigor•Dimitrov Based on 3D Virtual Reality Technology

    Directory of Open Access Journals (Sweden)

    Du Chuan Jia

    2016-01-01

    Full Text Available By using three-dimensional video analysis, we made a kinematic analysis on Grigor Dimitrov’s Serve technique, aiming at finding the kinematic characteristics of his serve technique during various stages. The results showed that: (1 During the stage of tossing the ball and lifting the racket, the tossing height of the ball was at minimum appropriately, while the elbow extension of the tossing arm was stright, and the angle of his left knee was 95.4°, which is beneficial to making greater kicking power; (2 At the back-swing stage, Dimitrov’s both feet made a great range of pedal and stretch quickly, and the “scratch-back” posture is obvious, and momentum caused by the kicking and coxae-turning was rather large; (3 When hitting the ball, the contact point was accurate and the speed of the racket head was high, which passed a relatively large initial momentum to the ball; (4 Dimitrov’s entire service action was integral and coordinate, smooth and powerful, which was in accordance relatedly with kinematic characteristics

  18. LONG TERM EFFECT OF CYRIAX PHYSIOTHERPY WITH SUPERVISED EXERCISE PROGRAM IN SUBJECTS WITH TENNIS ELBOW

    Directory of Open Access Journals (Sweden)

    Pallavi Shridhar Thakare

    2014-06-01

    Full Text Available Background: The purpose is to find long term effect of Cyriax physiotherapy with supervised exercise program in the reduction of pain and improvement of functional ability for subjects with tennis elbow. Method: An experimental study design, 30 subjects with Tennis Elbow randomized 15 subjects each into Study and Control group. Control group received Supervised Exercise program while Study group received Cyriax Physiotherapy with Supervised exercises program thrice in a week for 4 weeks and post intervention follow up after 2 weeks. Outcome measurements were measured for pain using Visual analogue Scale (VAS and Patient Rated Tennis Elbow Evaluation (PRTEE for functional ability. Results: There is no statistically significant difference in pre- intervention means of VAS and PRTEE when compared between the groups using independent ‘t’ test as a parametric and Mann Whitney U test as a non-parametric test. When means of post intervention and follow-up measurements were compared there is a statistically significant (p<0.05 difference in VAS and PRTEE scores between the groups. However greater percentage of improvements was obtained in study group than control group. Conclusion: It is concluded that there is significant long term effect with greater percentage of improvement in pain and functional ability up to 2 weeks follow-up following 4 weeks of combined Cyriax physiotherapy with supervised exercise program than only supervised exercise program for subjects with tennis elbow.

  19. The predictive value of diagnostic sonography for the effectiveness of conservative treatment of tennis elbow

    NARCIS (Netherlands)

    Struijs, P. A. A.; Spruyt, M.; Assendelft, W. J. J.; van Dijk, C. N.

    2005-01-01

    OBJECTIVE. Tennis elbow is a common complaint. Several treatment strategies have been described, but an optimal strategy has not been identified. Sonographic imaging as a predictive,factor has never been studied. The aim of our study was to determine the value of sonographic findings in predicting

  20. Local corticosteroid injection versus Cyriax-type physiotherapy for tennis elbow

    NARCIS (Netherlands)

    J.A.N. Verhaar (Jan); G.H.I.M. Walenkamp; H. van Mameren; A.D.M. Kester; A.J. van der Linden

    1996-01-01

    textabstractWe performed a prospective, randomised trial on 106 patients to compare the effects of local corticosteroid injections with physiotherapy as advocated by Cyriax in the treatment of tennis elbow. The main outcome measures were the severity of pain, pain provoked by resisted dorsiflexion

  1. Duloxetine in treatment of refractory chronic tennis elbow: Two case reports

    Directory of Open Access Journals (Sweden)

    Wani Zaid

    2008-09-01

    Full Text Available Abstract Introduction Tennis elbow is a common musculoskeletal disorder; management options include physiotherapeutic, medical, surgical, and other forms of intervention. Some patients remain symptomatic despite best efforts. We present two patients who did not respond to medical and surgical treatments, and whose symptoms were relieved with duloxetine. This is the first report on the use of duloxetine to treat tennis elbow. Case presentation Two mentally healthy young Asian women aged 32 and 27 years, each with tennis elbow of about 18 months duration continued to suffer pain despite treatment with analgesics, local steroid injections, physiotherapy, cryotherapy, ultrasound, and surgical release, among other interventions. Both showed substantial improvement within 4 to 6 weeks of receiving monotherapy with duloxetine 60 mg/day. Both were pain-free with continued treatment at a 6-month follow-up. Conclusion Duloxetine may be a useful treatment option in patients with chronic tennis elbow, even those who have failed conventional medical, physiotherapeutic, surgical, and other forms of management.

  2. Motivational Factors Affecting Athletes in Selecting the Sport Branches of Athletics, Ski and Tennis

    Science.gov (United States)

    Akyüz, Murat; Agar, Muharrem; Akyüz, Öznur; Dogru, Yeliz

    2016-01-01

    The aim of this study is to research the motivational factors affecting athletes to select the branches of athletics, ski and tennis. Within the scope of the research, the survey developed by H. Sunay in 1996 was implemented and solution for the problem of the research was searched through the findings that were obtained from the survey. SPSS…

  3. Effects of Tennis Training on Personality Development in Children and Early Adolescents

    Science.gov (United States)

    Demir, Erdal; Sahin, Gülsah; Sentürk, Ugur; Aydin, Halide; Altinkök, Mustafa

    2016-01-01

    The objective of this study was to investigate the effects of a 12-week basic tennis training program on the personality development of early adolescents aged between 9 and 11 years. The research methodology consisted of a single group pre-test/post-test design implemented with a total of eight volunteer children (three boys and five girls). The…

  4. Active Learning for Player Modeling

    DEFF Research Database (Denmark)

    Shaker, Noor; Abou-Zleikha, Mohamed; Shaker, Mohammad

    2015-01-01

    Learning models of player behavior has been the focus of several studies. This work is motivated by better understanding of player behavior, a knowledge that can ultimately be employed to provide player-adapted or personalized content. In this paper, we propose the use of active learning for player...... experience modeling. We use a dataset from hundreds of players playing Infinite Mario Bros. as a case study and we employ the random forest method to learn mod- els of player experience through the active learning approach. The results obtained suggest that only part of the dataset (up to half the size...... that the method can be used online during the content generation process where the mod- els can improve and better content can be presented as the game is being played....

  5. Application of expert systems

    Energy Technology Data Exchange (ETDEWEB)

    Basden, A

    1983-11-01

    This article seeks to bring together a number of issues relevant to the application of expert systems by discussing their advantages and limitations, their roles and benefits, and the influence that real-life applications might have on the design of expert systems software. Part of the expert systems strategy of one major chemical company is outlined. Because it was in constructing one particular expert system that many of these issues became important this system is described briefly at the start of the paper and used to illustrate much of the later discussion. It is of the plausible-inference type and has application in the field of materials engineering. 22 references.

  6. Being an expert

    International Nuclear Information System (INIS)

    Brechet, Y.; Musseau, O.; Bruna, G.; Sperandio, M.; Roulleaux-Dugage, M.; Andrieux, S.; Metteau, L.

    2014-01-01

    This series of short articles are dedicated to the role of the expert in the enterprise. There is an important difference between a scientific counsellor and an expert, the expert, recognized by his peers, can speak publicly in his field of expertise but has a duty of transparency while the job of a scientific counsellor requires confidentiality. The making and the use of an expert in an enterprise requires a dedicated organization. The organization of the expertise in 5 enterprises in nuclear industry are considered: CEA (French Alternative Energies and Atomic Energy Commission), IRSN (Institute of Radioprotection and Nuclear Safety), AREVA, ANDRA (National Radioactive Waste Management Agency) and EDF (Electricity of France)

  7. Self-appraisal of hockey players of high class of different playing position

    Directory of Open Access Journals (Sweden)

    Oleksiy Mikhnov

    2014-12-01

    Full Text Available Purpose: to expose the features of display of self-appraisal for the hockey players of high class of different playing position. Material and Methods: for the exposure of level of self-appraisal for hockey players, information of sportsmen of high class, taking part in the matches of the Kontinental hockey league (KHL in a season 2013–2014 was probed sixteen hockey players, having a sporting digit MS and MSWC, took part in researches. Methods were used: pedagogical supervision, pedagogical analysis and generalization of front-rank experience, psychological testing, analysis of data of the special scientific-methodical literature, expert questioning, an analysis of data is the Internet. Results: findings allowed to set that the players of line of attack (central and extreme forward have more high level of self-appraisal for certain, than players of defence and hockey goalkeepers. This tendency is looked over both on the separate constituents of self-appraisal and on the whole on all spectrums of the studied indexes. The got results of researches rotined that the hockey players of high class had or middle or high level of self-appraisal. Among testable hockey players, players were not exposed with the low level of self-appraisal. Conclusions: the exposed distinctions in the level of self-appraisal of hockey players of high class can be used for diagnostics of playing predisposition and choice of playing line of business in a command.

  8. The Hedonic Haptic Player

    DEFF Research Database (Denmark)

    Vallgårda, Anna; Boer, Laurens; Cahill, Ben

    2017-01-01

    In this design case we present the Hedonic Haptic Player—a wearable device that plays different patterns of vibrations on the body as a form of music for the skin. With this we begin to explore the enjoyability of vibrations in a wearable set-up. Instead of implementing vibrations as a haptic...... output for some form of communication we want to explore their hedonistic value. The process leading up to the Hedonic Haptic player served as a first step in getting a grasp of the design space of vibrotactile stimuli in a broader sense. This is reported as seven episodes of explorations. The Hedonic...

  9. Rectus abdominis muscle injuries in elite handball players: management and rehabilitation

    Directory of Open Access Journals (Sweden)

    Balius R

    2011-07-01

    Full Text Available Ramon Balius1, Carles Pedret2, Laura Pacheco1, Josep Antoni Gutierrez3, Joan Vives4, Jaume Escoda11Consell Català de l’Esport, Generalitat de Catalunya, Barcelona; 2Centro Mapfre de Medicina del Tenis, Barcelona; 3Spanish National Handball Team, Spain; 4Granollers Handball Club, Granollers, Barcelona, SpainAbstract: Muscle injuries generally occur in two-joint muscles with a high percentage of type II fibers during the performance of eccentric activity. Some muscle injuries, such as those located in the adductor longus, a monoarticular muscle, as well as rectus abdominis do not fully comply with these requirements. This study examines five cases of elite handball players with ruptured rectus abdominals. Sonographically, lesions in rectus abdominis are shown as a disruption of the fibrillar pattern with a hematic suffusion that invades the entire lesion. In some of the cases, the ultrasound study was complemented with a MRI. A unified rehabilitation protocol was applied and the return to play time of each handball player ranged between 16 and 22 days, with an average of 18.2 days. Follow-up at 15 months showed no evidence of re-injury or residual discomfort and all of them are playing at their highest level. The aim of this study was to illustrate a feature of handball injury that, as in tennis and volleyball, is uncommon and so far has not been specifically reported. The phenomenon of contralateral abdominal hypertrophy in handball appears in the dominant arm as in tennis and volleyball.Keywords: rectus abdominis, muscle injury, sonography, MRI, handball 

  10. The World (of Warcraft) through the eyes of an expert.

    Science.gov (United States)

    Marzouki, Yousri; Dusaucy, Valériane; Chanceaux, Myriam; Mathôt, Sebastiaan

    2017-01-01

    Negative correlations between pupil size and the tendency to look at salient locations were found in recent studies (e.g., Mathôt et al., 2015). It is hypothesized that this negative correlation might be explained by the mental effort put by participants in the task that leads in return to pupil dilation. Here we present an exploratory study on the effect of expertise on eye-movement behavior. Because there is no available standard tool to evaluate WoW players' expertise, we built an off-game questionnaire testing players' knowledge about WoW and acquired skills through completed raids, highest rated battlegrounds, Skill Points, etc. Experts ( N  = 4) and novices ( N  = 4) in the massively multiplayer online role-playing game World of Warcraft (WoW) viewed 24 designed video segments from the game that differ in regards with their content (i.e, informative locations) and visual complexity (i.e, salient locations). Consistent with previous studies, we found a negative correlation between pupil size and the tendency to look at salient locations (experts, r  =  - .17, p  WoW players than novice players ( Z  =  - 3.3, p  = .0011). This suggests that experts learned to improve control over eye-movement behavior by guiding their eyes towards informative, but potentially low-salient areas of the screen. These findings may contribute to our understanding of what makes an expert an expert.

  11. Efficiently detecting outlying behavior in video-game players

    Directory of Open Access Journals (Sweden)

    Young Bin Kim

    2015-12-01

    Full Text Available In this paper, we propose a method for automatically detecting the times during which game players exhibit specific behavior, such as when players commonly show excitement, concentration, immersion, and surprise. The proposed method detects such outlying behavior based on the game players’ characteristics. These characteristics are captured non-invasively in a general game environment. In this paper, cameras were used to analyze observed data such as facial expressions and player movements. Moreover, multimodal data from the game players (i.e., data regarding adjustments to the volume and the use of the keyboard and mouse was used to analyze high-dimensional game-player data. A support vector machine was used to efficiently detect outlying behaviors. We verified the effectiveness of the proposed method using games from several genres. The recall rate of the outlying behavior pre-identified by industry experts was approximately 70%. The proposed method can also be used for feedback analysis of various interactive content provided in PC environments.

  12. CUE USAGE IN VOLLEYBALL: A TIME COURSE COMPARISON OF ELITE, INTERMEDIATE AND NOVICE FEMALE PLAYERS

    Directory of Open Access Journals (Sweden)

    P Vansteenkiste

    2015-01-01

    Full Text Available This study compared visual search strategies in adult female volleyball players of three levels. Video clips of the attack of the opponent team were presented on a large screen and participants reacted to the final pass before the spike. Reaction time, response accuracy and eye movement patterns were measured. Elite players had the highest response accuracy (97.50 ± 3.5% compared to the intermediate (91.50 ± 4.7% and novice players (83.50 ± 17.6%; p<0.05. Novices had a remarkably high range of reaction time but no significant differences were found in comparison to the reaction time of elite and intermediate players. In general, the three groups showed similar gaze behaviour with the apparent use of visual pivots at moments of reception and final pass. This confirms the holistic model of image perception for volleyball and suggests that expert players extract more information from parafoveal regions.

  13. Network approaches for expert decisions in sports.

    Science.gov (United States)

    Glöckner, Andreas; Heinen, Thomas; Johnson, Joseph G; Raab, Markus

    2012-04-01

    This paper focuses on a model comparison to explain choices based on gaze behavior via simulation procedures. We tested two classes of models, a parallel constraint satisfaction (PCS) artificial neuronal network model and an accumulator model in a handball decision-making task from a lab experiment. Both models predict action in an option-generation task in which options can be chosen from the perspective of a playmaker in handball (i.e., passing to another player or shooting at the goal). Model simulations are based on a dataset of generated options together with gaze behavior measurements from 74 expert handball players for 22 pieces of video footage. We implemented both classes of models as deterministic vs. probabilistic models including and excluding fitted parameters. Results indicated that both classes of models can fit and predict participants' initially generated options based on gaze behavior data, and that overall, the classes of models performed about equally well. Early fixations were thereby particularly predictive for choices. We conclude that the analyses of complex environments via network approaches can be successfully applied to the field of experts' decision making in sports and provide perspectives for further theoretical developments. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. 75 FR 65323 - The Tennis Channel, Inc. v. Comcast Cable Communications, LLC; File No. CSR-8258-P

    Science.gov (United States)

    2010-10-22

    ... (formerly, Nielsen Media Research). There are 210 DMAs in the United States. In addition to its role as a... Starter tier. 9. In 2005, The Tennis Channel executed an affiliation agreement with Comcast that provided...

  15. Computer Based Expert Systems.

    Science.gov (United States)

    Parry, James D.; Ferrara, Joseph M.

    1985-01-01

    Claims knowledge-based expert computer systems can meet needs of rural schools for affordable expert advice and support and will play an important role in the future of rural education. Describes potential applications in prediction, interpretation, diagnosis, remediation, planning, monitoring, and instruction. (NEC)

  16. Real time expert systems

    International Nuclear Information System (INIS)

    Asami, Tohru; Hashimoto, Kazuo; Yamamoto, Seiichi

    1992-01-01

    Recently, aiming at the application to the plant control for nuclear reactors and traffic and communication control, the research and the practical use of the expert system suitable to real time processing have become conspicuous. In this report, the condition for the required function to control the object that dynamically changes within a limited time is presented, and the technical difference between the real time expert system developed so as to satisfy it and the expert system of conventional type is explained with the actual examples and from theoretical aspect. The expert system of conventional type has the technical base in the problem-solving equipment originating in STRIPS. The real time expert system is applied to the fields accompanied by surveillance and control, to which conventional expert system is hard to be applied. The requirement for the real time expert system, the example of the real time expert system, and as the techniques of realizing real time processing, the realization of interruption processing, dispersion processing, and the mechanism of maintaining the consistency of knowledge are explained. (K.I.)

  17. Expert systems: An overview

    International Nuclear Information System (INIS)

    Verdejo, F.

    1985-01-01

    The purpose of this article is to introduce readers to the basic principles of rule-based expert systems. Four topics are discussed in subsequent sections: (1) Definition; (2) Structure of an expert system; (3) State of the art and (4) Impact and future research. (orig.)

  18. Trendwatch combining expert opinion

    NARCIS (Netherlands)

    Hendrix, E.M.T.; Kornelis, M.; Pegge, S.M.; Galen, van M.A.

    2006-01-01

    In this study, focus is on a systematic way to detect future changes in trends that may effect the dynamics in the agro-food sector, and on the combination of opinions of experts. For the combination of expert opinions, the usefulness of multilevel models is investigated. Bayesian data analysis is

  19. Relationship between variability of practice and variability of execution in flat tennis service Relación entre variabilidad de la práctica y variabilidad en la ejecución del servicio plano en tenis

    Directory of Open Access Journals (Sweden)

    R. Menayo

    2010-12-01

    Full Text Available This study analyzes the relationship between the variability in the performance of the flat tennis service and its practice under variable conditions, taking as a starting point a predictive analysis of the instantaneous kinematic variables of the hand that holds the racket. Seventeen tennis players performed services under 8 practice conditions (rackets and balls were modified, and pre-test and post-test were carried out. The players performed 120 services with the instruction to hit the ball powerfully and maintaining maximum efficiency. Data showed that two variables related to the speed and the acceleration of the hand will predict efficacy at 57.7%: both the time variation coefficients until we reach the speed peak and the final acceleration of the hand in the Y axis. Significant differences were also obtained between some instantaneous kinematic variables measured in the pre-test and the practice series, and also negative and significant correlations between these variables and the efficacy of the services.
    Key Words: variability, tennis, service

    Este estudio investiga acerca de la relación existente entre la variabilidad en la ejecución del servicio plano en tenis y la práctica variable del mismo, partiendo de un análisis predictivo de las variables cinemáticas instantáneas que definen el movimiento de la mano que sujeta la raqueta. 17 tenistas pasaron por 8 condiciones de práctica precedidas de un test inicial y finalizadas con un test final. En dichas series se variaron el implemento utilizado y la pelota. Cada jugador realizó 120 golpeos, con la instrucción de golpear a la máxima potencia manteniendo la eficacia. Los datos obtenidos identifican como variables predictoras de la eficacia en un 57.7 % a dos parámetros relacionados con la velocidad y con la aceleración de la mano: los coeficientes de variación del tiempo hasta el pico de velocidad lineal de la mano en el eje Y y la aceleraci

  20. Correspondence between training load executed by volleyball players and the one observed by coaches.

    Science.gov (United States)

    Rodríguez-Marroyo, Jose A; Medina, Javier; García-López, Juan; García-Tormo, José V; Foster, Carl

    2014-06-01

    The main aim of this study was to compare the training load (TL) executed by volleyball players with that observed by coaches. Second, we analyzed the influence of the coaches' experience in the estimated TL. Twelve female volleyball players and 4 male coaches participated in this study. During a period of 15 weeks, physical (PT) and technical-tactical training sessions and matches were monitored. In each session, the session rating of perceived exertion (sRPE) was recorded to analyze the players' exercise intensity and TL(RP)E. Coaches were present in all sessions and rated their estimate of sRPE at the same time as the players to calculate the coaches' TL(RPE). Both players' and coaches' mean sRPE (4.0 ± 1.1, 3.7 ± 1.1, and 3.8 ± 1.0 in players and expert and beginning coaches, respectively) and TLRPE (380.1 ± 106.8, 358.3 ± 110.5, and 359.7 ± 108.0 in players and expert and beginning coaches, respectively) were similar. However, a higher (p volleyball.

  1. Expert Panel Elicitation

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, M. [Swedish Radiation Protection Authority, Stockholm (Sweden). Dept. of Waste Management and Environmental Protection; Hora, S.C. [Univ. of Hawaii, Hilo, HI (United States)

    2005-09-15

    Scientists are now frequently in a situation where data cannot be easily assessed, since they may have conflicting or uncertain sources. While expert judgment reflects private choices, it is possible both reduce the personal aspect as well as in crease confidence in the judgments by using formal protocols for choice and elicitation of experts. A full-scale elicitation made on seismicity following glaciation, now in its late phase and presented here in a preliminary form, illustrates the value of the technique and some essential issues in connection with the decision to launch such a project. The results show an unusual low variation between the experts.

  2. Experts on public trial

    DEFF Research Database (Denmark)

    Blok, Anders

    2007-01-01

    a case study of the May 2003 Danish consensus conference on environmental economics as a policy tool, the article reflects on the politics of expert authority permeating practices of public participation. Adopting concepts from the sociology of scientific knowledge (SSK), the conference is seen......-than-successful defense in the citizen perspective. Further, consensus conferences are viewed alternatively as "expert dissent conferences," serving to disclose a multiplicity of expert commitments. From this perspective, some challenges for democratizing expertise through future exercises in public participation...

  3. New Players, New Game

    DEFF Research Database (Denmark)

    Forstater, Maya; Christensen, Rasmus Corlin

    of technical expert debates to being topics of public interest and popular media reporting. In consequence, new political initiatives have also progressed at an unexpectedly high pace. How has this rapid and unexpected change come about? Existing accounts of international tax change have emphasised the role...... national fiscal systems, and attention focused on corporate tax practices deemed overly aggressive or immoral. International tax rules as a matter of ‘front page’ public debate is an unusual situation; while taxation itself is always and everywhere a political topic, the fine workings of international...... taxation has largely been the domain of technical debates between experts. This is no longer the case: issues such as tax havens, transfer pricing, and structures like the “Double Irish Dutch Sandwich” have become topics of popular debates and campaigns. These issues have gone from being solely the subject...

  4. Experts' meeting: Maintenance '83

    International Nuclear Information System (INIS)

    1983-01-01

    The brochure presents, in full wording, 20 papers read at the experts' meeting ''Maintenance '83'' in Wiesbaden. Most of the papers discuss reliability data (acquisition, evaluation, processing) of nearly all fields of industry. (RW) [de

  5. Does expert perceptual anticipation transfer to a dissimilar domain?

    Science.gov (United States)

    Müller, Sean; McLaren, Michelle; Appleby, Brendyn; Rosalie, Simon M

    2015-06-01

    The purpose of this experiment was to extend theoretical understanding of transfer of learning by investigating whether expert perceptual anticipation skill transfers to a dissimilar domain. The capability of expert and near-expert rugby players as well as novices to anticipate skill type within rugby (learning sport) was first examined using a temporal occlusion paradigm. Participants watched video footage of an opponent performing rugby skill types that were temporally occluded at different points in the opponent's action and then made a written prediction. Thereafter, the capability of participants to transfer their anticipation skill to predict pitch type in baseball (transfer sport) was examined. Participants watched video footage of a pitcher throwing different pitch types that were temporally occluded and made a written prediction. Results indicated that expert and near-expert rugby players anticipated significantly better than novices across all occlusion conditions. However, none of the skill groups were able to transfer anticipation skill to predict pitch type in baseball. The findings of this paper, along with existing literature, support the theoretical prediction that transfer of perceptual anticipation is expertise dependent and restricted to similar domains. (c) 2015 APA, all rights reserved).

  6. Exploring practical knowledge: a case study of an experienced senior tennis performer.

    Science.gov (United States)

    Langley, D J; Knight, S M

    1996-12-01

    The purpose of the study was to explore sport-related practical knowledge through the perceptions and experiences of a senior adult competitive tennis performer. Practical knowledge was defined as goal oriented, experiential knowledge developed within particular physical activity settings. Data were collected through formal interviews and participant observation and analyzed through narrative inquiry and conventional coding techniques. The data suggest that the tennis environment was perceived in terms of the opportunities afforded by that environment. Specifically, the participant's practical knowledge centered on performance capabilities and strategic planning that revealed opponent limitations. This knowledge appeared to be developed and expressed within the relationships among individual capabilities, the task, and the situated context of game play.

  7. Children's learning of tennis skills is facilitated by external focus instructions

    Directory of Open Access Journals (Sweden)

    Ricardo Hadler

    2014-12-01

    Full Text Available The present study examined the effects of instructions promoting external versus internal foci of attention on the learning of a tennis forehand stroke in 11-year old children. Three groups of participants practiced hitting tennis balls at a target. External focus group participants were instructed to direct their attention to the movement of the racquet, while participants in the internal focus group were asked to direct their attention to the movements of their arm. Participants in a control group did not receive attentional focus instructions. Two days after the practice phase (60 trials, learning was assessed in retention and transfer tests. The results showed that the external focus group demonstrated greater accuracy in hitting a target relative to the two other groups in retention, and relative to the internal focus group in transfer. We conclude that instructions inducing an external focus of attention can enhance children's sport skill learning.

  8. Posterolateral rotatory instability from multiple steroids injections for tennis elbow: a case report.

    Science.gov (United States)

    Chanlalit, Cholawish; Limsricharoen, Warodom

    2013-01-01

    This article reports the complication (lateral collateral ligament rupture) arising from improper numbers of steroids injections for the chronic lateral elbow pain (tennis elbow). Clinical sign and investigation with MRI confirmed a diagnosis of LCL rupture. In the present report, we describe the successful outcome of one year results in surgical debridement and lateral collateral ligament (LCL) reconstruction. A discussion of the proper conservative role for the chronic lateral epicondyalgia and the surgical decision to resolve this complication is also included.

  9. Tennis Leg: A Unique “Strain”, Management Approach and Review of the Literature

    OpenAIRE

    Mahdi Y Khalfaoui; Anthony McEvoy

    2016-01-01

    The term tennis leg is often used to denote any pathology resulting from acute injury to the medial head of the gastrocnemius muscle. Management of such cases is usually conservative, with scarce evidence in the literature describing cases of surgical intervention for such patients. Authors performing surgical repair, have done so for complete ruptures of the medial gastrocnemius head, usually in the acute setting. In these cases reported outcomes have been encouraging. A...

  10. El tenis: Entre la modernidad y la postmodernidad = Tennis, between modernity and post-modernity

    Directory of Open Access Journals (Sweden)

    Guillem Turró i Ortega

    2013-04-01

    Full Text Available En el presente artículo los autores ensayan una aproximación a la realidad tenística en tanto que metáfora de la modernidad y la postmodernidad (también llamada hipermodernidad. Sabido es que los orígenes del tenis se remontan a una época premoderna, cuando se conocía como jeu de paume, práctica de gran éxito durante el Antiguo Régimen. Se sostiene que este deporte permite reflexionar en torno a un conjunto de valores y características de nuestras sociedades actuales. La moda, la tecnología, la diversidad sexual y étnica, el espectáculo, la publicidad, la aceleración, el erotismo, el éxito y el fracaso o el capitalismo globalizado aparecen como componentes imprescindibles para poder captar el fenómeno tenístico en toda su amplitud. Igualmente, la historia del tenis puede servir para ilustrar como a través del deporte se puede comprender la evolución socio-cultural de la civilización occidental. --------------------------------------------In this paper, the authors investigate an approach to the practice of tennis as a metaphor of modernity and post-modernity (also called hypermodernity. It is a wellknown fact that the origins of tennis go back to pre-modern times, when it was known as jeu de paume and widely practiced during the Ancient Regime. The autors, argue that this sport enables reflection on a series of values and features of modern society. Fashion, technology, sexual and ethnic diversity, spectacle, advertising, acceleration, eroticism, success and failure or globalised capitalism emerge as indispensable elements for understanding the tennis phenomenon in all its breadth. Likewise, the history of tennis may also illustrate how the sociocultural evolution of Western civilisation can be understood through spor. 

  11. Diagnostyka i leczenie zachowawcze łokcia tenisisty = Diagnosis and conservative treatment of tennis elbow

    Directory of Open Access Journals (Sweden)

    Gustaw Wójcik

    2017-02-01

      Introduction. Tennis elbow is a relatively common disorder of the musculoskeletal system, for which effective treatment strategy is still unknown. It is responsible for considerable pain and loss of function of the affected limb. Characteristic for the diseases are degenerative changes in the structure of collagen and abnormalities in blood supply associated with the process of neovascularization. Pathology is due to cycles of repetitive stress leading to tissue damage. The sensitivity of imaging depends on the duration of the disease. The first period of the disease is usually caused by trauma, which may be accompanied by inflammation, which is why the most effective treatment may be anti-inflammatory therapy and immobilization of a limb. The subsequent period  is connected with degenerative changes, and treatment relies mainly on combating the painful symptoms. Conditions refractory to conservative treatment are eligible for surgery. The objective of the study. Presentation of current knowledge about diagnosis and treatment of enthesopathy of the lateral epicondyle of the humerus. Materials and method. The work is based on a review of literature of Baz PubMed, Scopus and Web of Science. Conclusions. The primary imaging technique for the diagnosis of tennis elbow is ultrasound. Classic radiology is rather used for the differentiation of other diseases related to the elbow. Modern methods of treatment of tennis elbow are based on the treatment of degenerative changes. Anti-inflammatory treatment is ineffective in the above disease.

  12. The Astro Learning Design Player

    NARCIS (Netherlands)

    Sharples, Paul; Wilson, Scott; Popat, Kris; Griffiths, David; Beauvoir, Phillip

    2010-01-01

    Sharples, Paul Wilson, S., Popat, K., Griffiths, D., Beauvoir, P. (2009) The Astro Learning Design Player. This software is distributed under the three clause BSD license, copyright TENCompetence Foundation

  13. Historia y evolución del Tenis = History and Evolutation of Tennis

    Directory of Open Access Journals (Sweden)

    Bernardino Javier Sánchez-Alcaraz Martínez

    2013-10-01

    Full Text Available El presente trabajo resume la historia y evolución del tenis desde sus orígenes, hasta el siglo XX, momento en el cual se establecen los eventos más importantes como los torneos de Grand Slam y la Copa Davis. Las primeros juegos de pelota semejantes al tenis aparecen en la Antigua Grecia y el Impero Romano, y alcanza su máximo auge en la Edad Media, a través del denominado “Jeu de la paume”, en Francia e Inglaterra, antes de producirse su declive en el siglo XVIII. Finalmente, la aparición del tenis moderno o “lawn tennis” a finales del siglo XIX y su expansión por Europa, América y Australia, produjo la creación de clubes, torneos y asociaciones destinadas a la difusión y práctica de este deporte. Finalmente, se realiza un breve repaso a la historia del tenis en nuestro país, desde al-Andalus hasta los grandes campeones españoles.-----------------------------------------------------------------This research summarizes the history and evolution of tennis from the origins, up to the 20th century, moment in which the most important events are established, like Grand Slam's tournaments and the Davis Cup. The first ball games similar to tennis appear in Greece and Roman Imperial, and it reaches his maximum summit in the Middle Ages in France and England, across called "Jeu of the paume", before his decline in the 18th century. Finally, the invent of the modern tennis or "lawn tennis" at the end of the 19th century and his expansion for Europe, America and Australia, produced the creation of clubs, tournaments and associations destined of the diffusion and practice of this sport. Finally, a brief revision is realized to the history of the tennis in our country, from to the al-Andalus to the great Spanish winners.

  14. The World (of Warcraft through the eyes of an expert

    Directory of Open Access Journals (Sweden)

    Yousri Marzouki

    2017-09-01

    Full Text Available Negative correlations between pupil size and the tendency to look at salient locations were found in recent studies (e.g., Mathôt et al., 2015. It is hypothesized that this negative correlation might be explained by the mental effort put by participants in the task that leads in return to pupil dilation. Here we present an exploratory study on the effect of expertise on eye-movement behavior. Because there is no available standard tool to evaluate WoW players’ expertise, we built an off-game questionnaire testing players’ knowledge about WoW and acquired skills through completed raids, highest rated battlegrounds, Skill Points, etc. Experts (N = 4 and novices (N = 4 in the massively multiplayer online role-playing game World of Warcraft (WoW viewed 24 designed video segments from the game that differ in regards with their content (i.e, informative locations and visual complexity (i.e, salient locations. Consistent with previous studies, we found a negative correlation between pupil size and the tendency to look at salient locations (experts, r =  − .17, p < .0001, and novices, r =  − .09, p < .0001. This correlation has been interpreted in terms of mental effort: People are inherently biased to look at salient locations (sharp corners, bright lights, etc., but are able (i.e., experts to overcome this bias if they invest sufficient mental effort. Crucially, we observed that this correlation was stronger for expert WoW players than novice players (Z =  − 3.3, p = .0011. This suggests that experts learned to improve control over eye-movement behavior by guiding their eyes towards informative, but potentially low-salient areas of the screen. These findings may contribute to our understanding of what makes an expert an expert.

  15. Larger right posterior parietal volume in action video game experts: a behavioral and voxel-based morphometry (VBM study.

    Directory of Open Access Journals (Sweden)

    Satoshi Tanaka

    Full Text Available Recent studies suggest that action video game players exhibit superior performance in visuospatial cognitive tasks compared with non-game players. However, the neural basis underlying this visuospatial cognitive performance advantage remains largely unknown. The present human behavioral and imaging study compared gray matter volume in action video game experts and non-experts using structural magnetic resonance imaging and voxel-based morphometry analysis. The results revealed significantly larger gray matter volume in the right posterior parietal cortex in experts compared with non-experts. Furthermore, the larger gray matter volume in the right posterior parietal cortex significantly correlated with individual performance in a visual working memory task in experts. These results suggest that differences in brain structure may be linked to extensive video game play, leading to superior visuospatial cognitive performance in action video game experts.

  16. Waste disposal experts meet

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1959-01-15

    Problems connected with the disposal into the sea of radioactive wastes from peaceful uses of atomic energy are being examined by a panel of experts, convened by the International Atomic Energy Agency. These experts from eight different countries held a first meeting at IAEA headquarters in Vienna from 4-9 December 1958, under the chairmanship of Dr. Harry Brynielsson, Director General of the Swedish Atomic Energy Company. The countries represented are: Canada, Czechoslovakia, France, Japan, Netherlands, United Kingdom and United States. The group will meet again in 1959. (author)

  17. Eye on the Ball: Table Tennis as a Pro-Health Form of Leisure-Time Physical Activity

    Directory of Open Access Journals (Sweden)

    Elżbieta Biernat

    2018-04-01

    Full Text Available Background: The article is devoted to an analysis of leisure-time (amateur table tennis in Poland, its practitioners and the regularities of their activity. Methods: The study examined 12,406 persons in 4689 households (representative for the population. We used binary logistic regression and descriptive statistics in order to identify the patterns and determinants of table-tennis practice in Poland. Results: Table tennis is practised by 2.8% of population, and by 6.6% of physically active Poles. Among adults it is predominantly an occasional recreational game, not performed as a sport per se. Among children, it is often the part of physical education (PE classes. Statistically significant predictors of contact with table tennis are: gender, age, income, place of residence, children in the household and being a student. Conclusions: Due to the undeniable benefits of table tennis (health, pleasure, personal and social development, the sport is recommended for use as a tool in increasing the (overall low physical activity of Poles. Its popularization requires promotion in the media (as a health-oriented activity and using various channels, including public places, the workplace (as part of corporate social responsibility and physical education classes at school.

  18. Price competition between an expert and a non-expert

    OpenAIRE

    Bouckaert, J.M.C.; Degryse, H.A.

    1998-01-01

    This paper characterizes price competition between an expert and a non-expert. In contrast with the expert, the non-expert’s repair technology is not always successful. Consumers visit the expert after experiencing an unsuccessful match at the non-expert. This re-entry affects the behaviour of both sellers. For low enough probability of successful repair at the non-expert, all consumers first visit the non-expert, and a ‘timid-pricing’ equilibrium results. If the non-expert’s repair technolog...

  19. A COMPARISON OF THE ANTHROPOMETRIC PARAMETERS BETWEEN BASKETBALL PLAYERS, HANDBALL PLAYERS AND VOLLEYBALL PLAYERS

    OpenAIRE

    Florian Miftari; Juel Jarani; Dhimitraq Stratoberdha; Hazir Salihu

    2017-01-01

    The purpose of this study was to compare the anthropometric measurement to the professional players of the three different disciplines of basketball, handball and volleyball. . For each player anthropometric measurements such as weight, body height, waist circumference, BMI and skinfold calculation on different sports are performed. Differences in terms of anthropometric measurements were assessed by independent static tests and the differences for each variable for each sport were evaluated ...

  20. Self-Regulation of Practice Behavior Among Elite Youth Soccer Players : An Exploratory Observation Study

    NARCIS (Netherlands)

    Toering, Tynke; Elferink-Gemser, Marije; Jordet, Geir; Jorna, Casper; Pepping, Gert-Jan; Visscher, Chris

    2011-01-01

    This study aimed to measure behavioral correlates of self-regulation in elite youth soccer players. Behaviors regarded as indicative of self-regulated learning were identified by interviewing six expert youth soccer coaches. These behaviors were observed during practice of eight elite youth soccer

  1. Expert Systems Research.

    Science.gov (United States)

    Duda, Richard O.; Shortliffe, Edward H.

    1983-01-01

    Discusses a class of artificial intelligence computer programs (often called "expert systems" because they address problems normally thought to require human specialists for their solution) intended to serve as consultants for decision making. Also discusses accomplishments (including information systematization in medical diagnosis and…

  2. Computers Simulate Human Experts.

    Science.gov (United States)

    Roberts, Steven K.

    1983-01-01

    Discusses recent progress in artificial intelligence in such narrowly defined areas as medical and electronic diagnosis. Also discusses use of expert systems, man-machine communication problems, novel programing environments (including comments on LISP and LISP machines), and types of knowledge used (factual, heuristic, and meta-knowledge). (JN)

  3. Expert Cold Structure Development

    Science.gov (United States)

    Atkins, T.; Demuysere, P.

    2011-05-01

    The EXPERT Program is funded by ESA. The objective of the EXPERT mission is to perform a sub-orbital flight during which measurements of critical aero- thermodynamic phenomena will be obtained by using state-of-the-art instrumentation. As part of the EXPERT Flight Segment, the responsibility of the Cold Structure Development Design, Manufacturing and Validation was committed to the Belgian industrial team SONACA/SABCA. The EXPERT Cold Structure includes the Launcher Adapter, the Bottom Panel, the Upper Panel, two Cross Panels and the Parachute Bay. An additional Launcher Adapter was manufactured for the separation tests. The selected assembly definition and manufacturing technologies ( machined parts and sandwich panels) were dictated classically by the mass and stiffness, but also by the CoG location and the sensitive separation interface. Used as support for the various on-board equipment, the Cold Structure is fixed to but thermally uncoupled from the PM 1000 thermal shield. It is protect on its bottom panel by a thermal blanket. As it is a protoflight, analysis was the main tool for the verification. Low level stiffness and modal analysis tests have also been performed on the Cold Structure equipped with its ballast. It allowed to complete its qualification and to prepare SONACA/SABCA support for the system dynamic tests foreseen in 2011. The structure was finally coated with a thermal control black painting and delivered on time to Thales Alenia Space-Italy end of March 201.

  4. Frontal Lobe Function in Chess Players

    Directory of Open Access Journals (Sweden)

    Vahid Nejati

    2012-05-01

    Full Text Available Chess is considered as a cognitive game because of severe engagement of the mental resources during playing. The purpose of this study is evaluation of frontal lobe function of chess players with matched non-players. Wisconsin Card Sorting Test (WCST data showed no difference between the player and non-player groups in preservation error and completed categories but surprisingly showed significantly lower grade of the player group in correct response. Our data reveal that chess players dont have any preference in any stage of Stroop test. Chess players dont have any preference in selective attention, inhibition and executive cognitive function. Chess players' have lower shifting abilities than non-players.

  5. Frontal lobe function in chess players.

    Science.gov (United States)

    Nejati, Majid; Nejati, Vahid

    2012-01-01

    Chess is considered as a cognitive game because of severe engagement of the mental resources during playing. The purpose of this study is evaluation of frontal lobe function of chess players with matched non-players. Wisconsin Card Sorting Test (WCST) data showed no difference between the player and non-player groups in preservation error and completed categories but surprisingly showed significantly lower grade of the player group in correct response. Our data reveal that chess players don't have any preference in any stage of Stroop test. Chess players don't have any preference in selective attention, inhibition and executive cognitive function. Chess players' have lower shifting abilities than non-players.

  6. Physical fitness of elite Belgian soccer players by player position.

    Science.gov (United States)

    Boone, Jan; Vaeyens, Roel; Steyaert, Adelheid; Vanden Bossche, Luc; Bourgois, Jan

    2012-08-01

    The purpose of this study was to gain an insight into the physical and physiological profile of elite Belgian soccer players with specific regard to the player's position on the field. The sample consisted of 289 adult players from 6 different first division teams. The players were divided into 5 subgroups (goalkeepers, center backs, full backs, midfielders, and strikers) according to their self-reported best position on the field. The subjects performed anaerobic (10-m sprint, 5 × 10-m shuttle run [SR], squat jump [SJ], and countermovement jump [CMJ]) and aerobic (incremental running protocol) laboratory tests. The strikers had significantly shorter sprinting times (5-, 5- to 10-m time, and SR) compared with the midfielders, center backs, and goalkeepers, whereas the full backs were also significantly faster compared with the goalkeepers and the center backs. The goalkeepers and the center backs displayed higher jumping heights (total mean SJ = 40.7 ± 4.6 cm and CMJ = 43.1 ± 4.9 cm) compared with the other 3 positions, whereas the strikers also jumped higher than the full backs and the midfielders did. Regarding the aerobic performance, both full backs and the midfielders (61.2 ± 2.7 and 60.4 ± 2.8 ml · min(-1) · kg(-1), respectively) had a higher VO2max compared with the strikers, center backs, and goalkeepers (56.8 ± 3.1, 55.6 ± 3.5, and 52.1 ± 5.0 ml · min(-1) · kg(-1), respectively). From this study, it could be concluded that players in different positions have different physiological characteristics. The results of this study might provide useful insights for individualized conditional training programs for soccer players. Aside from the predominant technical and tactical skills, a physical profile that is well adjusted to the position on the field might enhance game performance.

  7. Evaluation of a subject-specific, torque-driven computer simulation model of one-handed tennis backhand groundstrokes.

    Science.gov (United States)

    Kentel, Behzat B; King, Mark A; Mitchell, Sean R

    2011-11-01

    A torque-driven, subject-specific 3-D computer simulation model of the impact phase of one-handed tennis backhand strokes was evaluated by comparing performance and simulation results. Backhand strokes of an elite subject were recorded on an artificial tennis court. Over the 50-ms period after impact, good agreement was found with an overall RMS difference of 3.3° between matching simulation and performance in terms of joint and racket angles. Consistent with previous experimental research, the evaluation process showed that grip tightness and ball impact location are important factors that affect postimpact racket and arm kinematics. Associated with these factors, the model can be used for a better understanding of the eccentric contraction of the wrist extensors during one-handed backhand ground strokes, a hypothesized mechanism of tennis elbow.

  8. An investigation of player to player character identification via personal pronouns

    DEFF Research Database (Denmark)

    Hichens, Michael; Drachen, Anders; Richards, Deborah

    2012-01-01

    The player character is an important feature of many games, where it is through the character that the player interacts with game world. There has been considerable interest in the relationship between the player and the player character. Much of this work has examined the identification of players......, third) as an indication of the relationship between player and character. Results indicate that the presence of story and information about the player character had no effect on identification with the plater character. However, characteristics of the players, particularly gender and general experience...... in playing video games, did have a statistically significant affect, indicating that different levels of identification are more dependent on the player than on the game. This indicates that players are not a homogeneous group with respect to player character identification and is an important consideration...

  9. Secure Multi-Player Protocols

    DEFF Research Database (Denmark)

    Fehr, Serge

    While classically cryptography is concerned with the problem of private communication among two entities, say players, in modern cryptography multi-player protocols play an important role. And among these, it is probably fair to say that secret sharing, and its stronger version verifiable secret...... sharing (VSS), as well as multi-party computation (MPC) belong to the most appealing and/or useful ones. The former two are basic tools to achieve better robustness of cryptographic schemes against malfunction or misuse by “decentralizing” the security from one single to a whole group of individuals...... (captured by the term threshold cryptography). The latter allows—at least in principle—to execute any collaboration among a group of players in a secure way that guarantees the correctness of the outcome but simultaneously respects the privacy of the participants. In this work, we study three aspects...

  10. Expert PLSQL Practices

    CERN Document Server

    Beresniewicz, John

    2011-01-01

    Expert PL/SQL Practices is a book of collected wisdom on PL/SQL programming from some of the best and the brightest in the field. Each chapter is a deep-dive into a specific problem, technology, or feature set that you'll face as a PL/SQL programmer. Each author has chosen their topic out of the strong belief that what they share can make a positive difference in the quality and scalability of code that you write. The path to mastery begins with syntax and the mechanics of writing statements to make things happen. If you've reached that point with PL/SQL, then let the authors of Expert PL/SQL

  11. Bioethics for Technical Experts

    Science.gov (United States)

    Asano, Shigetaka

    Along with rapidly expanding applications of life science and technology, technical experts have been implicated more and more often with ethical, social, and legal problems than before. It should be noted that in this background there are scientific and social uncertainty elements which are inevitable during the progress of life science in addition to the historically-established social unreliability to scientists and engineers. In order to solve these problems, therefore, we should establish the social governance with ‘relief’ and ‘reliance’ which enables for both citizens and engineers to share the awareness of the issues, to design social orders and criterions based on hypothetical sense of values for bioethics, to carry out practical use management of each subject carefully, and to improve the sense of values from hypothetical to universal. Concerning these measures, the technical experts can learn many things from the present performance in the medical field.

  12. Expert tool use

    DEFF Research Database (Denmark)

    Thorndahl, Kathrine Liedtke; Ravn, Susanne

    2017-01-01

    on a case study of elite rope skipping, we argue that the phenomenological concept of incorporation does not suffice to adequately describe how expert tool users feel when interacting with their tools. By analyzing a combination of insights gained from participant observation of 11 elite rope skippers......According to some phenomenologists, a tool can be experienced as incorporated when, as a result of habitual use or deliberate practice, someone is able to manipulate it without conscious effort. In this article, we specifically focus on the experience of expertise tool use in elite sport. Based...... and autoethnographic material from one former elite skipper, we take some initial steps toward the development of a more nuanced understanding of the concept of incorporation; one that is able to accommodate the experiences of expert tool users. In sum, our analyses indicate that the possibility for experiencing...

  13. Beijing's nuclear strategy makes China a major player

    International Nuclear Information System (INIS)

    Bernstein, J.

    1988-01-01

    This article discusses China's nuclear strategy which is a subject of debate among Asia experts, even as Sino-Soviet relations warm to a point unseen since the 1950s. China lags in the number and sophistication of its weapons. But modernization, national pride and the shrinking U.S. and Soviet arsenals have made Beijing and an increasingly important player. Beijing insists that its arsenal is strictly for defensive purposes; they have signed an agreement to make the South Pacific a nuclear-free zone

  14. The Boyd–McLeod procedure for tennis elbow: mid- to long-term results

    Science.gov (United States)

    Jeavons, Richard; Richards, Ian; Bayliss, Neil

    2014-01-01

    Background Tennis elbow is a common condition that usually responds to conservative measures. In refractory cases, surgical intervention is indicated. A plethora of surgical techniques have been described. We report the mid- to long-term outcomes of the Boyd–McLeod procedure for refractory tennis elbow. Methods A retrospective analysis and current review of patients that had undergone the Boyd–McLeod procedure over a 12-year period was undertaken. Demographics, time to discharge, length of follow-up and outcome scores were collected. Results Seventy patients underwent surgery. Mean time to discharge was 15.35 weeks, with 88% successful outcomes. Fifty-four patients were available for current follow-up at mean of 5.52 years (range 1.17 years to 11.49 years). Range of motion in all patients was unchanged. There were no revision procedures. Mean (SD) Mayo Elbow Performance Score was 90.85 (13.11), with 75.5% returning a good or excellent score and 24.5% a fair outcome. The mean (SD) Oxford Elbow Score was 44.04 (6.92); mean (SD) pain score was 89.5 (17.58); mean (SD) function score was 95.34 (9.59) and mean (SD) socio-psychological score was 91.50 (17.01). Overall, 83% of patients had an Oxford Elbow Score of 43 or greater, suggesting excellent outcome. Conclusions We show that the Boyd–McLeod procedure is an excellent option over both the short- and long-term for refractory tennis elbow. PMID:27582946

  15. The effect of internal and external focus of attention on game performance in tennis

    Directory of Open Access Journals (Sweden)

    Marina Tsetseli

    2016-12-01

    Full Text Available Background: Great importance has been given in recent years to the impact of focus of attention cues during skills execution but not during real game play, where more cognitive skills are involved besides technical performance. Objective: The purpose of the present study was to examine the effect of internal and external focus of attention instructions on the components of the game performance (decision making, skill execution, base in tennis. Methods: The participants (N = 60 were divided into three groups and followed an intervention training program that lasted 6 weeks; IF group (n = 20 under internal focus of attention instructions, EF group (n = 20 under external focus of attention instructions and CON group (n = 20 under no attentional focus instructions. Three measurements took place (pre, post and ret in which the participants were recorded on video while playing matches in real scoring conditions. Game Performance Assessment Instrument (GPAI was used to evaluate the components of game performance in tennis in three game situations; service, return of the service, base line game. Results: ANOVA repeated measures in a 3 (groups: IF, EF & CON × 3 (measurements: pre, post, ret revealed a significant interaction between groups and measurements and post hoc analysis indicated that the group that was instructed to focus externally improved significantly only in decision making compared to the internal focus of attention and to the control group. The score difference was maintained at the retention test as well, which indicates that the impact concerned not only performance but also learning. Conclusions: Instructions that aim to an external focus of attention enhance decision making skills, which are considered the most important element of game performance in tennis.

  16. THE INFLUENCE OF BALL VELOCITY AND COURT ILLUMINATION ON REACTION TIME FOR TENNIS VOLLEY

    Directory of Open Access Journals (Sweden)

    Jui-hung Tu

    2010-03-01

    Full Text Available The he purpose of this study is to examine the effects of ball velocity, court illumination, and volley type on the reaction time (RT of a tennis athlete for a volley stroke. Eights cases with two different ball velocities (high and low, two volley types (forehand and backhand and two court illumination levels (dark and bright were studied. The 30 participating subjects consisted of 18 male and 12 female college tennis athletes (age: 24 ± 3.2 yr, with a United States Tennis Association (USTA ranking above 2.5. In order to ensure the validity of real-world correlations, the experiments were designed to simulate real competition situations. Reaction times were measured for volley strokes in response to different approaching ball velocities (high: 25.05 ± 0.37 m/s and low: 17.56 ± 0.92 m·s-1 for several volley types (forehand and backhand and court illumination levels (55649 ± 4292 lux and 363.24 ± 6.53 lux on the court. During the tests, the signals from an electromyogram sensor and a 3-axis accelerometer (± 50 g were recorded using an NI DAQ card (NI PXI-6251 and then analyzed to determine reaction time (RT, premotor reaction time (PRT, and motor reaction time (MRT through the LabVIEW system. Subsequent 3-way ANOVA analysis indicated no RT, PRT, or MRT interaction between ball velocity, volley type and illumination. The ball velocity and illumination parameters did affect RT and PRT values significantly with p < 0.05, no significant variation in MRT was observed across any implemented experimental conditions. All experimental results indicate that ball velocity and illumination levels strongly affect the value of PRT, but have no significant effect on the value of MRT, the changes in RT were dominated by PRT

  17. ALICE Expert System

    CERN Document Server

    Ionita, C

    2014-01-01

    The ALICE experiment at CERN employs a number of human operators (shifters), who have to make sure that the experiment is always in a state compatible with taking Physics data. Given the complexity of the system and the myriad of errors that can arise, this is not always a trivial task. The aim of this paper is to describe an expert system that is capable of assisting human shifters in the ALICE control room. The system diagnoses potential issues and attempts to make smart recommendations for troubleshooting. At its core, a Prolog engine infers whether a Physics or a technical run can be started based on the current state of the underlying sub-systems. A separate C++ component queries certain SMI objects and stores their state as facts in a Prolog knowledge base. By mining the data stored in dierent system logs, the expert system can also diagnose errors arising during a run. Currently the system is used by the on-call experts for faster response times, but we expect it to be adopted as a standard tool by reg...

  18. ALICE Expert System

    International Nuclear Information System (INIS)

    Ionita, C; Carena, F

    2014-01-01

    The ALICE experiment at CERN employs a number of human operators (shifters), who have to make sure that the experiment is always in a state compatible with taking Physics data. Given the complexity of the system and the myriad of errors that can arise, this is not always a trivial task. The aim of this paper is to describe an expert system that is capable of assisting human shifters in the ALICE control room. The system diagnoses potential issues and attempts to make smart recommendations for troubleshooting. At its core, a Prolog engine infers whether a Physics or a technical run can be started based on the current state of the underlying sub-systems. A separate C++ component queries certain SMI objects and stores their state as facts in a Prolog knowledge base. By mining the data stored in different system logs, the expert system can also diagnose errors arising during a run. Currently the system is used by the on-call experts for faster response times, but we expect it to be adopted as a standard tool by regular shifters during the next data taking period

  19. Double pendulum model for a tennis stroke including a collision process

    Science.gov (United States)

    Youn, Sun-Hyun

    2015-10-01

    By means of adding a collision process between the ball and racket in the double pendulum model, we analyzed the tennis stroke. The ball and the racket system may be accelerated during the collision time; thus, the speed of the rebound ball does not simply depend on the angular velocity of the racket. A higher angular velocity sometimes gives a lower rebound ball speed. We numerically showed that the proper time-lagged racket rotation increased the speed of the rebound ball by 20%. We also showed that the elbow should move in the proper direction in order to add the angular velocity of the racket.

  20. Studying hand grip strength development among students who have taken tennis and massage courses

    Directory of Open Access Journals (Sweden)

    Erzeybek Mustafa Said

    2017-01-01

    Full Text Available In this study, the finger and hand force developments of the students who have taken selective/applied Tennis and Massage courses at the University have been examined. From the students of the Department of Physical Education and Sport, 19 healthy females and 73 healthy males (age = 21.25 ± 1.55 years (average ± SD who have taken selective Tennis courses;51 healthy males (age = 22.00 ± 1.04 years (average ± SD who have taken Massage courses; and as the control group,16 healthy womenand50 healthy males(age = 21.72 ± 1.47 years (average ± SD have been participated to the study. The age, length, body weight, grip strength of both hands as well as the finger grip strength of the subjects have been recorded. The course schedule has been set as once a week four hours practice for both tennis and massage. Two weeks of the education and training program that takes twelve weeks in total were assigned for theoretical classes. The remaining period of ten weeks was for practice classes and the measurements were performed before and after this ten weeks period. The hand grip strength measurement has been carried out with a Takkei branded hand dynamometer whereas for the measurement of the finger grip strength, a Baseline branded pinch meter has been used. For both the pre-test and final test of the finger grip and hand grip strength measurements, the paired sample t test has been used in terms of in-group comparisons, whereas for the inter-group comparisons, one-way ANOVA has been used. For the significant F values, post hoc Tukey test has been used. The right hand and the left hand grip values of both test groups as well as the values of the control group have been significantly increased between the pre-test and final test. Particularly, preferring the exercises that improve the hand and finger grip strengths would enable a better racket handle grip as well as an improved shot efficiency for tennis. This would also enable masseurs/masseuses to apply

  1. The Effectiveness Evaluation among Different Player-Matching Mechanisms in a Multi-Player Quiz Game

    Science.gov (United States)

    Tsai, Fu-Hsing

    2016-01-01

    This study aims to investigate whether different player-matching mechanisms in educational multi-player online games (MOGs) can affect students' learning performance, enjoyment perception and gaming behaviors. Based on the multi-player quiz game, TRIS-Q, developed by Tsai, Tsai and Lin (2015) using a free player-matching (FPM) mechanism, the same…

  2. Measuring chess experts' single-use sequence knowledge: an archival study of departure from 'theoretical' openings.

    Directory of Open Access Journals (Sweden)

    Philippe Chassy

    Full Text Available The respective roles of knowledge and search have received considerable attention in the literature on expertise. However, most of the evidence on knowledge has been indirect--e.g., by inferring the presence of chunks in long-term memory from performance in memory recall tasks. Here we provide direct estimates of the amount of monochrestic (single use and rote knowledge held by chess players of varying skill levels. From a large chess database, we analyzed 76,562 games played in 2008 by individuals ranging from Class B players (average players to Masters to measure the extent to which players deviate from previously known initial sequences of moves ("openings". Substantial differences were found in the number of moves known by players of different skill levels, with more expert players knowing more moves. Combined with assumptions independently made about the branching factor in master games, we estimate that masters have memorized about 100,000 opening moves. Our results support the hypothesis that monochrestic knowledge is essential for reaching high levels of expertise in chess. They provide a direct, quantitative estimate of the number of opening moves that players have to know to reach master level.

  3. Effects of new sports tennis type exercise on aerobic capacity, follicle stimulating hormone and N-terminal telopeptide in the postmenopausal women.

    Science.gov (United States)

    Shin, Hyun-Jae; Lee, Ha-Yan; Cho, Hye-Young; Park, Yun-Jin; Moon, Hyung-Hoon; Lee, Sung-Hwan; Lee, Sung-Ki; Kim, Myung-Ki

    2014-04-01

    Menopause is characterized by rapid decreases in bone mineral density, aerobic fitness, muscle strength, and balance. In the present study, we investigated the effects of new sports tennis type exercise on aerobic capacity, follicle stimulating hormone (FSH) and N-terminal telopeptide (NTX) in the postmenopausal women. Subjects were consisted of 20 postmenopausal women, who had not menstruated for at least 1 yr and had follicle-stimulating hormone levels > 35 mIU/L, estradiol levelssports tennis type exercise group (n= 10). New sports tennis type exercise was consisted of warm up (10 min), new sports tennis type exercise (40 min), cool down (10 min) 3 days a per week for 12 weeks. The aerobic capacities were increased by 12 weeks new sports tennis type exercise. New sports tennis type exercise significantly increased FSH and NTx levels, indicating biochemical markers of bone formation and resorption. These findings indicate that 12 weeks of new sports tennis type exercise can be effective in prevention of bone loss and enhancement of aerobic capacity in postmenopausal women.

  4. Sophisticated Players and Sophisticated Agents

    NARCIS (Netherlands)

    Rustichini, A.

    1998-01-01

    A sophisticated player is an individual who takes the action of the opponents, in a strategic situation, as determined by decision of rational opponents, and acts accordingly. A sophisticated agent is rational in the choice of his action, but ignores the fact that he is part of a strategic

  5. The NBA’s Maximum Player Salary and the Distribution of Player Rents

    Directory of Open Access Journals (Sweden)

    Kelly M. Hastings

    2015-03-01

    Full Text Available The NBA’s 1999 Collective Bargaining Agreement (CBA included provisions capping individual player pay in addition to team payrolls. This study examines the effect the NBA’s maximum player salary on player rents by comparing player pay from the 1997–1998 and 2003–2004 seasons while controlling for player productivity and other factors related to player pay. The results indicate a large increase in the pay received by teams’ second highest and, to a lesser extent, third highest paid players. We interpret this result as evidence that the adoption of the maximum player salary shifted rents from stars to complementary players. We also show that the 1999 CBA’s rookie contract provisions reduced salaries of early career players.

  6. Expert Oracle Exadata

    CERN Document Server

    Johnson, Randy

    2011-01-01

    Throughout history, advances in technology have come in spurts. A single great idea can often spur rapid change as the idea takes hold and is propagated, often in totally unexpected directions. Exadata embodies such a change in how we think about and manage relational databases. The key change lies in the concept of offloading SQL processing to the storage layer. That concept is a huge win, and its implementation in the form of Exadata is truly a game changer. Expert Oracle Exadata will give you a look under the covers at how the combination of hardware and software that comprise Exadata actua

  7. The naked experts

    International Nuclear Information System (INIS)

    Martin, B.

    1982-01-01

    In an article critical of experts, the cases argued for and against nuclear power are discussed under the headings: environmental hazards arising from the nuclear fuel cycle; proliferation of nuclear weapons capabilities via expansion of the nuclear power industry; political and social threats and restraints of a nuclear society (terrorism, reduction in civil liberties, centralised political and economic power); economic and employment disadvantages of nuclear power; impact of uranium mining on (Australian) aboriginal culture; inadequacy of nuclear power as a solution to energy problems; advantages of a 'soft energy path' based around conservation and renewable energy technologies. (U.K.)

  8. Performance Factors Related to the Different Tennis Backhand Groundstrokes: A Review

    Directory of Open Access Journals (Sweden)

    Cyril Genevois, Machar Reid, Isabelle Rogowski, Miguel Crespo

    2015-03-01

    Full Text Available The backhand is one of the two basic groundstrokes in tennis and can be played both with one or two hands, with topspin or backspin. Despite its variety of derivatives, the scientific literature describing the backhand groundstroke production has not been reviewed as extensively as with the serve and the forehand. The purpose of this article is to review the research describing the mechanics of one and two-handed backhands, with a critical focus on its application to clinicians and coaches. One hundred and thirty four articles satisfied a key word search (tennis, backhand in relevant databases and manual search, with only 61 of those articles considered directly relevant to our review. The consensus of this research supports major differences between both the one- and two-handed strokes, chiefly about their respective contributions of trunk rotation and the role of the non-dominant upper extremity. Two-handed backhand strokes rely more on trunk rotation for the generation of racquet velocity, while the one-handed backhands utilize segmental rotations of the upper limb to develop comparable racquet speeds. There remains considerable scope for future research to examine expertise, age and/or gender-related kinematic differences to strengthen the practitioner’s understanding of the key mechanical considerations that may shape the development of proficient backhand strokes.

  9. Rupture of the medial gastrocnemius muscle during namaz praying: an unusual cause of tennis leg.

    Science.gov (United States)

    Yilmaz, Cengiz; Orgenc, Yaman; Ergenc, Ruken; Erkan, Nazif

    2008-12-01

    The aim of this retrospective study is to report a unique group of patients in whom rupture of the medial gastrocnemius muscle (tennis leg) occurred during namaz praying. We reviewed the sonographic and/or MR imaging findings of 543 patients who were referred for the evaluation of leg pain and swelling during the last 7 years. Fourteen patients with a final diagnosis of tennis leg that occured during namaz praying were included in this study. Nine of 14 (64.2%) patients had incomplete and the remainder 5 (35.8%) patients had a partial tear at the musculotendinous junction (MTJ). Four of 14 (28.6%) patients were mistaken for deep vein thrombosis (DVT) on the basis of clinical findings and presentation. Associated fluid collection between the gastrocnemius and soleus muscle was noted in 11 (78.5%) patients. Isolated fluid collection between the gastrocnemius and soleus muscle without disruption of the gastrocnemius muscle was seen in 1 patient. Rupture of the medial gastrocnemius muscle may occur during namaz praying. The clinical presentation is not always characteristic and may simulate DVT. US and MRI are useful diagnostic tools to establish the correct diagnosis and prompt further treatment.

  10. Strength and fatigability of selected muscles in upper limb: assessing muscle imbalance relevant to tennis elbow.

    Science.gov (United States)

    Alizadehkhaiyat, O; Fisher, A C; Kemp, G J; Frostick, S P

    2007-08-01

    The aetiology of tennis elbow has remained uncertain for more than a century. To examine muscle imbalance as a possible pathophysiological factor requires a reliable method of assessment. This paper describes the development of such a method and its performance in healthy subjects. We propose a combination of surface and fine-wire EMG of shoulder and forearm muscles and wrist strength measurements as a reliable tool for assessing muscle imbalance relevant to the pathophysiology of tennis elbow. Six healthy volunteers participated. EMG data were acquired at 50% maximal voluntary isometric contraction from five forearm muscles during grip and three shoulder muscles during external rotation and abduction, and analysed using normalized median frequency slope as a fatigue index. Wrist extension/flexion strength was measured using a purpose-built dynamometer. Significant negative slope of median frequency was found for all muscles, with good reproducibility, and no significant difference in slope between the different muscles of the shoulder and the wrist. (Amplitude slope showed high variability and was therefore unsuitable for this purpose.) Wrist flexion was 27+/-8% stronger than extension (mean+/-SEM, p=0.006). This is a reliable method for measuring muscle fatigue in forearm and shoulder. EMG and wrist strength studies together can be used for assessing and identifying the muscle balance in the wrist-forearm-shoulder chain.

  11. [Deontology of the medical expert].

    Science.gov (United States)

    Raszeja, S

    1995-09-01

    The authority of prosecuting organ to choose the expert, set his task and verify the following opinion is defined. The qualities of the medical expert and his duties are described, referring to: -his expertise; -his morality; -his ability to issue an independent (objective) opinion. Detailed rules, which can be ascribed to a specific medical expert's deontological code, are listed and explained.

  12. Chronic elbow dislocation: a rare complication of tennis elbow surgery. Successful treatment by open reduction and external fixator.

    Science.gov (United States)

    Degreef, I; De Smet, L

    2007-06-01

    A case is presented of chronic dislocation of the elbow after tennis elbow surgery combined with posterior interosseous nerve (PIN) release. An open reduction with repair of the collateral ligaments was performed. Postoperative rehabilitation involved the use of an articulated external fixator and there was a successful outcome. Possible causes of the dislocation are discussed.

  13. Cross-cultural adaptation and reliability and validity of the Dutch Patient-Rated Tennis Elbow Evaluation (PRTEE-D)

    NARCIS (Netherlands)

    van Ark, Mathijs; Zwerver, Johannes; Diercks, Ronald L; van den Akker-Scheek, Inge

    2014-01-01

    Background: Lateral Epicondylalgia (LE) is a common injury for which no reliable and valid measure exists to determine severity in the Dutch language. The Patient-Rated Tennis Elbow Evaluation (PRTEE) is the first questionnaire specifically designed for LE but in English. The aim of this study was

  14. Tennis Elbow Diagnosis Using Equivalent Uniform Voltage to Fit the Logistic and the Probit Diseased Probability Models

    Directory of Open Access Journals (Sweden)

    Tsair-Fwu Lee

    2015-01-01

    Full Text Available To develop the logistic and the probit models to analyse electromyographic (EMG equivalent uniform voltage- (EUV- response for the tenderness of tennis elbow. In total, 78 hands from 39 subjects were enrolled. In this study, surface EMG (sEMG signal is obtained by an innovative device with electrodes over forearm region. The analytical endpoint was defined as Visual Analog Score (VAS 3+ tenderness of tennis elbow. The logistic and the probit diseased probability (DP models were established for the VAS score and EMG absolute voltage-time histograms (AVTH. TV50 is the threshold equivalent uniform voltage predicting a 50% risk of disease. Twenty-one out of 78 samples (27% developed VAS 3+ tenderness of tennis elbow reported by the subject and confirmed by the physician. The fitted DP parameters were TV50 = 153.0 mV (CI: 136.3–169.7 mV, γ50 = 0.84 (CI: 0.78–0.90 and TV50 = 155.6 mV (CI: 138.9–172.4 mV, m = 0.54 (CI: 0.49–0.59 for logistic and probit models, respectively. When the EUV ≥ 153 mV, the DP of the patient is greater than 50% and vice versa. The logistic and the probit models are valuable tools to predict the DP of VAS 3+ tenderness of tennis elbow.

  15. Arm Care. Relief and Prevention for Shoulder Tendonitis, Tennis Elbow, Bursitis and Wrist Sprain in Athletics and Other Activities.

    Science.gov (United States)

    Nirschl, Robert P.

    The book provides a practical and meaningful treatment program for athletes involved in sports which injure the arm or shoulder to a high degree, such as tennis, baseball, swimming, raquetball, pole vaulting, javelin throwing, and weight training. The book's chapters present information on: (1) symptoms of injury; (2) the anatomy of injury; (3)…

  16. Tennis Elbow Diagnosis Using Equivalent Uniform Voltage to Fit the Logistic and the Probit Diseased Probability Models

    Science.gov (United States)

    Lin, Wei-Chun; Lin, Shu-Yuan; Wu, Li-Fu; Guo, Shih-Sian; Huang, Hsiang-Jui; Chao, Pei-Ju

    2015-01-01

    To develop the logistic and the probit models to analyse electromyographic (EMG) equivalent uniform voltage- (EUV-) response for the tenderness of tennis elbow. In total, 78 hands from 39 subjects were enrolled. In this study, surface EMG (sEMG) signal is obtained by an innovative device with electrodes over forearm region. The analytical endpoint was defined as Visual Analog Score (VAS) 3+ tenderness of tennis elbow. The logistic and the probit diseased probability (DP) models were established for the VAS score and EMG absolute voltage-time histograms (AVTH). TV50 is the threshold equivalent uniform voltage predicting a 50% risk of disease. Twenty-one out of 78 samples (27%) developed VAS 3+ tenderness of tennis elbow reported by the subject and confirmed by the physician. The fitted DP parameters were TV50 = 153.0 mV (CI: 136.3–169.7 mV), γ 50 = 0.84 (CI: 0.78–0.90) and TV50 = 155.6 mV (CI: 138.9–172.4 mV), m = 0.54 (CI: 0.49–0.59) for logistic and probit models, respectively. When the EUV ≥ 153 mV, the DP of the patient is greater than 50% and vice versa. The logistic and the probit models are valuable tools to predict the DP of VAS 3+ tenderness of tennis elbow. PMID:26380281

  17. Hybrid expert system

    International Nuclear Information System (INIS)

    Tsoukalas, L.; Ikonomopoulos, A.; Uhrig, R.E.

    1991-01-01

    This paper presents a methodology that couples rule-based expert systems using fuzzy logic, to pre-trained artificial neutral networks (ANN) for the purpose of transient identification in Nuclear Power Plants (NPP). In order to provide timely concise, and task-specific information about the may aspects of the transient and to determine the state of the system based on the interpretation of potentially noisy data a model-referenced approach is utilized. In it, the expert system performs the basic interpretation and processing of the model data, and pre-trained ANNs provide the model. having access to a set of neural networks that typify general categories of transients, the rule based system is able to perform identification functions. Membership functions - condensing information about a transient in a form convenient for a rule-based identification system characterizing a transient - are the output of neural computations. This allows the identification function to be performed with a speed comparable to or faster than that of the temporal evolution of the system. Simulator data form major secondary system pipe rupture is used to demonstrate the methodology. The results indicate excellent noise-tolerance for ANN's and suggest a new method for transient identification within the framework of Fuzzy Logic

  18. Qual é o perfil motivacional característico de tenistas infanto-juvenis brasileiros? What is the motivational profile characteristic of children and young Brazilian players?

    Directory of Open Access Journals (Sweden)

    Marcos Alencar Abaide Balbinotti

    2012-12-01

    Full Text Available Motivação, na Teoria da Autodeterminação (TAD, é entendida como a chave principal do bom funcionamento psicológico do indivíduo e de seu bem-estar geral. De acordo com esta teoria, o "Prazer" é a dimensão que melhor explica o comportamento humano autodeterminado. Este estudo descreve o perfil motivacional característico de tenistas infanto-juvenis brasileiros e explora possíveis diferenças significativas nas médias das dimensões que integram o perfil avaliado pelo Inventário de Motivação à Prática Regular de Atividades Físicas e/ou Esportivas (IMPRAFE-126, controladas pela variável "Sexo". Uma amostra de 226 tenistas gaúchos e catarinenses, com idades entre 13 e 16 anos. Os resultados indicam que a dimensão que mais motiva esses tenistas, independente do sexo, é o Prazer, seguida, respectivamente, pelas dimensões: Competitividade, Saúde, Sociabilidade, Estética e Controle de Estresse. Além de este resultado ser um importante indicador à formulação de modelos de treino, uma das principais conclusões é que este estudo confirma a teoria de base.Motivation, in the Self-Determination Theory, is understood as the main key of the individual good psychological functioning and its general well-being. According to this theory, the "Pleasure" is the dimension that better explains the self-determinate human behavior. This study describes the juvenile tennis player motivational profile and explores differences in the average levels of the motivational dimensions that integrate the profile evaluated for the Inventário de Motivação à Prática Regular de Atividades Físicas e/ou Esportivas (IMPRAFE-126, controlled for the variable "Sex". A sample of 226 youthful tennis player (13 to 16 years old, of both sex. The results indicate the dimension that more motivates these tennis player, independent of the sex in analysis, is the Pleasure; followed, respectively, for the Competitiveness, Health, Sociability, Aesthetic and

  19. THE EFFECT OF n-3 LC-PUFA SUPPLEMENTATION ON TENNIS SKILL ACQUISITION IN 10-12 YEAR OLD GIRLS

    Directory of Open Access Journals (Sweden)

    Asuman Şahan

    2012-07-01

    Full Text Available The purpose of this study was to investigate the effects of 16 weeks of n-3 LC-PUFA (omega 3 long-chain polyunsaturated fatty acid supplementation on tennis skill acquisition in 10-12 year old girls. This research was a single-blind placebo-controlled trial. 29 girls (10-12 years of age who had never played tennis before took part in the study. Ball Throws to the Target (BTT and Tennis Ability Test (TAT were performed three times. Before participants were allocated to the groups and received n-3 LC-PUFA or olive oil, they underwent preparatory training for three weeks. Anthropometric measurements, nutrition analysis, and 1st BTT and TAT tests were performed and they continued the preparatory training until the 3rd week. Then they were randomly allocated to two groups to receive either n-3 LC-PUFA (omega group; 670 mg · day-1; n=16 or olive oil (placebo group; 670 mg · day-1; n=13 during 16 weeks of tennis training which involved 3 hours per week for 19 weeks. The results show that significant improvements in TAT were found in both groups but the omega group had significantly higher scores than the placebo group at the 3rd measurements. Although there were no differences between groups at all measurements of BTT, the omega group showed significant improvement between the 1st and 3rd measurements. This study suggests that daily 670 mg n-3 LC-PUFA supplementation for 16 weeks might improve tennis ability test scores of 10-12 year old girls.

  20. Football experts versus sports economists: Whose forecasts are better?

    Science.gov (United States)

    Frick, Bernd; Wicker, Pamela

    2016-08-01

    Given the uncertainty of outcome in sport, predicting the outcome of sporting contests is a major topic in sport sciences. This study examines the accuracy of expert predictions in the German Bundesliga and compares their predictions to those of sports economists. Prior to the start of each season, a set of distinguished experts (head coaches and players) express their subjective evaluations of the teams in school grades. While experts may be driven by irrational sentiments and may therefore systematically over- or underestimate specific teams, sports economists use observable characteristics to predict season outcomes. The latter typically use team wage bills given the positive pay-performance relationship as well as other factors (average team age, tenure, appearances on national team, and attendance). Using data from 15 consecutive Bundesliga seasons, the predictive accuracy of expert evaluations and sports economists is analysed. The results of separate estimations show that relative grade and relative wage bill significantly affect relative points, while age, tenure, appearances, and attendance are insignificant. In a joint model, relative grade and relative wage bill are still statistically significant, suggesting that the two types of predictions are complements rather than substitutes. Consequently, football experts and sports economists seem to rely on completely different sources of information when making their predictions.

  1. Der Patient als Experte.

    Science.gov (United States)

    Dubs

    1998-01-01

    Patients as Experts: Determining Benefit by Using Assessments of Ability (ICIDH)When health economy and quality mangement are dealing with the cost-benefit relationship, to this day description, calculation, and assessment of the benefit are missing to a great extent. Deliberations in terms of cause and effect do not go beyond the model of pathogenesis (etiology - pathology - manifestation) and descriptions on the organ level (ICD). Only the international classification of impairments, disabilities, and handicaps (ICIDH) as a separate estimation of the resulting manifestations of illness on the levels of organ, individual, and society is capable to elucidate this benefit. It is the patient who is the expert to decide what he needs, what he wants, and what he can do, thus, evaluating on an individual level his loss of capability. The ICIDH is regarded as the key for the management of chronic diseases. The characteristics of being chronically ill require the integration of salutogenesis and the consideration of the hierarchy of needs. The specially developed MARA model serves as pragmatic basis for the description of the benefits of carried out and omitted interventions as changes of abilities by using the MARA curve (mean age-related ability) as ethical guideline. In quality circles the MARA model, which is based on ICIDH, hierarchy of needs and salutogenesis, can offer apatient-oriented basis of discussion for benefit assessments, and, in a pragmatical way, it can facilitate the introduction of evidence-based medicine. By the change of view from the organ level with multifactorial aspects to the individual level, in which the abilities can be understood as a monofactor, a high consensus potential between several participants of discussion in health service is possible.

  2. Mechanisms of traumatic shoulder injury in elite rugby players

    Science.gov (United States)

    Crichton, James; Jones, Doug R; Funk, Lennard

    2012-01-01

    Background Shoulder injuries in rugby players are common, but the mechanisms of injury are less well understood. This study aims to elucidate common mechanisms of injury and identify the patterns of injury they produce. Materials and methods Twenty-four elite rugby players, referred to the senior author for diagnosis and management of shoulder injuries, were selected. Videos of the injuries were independently reviewed by rugby-medical experts to describe the mechanisms of injury. The mechanisms reported were collated and analysed to determine the level of agreement between reviewers and conclude an overall description of injury mechanisms. Results The authors identified three mechanisms of shoulder injury from the video analysis. These are the ‘Try-Scorer’, characterised by hyperflexion of the outstretched arm such as when scoring a try; the ‘Tackler’, extension of the abducted arm behind the player while tackling; and the ‘Direct Impact’, a direct blow to the arm or shoulder when held by the side in neutral or slight adduction. The Try Scorer and Tackler mechanisms both involve a levering force on the glenohumeral joint (GHJ). These mechanisms predominantly cause GHJ dislocation, with Bankart, reverse Bankart and superior labrum anterior–posterior tears. The Try-Scorer Mechanism also caused the majority (83%) of rotator cuff tears. The Direct Hit mechanism resulted in GHJ dislocation and labral injury in 37.5% of players and was most likely to cause acromioclavicular joint dislocation and scapula fractures, injuries that were not seen with the other mechanisms. Conclusion Greater understanding of the mechanisms involved in rugby shoulder injury is useful in understanding the pathological injuries, guiding treatment and rehabilitation and aiding the development of injury-prevention methods. PMID:22510645

  3. Adapting playware to multiple players

    DEFF Research Database (Denmark)

    Þorsteinsson, Arnar Tumi; Lund, Henrik Hautop; Mastorakis, Nikos

    2011-01-01

    With the creation of playware as intelligent hardware and software that creates play, it is possible to adapt the play tool to the individual user, and even to multiple users playing at the same time with the play tool. In this paper, we show how it is possible to implement adaptivity in modular...... to such differences, and argues that adaptivity is needed to make games fit to the individual users in both single-player games and multi-player games. As a case study, we implemented such adaptivity on modular interactive tiles for the single-user game ColorTimer, and for the multiple-user games PingPong, in which...

  4. Motivational profile quality players handball

    Directory of Open Access Journals (Sweden)

    Alfonso Martínez Moreno

    2017-06-01

    Full Text Available In the sport context, elite category, it is necessary to know all the factors, which in one way or another, affect the athletes throughout the different competitions. The object of study is to know the motivational profile of elite handball players. The sample consisted of 495 players, of whom 47.8% were boys and 52.2% girls, their ages ranged from 12 to 16 years, with an average of 13.8 years (dt = 1.0. Descriptive statistical analyzes of the sample, absolute and relative frequencies were performed for the qualitative variables and for the quantitative values minimum, maximum, mean, standard deviation, Cronbach's alpha. Correlation between variables, with the Pearson correlation coefficient. The MANCOVA test was performed to determine if there were differences between the dimensions of the questionnaire, according to age and years of practice. The results reveal that handball players elite category of the sample object of study have mainly intrinsic motivation, achieving high scores on general motivation, motivation achievement and motivation stimulation. In addition to moderately high values in introjected regulation and very low values in demotivation.

  5. [Dietary behaviours of volleyball and basketball players].

    Science.gov (United States)

    Szczepańska, Elzbieta; Spałkowska, Agnieszka

    2012-01-01

    In sports, such as basketball and volleyball, players must demonstrate the speed, strength, stamina and concentration. Correct nutrition affects the strength of the muscles and the extension of capacity. It is also necessary for the proper functioning of the nervous system and determines the rate of regeneration after physical effort. The aim of this study was to assess dietary behaviours of professional volleyball and basketball players and compare the prevalence of correct behaviours in both groups. 209 professional volleyball and basketball players from sports clubs localized in six Silesian cities were survived with the mean of author questionnaire. The chi-square test was used to examine differences in the prevalence of the correct behaviours among players. Analysis of the results obtained showed that 52% of the players had 4-5 meals a day. 35% of respondents had wholemeal bread and/or groats daily. Milk and dairy products daily ate 71% of surveyed players, meat and sausages 70% respectively. 41% of respondents had cottage cheese and 28% had fish several times a week. Vegetables and fruit were eaten by 21% and respectively 23% of respondents. Sweets were eaten daily by 40% of surveyed, while fast-food were eaten several times a week by 17% of players. Nutrients for athletes were used by 32%, and vitamin supplementation by 48% of respondents. Prevalence of correct dietary behaviour in the group of professional volleyball and basketball players differed. Basketball players statistically more frequently than volleyball players had 4-5 meals a day, had wholemeal bread and/or thick groats, milk and dairy products, meat and sausages, especially poultry. They had raw vegetables and fruit several times a day. They drank more than 2.5 liters of fluids per day. They also significantly more frequently than volleyball players consumed the fast-food occasionally or never. Dietary behaviours of surveyed players were incorrect. Comparison of prevalence of proper behaviours

  6. Feasibility of precompetition medical assessment at FIFA World Cups for female youth players.

    Science.gov (United States)

    Dvorak, Jiri; Grimm, Katharina; Schmied, Christian; Junge, Astrid

    2012-12-01

    Although most experts agree that preparticipation screening is important to prevent sudden cardiac death in sport, only a few reports have been published on the feasibility of its practical implementation. The football associations participating in the U-17 and U-20 Women's World Cups 2010 were asked to perform a standardised precompetition medical assessment (PCMA) of their players (in total 672). Compliance with the requirement for performing the PCMA was high among all teams, particularly from African, Asian and Central/South American countries. No relevant abnormal findings in personal history and clinical cardiological examination were reported. Athletic ECG patterns were frequent, but very few findings were considered to require further investigation. All players were declared as eligible to play. Based on the demonstrated feasibility of performing a comprehensive PCMA in elite female youth players, the Fédération Internationale de Football Association (FIFA) Executive Committee decided to make the PCMA a compulsory requirement for all FIFA competitions.

  7. Expert system in PNC, 5

    International Nuclear Information System (INIS)

    Tobita, Yoshimasa; Yamaguchi, Takashi; Matsumoto, Mitsuo; Ono, Kiyoshi.

    1990-01-01

    The computer code system which can evaluate the mass balance and cycle cost in nuclear fuel cycle has been developing a PNC using an artificial intelligence technique. This system is composed of the expert system, data base and analysis codes. The expert system is the most important one in the system and the content of the expert system is explained in this paper. The expert system has the three functions. The first is the function of understanding the meaning of user's questions by natural language, the second is the function of selecting the best way to solve the problem given by the user using the knowledge which is already installed in the system, and the last is the function of answering the questions. The knowledge of the experts installed in the expert system is represented by the frame-type rules. Therefore, the knowledge will be simply added to the system, and consequently the system will be easily extended. (author)

  8. The estimation of the correlation between technical-tactical and special physical performance in qualified women volleyball players

    OpenAIRE

    Wnorowski, Krzysztof; Smulskij, Walerij

    2007-01-01

    The article deals with the correlation between technical-tactical and special physical performance in qualified women volleyball players. The experts estimation of technical-tactical performance and seven indices of special physical capacities of athletes were correlated. Most correlation (r = 0,68; p

  9. The First Expert CAI System

    Science.gov (United States)

    Feurzeig, Wallace

    1984-01-01

    The first expert instructional system, the Socratic System, was developed in 1964. One of the earliest applications of this system was in the area of differential diagnosis in clinical medicine. The power of the underlying instructional paradigm was demonstrated and the potential of the approach for valuably supplementing medical instruction was recognized. Twenty years later, despite further educationally significant advances in expert systems technology and enormous reductions in the cost of computers, expert instructional methods have found very little application in medical schools.

  10. Vitamin D Deficiency Among Professional Basketball Players.

    Science.gov (United States)

    Fishman, Matthew P; Lombardo, Stephen J; Kharrazi, F Daniel

    2016-07-01

    Vitamin D plays an important role in several systems of the human body. Various studies have linked vitamin D deficiency to stress and insufficiency fractures, muscle recovery and function, and athletic performance. The prevalence of vitamin D deficiency in the elite athletic population has not been extensively studied, and very few reports exist among professional athletes. There is a high prevalence of vitamin D deficiency or insufficiency among players attending the National Basketball Association (NBA) Combine. Cross-sectional study; Level of evidence, 3. This is a retrospective review of data previously collected as part of the routine medical evaluation of players in the NBA Combines from 2009 through 2013. Player parameters evaluated were height, weight, body mass index (BMI), and vitamin D level. Statistical analysis using t tests and analysis of variance was used to detect any correlation between the player parameters and vitamin D level. Vitamin D levels were categorized as deficient (32 ng/mL). After institutional review board approval was submitted to the NBA, the NBA released deidentified data on 279 players who participated in the combines from 2009 through 2013. There were 90 players (32.3%) who were deficient, 131 players (47.0%) who were insufficient, and 58 players (20.8%) who were sufficient. A total of 221 players (79.3%) were either vitamin D deficient or insufficient. Among all players included, the average vitamin D level was 25.6 ± 10.2 ng/mL. Among the players who were deficient, insufficient, and sufficient, the average vitamin D levels were 16.1 ± 2.1 ng/mL, 25.0 ± 3.4 ng/mL, and 41.6 ± 8.6 ng/mL, respectively. Player height and weight were significantly increased in vitamin D-sufficient players compared with players who were not sufficient (P = .0008 and .009, respectively). Player age and BMI did not significantly differ depending on vitamin D status (P = .15 and .77, respectively). There is a high prevalence of vitamin D deficiency

  11. Laser radiation in tennis elbow treatment: a new minimally invasive alternative

    Science.gov (United States)

    Paganini, Stefan; Thal, Dietmar R.; Werkmann, Klaus

    1998-01-01

    The epicondylitis humeri radialis (EHR) (tennis elbow), is a common disease in elbow joint pain syndromes. We treated patients with chronic pain for at least one year and no improvement with conservative or operative therapies with a new minimal invasive method, the EHR-Laser radiation (EHR- LR). With this method periepicondylar coagulations were applied to the trigger points of the patients. For this the previously established technique of facet joint coagulation with the Nd:Yag-laser was modified. In a follow-up study of between 6 weeks and 2 years all patients reported either a significant pain reduction or were symptom free. EHR-LR is a new method situated between conservative and surgical treatments for minimal invasive therapy of EHR. Several therapeutic rationales were discussed for the resulting pain reduction.

  12. Are “knife and fork” good enough for day case surgery of resistant tennis elbow?

    Science.gov (United States)

    Govindaswamy, Raja; Elbouni, Tariq; Chambler, Andrew F. W.

    2008-01-01

    This observational retrospective study was performed on 22 consecutive patients treated surgically in a day surgery unit for resistant tennis elbow to ascertain the effectiveness of the “knife and fork” procedure. All patients had an unfavourable response to nonsurgical treatment lasting at least six months. A simple and inexpensive “knife and fork” technique yielded excellent results in 90.5% of patients and a high percentage (95.2%) of satisfied patients at an average follow-up of two years. There were no fair or poor results and no complications. We conclude that the “knife and fork” technique is a simple and dependable day case procedure. In the present National Health Service (NHS) era of tariff and “payment by results”, this approach is more cost effective than an arthroscopic alternative. PMID:19096844

  13. Measurement of Strain and Strain Rate during the Impact of Tennis Ball Cores

    Directory of Open Access Journals (Sweden)

    Ben Lane

    2018-03-01

    Full Text Available The aim of this investigation was to establish the strains and strain rates experienced by tennis ball cores during impact to inform material characterisation testing and finite element modelling. Three-dimensional surface strains and strain rates were measured using two high-speed video cameras and corresponding digital image correlation software (GOM Correlate Professional. The results suggest that material characterisation testing to a maximum strain of 0.4 and a maximum rate of 500 s−1 in tension and to a maximum strain of −0.4 and a maximum rate of −800 s−1 in compression would encapsulate the demands placed on the material during impact and, in turn, define the range of properties required to encapsulate the behavior of the material during impact, enabling testing to be application-specific and strain-rate-dependent properties to be established and incorporated in finite element models.

  14. Surgical experts: born or made?

    Science.gov (United States)

    Sadideen, Hazim; Alvand, Abtin; Saadeddin, Munir; Kneebone, Roger

    2013-01-01

    The concept of surgical expertise and the processes involved in its development are topical, and there is a constant drive to identify reliable measures of expert performance in surgery. This review explores the notion of whether surgical experts are "born" or "made", with reference to educational theory and pertinent literature. Peer-reviewed publications, books, and online resources on surgical education, expertise and training were reviewed. Important themes and aspects of expertise acquisition were identified in order to better understand the concept of a surgical expert. The definition of surgical expertise and several important aspects of its development are highlighted. Innate talent plays an important role, but is insufficient on its own to produce a surgical expert. Multiple theories that explore motor skill acquisition and memory are relevant, and Ericsson's theory of the development of competence followed by deliberate self-practice has been especially influential. Psychomotor and non-technical skills are necessary for progression in the current climate in light of our training curricula; surgical experts are adaptive experts who excel in these. The literature suggests that surgical expertise is reached through practice; surgical experts are made, not born. A deeper understanding of the nature of expert performance and its development will ensure that surgical education training programmes are of the highest possible quality. Surgical educators should aim to develop an expertise-based approach, with expert performance as the benchmark. Copyright © 2013 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  15. Expert Systems for the Analytical Laboratory.

    Science.gov (United States)

    de Monchy, Allan R.; And Others

    1988-01-01

    Discusses two computer problem solving programs: rule-based expert systems and decision analysis expert systems. Explores the application of expert systems to automated chemical analyses. Presents six factors to consider before using expert systems. (MVL)

  16. Expert Systems as Tools for Technical Communicators.

    Science.gov (United States)

    Grider, Daryl A.

    1994-01-01

    Discusses expertise, what an expert system is, what an expert system shell is, what expert systems can and cannot do, knowledge engineering and technical communicators, and planning and managing expert system projects. (SR)

  17. Mapping on complex neutrosophic soft expert sets

    Science.gov (United States)

    Al-Quran, Ashraf; Hassan, Nasruddin

    2018-04-01

    We introduce the mapping on complex neutrosophic soft expert sets. Further, we investigated the basic operations and other related properties of complex neutrosophic soft expert image and complex neutrosophic soft expert inverse image of complex neutrosophic soft expert sets.

  18. System Experts and Decision Making Experts in Transdisciplinary Projects

    Science.gov (United States)

    Mieg, Harald A.

    2006-01-01

    Purpose: This paper aims at a better understanding of expert roles in transdisciplinary projects. Thus, the main purpose is the analysis of the roles of experts in transdisciplinary projects. Design/methodology/approach: The analysis of the ETH-UNS case studies from the point of view of the psychology of expertise and the sociology of professions…

  19. Online-Expert: An Expert System for Online Database Selection.

    Science.gov (United States)

    Zahir, Sajjad; Chang, Chew Lik

    1992-01-01

    Describes the design and development of a prototype expert system called ONLINE-EXPERT that helps users select online databases and vendors that meet users' needs. Search strategies are discussed; knowledge acquisition and knowledge bases are described; and the Analytic Hierarchy Process (AHP), a decision analysis technique that ranks databases,…

  20. A Study on the Effect of Applying Cast Splints in Treatment of Tennis Elbow

    Directory of Open Access Journals (Sweden)

    A Zarezadeh

    2004-02-01

    Full Text Available Background: Tennis elbow is a common orthopedic disease affecting elbow in middle aged people. Ninety percent of patients are cured using conservative treatments. In the past, emphasis was placed on the use of long arm splints for its treatment; however, recent studies put doubt on the use of this method of treatment for the complications arising from the application of splints. The results of using long arm splints for the treatment of Methods: This was a case series non randomized clinical trial involving 25 patients treated with long arm castsplints, and 25 patients treated without the use of splint. Local corticosteroid injections and oral NSAIDs were administered for all patients. The two groups were compared in the third week, third month and sixth month of their treatment for the presence of local tenderness and pain in passive flexion test of wrist and fingers against resistance. Using SPSS 9.0, data were analyzed via repeated measurements test of ANOVA Results: Patients in case and control groups had mean ages 43.6 ± 7.2 and 43.6 ± 6 years, respectively. Prior to any treatments, all patients in this study suffered from pain and tenderness in the origin of forearm extensor muscles. Their pain exacerbated upon passive flexion of wrist and fingers against resistance. No significant difference was seen in third week, third month and sixth month (P value =0.32, and no significant difference was seen in the results of our tests regarding the presence of local tenderness and pain in passive flexion of wrist and fingers against resistance between the two groups Conclusions: After a follow-up period of six months, this study demonstrated no statistically significant difference between the two groups treated with and without long arm splints. Keywords: Tennis elbow, Conservative treatment, Laterals epicondylitis, Cast splint

  1. Estimating distribution of hidden objects with drones: from tennis balls to manatees.

    Directory of Open Access Journals (Sweden)

    Julien Martin

    Full Text Available Unmanned aerial vehicles (UAV, or drones, have been used widely in military applications, but more recently civilian applications have emerged (e.g., wildlife population monitoring, traffic monitoring, law enforcement, oil and gas pipeline threat detection. UAV can have several advantages over manned aircraft for wildlife surveys, including reduced ecological footprint, increased safety, and the ability to collect high-resolution geo-referenced imagery that can document the presence of species without the use of a human observer. We illustrate how geo-referenced data collected with UAV technology in combination with recently developed statistical models can improve our ability to estimate the distribution of organisms. To demonstrate the efficacy of this methodology, we conducted an experiment in which tennis balls were used as surrogates of organisms to be surveyed. We used a UAV to collect images of an experimental field with a known number of tennis balls, each of which had a certain probability of being hidden. We then applied spatially explicit occupancy models to estimate the number of balls and created precise distribution maps. We conducted three consecutive surveys over the experimental field and estimated the total number of balls to be 328 (95%CI: 312, 348. The true number was 329 balls, but simple counts based on the UAV pictures would have led to a total maximum count of 284. The distribution of the balls in the field followed a simulated environmental gradient. We also were able to accurately estimate the relationship between the gradient and the distribution of balls. Our experiment demonstrates how this technology can be used to create precise distribution maps in which discrete regions of the study area are assigned a probability of presence of an object. Finally, we discuss the applicability and relevance of this experimental study to the case study of Florida manatee distribution at power plants.

  2. The effect of haptic guidance and visual feedback on learning a complex tennis task.

    Science.gov (United States)

    Marchal-Crespo, Laura; van Raai, Mark; Rauter, Georg; Wolf, Peter; Riener, Robert

    2013-11-01

    While haptic guidance can improve ongoing performance of a motor task, several studies have found that it ultimately impairs motor learning. However, some recent studies suggest that the haptic demonstration of optimal timing, rather than movement magnitude, enhances learning in subjects trained with haptic guidance. Timing of an action plays a crucial role in the proper accomplishment of many motor skills, such as hitting a moving object (discrete timing task) or learning a velocity profile (time-critical tracking task). The aim of the present study is to evaluate which feedback conditions-visual or haptic guidance-optimize learning of the discrete and continuous elements of a timing task. The experiment consisted in performing a fast tennis forehand stroke in a virtual environment. A tendon-based parallel robot connected to the end of a racket was used to apply haptic guidance during training. In two different experiments, we evaluated which feedback condition was more adequate for learning: (1) a time-dependent discrete task-learning to start a tennis stroke and (2) a tracking task-learning to follow a velocity profile. The effect that the task difficulty and subject's initial skill level have on the selection of the optimal training condition was further evaluated. Results showed that the training condition that maximizes learning of the discrete time-dependent motor task depends on the subjects' initial skill level. Haptic guidance was especially suitable for less-skilled subjects and in especially difficult discrete tasks, while visual feedback seems to benefit more skilled subjects. Additionally, haptic guidance seemed to promote learning in a time-critical tracking task, while visual feedback tended to deteriorate the performance independently of the task difficulty and subjects' initial skill level. Haptic guidance outperformed visual feedback, although additional studies are needed to further analyze the effect of other types of feedback visualization on

  3. Estimating distribution of hidden objects with drones: from tennis balls to manatees.

    Science.gov (United States)

    Martin, Julien; Edwards, Holly H; Burgess, Matthew A; Percival, H Franklin; Fagan, Daniel E; Gardner, Beth E; Ortega-Ortiz, Joel G; Ifju, Peter G; Evers, Brandon S; Rambo, Thomas J

    2012-01-01

    Unmanned aerial vehicles (UAV), or drones, have been used widely in military applications, but more recently civilian applications have emerged (e.g., wildlife population monitoring, traffic monitoring, law enforcement, oil and gas pipeline threat detection). UAV can have several advantages over manned aircraft for wildlife surveys, including reduced ecological footprint, increased safety, and the ability to collect high-resolution geo-referenced imagery that can document the presence of species without the use of a human observer. We illustrate how geo-referenced data collected with UAV technology in combination with recently developed statistical models can improve our ability to estimate the distribution of organisms. To demonstrate the efficacy of this methodology, we conducted an experiment in which tennis balls were used as surrogates of organisms to be surveyed. We used a UAV to collect images of an experimental field with a known number of tennis balls, each of which had a certain probability of being hidden. We then applied spatially explicit occupancy models to estimate the number of balls and created precise distribution maps. We conducted three consecutive surveys over the experimental field and estimated the total number of balls to be 328 (95%CI: 312, 348). The true number was 329 balls, but simple counts based on the UAV pictures would have led to a total maximum count of 284. The distribution of the balls in the field followed a simulated environmental gradient. We also were able to accurately estimate the relationship between the gradient and the distribution of balls. Our experiment demonstrates how this technology can be used to create precise distribution maps in which discrete regions of the study area are assigned a probability of presence of an object. Finally, we discuss the applicability and relevance of this experimental study to the case study of Florida manatee distribution at power plants.

  4. Swimming literacy field hockey woman player ground.

    OpenAIRE

    Baštová, Miroslava

    2012-01-01

    Title: Swimming literacy field hockey woman player ground. Objectives: To obtain and analyze data on the level ground swimming literacy field hockey woman player. Their perception swimming literacy for life, the use of non-specific regeneration and as a training resource. Methods: Analysis of scientific literature, survey, case study, data analysis and graphical presentation of results. Results of the work: field hockey player as swimming literate, benefits swimming but not used as a means of...

  5. Plutonium - the ultrapoison? An expert's opinion about an expert opinion

    International Nuclear Information System (INIS)

    Stoll, W.; Becker, K.

    1989-01-01

    In an expert opinion written by Professor H. Kuni, Marburg, for the North Rhine-Westphalian state government, plutonium is called by far the most dangerous element in the Periodic Table. The Marburg medical expert holds that even improved legal instruments are unable to warrant effective protection of the workers handling this material, in the light of the present standards of industrial safety, because of radiological conditions and measuring problems with plutonium isotopes. In this article by an internationally renowned expert in the field, the ideas expressed in the expert opinion about the toxicity of plutonium, the cause-and-effect relationship in radiation damage by plutonium, and recent findings about the toxicity are subjected to a critical review. On the basis of results of radiation protection and of case studies, the statements in the expert opinion are contrasted with facts which make them appear in a very different light. (orig./RB) [de

  6. Psychological Characteristics in Talented Soccer Players - Recommendations on How to Improve Coaches' Assessment.

    Science.gov (United States)

    Musculus, Lisa; Lobinger, Babett H

    2018-01-01

    Psychological characteristics, including personality traits and psychological skills, have been shown to be relevant predictors of soccer performance. In research, general and sport specific standardized self-report questionnaires have been applied in psychological diagnostics of sports talent. However, with regard to the assessment of psychological characteristics of talented soccer players, a gap between research and practice is apparent. While soccer clubs often ask their coaches to assess their players on self-designed, unevaluated scouting sheets, research widely neglects expert coaches' and clubs' perspectives on relevant performance characteristics. As we believe that expert coaches' assessments could be a valid predictor of a player's current performance and future success, we provide recommendations on how to improve coaches' assessment of psychological characteristics. As the quality of the assessment of psychological characteristics is crucial, we provide recommendations on how to ensure the central diagnostic standards: objectivity, reliability, and validity in talent assessment. Further, we argue that assessing psychological characteristics should combine self ratings of players and external ratings of coaches in talent development. Sport psychologists should assist clubs and coaches in improving the diagnostics of psychological characteristics as well as in embedding psychological diagnostics and interventions in the talent development process.

  7. Rationale set of indicators and prioritize relevant to assess competitive activity of hockey players of high qualification of different roles

    Directory of Open Access Journals (Sweden)

    A.P. Mikhnov

    2015-02-01

    Full Text Available Purpose: organize technical and tactical actions and determine their priority importance for high-end players of different roles. Establish their priority importance for the success of competitive activity hockey with the game roles. Material : the study involved 54 experts on hockey coaches and players of high class. The significance of technical and tactical actions evaluated for players of different roles. Results : systematic account of technical and tactical actions of athletes and prioritize them to assess the significance of competitive activity. Three groups of technical and tactical actions: 1 active attacks; 2 - active safety; 3 - organizational and maneuvering. Set priorities for technical and tactical actions for players of different roles. Conclusions : the proposed technical and tactical actions can be recommended for the evaluation of the effectiveness of competitive activity players. In the process of estimating the action game players need to consider their role playing. Identification of priority in the implementation of technical and tactical actions in the game can be used in integrated assessment of actions players different roles.

  8. The Prevalence of Injuries in Professional Turkish Soccer Players

    Science.gov (United States)

    Yamaner, Faruk; Gumusdag, Hayrettin; Kartal, Alparslan; Gumus, M.; Gullu, A.; Imamoglu, O.

    2011-01-01

    Study aim: To assess the prevalence and anatomical sites of injuries in professional soccer players in one game season. Material and methods: A cohort of 510 professional male soccer players consisting of 48 goalkeepers, 194 defence players, 189 mid-field players and 79 forward players of the 1st and 2nd Turkish Professional Soccer Leagues in…

  9. Chess players' fame versus their merit.

    Science.gov (United States)

    Simkin, M V; Roychowdhury, V P

    2015-12-12

    We investigate a pool of international chess title holders born between 1901 and 1943. Using Elo ratings, we compute for every player his expected score in a game with a randomly selected player from the pool. We use this figure as the player's merit. We measure players' fame as the number of Google hits. The correlation between fame and merit is 0.38. At the same time, the correlation between the logarithm of fame and merit is 0.61. This suggests that fame grows exponentially with merit.

  10. The things we learned on Liberty Island: designing games to help people become competent game players

    OpenAIRE

    Pelletier, Caroline

    2005-01-01

    Although interest in the use of games to support education is growing (e.g. Dawes & Dumbleton, 2001; McFarlane et al, 2002; Mitchell & Savill-Smith, 2004), there is relatively little research into how people learn to play games. This is surprising, since VanDeventer and White (2002) have demonstrated that game players demonstrate characteristics of expert behaviour and Gee (2003) argues that highly successful implicit theories of learning are embedded in well-designed games. In spite ...

  11. Law for nuclear experts only

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, H [Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.)

    1980-02-01

    The Federal Ministry of the Interior is preparing an ordinance on expert consultants under the Atomic Energy Act which, among other topics, is to include legal norms for the criteria to be met by experts in terms of non-partisanship, training, capabilities, technical equipment and cooperation in expert organizations of members of various scientific and technical disciplines. A summary of general criteria relating to the qualification, selection and status of experts called in by the legislative and executive branches and by courts of law, which could be organized as a series of guidelines without any original qualities of legal norms, could be recommended in view of the increasing quantitative and qualitative importance of experts. However, passing an ordinance merely fixing and putting into concrete terms the image of an 'expert under the Atomic Energy Act' is intolerable, because the status of scientific and technical experts by far extends beyond the field of nuclear law in our industrial society characterized by a far reaching division of labor. Weak points in the organization of expert services are not confined to technology or nuclear power. Separate rules establishing legal norms are not convincing also for reasons of technology policy and legal policy as well as for those of social psychology and practice.

  12. Expert Systems in Reference Services.

    Science.gov (United States)

    Roysdon, Christine, Ed.; White, Howard D., Ed.

    1989-01-01

    Eleven articles introduce expert systems applications in library and information science, and present design and implementation issues of system development for reference services. Topics covered include knowledge based systems, prototype development, the use of artificial intelligence to remedy current system inadequacies, and an expert system to…

  13. Artificial Intelligence: The Expert Way.

    Science.gov (United States)

    Bitter, Gary G.

    1989-01-01

    Discussion of artificial intelligence (AI) and expert systems focuses on their use in education. Characteristics of good expert systems are explained; computer software programs that contain applications of AI are described, highlighting one used to help educators identify learning-disabled students; and the future of AI is discussed. (LRW)

  14. Reflection group on 'Expert Culture'

    International Nuclear Information System (INIS)

    Eggermont, G.

    2000-01-01

    As part of SCK-CEN's social sciences and humanities programme, a reflection group on 'Expert Culture' was established. The objectives of the reflection group are: (1) to clarify the role of SCK-CEN experts; (2) to clarify the new role of expertise in the evolving context of risk society; (3) to confront external views and internal SCK-CEN experiences on expert culture; (4) to improve trust building of experts and credibility of SCK-CEN as a nuclear actor in society; (5) to develop a draft for a deontological code; (6) to integrate the approach in training on assertivity and communication; (7) to create an output for a topical day on the subject of expert culture. The programme, achievements and perspectives of the refection group are summarised

  15. Preserving experience through expert systems

    International Nuclear Information System (INIS)

    Jelinek, J.B.; Weidman, S.H.

    1989-01-01

    Expert systems technology, one of the branches in the field of computerized artificial intelligence, has existed for >30 yr but only recently has been made available on commercially standard hardware and software platforms. An expert system can be defined as any method of encoding knowledge by representing that knowledge as a collection of facts or objects. Decisions are made by the expert program by obtaining data about the problem or situation and correlating encoded facts (knowledge) to the data until a conclusion can be reached. Such conclusions can be relayed to the end user as expert advice. Realizing the potential of this technology, General Electric (GE) Nuclear Energy (GENE) has initiated a development program in expert systems applications; this technology offers the potential for packaging, distributing, and preserving nuclear experience in a software form. The paper discusses application fields, effective applications, and knowledge acquisition and knowledge verification

  16. THE STRUCTURE OF MOTOR ABILITIES IN BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Jadranka Kocić

    2013-07-01

    Full Text Available The expansion of basketball game, just like up-to-date sports results represent the stimulus for further fundamental researches in the aim of improvement scientific and methodological basis of a training work and all other factors connected to the improvement of a training process and top sports creativity. The research was conducted with the aim to determine the specifics of motor abilities in basketball players of the junior rank of competition. All the examinees were male, 16 (+/-6 months years old, 132 in total, all of them were basketball players of the basketball club ”Student” from Nis. The batery of tests for the evaluation of motor abilities included tests for the evaluation of coordination, strength (explosive, repetitive and static, flexibility and stamina and it consisted of 13 motor tests in total. The gained results were processed by the program system for multivariant analysis of data, especially made by Popovic D. for personal computers. The gained results are shown in tables and they give insight into the structure of latent dimensions of basketball players. The motor structure of basketball players is explained by 72.3% of common variance. From the matrix of intercorrelations, four main components were gained. The fist defines tests of static strength, flexibility and repetitive strength; the second is saturated by the test for the evaluation of explosive strength, balance and two tests for the evaluation of repetitive strength. The third is the best explained by the test for the evaluation of balance, flexibility and coordination. The fourth main component is defined by explosive strength. Then, the rotation of components into the oblimin solution is conducted and some better structure of latent dimensions is gained that way. In basketball and other popular sports games in our country, scientific and expert methods and possibilities of scientific fundation of the trainig work are very slowly but surely accepted.The trend

  17. No effect of forearm band and extensor strengthening exercises for the treatment of tennis elbow: a prospective randomised study.

    Science.gov (United States)

    Luginbühl, Rolf; Brunner, Florian; Schneeberger, Alberto G

    2008-01-01

    The objective of this prospective randomised study was to analyse the effect of the forearm support band and of strengthening exercises for the treatment of tennis elbow. Twenty-nine patients with 30 tennis elbows were randomised into 3 groups of treatment: (I) forearm support band, (II) strengthening exercises and (III) both methods. The patients had a standardised examination at their first visit, and then after 6 weeks, 3 months and 1 year. At the latest follow-up, there was a significant improvement of the symptoms compared to before treatment (p<0.0001), considering all patients independently of the methods of treatment. However, no differences in the scores were found between the 3 groups of treatment (p=0.27), indicating that no beneficial influence was found either for the strengthening exercises or for the forearm support band. Improvement seems to occur with time, independent of the method of treatment used.

  18. Comparing sports vision among three groups of soft tennis adolescent athletes: Normal vision, refractive errors with and without correction

    Directory of Open Access Journals (Sweden)

    Shih-Tsun Chang

    2015-01-01

    Full Text Available Background: The effect of correcting static vision on sports vision is still not clear. Aim: To examine whether sports vision (depth perception [DP], dynamic visual acuity [DVA], eye movement [EM], peripheral vision [PV], and momentary vision [MV], were different among soft tennis adolescent athletes with normal vision (Group A, with refractive error and corrected with (Group B and without eyeglasses (Group C. Setting and Design: A cross-section study was conducted. Soft tennis athletes aged 10–13 who played softball tennis for 2–5 years, and who were without any ocular diseases and without visual training for the past 3 months were recruited. Materials and Methods: DPs were measured in an absolute deviation (mm between a moving rod and fixing rod (approaching at 25 mm/s, receding at 25 mm/s, approaching at 50 mm/s, receding at 50 mm/s using electric DP tester. A smaller deviation represented better DP. DVA, EM, PV, and MV were measured on a scale from 1 (worse to 10 (best using ATHLEVISION software. Statistical Analysis: Chi-square test and Kruskal–Wallis test was used to compare the data among the three study groups. Results: A total of 73 athletes (37 in Group A, 8 in Group B, 28 in Group C were enrolled in this study. All four items of DP showed significant difference among the three study groups (P = 0.0051, 0.0004, 0.0095, 0.0021. PV displayed significant difference among the three study groups (P = 0.0044. There was no significant difference in DVA, EM, and MV among the three study groups. Conclusions: Significant better DP and PV were seen among soft tennis adolescent athletes with normal vision than those with refractive error regardless whether they had eyeglasses corrected. On the other hand, DVA, EM, and MV were similar among the three study groups.

  19. Diagnosis and Follow-up US Evaluation of Ruptures of the Medial Head of the Gastrocnemius ("Tennis Leg")

    OpenAIRE

    Kwak, Hyo-Sung; Han, Young-Min; Lee, Sang-Yong; Kim, Ki-Nam; Chung, Gyung Ho

    2006-01-01

    Objective The purpose of this study was to demonstrate the ultrasonographic (US) findings of rupture and the healing process of the medial head of the gastrocnemius ("Tennis Leg"). Materials and Methods Twenty-two patients (age range: 30 to 45 years) with clinically suspected ruptures of the medial head of the gastrocnemius were referred to us for US examination. All the patients underwent US of the affected limb and the contralateral asymptomatic limb. Follow-up clinical evaluation and US im...

  20. Cooperation: New Players in Africa

    Directory of Open Access Journals (Sweden)

    Philippe Hugon

    2010-03-01

    Full Text Available In the context of globalisation and the current global financial crisis, new players are emerging in cooperation in Africa. These partners loosen financial constraints and conditionalities, increase the room for manoeuvre and stimulate commodity markets. On the other hand, they also increase the risks of renewed indebtedness and potentially weaken the coordination of aid policies. Do these partnerships call the new cooperation practices of OECD countries into question? Do they justify the return to a realpolitik or are they repeating the earlier mistakes of industrial powers? Can these mistakes be corrected? The question also arises as to whether the global crisis, which has a profound effect on Africa, will lead to a withdrawal or to a passing of the baton on to new, emerging powers. This article highlights the new geopolitical issues concerning Africa in a multipolar world, then discusses the new players involved in cooperation in Africa, before going on to explore the horizons that are opening up for cooperation in Africa, in particular with regard to the global crisis.

  1. Focused and Radial Shock Wave Therapy in the Treatment of Tennis Elbow: A Pilot Randomised Controlled Study

    Directory of Open Access Journals (Sweden)

    Król Piotr

    2015-09-01

    Full Text Available The purpose of this article was to evaluate and compare the efficacy of radial and focused shock wave therapies applied to treat tennis elbow. Patients with tennis elbow were randomized into two comparative groups: focused shock wave therapy (FSWT; n=25 and radial shock wave therapy (RSWT; n=25. Subjects in the FSWT and RSWT groups were applied with a focused shock wave (3 sessions, 2000 shocks, 4 Hz, 0.2 mJ/mm2 and a radial shock wave (3 sessions, 2000 + 2000 shocks, 8 Hz, 2.5 bar, respectively. The primary study endpoints were pain relief and functional improvement (muscle strength one week after therapy. The secondary endpoint consisted of the results of the follow-up observation (3, 6 and 12 weeks after the study. Successive measurements showed that the amount of pain patients felt decreased in both groups. At the same time grip strength as well as strength of wrist extensors and flexors of the affected extremity improved significantly. Both focused and radial shock wave therapies can comparably and gradually reduce pain in subjects with tennis elbow. This process is accompanied by steadily improved strength of the affected extremity.

  2. Visual- spatial capacity: gender and sport differences in young volleyball and tennis athletes and non-athletes.

    Science.gov (United States)

    Notarnicola, Angela; Maccagnano, Giuseppe; Pesce, Vito; Tafuri, Silvio; Novielli, Grazia; Moretti, Biagio

    2014-01-21

    In the general population visual-spatial ability is better in males, due to the influence of biological and socio-cultural factors. We know that sport activity improves motor skills. The aim of this work is to determine if these gender differences exist in young athletes. The orientation test described by Terzi and standardized by Cesaroni, used to measure spatial ability, was carried out on 60 volleyball or 60 tennis athletes as well as on 60 non-sporting subjects. The data analysis revealed a worse performance for non-athletes in comparison with athletes in both components of test (p volleyball and tennis groups. As far as gender comparison is concerned, as expected in the non- sport group the males presented better values (p volleyball and tennis the specific training is able to develop spatial ability. Besides, boys and girls have similar performance demands and training experience. It appears that this specific training could be responsible for modifying gender differences in performance of spatial ability during adolescence.

  3. Computing Decoupled Residuals for Compact Disc Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2006-01-01

    a pair of residuals generated by Compact Disc Player. However, these residuals depend on the performance of position servos in the Compact Disc Player. In other publications of the same authors a pair of decoupled residuals is derived. However, the computation of these alternative residuals has been...

  4. Fault Predictive Control of Compact Disk Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Wickerhauser, Mladen Victor

    2006-01-01

    Optical disc players such as CD-players have problems playing certain discs with surface faults like scratches and fingerprints. The problem is to be found in the servo controller which positions the optical pick-up, such that the laser beam is focused on the information track. A scheme handling...

  5. Quantum Two Player Game in Thermal Environment.

    Directory of Open Access Journals (Sweden)

    Jerzy Dajka

    Full Text Available A two-player quantum game is considered in the presence of thermal decoherence. It is shown how the thermal environment modeled in terms of rigorous Davies approach affects payoffs of the players. The conditions for either beneficial or pernicious effect of decoherence are identified. The general considerations are exemplified by the quantum version of Prisoner Dilemma.

  6. Player behavioural modelling for video games

    NARCIS (Netherlands)

    van Lankveld, G.; Spronck, P.H.M.; Bakkes, S.C.J.

    2012-01-01

    Player behavioural modelling has grown from a means to improve the playing strength of computer programs that play classic games (e.g., chess), to a means for impacting the player experience and satisfaction in video games, as well as in cross-domain applications such as interactive storytelling. In

  7. Expert software for accident identification

    International Nuclear Information System (INIS)

    Dobnikar, M.; Nemec, T.; Muehleisen, A.

    2003-01-01

    Each type of an accident in a Nuclear Power Plant (NPP) causes immediately after the start of the accident variations of physical parameters that are typical for that type of the accident thus enabling its identification. Examples of these parameter are: decrease of reactor coolant system pressure, increase of radiation level in the containment, increase of pressure in the containment. An expert software enabling a fast preliminary identification of the type of the accident in Krsko NPP has been developed. As input data selected typical parameters from Emergency Response Data System (ERDS) of the Krsko NPP are used. Based on these parameters the expert software identifies the type of the accident and also provides the user with appropriate references (past analyses and other documentation of such an accident). The expert software is to be used as a support tool by an expert team that forms in case of an emergency at Slovenian Nuclear Safety Administration (SNSA) with the task to determine the cause of the accident, its most probable scenario and the source term. The expert software should provide initial identification of the event, while the final one is still to be made after appropriate assessment of the event by the expert group considering possibility of non-typical events, multiple causes, initial conditions, influences of operators' actions etc. The expert software can be also used as an educational/training tool and even as a simple database of available accident analyses. (author)

  8. Intelligent programs-expert systems

    Energy Technology Data Exchange (ETDEWEB)

    Gledhill, V X

    1982-01-01

    In recent years, computer scientists have developed what are called expert systems. These programs have three fundamental components: a knowledge base, which changes with experience; an inference engine which enables the program to make decisions; and an interface that allows the program to communicate with the person using the system. Expert systems have been developed successfully in areas such as medical diagnosis, geology, and computer maintenance. This paper describes the evolution and basic principles of expert systems and give some examples of their use.

  9. Outcomes of microfracture in professional basketball players.

    Science.gov (United States)

    Cerynik, Douglas L; Lewullis, Gabriel E; Joves, Brian C; Palmer, Michael P; Tom, James A

    2009-09-01

    Surgical treatment for chondral defects of the knee in competitive running and jumping athletes remains controversial. This study evaluated the performance outcomes of professional basketball players in the National Basketball Association (NBA) who underwent microfracture. Data from 24 professional basketball players from 1997 to 2006 was obtained and analyzed. NBA player efficiency ratings (PER) were calculated for two seasons before and after injury. A control group of 24 players was used for comparison. Study group and control group demographics including age, NBA experience, and minutes per game demonstrated no statistical difference. Mean time to return to an NBA game was 30.0 weeks from the time of surgery. The first season after returning to competition PER and minutes per game decreased by 3.5 (P 0.05) and 3.0 min (P NBA game. On return to competition player performance and minutes per game are diminished.

  10. An embouchure aid for saxophone player

    Directory of Open Access Journals (Sweden)

    Ho-Jin Moon

    2012-02-01

    Full Text Available This study aims to introduce the method that can relieve vibrating forces to oral environment by making an embouchure aid. Thin plastic crown forms were fabricated to prevent tooth abrasion and irritation to lip mucosa for the saxophone player. After application to the player, the most comfort form was chosen and delivered to 3 professional saxophone players. After 5 mon, the players responded to the survey. This embouchure aid did not disturb playing and gave comfort to lower lip. In general, the players preferred thin soft type and thought it caused little effect on sound. Far too little attention has been paid to the problems encountered by single-reed wind instrumentalist who suffer from tooth abrasion and irritation to lip mucosa. The embouchure aid not only prevent tooth damage but also diminish the discomfort of tight embouchure.

  11. Functional MRI reveals expert-novice differences during sport-related anticipation.

    Science.gov (United States)

    Wright, Michael J; Bishop, Daniel T; Jackson, Robin C; Abernethy, Bruce

    2010-01-27

    We examined the effect of expertise on cortical activation during sports anticipation using functional MRI. In experiment 1, recreational players predicted badminton stroke direction and the pattern of active clusters was consistent with a proposed perception-of-action network. This pattern was not replicated in a stimulus-matched, action-unrelated control task. In experiment 2, players of three different skill levels anticipated stroke direction from clips occluded either 160 ms before or 80 ms after racquet-shuttle contact. Early-occluded sequences produced more activation than late-occluded sequences overall, in most cortical regions of interest, but experts showed an additional enhancement in medial, dorsolateral and ventrolateral frontal cortex. Anticipation in open-skill sports engages cortical areas integral to observing and understanding others' actions; such activity is enhanced in experts.

  12. Finite stage asymmetric repeated games: Both players' viewpoints

    KAUST Repository

    Li, Lichun; Feron, Eric; Shamma, Jeff S.

    2017-01-01

    the opponents' corresponding best responses depends only on the informed player's history action sequences. Moreover, efficient LP formulations to compute both player's security strategies are provided.

  13. Finite stage asymmetric repeated games: Both players' viewpoints

    KAUST Repository

    Li, Lichun

    2017-01-05

    In asymmetric zero-sum games, one player has superior information about the game over the other. It is known that the informed players (maximizer) face the tradeoff of exploiting its superior information at the cost of revealing its superior information, but the basic point of the uninformed player (minimizer)\\'s decision making remains unknown. This paper studies the finite stage asymmetric repeated games from both players\\' viewpoints, and derives that not only security strategies but also the opponents\\' corresponding best responses depends only on the informed player\\'s history action sequences. Moreover, efficient LP formulations to compute both player\\'s security strategies are provided.

  14. A Game Player Expertise Level Classification System Using Electroencephalography (EEG

    Directory of Open Access Journals (Sweden)

    Syed Muhammad Anwar

    2017-12-01

    Full Text Available The success and wider adaptability of smart phones has given a new dimension to the gaming industry. Due to the wide spectrum of video games, the success of a particular game depends on how efficiently it is able to capture the end users’ attention. This leads to the need to analyse the cognitive aspects of the end user, that is the game player, during game play. A direct window to see how an end user responds to a stimuli is to look at their brain activity. In this study, electroencephalography (EEG is used to record human brain activity during game play. A commercially available EEG headset is used for this purpose giving fourteen channels of recorded EEG brain activity. The aim is to classify a player as expert or novice using the brain activity as the player indulges in the game play. Three different machine learning classifiers have been used to train and test the system. Among the classifiers, naive Bayes has outperformed others with an accuracy of 88 % , when data from all fourteen EEG channels are used. Furthermore, the activity observed on electrodes is statistically analysed and mapped for brain visualizations. The analysis has shown that out of the available fourteen channels, only four channels in the frontal and occipital brain regions show significant activity. Features of these four channels are then used, and the performance parameters of the four-channel classification are compared to the results of the fourteen-channel classification. It has been observed that support vector machine and the naive Bayes give good classification accuracy and processing time, well suited for real-time applications.

  15. Executive Functioning in Highly Talented Soccer Players

    Science.gov (United States)

    Verburgh, Lot; Scherder, Erik J. A.; van Lange, Paul A.M.; Oosterlaan, Jaap

    2014-01-01

    Executive functions might be important for successful performance in sports, particularly in team sports requiring quick anticipation and adaptation to continuously changing situations in the field. The executive functions motor inhibition, attention and visuospatial working memory were examined in highly talented soccer players. Eighty-four highly talented youth soccer players (mean age 11.9), and forty-two age-matched amateur soccer players (mean age 11.8) in the age range 8 to 16 years performed a Stop Signal task (motor inhibition), the Attention Network Test (alerting, orienting, and executive attention) and a visuospatial working memory task. The highly talented soccer players followed the talent development program of the youth academy of a professional soccer club and played at the highest national soccer competition for their age. The amateur soccer players played at a regular soccer club in the same geographical region as the highly talented soccer players and play in a regular regional soccer competition. Group differences were tested using analyses of variance. The highly talented group showed superior motor inhibition as measured by stop signal reaction time (SSRT) on the Stop Signal task and a larger alerting effect on the Attention Network Test, indicating an enhanced ability to attain and maintain an alert state. No group differences were found for orienting and executive attention and visuospatial working memory. A logistic regression model with group (highly talented or amateur) as dependent variable and executive function measures that significantly distinguished between groups as predictors showed that these measures differentiated highly talented soccer players from amateur soccer players with 89% accuracy. Highly talented youth soccer players outperform youth amateur players on suppressing ongoing motor responses and on the ability to attain and maintain an alert state; both may be essential for success in soccer. PMID:24632735

  16. Executive functioning in highly talented soccer players.

    Directory of Open Access Journals (Sweden)

    Lot Verburgh

    Full Text Available Executive functions might be important for successful performance in sports, particularly in team sports requiring quick anticipation and adaptation to continuously changing situations in the field. The executive functions motor inhibition, attention and visuospatial working memory were examined in highly talented soccer players. Eighty-four highly talented youth soccer players (mean age 11.9, and forty-two age-matched amateur soccer players (mean age 11.8 in the age range 8 to 16 years performed a Stop Signal task (motor inhibition, the Attention Network Test (alerting, orienting, and executive attention and a visuospatial working memory task. The highly talented soccer players followed the talent development program of the youth academy of a professional soccer club and played at the highest national soccer competition for their age. The amateur soccer players played at a regular soccer club in the same geographical region as the highly talented soccer players and play in a regular regional soccer competition. Group differences were tested using analyses of variance. The highly talented group showed superior motor inhibition as measured by stop signal reaction time (SSRT on the Stop Signal task and a larger alerting effect on the Attention Network Test, indicating an enhanced ability to attain and maintain an alert state. No group differences were found for orienting and executive attention and visuospatial working memory. A logistic regression model with group (highly talented or amateur as dependent variable and executive function measures that significantly distinguished between groups as predictors showed that these measures differentiated highly talented soccer players from amateur soccer players with 89% accuracy. Highly talented youth soccer players outperform youth amateur players on suppressing ongoing motor responses and on the ability to attain and maintain an alert state; both may be essential for success in soccer.

  17. Expert robots in nuclear plants

    International Nuclear Information System (INIS)

    Byrd, J.S.; Fisher, J.J.; DeVries, K.R.; Martin, T.P.

    1987-01-01

    Expert robots enhance a safety and operations in nuclear plants. E.I. du Pont de Nemours and Company, Savannah River Laboratory, is developing expert mobile robots for deployment in nuclear applications at the Savannah River Plant. Knowledge-based expert systems are being evaluated to simplify operator control, to assist in navigation and manipulation functions, and to analyze sensory information. Development work using two research vehicles is underway to demonstrate semiautonomous, intelligence, expert robot system operation in process areas. A description of the mechanical equipment, control systems, and operating modes is presented, including the integration of onboard sensors. A control hierarchy that uses modest computational methods is being used to allow mobile robots to autonomously navigate and perform tasks in known environments without the need for large computer systems

  18. Expert Systems: An Introduction -46 ...

    Indian Academy of Sciences (India)

    Research Scientist in the. Knowledge Based. Computer Systems Group at NeST. He is one of the ... Expert systems encode human expertise in limited domains ... answers questions the user has and provides an explanation of its reasoning.

  19. Introducing Managers to Expert Systems.

    Science.gov (United States)

    Finlay, Paul N.; And Others

    1991-01-01

    Describes a short course to expose managers to expert systems, consisting of (1) introductory lecture; (2) supervised computer tutorial; (3) lecture and discussion about knowledge structuring and modeling; and (4) small group work on a case study using computers. (SK)

  20. Expert system in PNC, 6

    International Nuclear Information System (INIS)

    Tsubota, Koji

    1990-01-01

    The application of Artificial Intelligence (AI) as a tool for mineral exploration started only a decade ago. The systems that have been reported are in the most cases the expert systems that can simulate the decision of the experts or help numerical calculation for more reasonable and/or fast decision making. PNC started the development of the expert system for uranium exploration in 1983. Since then, KOGITO, a expert system to find the favorability of the target area, has been developed. Two years ago, the second generation development, Intelligent Research Environment and Support System, IRESS was initiated aiming at the establishment of a total support system for a project evaluation. We will review our effort for development of our system and introduce the application of the Data directed Numerical method as a new tool to Ahnemland area in Australia. (author)