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Sample records for volleyball block jump

  1. The Effects of Opposition and Gender on Knee Kinematics and Ground Reaction Force during Landing from Volleyball Block Jumps

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    Hughes, Gerwyn; Watkins, James; Owen, Nick

    2010-01-01

    The aim of this study was to examine the effect of opposition and gender on knee kinematics and ground reaction force during landing from a volleyball block jump. Six female and six male university volleyball players performed two landing tasks: (a) an unopposed and (b) an opposed volleyball block jump and landing. A 12-camera motion analysis…

  2. Analysis of jumping in the spike, block and set skills of female volleyball players

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    Valdir José Barbanti

    2007-09-01

    Full Text Available The purpose of this study was to quantify the different types of jump observed during volleyball matches. Jumps were classifi ed as block jumps, spike jumps or set jumps. The sample was 12 video-taped National Women’s Volleyball League matches. They were analyzed for specifi c types of jumping, such as spike jumps with and without approach; block jumps with and without step movement; and set jumps. Matches were recorded by two video cameras placed at the back court on each side of the net. Data were collected from the video tapes and each variable was recorded on a sheet of paper for subsequent statistical analysis. The results demonstrated that the highest mean numbers of any jump type per game performed by setters were of the type set jump: 39.0 ± 5.51, 57.3 ± 32.23 and 33 ± 8.49, in games of 3, 4 and 5 sets respectively. For outside hitter players the greatest number of jumps were of the type spike jump with approach, in games of 3, 4 and 5 sets respectively (20.44 ± 5.15, 29.23 ± 7.16 and 35.67 ± 13.21. Middle block players exhibited mean values for block jumps with step movements of 17.04 ± 8.19, 29.9 ± 10.85 and 34.25 ± 5.62, respectively. These results indicate that there was no difference between outside hitters and middle block players in 5-set games in terms of numbers of spike jumps with approach. There was a significant difference between setters and outside hitters in numbers of spike jumps without approach, in games of 3 and 5 sets. There were no differences between any of the positions in block jumps with step in games of 3, 4 or 5 sets. There was no difference between middle block and outside hitter players in terms of set jumps. It was concluded that setters exhibited the highest average number of set jumps per game, outside hitters exhibited the highest mean number of spike jumps with approach and middle block players exhibited highest mean numbers per match of block jumps with step movement. ABSTRACT O presente

  3. METRIC TESTS CHARACTERISTIC FOR ESTIMATING JUMPING FOR VOLLEYBALL PLAYERS

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    Toplica Stojanović

    2008-08-01

    Full Text Available With goal to establish metric tests characteristics for estimating jumping for volleyball players, it was organized a pilot research on pattern of 23 volleyball players from cadet team and 23 students from high-school. For needs of this research four tests are valid for estimation, jump in block with left and right leg and jump in spike with left and right leg. Each test has been taken three times, so that we could with test-re test method determine their reliability, and with factor analysis their validity. Data were processed by multivariate analysis (item analysis, factor analysis from statistical package „Statistica 6.0 for windows“. On the results of research and discussion we can say that the tests had high coefficient of reliability, as well as factor validity, and these tests can be used to estimate jumping for volleyball players.

  4. A comparison of take-off dynamics during three different spikes, block and counter-movement jump in female volleyball players.

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    Kabacinski, Jaroslae; Dworak, Lecholslaw B; Murawa, Michal; Ostarello, John; Rzepnicka, Agata; Maczynski, Jacek

    2016-12-01

    The purpose of the study was to compare the take-off dynamics in counter-movement jump (CMJ), volleyball block and spikes. Twelve professional female players, representing the highest volleyball league in Poland, participated in the laboratory tests. A force platform was used to record ground reaction force (GRF) during take-off phase in CMJ test, block from a run-up and spikes: front row attack, slide attack, back row attack. Vertical (v) GRF (peak: Rmax and integral mean: ), impulse of vGRF (J) and mechanical power (peak: Pmax and integral mean: ) were analyzed. Significant differences (P, J, Pmax, and ) were found between CMJ, block from a run-up and three different technique spikes. The highest values were recorded during take-off in the back row attack: peak vGRF (2.93±0.05 BW), integral mean vGRF (1.90±0.08 BW), impulse of vGRF (354±40 Ns), peak power (5320±918 W) and integral mean power (3604±683 W). Peak power (2608±217 W) and integral mean power (1417±94 W) were determined in CMJ test to evaluate the force-velocity capabilities of the players. In terms of GRF and the mechanical power, high level of dynamics in take-off influences positively the jumping height and significantly increases the effectiveness of attacks during spike of the ball over the block of the opponent.

  5. Vertical jumping tests in volleyball: reliability, validity, and playing-position specifics.

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    Sattler, Tine; Sekulic, Damir; Hadzic, Vedran; Uljevic, Ognjen; Dervisevic, Edvin

    2012-06-01

    Vertical jumping is known to be important in volleyball, and jumping performance tests are frequently studied for their reliability and validity. However, most studies concerning jumping in volleyball have dealt with standard rather than sport-specific jumping procedures and tests. The aims of this study, therefore, were (a) to determine the reliability and factorial validity of 2 volleyball-specific jumping tests, the block jump (BJ) test and the attack jump (AJ) test, relative to 2 frequently used and systematically validated jumping tests, the countermovement jump test and the squat jump test and (b) to establish volleyball position-specific differences in the jumping tests and simple anthropometric indices (body height [BH], body weight, and body mass index [BMI]). The BJ was performed from a defensive volleyball position, with the hands positioned in front of the chest. During an AJ, the players used a 2- to 3-step approach and performed a drop jump with an arm swing followed by a quick vertical jump. A total of 95 high-level volleyball players (all men) participated in this study. The reliability of the jumping tests ranged from 0.97 to 0.99 for Cronbach's alpha coefficients, from 0.93 to 0.97 for interitem correlation coefficients and from 2.1 to 2.8 for coefficients of variation. The highest reliability was found for the specific jumping tests. The factor analysis extracted one significant component, and all of the tests were highly intercorrelated. The analysis of variance with post hoc analysis showed significant differences between 5 playing positions in some of the jumping tests. In general, receivers had a greater jumping capacity, followed by libero players. The differences in jumping capacities should be emphasized vis-a-vis differences in the anthropometric measures of players, where middle hitters had higher BH and body weight, followed by opposite hitters and receivers, with no differences in the BMI between positions.

  6. EFFECTS OF WHOLE BODY VIBRATION ON STRENGTH AND JUMPING PERFORMANCE IN VOLLEYBALL AND BEACH VOLLEYBALL PLAYERS

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    Zmijewski, P.; Jimenez-Olmedo, J.M.; Jové-Tossi, M.A.; Martínez-Carbonell, A.; Suárez-Llorca, C.; Andreu-Cabrera, E.

    2014-01-01

    The primary aim of this study was to examine the effects of 6-week strength training with whole body vibration (WBV) on leg strength and jumping performance in volleyball and beach volleyball players. Twenty-three sub-elite male volleyball (VB; n=12) and beach volleyball players (BVB; n=11) aged 21.2±3.0 years were divided into two groups and subjected to 6 weeks of strength training (three one-hour sessions per week): (I) 12 players (6 VB and 6 BVB players) underwent training with WBV (30-40 Hz, 1.7-2.5 mm, 3.0-5.7 g), and (II) 11 players (6 VB and 5 BVB players) underwent traditional strength training. Squat jump (SJ) and countermovement squat jump (CMJ) measurements by the Ergo Tester contact platform and maximum leg press test (1RM) were conducted. Three-factor (2 time x 2 WBV use x 2 discipline) analysis of variance for SJ, CMJ and 1RM revealed a significant time main effect (pvolleyball and beach volleyball players increases leg strength more and leads to greater improvement in jump performance than traditional strength training, but greater improvements can be expected in beach volleyball players than in volleyball players. PMID:25187676

  7. Validation of the VERT wearable jump monitor device in elite youth volleyball players

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    Borges, Thiago O.; Moreira, Alexandre; Bacchi, Renato; Finotti1, Ronaldo L.; Ramos, Mayara; Lopes, Charles R.

    2017-01-01

    This technical report aims to determine the validity and the accuracy of the VERT Wearable Jump Monitor. The participants of this study were all experienced volleyball players from the U18 category from the Brazilian National team. To assess jump performance, the VERT scores were compared to the VERTEC (jump and reach device). Each athlete performed 3 attack and 3 block jumps in a random, counterbalanced order, and the average score was registered. In the attack jumps, the VERTEC and VERT mean ± SD scores were 70.9±8.2 and 76.3±7.5 cm, respectively, and the typical error of the estimate (TEE) as a coefficient of variation (CV) was 7.8% (90% CL 7.0 to 8.9%). VERTEC and VERT devices presented a very large Pearson’s correlation for attack jumps (r=0.75; 90% CL 0.68 to 0.81). In addition, the mean±SD block jumps were 53.7±6.1 and 58.5±5.7 cm for the VERTEC and VERT, respectively and the TEE as a CV was 7.9% (90% CL 7.1 to 8.9%). Pearson’s correlation coefficient was very large for block jumps (r=0.75; 90% CL 0.67 to 0.81). The VERT device was found to be a very practical tool to quantify jump performance in volleyball players. PMID:29158616

  8. EFFECTS OF PLYOMETRIC TRAINING ON THE DEVELOPMENT THE VERTICAL JUMP IN VOLLEYBALL PLAYERS

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    Soundara rajan R

    2010-08-01

    Full Text Available Abstract:The present study investigated the effect of plyometric training on development of the vertical jump of volleyball players. The study consisted of 30 male volleyball players from PSG College of Arts & Science, Coimbatore, their age ranged from 18 to 25 years. Participants articipants were randomly assigned Group I underwent plyometric training group and Group II control group. The plyometric training group carried out a set of plyometric exercises also designed by the researcher twice a week for six weeks. The control group was allowed to play their game, but they were not given any treatments. For the purpose of this research, two tests forthe evaluation of the volleyball vertical jump were validated: the block jump and spike jump. The data was analysed using Paired t-tests which were used to test the effect of treatment groups individually between pre and post –tests, of all the groups, on variables used in the present study. The analysis of covariance was used toanalsze the collected data. The result of the study reveals that there was significant difference in 0.05 levels.Based on the findings of the research and the discussion, one could conclude that the exercise model for the development of the vertical jump that had been used, as the fundamental factor of the experimental group, has contributed to the statistically significant difference in the increase of the vertical jump in comparison to thecontrol group, which had used technically tactical contents to develop the vertical jump.

  9. Vertical jump performance of professional male and female volleyball players: effects of playing position and competition level.

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    Sattler, Tine; Hadžić, Vedran; Dervišević, Edvin; Markovic, Goran

    2015-06-01

    Vertical jump (VJ) performance is an important element for successful volleyball practice. The aims of the study were (a) to explore the overall VJ performance of elite volleyball players of both sexes, (b) to explore the differences in VJ performance among different competition levels and different playing positions, and (c) to evaluate the sex-related differences in the role of the arm swing and 3-step approach with arm swing on the jump height. We assessed the VJ capacity in 253 volleyball players (113 males and 140 females) from Slovenian first and second Volleyball Division. The height of squat jump (SJ), countermovement jump, block jump, and attack jump was tested using an Optojump system. We observed significant differences (p ≤ 0.05) in VJ height between different levels of play that were most pronounced in the SJ. Position-related differences in VJ performance were observed in male players between receivers and setters (p ≤ 0.05), whereas in females, VJ performance across different playing positions seems equal. Finally, we found that male players significantly better use the arm swing during VJ than females (p ≤ 0.05), whereas the use of eccentric part of the jump and approach before the spike to improve VJ performance seem to be equally mastered activity in both sexes. These results could assist coaches in the development of jumping performance in volleyball players. Furthermore, presented normative data for jump heights of elite male and female volleyball players could be useful in selection and profiling of young volleyball players.

  10. A simple method for quantifying jump loads in volleyball athletes.

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    Charlton, Paula C; Kenneally-Dabrowski, Claire; Sheppard, Jeremy; Spratford, Wayne

    2017-03-01

    Evaluate the validity of a commercially available wearable device, the Vert, for measuring vertical displacement and jump count in volleyball athletes. Propose a potential method of quantifying external load during training and match play within this population. Validation study. The ability of the Vert device to measure vertical displacement in male, junior elite volleyball athletes was assessed against reference standard laboratory motion analysis. The ability of the Vert device to count jumps during training and match-play was assessed via comparison with retrospective video analysis to determine precision and recall. A method of quantifying external load, known as the load index (LdIx) algorithm was proposed using the product of the jump count and average kinetic energy. Correlation between two separate Vert devices and three-dimensional trajectory data were good to excellent for all jump types performed (r=0.83-0.97), with a mean bias of between 3.57-4.28cm. When matched against jumps identified through video analysis, the Vert demonstrated excellent precision (0.995-1.000) evidenced by a low number of false positives. The number of false negatives identified with the Vert was higher resulting in lower recall values (0.814-0.930). The Vert is a commercially available tool that has potential for measuring vertical displacement and jump count in elite junior volleyball athletes without the need for time-consuming analysis and bespoke software. Subsequently, allowing the collected data to better quantify load using the proposed algorithm (LdIx). Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  11. THE EFFECTS OF SIXWEEKS PROGRAM OF PLYOMETRIC TRENING ON VOLLEYBALL JUMPING

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    Vladan Milić

    2008-08-01

    Full Text Available With goal to examine effects of plyometric training program on development of jumping strength for volleyball players, it was organized an experimental research on pattern of 23 volleyball players from cadet team and 23 students from high-school. Guided by general principles for plyometric training, individual plans for training were made. For estimating the effects of sports training on development of jumping, eight variables were used. For needs of this research four tests are valid for estimation, jump in block with left and right leg and jump in spike with left and right leg. Experiment has been realized in the second part on conditional preparations, and lasted for six weeks with two or three trainings per week. Control group had physical education lessons at their schools twice a week. Data were processed by in variant, multivariate analysis and analysis of covariance. On the results of research and discussion we can say that the model of training we used for development of jumping as a basic factor in experimental group brought statistically bigger difference in improving jumping that it brought in control group.

  12. The effect of assisted jumping on vertical jump height in high-performance volleyball players.

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    Sheppard, Jeremy M; Dingley, Andrew A; Janssen, Ina; Spratford, Wayne; Chapman, Dale W; Newton, Robert U

    2011-01-01

    Assisted jumping may be useful in training higher concentric movement speed in jumping, thereby potentially increasing the jumping abilities of athletes. The purpose of this study was to evaluate the effects of assisted jump training on counter-movement vertical jump (CMVJ) and spike jump (SPJ) ability in a group of elite male volleyball players. Seven junior national team volleyball players (18.0±1.0 yrs, 200.4±6.7 cm, and 84.0±7.2 kg) participated in this within-subjects cross-over counter-balanced training study. Assisted training involved 3 sessions per week of CMVJ training with 10 kg of assistance, applied through use of a bungee system, whilst normal jump training involved equated volume of unassisted counter-movement vertical jumps. Training periods were 5 weeks duration, with a 3-week wash-out separating them. Prior to and at the conclusion of each training period jump testing for CMVJ and SPJ height was conducted. Assisted jump training resulted in gains of 2.7±0.7 cm (pSports Medicine Australia. All rights reserved.

  13. Isokinetic knee strength qualities as predictors of jumping performance in high-level volleyball athletes: multiple regression approach.

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    Sattler, Tine; Sekulic, Damir; Spasic, Miodrag; Osmankac, Nedzad; Vicente João, Paulo; Dervisevic, Edvin; Hadzic, Vedran

    2016-01-01

    Previous investigations noted potential importance of isokinetic strength in rapid muscular performances, such as jumping. This study aimed to identify the influence of isokinetic-knee-strength on specific jumping performance in volleyball. The secondary aim of the study was to evaluate reliability and validity of the two volleyball-specific jumping tests. The sample comprised 67 female (21.96±3.79 years; 68.26±8.52 kg; 174.43±6.85 cm) and 99 male (23.62±5.27 years; 84.83±10.37 kg; 189.01±7.21 cm) high- volleyball players who competed in 1st and 2nd National Division. Subjects were randomly divided into validation (N.=55 and 33 for males and females, respectively) and cross-validation subsamples (N.=54 and 34 for males and females, respectively). Set of predictors included isokinetic tests, to evaluate the eccentric and concentric strength capacities of the knee extensors, and flexors for dominant and non-dominant leg. The main outcome measure for the isokinetic testing was peak torque (PT) which was later normalized for body mass and expressed as PT/Kg. Block-jump and spike-jump performances were measured over three trials, and observed as criteria. Forward stepwise multiple regressions were calculated for validation subsamples and then cross-validated. Cross validation included correlations between and t-test differences between observed and predicted scores; and Bland Altman graphics. Jumping tests were found to be reliable (spike jump: ICC of 0.79 and 0.86; block-jump: ICC of 0.86 and 0.90; for males and females, respectively), and their validity was confirmed by significant t-test differences between 1st vs. 2nd division players. Isokinetic variables were found to be significant predictors of jumping performance in females, but not among males. In females, the isokinetic-knee measures were shown to be stronger and more valid predictors of the block-jump (42% and 64% of the explained variance for validation and cross-validation subsample, respectively

  14. Lower Extremity Kinematics Differed Between a Controlled Drop-Jump and Volleyball-Takeoffs.

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    Beardt, Bradley S; McCollum, Myranda R; Hinshaw, Taylour J; Layer, Jacob S; Wilson, Margaret A; Zhu, Qin; Dai, Boyi

    2018-04-03

    Previous studies utilizing jump-landing biomechanics to predict anterior cruciate ligament injuries have shown inconsistent findings. The purpose of this study was to quantify the differences and correlations in jump-landing kinematics between a drop-jump, a controlled volleyball-takeoff, and a simulated-game volleyball-takeoff. Seventeen female volleyball players performed these three tasks on a volleyball court while three-dimensional kinematic data were collected by three calibrated camcorders. Participants demonstrated significantly increased jump height, shorter stance time, increased time differences in initial contact between two feet, increased knee and hip flexion at initial contact and decreased peak knee and hip flexion for both left and right legs, and decreased knee-ankle distance ratio at the lowest height of mid-hip for the two volleyball-takeoffs compared with the drop-jump (p jump and two volleyball-takeoffs. Controlled drop-jump kinematics may not represent jump-landing kinematics exhibited during volleyball competition. Jump-landing mechanics during sports-specific tasks may better represent those exhibited during sports competition and their associated risk of ACL injury compared with the drop-jump.

  15. Analysis of the association between isokinetic knee strength with offensive and defensive jumping capacity in high-level female volleyball athletes.

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    Sattler, Tine; Sekulic, Damir; Esco, Michael R; Mahmutovic, Ifet; Hadzic, Vedran

    2015-09-01

    Isokinetic-knee-strength was hypothesized to be an important factor related to jumping performance. However, studies examining this relation among elite female athletes and sport-specific jumps are lacking. This investigation determined the influence of isokinetic-knee flexor/extensor strength measures on spike-jump (offensive) and block-jump (defensive) performance among high-level female volleyball players. Cross-sectional laboratory study. Eighty-two female volleyball athletes (age = 21.3 ± 3.8 years, height = 175.4 ± 6.76 cm, and weight = 68.29 ± 8.53 kg) volunteered to participate in this study. The studied variables included spike-jump and block-jump performance and a set of isokinetic tests to evaluate the eccentric and concentric strength capacities of the knee extensors (quadriceps - Q), and flexors (hamstring - H) for both legs. Both jumping tests showed high intra-session reliability (ICC of 0.87 and 0.95 for spike-jump and block-jump, respectively). The athletes were clustered into three achievement-groups based on their spike-jump and block-jump performances. For the block-jump, ANOVA identified significant differences between achievement-groups for all isokinetic variables except the Right-Q-Eccentric-Strength. When observed for spike-jump, achievement-groups differed significantly in all tests but Right-H-Concentric-Strength. Discriminant canonical analysis showed that the isokinetic-strength variables were more associated with block-jump then spike-jump-performance. The eccentric isokinetic measures were relatively less important determinants of block-jump than for the spike-jump performance. Data support the hypothesis of the importance of isokinetic strength measures for the expression of rapid muscular performance in volleyball. The results point to the necessity of the differential approach in sport training for defensive and offensive duties. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  16. Effects of Experimental Volleyball Rules Quantified by Type and Number of Jumps, Hits and Contacts

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    Mladen Stankovic

    2017-10-01

    Full Text Available The purpose of this study was to determine the influence of the two new rules tested at the inaugural U23 Men’s Volleyball World Championship (21-point set excluding the fifth set, and 15 seconds between rallies–10 seconds from the finished point until the referee’s whistle for serve and five seconds for performing the serve on number and types of jumps and number of contacts and hits. The analysis comprised 25,930 jumps (an essential physical activity for volleyball, 15,706 contacts and 10,224 hits during 36 matches played by 144 males aged under 23 at the first Under 23 Men’s World Championships organized in Uberlandia, Brazil, in 2013. Two investigations were conducted: 1 Analysis of jumps by Jump type, In-game role and Level of set win; 2 Analysis of contacts (reception, setting, block, defense and hits (serve and attack by Type, In-game role and Set outcome. Significant differences (p=0.000 were found between in-game role and jump type, as Middle blocker performed the most (34.7%, followed by Outside hitter (24.9%, Setter (24.6% and Opposite (15.8%. Significant differences were found for number and types of Hits between set Winner and Loser teams only for serves by Setter (p<0.001 and Middle blocker (p<0.05. The results showed major differences in jumps, hits and contacts between in-game roles: Middle blocker was the most frequent jumping position, followed by Outside hitter and Setter. The Libero showed a new tendency of being Setter with a jump after the initial Setter defense.

  17. A valid and reliable method to measure jump-specific training and competition load in elite volleyball players.

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    Skazalski, C; Whiteley, R; Hansen, C; Bahr, R

    2018-05-01

    Use of a commercially available wearable device to monitor jump load with elite volleyball players has become common practice. The purpose of this study was to evaluate the validity and reliability of this device, the Vert, to count jumps and measure jump height with professional volleyball players. Jump count accuracy was determined by comparing jumps recorded by the device to jumps observed through systematic video analysis of three practice sessions and two league matches performed by a men's professional volleyball team. Jumps performed by 14 players were each coded for time and jump type and individually matched to device recorded jumps. Jump height validity of the device was examined against reference standards as participants performed countermovement jumps on a force plate and volleyball-specific jumps with a Vertec. The Vert device accurately counted 99.3% of the 3637 jumps performed during practice and match play. The device showed excellent jump height interdevice reliability for two devices placed in the same pouch during volleyball jumps (r = .99, 95% CI 0.98-0.99). The device had a minimum detectable change (MDC) of 9.7 cm and overestimated jump height by an average of 5.5 cm (95% CI 4.5-6.5) across all volleyball jumps. The Vert device demonstrates excellent accuracy counting volleyball-specific jumps during training and competition. While the device is not recommended to measure maximal jumping ability when precision is needed, it provides an acceptable measure of on-court jump height that can be used to monitor athlete jump load. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Dynamic load indicators for take-off-landing sequence in blocks and attacks of elite female volleyball players.

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    Kabaciński, Jarosław; Dworak, Lechosław Bogdan; Murawa, Michał; Rzepnicka, Agata

    2016-01-01

    Dynamic loads during landings determined by the ground reaction forces (GRFs) may elaborate internal loads and increase the risk of overload knee injuries as a result of performing volleyball jumps many times. The study dealt with a biomechanical assessment of dynamic load indicators in female volleyball players for the motion sequence of take-off-landing in blocks and attacks. Twelve professional female volleyball players participated in the study. Blocks and attacks were filmed by two cameras. GRFs vs. time graphs were recorded with the use of a force platform. Values of dynamic load indicators in terms of the relations of peak of vertical component of GRF, build-up index of this force (BIF), and power output (P) during landing to the vGRF, BIF and P during take-off (L/T) were calculated. The statistically significant ( p volleyball players.

  19. Vertical Jumping Tests versus Wingate Anaerobic Test in Female Volleyball Players: The Role of Age

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    Nikolaidis, Pantelis Theodoros; Afonso, Jose; Clemente-Suarez, Vicente Javier; Alvarado, Jose Rafael Padilla; Driss, Tarak; Knechtle, Beat; Torres-Luque, Gema

    2016-01-01

    Single and continuous vertical jumping tests, as well as the Wingate anaerobic test (WAnT), are commonly used to assess the short-term muscle power of female volleyball players; however, the relationship among these tests has not been studied adequately. Thus, the aim of the present study was to examine the relationship of single and continuous vertical jumps with the WAnT in female volleyball players. Seventy adolescent (age 16.0 ± 1.0 years, body mass 62.5 ± 7.1 kg, height 170.4 ± 6.1 cm, body fat 24.2% ± 4.3%) and 108 adult female volleyball players (age 24.8 ± 5.2 years, body mass 66.5 ± 8.7 kg, height 173.2 ± 7.4 cm, body fat 22.0% ± 5.1%) performed the squat jump (SJ), countermovement jump (CMJ), Abalakov jump (AJ), 30 s Bosco test and WAnT (peak power, Ppeak; mean power, Pmean). Mean power in the Bosco test was correlated (low to large magnitude) with Pmean of the WAnT (r = 0.27, p = 0.030 in adolescents versus r = 0.56, p volleyball players. These findings should be taken into account by volleyball coaches and fitness trainers during the assessment of short-term muscle power of their athletes.

  20. Association of anthropometric qualities with vertical jump performance in elite male volleyball players.

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    Aouadi, R; Jlid, M C; Khalifa, R; Hermassi, S; Chelly, M S; Van Den Tillaar, R; Gabbett, T

    2012-02-01

    The objective of this study was to examine the association between physical and anthropometric profiles and vertical jump performance in elite volleyball players. Thirty-three elite male volleyball players (21±1 y, 76.9±5.2 kg, 186.5±5 cm) were studied. Several anthropometric measurements (body mass, stature, body mass index, lower limb length and sitting height) together with jumping height anaerobic power of counter movement jump with arm swing (CMJarm) were obtained from all subjects. Forward stepwise multiple linear regression analysis was performed to determine if any of the anthropometric parameters were predictive of CMJarm. Anaerobic power was significantly higher (P≤0.05) in the tallest players relative to their shorter counterparts. A significant relationship was observed between CMJarm and lower limb length (r2=0.69; P0.05) predictors of CMJarm performance. This study demonstrates that lower limb length is correlated with CMJarm in elite male volleyball players. The players with longer lower limbs have the better vertical jump performances and their anaerobic power is higher. These results could be of importance for trained athletes in sports relying on jumping performance, such as basketball, handball or volleyball. Thus, the measurement of anthropometric characteristics, such as stature and lower limb length may assist coaches in the early phases of talent identification in volleyball.

  1. Effect of an Arm Swing on Countermovement Vertical Jump Performance in Elite Volleyball Players

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    Vaverka Frantisek

    2016-12-01

    Full Text Available The aim of this study was to determine how elite volleyball players employed the arm swing (AS to enhance their jump performance. The study assessed how the AS influenced the duration and magnitude of the vertical ground reaction force (VGRF during the main phases (preparatory, braking and accelerating of the countermovement vertical jump (CMVJ, the starting position of the body at the beginning of the accelerating phase and the moment when the AS began contributing to increasing the jump height. Eighteen elite volleyball players performed three CMVJs with and without an AS. Kinetics and kinematics data were collected using two Kistler force plates and the C-motion system. The time and force variables were evaluated based on the VGRF, and the position of the body and the trajectory of the arm movement were determined using kinematic analysis. The AS improved the CMVJ by increasing the jump height by 38% relative to jumping without an AS. The AS significantly shortened the braking phase and prolonged the accelerating phase, however, it did not influence the preparatory phase or the overall jump duration. The AS also significantly increased the average force during the accelerating phase as well as the accelerating impulse. The AS upward began at 76% into the overall jump duration. The AS did not influence the body position at the beginning of the accelerating phase. These findings can be used to improve performance of the CMVJ with the AS and in teaching beginning volleyball players proper jumping technique.

  2. THE MODEL CHARACTERISTICS OF JUMP ACTIONS STRUCTURE OF HIGH PERFORMANCE FEMALE VOLLEYBALL PLAYERS

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    Stech M.

    2012-12-01

    Full Text Available The purpose of this study was to develop generalized and individual models of the jump actions of skilled female volleyball players. The main prerequisite for the development of the jump actions models were the results of our earlier studies of factor structure of jump actions of 10 sportswomen of the Polish volleyball team "Gedania" (Premier League in the preparatory and competitive periods of the annual cycle of preparation. The athletes age was 22.0 +- 2.9 years, the sports experience - 8.1 +- 3.1 years, body height - 181.9 +- 8.4 years and body weight - 72.8 +- 10.8 kg. Mathematical and statistical processing of the data (the definition of M ± SD and significant differences between the samples was performed using a standard computer program "STATISTICA 7,0". Based on the analysis of the factor structure of 20 jump actions of skilled women volleyball players determined to within 5 of the most informative indexes and their tentative values recommended for the formation of a generalized model of this structure. Comparison of individual models of jump actions of skilled women volleyball players with their generalized models in different periods of preparation can be used for the rational choice of means and methods for the increasing of the training process efficiency.

  3. Loaded and unloaded jump performance of top-level volleyball players from different age categories.

    Science.gov (United States)

    Kitamura, Katia; Pereira, Lucas Adriano; Kobal, Ronaldo; Cal Abad, Cesar Cavinato; Finotti, Ronaldo; Nakamura, Fábio Yuzo; Loturco, Irineu

    2017-09-01

    The aim of this study was to investigate the differences in loaded and unloaded jump performances between different age categories of top-level volleyball players from the same club. Forty-three volleyball players were divided into four age groups: under-17, under-19, under-21 and professional. Vertical jumping height for squat jump (SJ), countermovement jump (CMJ) and CMJ with arm swing (CMJa) and mean propulsive velocity (MPV) in the loaded jump squat exercise with 40% of the athlete's body mass were compared among the different age categories, considering body mass as a covariate. SJ and CMJ jump height values were higher for professional and under-21 players than under-17 players (pjump squat was higher for under-21 players than under-17 players (pjump performances across different age categories of top-level volleyball players. Therefore, to increase the vertical jumping ability of these team sport athletes throughout their long-term development, coaches and strength and conditioning professionals are encouraged to implement consistent neuromuscular training strategies, in accordance with the specific needs and physiological characteristics of each age group.

  4. Who jumps the highest? Anthropometric and physiological correlations of vertical jump in youth elite female volleyball players.

    Science.gov (United States)

    Nikolaidis, Pantelis T; Gkoudas, Konstantinos; Afonso, José; Clemente-Suarez, Vicente J; Knechtle, Beat; Kasabalis, Stavros; Kasabalis, Athanasios; Douda, Helen; Tokmakidis, Savvas; Torres-Luque, Gema

    2017-06-01

    The aim of the present study was to examine the relationship of vertical jump (Abalakov jump [AJ]) with anthropometric and physiological parameters in youth elite female volleyball players. Seventy-two selected volleyball players from the region of Athens (age 13.3±0.7 years, body mass 62.0±7.2 kg, height 171.5±5.7 cm, body fat 21.2±4.5%), classified into quartiles according to AJ performance (group A, 21.4-26.5 cm; group B, 26.8-29.9 cm; group C, 30.5-33.7 cm; group D, 33.8-45.9 cm), performed a series of physical fitness tests. AJ was correlated with anthropometric (age at peak height velocity [APHV]: r=0.38, Pvolleyball players that jumped the highest were those who matured later than others.

  5. Influence of dorsiflexion shoes on neuromuscular fatigue of the plantar flexors after combined tapping-jumping exercises in volleyball players.

    Science.gov (United States)

    Lapole, Thomas; Ahmaidi, Said; Gaillien, Benjamin; Leprêtre, Pierre-Marie

    2013-07-01

    Dorsiflexion shoes could be useful to increase jumping performance. The aim of the present study was to investigate the impact of wearing shoes inducing moderate dorsiflexion (2°) on neuromuscular fatigue induced by volleyball exercises involving multiple stretch-shortening cycles. Squat jump (SJ) and countermovement jump (CMJ) performance, and plantar flexors isometric voluntary and evoked contractile properties were assessed in 10 unfamiliarized trained volleyball players before and after a 10-minute intensive combined tapping-jumping volleyball exercise performed, in blinded randomized conditions, with neutral (0°) or moderate dorsiflexion (2°). No significant difference was observed on SJ performance in neutral and moderate dorsiflexion conditions. However, CMJ height was initially lower with 2° dorsiflexion compared with 0° (p volleyball exercise also induced a significant decrease in maximal voluntary contraction (p volleyball players.

  6. The jumping action's indices of female volleyball players and their relation at some somatic characteristics

    Directory of Open Access Journals (Sweden)

    Stech M.

    2010-02-01

    Full Text Available In the paper the results of correlation analysis between of most significance jumping action's indices of high performance polish female volleyball players and their some somatic characteristics (stature, weight and body composition indices: BMI, FATkg, FAT%, FFMkg,FFM%, TBWkg and TBW% are presented. It has been found close correlation between of height of attack jump and stature (r=0,98, weight (r=0,76, FFMkg(r=0,88 and TBWkg (r=0,88. But correlation of height of attack jump with FFM% and TBW% was nonessential. Statistical essential correlation between basic indices of plyometric factor and FAT%, FFM% and TBW% indices (accordingly r = -0,65; 0,65 and 0,66 has been found. The results of the study may be taking into consideration in order to elaboration of effective jumping methods for volleyball players.

  7. Comparison of biomechanical parameters obtained during various types of vertical jumps in volleyball and basketball players

    Directory of Open Access Journals (Sweden)

    Joanna Mazur-Różycka

    2017-07-01

    Full Text Available The aim of the study was to compare selected biomechanical parameters obtained during various types of vertical jumps made by volleyball and basketball players on a dynamometric platform. The study involved 10 volleyball players and 10 basketball players in the age of 21.1 ± 1.81 years of the AZS AWF Warsaw sport club. The athletes performed two vertical jumps on a KISTLER platform. The first jump was a counter-movement jump (CMJ and the second was a spike jump (SPJ – a vertical jump which is performed with a 3-4 step run-up before the take-off. The participant's task was to take off and land on the platform. On the basis of the statistical analysis it was shown that only the type of jump had a significant effect on the height and power. The type of team sport did not affect the level of performance. In addition, it was found that the height of the jump is affected by the counter movement phase with hand swing and run-up. The volleyball and basketball players were equally able to get higher values for certain parameters in successive runs. Due to lack of statistically significant differences it was decided to combine two groups of athletes into one. For both jumps, the relationship between peak power and jump height was found at significance level p <0.001. Dynamometric platform can be used to check the athlete's height of jump and power of lower extremities. This method allows to verify the effectiveness of different types of training.

  8. Application of a tri-axial accelerometer to estimate jump frequency in volleyball.

    Science.gov (United States)

    Jarning, Jon M; Mok, Kam-Ming; Hansen, Bjørge H; Bahr, Roald

    2015-03-01

    Patellar tendinopathy is prevalent among athletes, and most likely associated with a high jumping load. If methods for estimating jump frequency were available, this could potentially assist in understanding and preventing this condition. The objective of this study was to explore the possibility of using peak vertical acceleration (PVA) or peak resultant acceleration (PRA) measured by an accelerometer to estimate jump frequency. Twelve male elite volleyball players (22.5 ± 1.6 yrs) performed a training protocol consisting of seven typical motion patterns, including jumping and non-jumping movements. Accelerometer data from the trial were obtained using a tri-axial accelerometer. In addition, we collected video data from the trial. Jump-float serving and spike jumping could not be distinguished from non-jumping movements using differences in PVA or PRA. Furthermore, there were substantial inter-participant differences in both the PVA and the PRA within and across movement types (p volleyball. A method for acquiring real-time estimates of jump frequency remains to be verified. However, there are several alternative approaches, and further investigations are needed.

  9. Are the take-off and landing phase dynamics of the volleyball spike jump related to patellar tendinopathy?

    NARCIS (Netherlands)

    Bisseling, R.W.; Hof, A.L.; Bredeweg, S.W.; Zwerver, J.; Mulder, T.

    Objective: The causal mechanism of the chronic sports injury patellar tendinopathy is not well understood. The aim of the present study was to compare ankle and knee joint dynamics during the performance of the volleyball spike jump between healthy volleyball players (n = 8) and asymptomatic

  10. Loaded and unloaded jump performance of top-level volleyball players from different age categories

    Science.gov (United States)

    Kitamura, Katia; Pereira, Lucas Adriano; Kobal, Ronaldo; Cal Abad, Cesar Cavinato; Finotti, Ronaldo; Nakamura, Fábio Yuzo

    2017-01-01

    The aim of this study was to investigate the differences in loaded and unloaded jump performances between different age categories of top-level volleyball players from the same club. Forty-three volleyball players were divided into four age groups: under-17, under-19, under-21 and professional. Vertical jumping height for squat jump (SJ), countermovement jump (CMJ) and CMJ with arm swing (CMJa) and mean propulsive velocity (MPV) in the loaded jump squat exercise with 40% of the athlete’s body mass were compared among the different age categories, considering body mass as a covariate. SJ and CMJ jump height values were higher for professional and under-21 players than under-17 players (pvolleyball players. Therefore, to increase the vertical jumping ability of these team sport athletes throughout their long-term development, coaches and strength and conditioning professionals are encouraged to implement consistent neuromuscular training strategies, in accordance with the specific needs and physiological characteristics of each age group. PMID:29158621

  11. Landing Techniques in Beach Volleyball

    Science.gov (United States)

    Tilp, Markus; Rindler, Michael

    2013-01-01

    The aims of the present study were to establish a detailed and representative record of landing techniques (two-, left-, and right-footed landings) in professional beach volleyball and compare the data with those of indoor volleyball. Beach volleyball data was retrieved from videos taken at FIVB World Tour tournaments. Landing techniques were compared in the different beach and indoor volleyball skills serve, set, attack, and block with regard to sex, playing technique, and court position. Significant differences were observed between men and women in landings following block actions (χ2(2) = 18.19, p volleyball revealed overall differences both in men (χ2(2) = 161.4, p volleyball players land more often on both feet than indoor volleyball players. Besides the softer surface in beach volleyball, and therefore resulting lower loads, these results might be another reason for fewer injuries and overuse conditions compared to indoor volleyball. Key Points About 1/3 of all jumping actions in beach volleyball result in a landing on one foot. Especially following block situations men land on one foot more often than women. Landing techniques are related to different techniques and positions. Landings on one foot are less common in beach volleyball than indoor volleyball. This could be a reason for fewer injuries and overuse conditions. PMID:24149150

  12. Vertical Jumping Tests versus Wingate Anaerobic Test in Female Volleyball Players: The Role of Age

    Directory of Open Access Journals (Sweden)

    Pantelis Theodoros Nikolaidis

    2016-02-01

    Full Text Available Single and continuous vertical jumping tests, as well as the Wingate anaerobic test (WAnT, are commonly used to assess the short-term muscle power of female volleyball players; however, the relationship among these tests has not been studied adequately. Thus, the aim of the present study was to examine the relationship of single and continuous vertical jumps with the WAnT in female volleyball players. Seventy adolescent (age 16.0 ± 1.0 years, body mass 62.5 ± 7.1 kg, height 170.4 ± 6.1 cm, body fat 24.2% ± 4.3% and 108 adult female volleyball players (age 24.8 ± 5.2 years, body mass 66.5 ± 8.7 kg, height 173.2 ± 7.4 cm, body fat 22.0% ± 5.1% performed the squat jump (SJ, countermovement jump (CMJ, Abalakov jump (AJ, 30 s Bosco test and WAnT (peak power, Ppeak; mean power, Pmean. Mean power in the Bosco test was correlated (low to large magnitude with Pmean of the WAnT (r = 0.27, p = 0.030 in adolescents versus r = 0.56, p < 0.001 in adults. SJ, CMJ and AJ also correlated with Ppeak (0.28 ≤ r ≤ 0.46 in adolescents versus 0.58 ≤ r ≤ 0.61 in adults and with Pmean (0.43 ≤ r ≤ 0.51 versus 0.67 ≤ r ≤ 0.71, respectively of the WAnT (p < 0.05. In summary, the impact of the Bosco test and WAnT on muscle power varied, especially in the younger age group. Single jumping tests had larger correlations with WAnT in adults than in adolescent volleyball players. These findings should be taken into account by volleyball coaches and fitness trainers during the assessment of short-term muscle power of their athletes.

  13. Specific warm-up exercise is the best for vertical countermovement jump in young volleyball players

    Directory of Open Access Journals (Sweden)

    Fernando Nazário de Rezende

    Full Text Available Abstract We evaluated the effect of performing various distinct warm-up exercises on vertical countermovement jump (VCMJ performance. Eight volleyball players (age 15.4 ± 0.5 yrs performed five different warm-up activities (in a counterbalanced, randomized crossover study over five days, at 24-h intervals: stretching (4 × 30 s, 30 s between sets, cycloergometer (5 min at 50 W + 5 min at 100 W, resistance exercise (leg press 45°, 3 × 5 repetitions maximum, 3-min pause between sets, specific vertical jumping (4 × 10 VCMJ, 2-min pause between sets, and no warm-up at all (control condition. Beginning 3 min after their warm-up, the players performed 3 attempts (at intervals of 3 min of VCMJ (on a contact carpet, and each player's best jump was considered in the analysis. All warm-up activities presented higher VCMJ performance (p< 0.05 than the control condition, with the exception of stretching. Vertical jumping revealed a large effect size(0.8 than other interventions. We conclude that in practical terms, vertical jumps are the best warm-up exercise (when applied by itself to acutely improve VCMJ performance in volleyball players, but that other exercises can make a complementary contribution.

  14. Effect Of Plyometric Training On Vertical Jump Performance And Neuromuscular Adaptation In Volleyball Player

    Directory of Open Access Journals (Sweden)

    Dara Hosseini

    2012-12-01

    Full Text Available The purpose of this study was to examine the effectiveness of 12-week plyometric training on vertical jump performance (Vj, maximal surface EMG, M-wave amplitude, M�wave latency, and nerve conduction velocity (NCV in men volleyball player. Thirty junior high school volleyball players' volunteers (age: 17.53� 0.74; Height: 177.67� 3.14; Weight: 61.31 � 5.32 were divided into plyometric training [PT] (n=15 and control group[c] (n=15. PT group trained so.w' but C group didn't participate in this training. Both groups were pre- and post tested in EMG, M-wave parameters, NCV and Vj test. Tow way ANOVA (group*time interaction and Bonferroni post hoes test demonstrated significant differences (P

  15. Identification of types of landings after blocking in volleyball associated with risk of ACL injury.

    Science.gov (United States)

    Zahradnik, David; Jandacka, Daniel; Farana, Roman; Uchytil, Jaroslav; Hamill, Joseph

    2017-03-01

    Landing with a low knee flexion angle after volleyball block jumps may be associated with an increased risk of anterior cruciate ligament (ACL) injury. The aim of the present study was to identify the types of volleyball landings after blocks where the knee flexion angle is found to be under a critical knee flexion angle value of 30° at the instant of the first peak of the ground reaction force (GRF). Synchronized kinematic and kinetic data were collected for each trial. T-tests were used to determine if each knee flexion angle at the instant of the peak GRF was significantly different from the critical value of 30°. A repeated measures ANOVA was used to compare knee flexion angle, time to first peak and the magnitude of the first peak of the resultant GRF and knee stiffness. Significantly lower knee flexion angles were found in the "go" landing (p = .01, ES = 0.6) and the "reverse" landing (p = .02, ES = 0.6) only. The results for knee flexion angle and GRF parameters indicated a significant difference between a "reverse" and "go" and other types of landings, except the "side stick" landing for GRF. The "reverse" and "go" landings may present a risk for ACL injury due to the single-leg landing of these activities that have an associated mediolateral movement.

  16. Biomechanical differences of arm swing countermovement jumps on sand and rigid surface performed by elite beach volleyball players.

    Science.gov (United States)

    Giatsis, George; Panoutsakopoulos, Vassilios; Kollias, Iraklis A

    2018-05-01

    The purpose of this study was to investigate the possible arm swing effect on the biomechanical parameters of vertical counter movement jump due to differences of the compliance of the take-off surface. Fifteen elite male beach-volleyball players (26.2 ± 5.9 years; 1.87 ± 0.05 m; 83.4 ± 6.0 kg; mean ± standard deviation, respectively) performed counter movement jumps on sand and on a rigid surface with and without an arm swing. Results showed significant (p volleyball.

  17. Effect Of Plyometric Training On Vertical Jump Performance And Neuromuscular Adaptation In Volleyball Player

    Directory of Open Access Journals (Sweden)

    Dara Hosseini

    2012-12-01

    Full Text Available The purpose of this study was to examine the effectiveness of 12-week plyometric training on vertical jump performance (Vj, maximal surface EMG, M-wave amplitude, Mwave latency, and nerve conduction velocity (NCV in men volleyball player. Thirty junior high school volleyball players' volunteers (age: 17.53 0.74; Height: 177.67 3.14; Weight: 61.31 5.32 were divided into plyometric training [PT] (n=15 and control group[c] (n=15. PT group trained so.w' but C group didn't participate in this training. Both groups were pre- and post tested in EMG, M-wave parameters, NCV and Vj test. Tow way ANOVA (group*time interaction and Bonferroni post hoes test demonstrated significant differences (P<0.05 in PT group of pre to post test in VJ performance (9.67 % and in M-wave latency 16.55 % t ; nerve conduction velocity 14.19 % t ; there is no significant differences in IEMG (4.6 5 % J, and M-wave amplitude (20.91 % t , but there is no significant improvement during this period in control group. Comparison between groups after 12wk showed that there was a significant improvement in Latency (16.74 % J, and NCV (19.10% t in PT group during the course of the study than C group (P<0.05. based on the results of this study, it is possible to conclude that coaches and trainers consider PT as a strategy for increasing volleyball players' explosive performance that this may have taken place in neuromuscular responses such as; optimizing motor unites (MU pattern, optimizing MUs recruitment, augmentation in nerve conduction velocity, decrement in reflex excitability of the motor pool.

  18. Plyometric Training Improves Sprinting, Jumping and Throwing Capacities of High Level Female Volleyball Players Better Than Skill-Based Conditioning

    Directory of Open Access Journals (Sweden)

    Bahri Gjinovci, Kemal Idrizovic, Ognjen Uljevic, Damir Sekulic

    2017-12-01

    Full Text Available There is an evident lack of studies on the effectiveness of plyometric- and skill-based-conditioning in volleyball. This study aimed to evaluate effects of 12-week plyometric- and volleyball-skill-based training on specific conditioning abilities in female volleyball players. The sample included 41 high-level female volleyball players (21.8 ± 2.1 years of age; 1.76 ± 0.06 cm; 60.8 ± 7.0 kg, who participated in plyometric- (n = 21, or skill-based-conditioning-program (n = 20. Both programs were performed twice per week. Participants were tested on body-height, body-mass (BM, countermovement jump (CMJ, standing broad jump (SBJ, medicine ball throw, (MBT and 20-m sprint (S20M. All tests were assessed at the study baseline (pre- and at the end of the 12-week programs (post-testing. Two-way ANOVA for repeated measurements showed significant (p<0.05 “Group x Time” effects for all variables but body-height. Plyometric group significantly reduced body-mass (trivial effect size [ES] differences; 1% average pre- to post-measurement changes, and improved their performance in S20M (moderate ES; 8%, MBT (very large ES; 25%, CMJ (large ES; 27%, and SBJ (moderate ES; 8%. Players involved in skill-based-conditioning significantly improved CMJ (large ES; 18%, SBJ (small ES; 3%, and MBT (large ES; 9%. The changes which occurred between pre- and post-testing were more inter-correlated in plyometric-group. Although both training-modalities induced positive changes in jumping- and throwing-capacities, plyometric-training is found to be more effective than skill-based conditioning in improvement of conditioning capacities of female senior volleyball players. Future studies should evaluate differential program effects in less experienced and younger players.

  19. Plyometric Training Improves Sprinting, Jumping and Throwing Capacities of High Level Female Volleyball Players Better Than Skill-Based Conditioning

    Science.gov (United States)

    Gjinovci, Bahri; Idrizovic, Kemal; Uljevic, Ognjen; Sekulic, Damir

    2017-01-01

    There is an evident lack of studies on the effectiveness of plyometric- and skill-based-conditioning in volleyball. This study aimed to evaluate effects of 12-week plyometric- and volleyball-skill-based training on specific conditioning abilities in female volleyball players. The sample included 41 high-level female volleyball players (21.8 ± 2.1 years of age; 1.76 ± 0.06 cm; 60.8 ± 7.0 kg), who participated in plyometric- (n = 21), or skill-based-conditioning-program (n = 20). Both programs were performed twice per week. Participants were tested on body-height, body-mass (BM), countermovement jump (CMJ), standing broad jump (SBJ), medicine ball throw, (MBT) and 20-m sprint (S20M). All tests were assessed at the study baseline (pre-) and at the end of the 12-week programs (post-testing). Two-way ANOVA for repeated measurements showed significant (pvolleyball players. Future studies should evaluate differential program effects in less experienced and younger players. Key points Plyometric- and skill-based-conditioning resulted in improvements in jumping and throwing capacities, but plyometric training additionally induced positive changes in anthropometrics and sprint-capacity The changes induced by plyometric training were larger in magnitude than those achieved by skill-based conditioning. The higher intensity together with possibility of more accurate adjustment of training load in plyometric training are probably the most important determinant of such differential influence. It is likely that the skill-based conditioning program did not result in changes of higher magnitude because of the players’ familiarity with volleyball-related skills. PMID:29238253

  20. Plyometric Training Improves Sprinting, Jumping and Throwing Capacities of High Level Female Volleyball Players Better Than Skill-Based Conditioning.

    Science.gov (United States)

    Gjinovci, Bahri; Idrizovic, Kemal; Uljevic, Ognjen; Sekulic, Damir

    2017-12-01

    There is an evident lack of studies on the effectiveness of plyometric- and skill-based-conditioning in volleyball. This study aimed to evaluate effects of 12-week plyometric- and volleyball-skill-based training on specific conditioning abilities in female volleyball players. The sample included 41 high-level female volleyball players (21.8 ± 2.1 years of age; 1.76 ± 0.06 cm; 60.8 ± 7.0 kg), who participated in plyometric- (n = 21), or skill-based-conditioning-program (n = 20). Both programs were performed twice per week. Participants were tested on body-height, body-mass (BM), countermovement jump (CMJ), standing broad jump (SBJ), medicine ball throw, (MBT) and 20-m sprint (S20M). All tests were assessed at the study baseline (pre-) and at the end of the 12-week programs (post-testing). Two-way ANOVA for repeated measurements showed significant (pPlyometric group significantly reduced body-mass (trivial effect size [ES] differences; 1% average pre- to post-measurement changes), and improved their performance in S20M (moderate ES; 8%), MBT (very large ES; 25%), CMJ (large ES; 27%), and SBJ (moderate ES; 8%). Players involved in skill-based-conditioning significantly improved CMJ (large ES; 18%), SBJ (small ES; 3%), and MBT (large ES; 9%). The changes which occurred between pre- and post-testing were more inter-correlated in plyometric-group. Although both training-modalities induced positive changes in jumping- and throwing-capacities, plyometric-training is found to be more effective than skill-based conditioning in improvement of conditioning capacities of female senior volleyball players. Future studies should evaluate differential program effects in less experienced and younger players.

  1. Influence of a sport-specific training background on vertical jumping and throwing performance in young female basketball and volleyball players.

    Science.gov (United States)

    Battaglia, G; Paoli, A; Bellafiore, M; Bianco, A; Palma, A

    2014-10-01

    The purpose of this study was to evaluate the influence of 3 years of sport-specific training background (SSTB) on vertical jumping and throwing performance in young female basketball and volleyball players. Thirty-one healthy adolescent girls, of which 11 age-matched control subjects [C], 10 basketballers (BP) and 10 volleyballers (VP) participated to the study. The throwing performance was assessed by seated backward overhead ball throw (SBOMBT) and seated chest pass throw (SCPT) using a 3-kg rubber medicine ball. Instead, the vertical jumping performance was evaluated by squat jump (SJ) and countermovement jump with (CMJ-AS) and without arm swing (CMJ) using Optojump system (Microgate srl, Italy). During SJ and CMJ with and without arm swing VP group showed a higher vertical jump performance than BP and C ones. In particular we showed that VP exhibited a higher flight time and jump height than C (Pbasketball athletes' maximal power compared to age-matched control subjects.

  2. Effects of Caffeine on Countermovement-Jump Performance Variables in Elite Male Volleyball Players.

    Science.gov (United States)

    Zbinden-Foncea, Hermann; Rada, Isabel; Gomez, Jesus; Kokaly, Marco; Stellingwerff, Trent; Deldicque, Louise; Peñailillo, Luis

    2018-02-01

    To examine the effects of a moderate dose of caffeine in elite male volleyball players on countermovement-jump (CMJ) performance, as well as temporal concentric- and eccentric-phase effects. Ten elite male volleyball players took part in 2 experimental days via a randomized crossover trial 1 wk apart in which they ingested either 5 mg/kg of caffeine or a placebo in double-blind fashion. Heart rate and blood pressure were measured at rest and 60 min postingestion. Afterward, subjects also performed 3 CMJ trials 60 min postingestion, of which the average was used for further analysis. They filled out a questionnaire on possible side effects 24 h posttrial. Caffeine intake, compared with placebo, increased CMJ peak concentric force (6.5% ± 6.4%; P = .01), peak power (16.2% ± 8.3%; P < .01), flight time (5.3% ± 3.4%; P < .01), velocity at peak power (10.6% ± 8.0%; P < .01), peak displacement (10.8% ± 6.5%; P < .01), peak velocity (12.6% ± 7.4%; P < .01), peak acceleration (13.5% ± 8.5%; P < .01), and the force developed at peak power (6.0% ± 4.0%; P < .01) and reduced the time between peak power and peak force (16.7% ± 21.6%, P = .04). Caffeine increased diastolic blood pressure by 13.0% ± 8.9% (P < .05), whereas no adverse side effects were found. The ingestion of 5 mg/kg of anhydrous caffeine improves overall CMJ performance without inducing side effects.

  3. Stature and jumping height are required in female volleyball, but motor coordination is a key factor for future elite success.

    Science.gov (United States)

    Pion, Johan A; Fransen, Job; Deprez, Dieter N; Segers, Veerle I; Vaeyens, Roel; Philippaerts, Renaat M; Lenoir, Matthieu

    2015-06-01

    It was hypothesized that differences in anthropometry, physical performance, and motor coordination would be found between Belgian elite and sub-elite level female volleyball players using a retrospective analysis of test results gathered over a 5-year period. The test sample in this study consisted of 21 young female volleyball players (15.3 ± 1.5 years) who were selected to train at the Flemish Top Sports Academy for Volleyball in 2008. All players (elite, n = 13; sub-elite, n = 8) were included in the same talent development program, and the elite-level athletes were of a high to very high performance levels according to European competition level in 2013. Five multivariate analyses of variance were used. There was no significant effect of playing level on measures of anthropometry (F = 0.455, p = 0.718, (Equation is included in full-text article.)= 0.07), flexibility (F = 1.861, p = 0.188, (Equation is included in full-text article.)= 0.19), strength (F = 1.218, p = 0.355, (Equation is included in full-text article.)= 0.32); and speed and agility (F = 1.176, p = 0.350, (Equation is included in full-text article.)= 0.18). Multivariate analyses of variance revealed significant multivariate effects between playing levels for motor coordination (F = 3.470, p = 0.036, (Equation is included in full-text article.)= 0.59). A Mann-Whitney U test and a sequential discriminant analysis confirmed these results. Previous research revealed that stature and jump height are prerequisites for talent identification in female volleyball. In addition, the results show that motor coordination is an important factor in determining inclusion into the elite level in female volleyball.

  4. Blocking landing techniques in volleyball and the possible association with anterior cruciate ligament injury.

    Science.gov (United States)

    Zahradnik, David; Jandacka, Daniel; Holcapek, Michal; Farana, Roman; Uchytil, Jaroslav; Hamill, Joseph

    2018-04-01

    The number and type of landings performed after blocking during volleyball matches has been related to the potential risk of ACL injury. The aim of the present study was to determine whether gender affects the frequency of specific blocking landing techniques with potential risk of ACL injury from the perspective of foot contact and subsequent movement after the block used by volleyball players during competitive matches. Three matches involving four female volleyball teams (fourteen sets) and three matches involving four male volleyball teams (thirteen sets) in the Czech Republic were analyzed for this study. A Pearson chi-square test of independence was used to detect the relationship between gender and different blocking techniques. The results of the present study showed that gender affected single-leg landings with subsequent movement in lateral direction and double-leg landings. Although the total number of landings was lower for male athletes than for female athletes, a larger portion of male athletes demonstrated single leg landings with a subsequent movement than female athletes. Single leg landings with a subsequent movement have a higher potential risk of ACL injury.

  5. Caffeinated energy drinks improve volleyball performance in elite female players.

    Science.gov (United States)

    Pérez-López, Alberto; Salinero, Juan José; Abian-Vicen, Javier; Valadés, David; Lara, Beatriz; Hernandez, Cesar; Areces, Francisco; González, Cristina; Del Coso, Juan

    2015-04-01

    The objective of this study is to determine the effects of a caffeine-containing energy drink on female volleyball players' performance. Thirteen elite female volleyball players ingested 3 mg·kg of caffeine with an energy drink or the same drink without caffeine (placebo drink) in a double-blind and randomized study. Then, participants performed the following: standing spike, jumping spike, spike jump, blocking jump, squat jump, countermovement jump, manual dynamometry, and the agility t-test. A simulated volleyball game was played, videotaped, and notated afterward. In comparison to the placebo drink, the ingestion of the caffeinated energy drink increased the ball velocity in the standing spike (19.2 ± 2.1 vs 19.7 ± 1.9 m·s, P = 0.023) and in the jumping spike (17.9 ± 2.2 vs 18.8 ± 2.2 m·s, P = 0.038) and the jump height in the squat jump (28.1 ± 3.2 vs 29.4 ± 3.6 cm, P = 0.028), countermovement jump (32.0 ± 4.6 vs 33.1 ± 4.5 cm, P = 0.018), spike jump (43.3 ± 4.7 vs 44.4 ± 5.0 cm, P = 0.025), and block jump (35.2 ± 5.1 vs 36.1 ± 5.1 cm, P = 0.044). Furthermore, the caffeinated energy drink decreased the time needed to complete the agility t-test (11.1 ± 0.5 vs 10.9 ± 0.3 s, P = 0.036). During the game, the volleyball actions categorized as successful were more frequent with the caffeinated energy drink (34% ± 9% vs 45% ± 9%, P volleyball players. Increased physical performance led to improved accuracy during an actual volleyball match.

  6. Jump frequency may contribute to risk of jumper's knee: a study of interindividual and sex differences in a total of 11,943 jumps video recorded during training and matches in young elite volleyball players.

    Science.gov (United States)

    Bahr, Martin A; Bahr, Roald

    2014-09-01

    Male sex, total training volume (number of hours per week) and match exposure (number of sets played per week) are risk factors for jumper's knee among young elite volleyball players. However, it is not known whether jump frequency differs among players on the same squad. To examine interindividual and sex differences in jump frequency during training and matches in young elite volleyball players. Observational study. Norwegian elite volleyball boarding school training programme. Student-athletes (26 boys and 18 girls, 16-18 years). Individual jump counts were recorded based on visual analysis of video recordings obtained from 1 week of volleyball training (9 training sessions for boys and 10 for girls, 14.1 h and 17.8 h of training, respectively) and 10 matches (5.9 h for boys (16 sets) and 7.7 h for girls (21 sets). A total of 11,943 jumps were recorded, 4138 during matches and 7805 during training. As training attendance and jump frequency varied substantially between players, the total exposure in training ranged from 50 to 666 jumps/week among boys and from 11 to 251 jumps/week among girls. On average, this corresponded to 35.7 jumps/h for boys and 13.7 jumps/h for girls (Student t test, p=0.002). Total jump exposure during matches ranged between 1 and 339 jumps among boys and between 0 and 379 jumps among girls, corresponding to an average jump frequency of 62.2 jumps/h for boys and 41.9 jumps/h for girls (Student t test, pvolleyball players. Total jump volume may represent a more important risk factor for jumper's knee than total training volume, warranting further research attention. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  7. Comparison of whole-body vibration exercise and plyometric exercise to improve isokinetic muscular strength, jumping performance and balance of female volleyball players

    OpenAIRE

    Kim, Yong-Youn; Park, Si-Eun

    2016-01-01

    [Purpose] The purpose of this study was to assess the effect of whole-body vibration exercise and plyometric exercise on female volleyball players. [Subjects and Methods] Subjects were randomly allocated to two exercise groups (whole-body vibration exercise group and plyometric exercise group). The exercise was conducted three times each week for 8 weeks. Isokinetic muscular strength, jumping performance, and balance were measured before starting the exercise and after finishing the 8 weeks o...

  8. Side-to-side differences in lower extremity biomechanics during multi-directional jump landing in volleyball athletes.

    Science.gov (United States)

    Sinsurin, Komsak; Srisangboriboon, Sarun; Vachalathiti, Roongtiwa

    2017-07-01

    Side-to-side differences of lower extremities may influence the likelihood of injury. Moreover, adding the complexity of jump-landing direction would help to explain lower extremity control during sport activities. The aim was to determine the effects of limb dominance and jump-landing direction on lower extremity biomechanics. Nineteen female volleyball athletes participated. Both dominant limbs (DLs) and non-dominant limbs (NLs) were examined in single-leg jump-landing tests in four directions, including forward (0°), diagonal (30° and 60°), and lateral (90°) directions. Kinematic marker trajectories and ground reaction forces were collected using a 10 camera Vicon system and an AMTI force plate. Repeated measures ANOVA (2 × 4, limb × direction) was used to analyse. The finding showed that, at peak vertical GRF, a significant interaction of limb dominance and direction effects was found in the hip flexion angle and lower extremity joint kinetics (p < .05). NLs and DLs exhibited significantly different strategies while landing in various directions. Significantly higher increase of ankle dorsiflexion angle was observed in lateral direction compared to other directions for both DLs and NLs (p < .05). Increasingly using ankle dorsiflexion was observed from the forward to the lateral direction for both DLs and NLs. However, NLs and DLs preferentially used different strategies of joint moment organization to respond to similar VGRFs in various directions. The response pattern of DLs might not be effective and may expose DLs to a higher injury risk, especially with regard to landing with awkward posture compared with NLs.

  9. Identification af explosive power factors as predictors of player quality in young female volleyball players.

    Science.gov (United States)

    Grgantov, Zoran; Milić, Mirjana; Katić, Ratko

    2013-05-01

    With the purpose of determining the factor structure of explosive power, as well as the influence of each factor on situational efficiency, 56 young female volleyball players were tested using 14 tests for assessing nonspecific and specific explosive power. By factor analysis, 4 significant factors were isolated which explained the total of over 80% of the common variability in young female volleyball players. The first factor was defined as volleyball-specific jumping, the second factor as nonspecific jumping and sprinting, the third factor as throwing explosive power, while the fourth factor was interpreted as volleyball-specific throwing and spiking speed from the ground. Results obtained by regression analysis in the latent space of explosive power indicate that the identified factors are good predictors of player quality in young female volleyball players. The fourth factor defined as throwing and spiking speed from the ground had the largest influence on player quality, followed by volleyball-specific jumping and nonspecific jumping and sprinting, and to a much lesser extent, by throwing explosive power The results obtained in this age group bring to the fore the ability of spiking and serving a ball of high speed, which hinders the opponents from playing those balls in serve reception and field defence. This ability, combined with a high standing vertical jump reach and spike approach vertical jump reach (which is the basis of the 1st varimax factor) enables successful performance of all volleyball elements by which points are won in complex 1 (spike) and complex 2 (serve and block). Even though the 2nd factor (nonspecific jumping and sprinting) has a slightly smaller impact on situational efficiency in young players, this ability provides preconditions i.e. preparation for successful realisation of all volleyball elements, so greater attention must be paid to perfecting it in young female volleyball players.

  10. Effect of different stretching strategies on the kinetics of vertical jumping in female volleyball athletes

    Directory of Open Access Journals (Sweden)

    Nicholas T. Kruse

    2015-12-01

    Conclusion: Together these findings suggest that when training and competing to jump quickly and maximally the female athlete should incorporate DS instead of SS as part of their pre-competition warm-up, but conduct performance within 15 min of their warm-up to elicit maximal gains.

  11. Previously identified patellar tendinopathy risk factors differ between elite and sub-elite volleyball players.

    Science.gov (United States)

    Janssen, I; Steele, J R; Munro, B J; Brown, N A T

    2015-06-01

    Patellar tendinopathy is the most common knee injury incurred in volleyball, with its prevalence in elite athletes more than three times that of their sub-elite counterparts. The purpose of this study was to determine whether patellar tendinopathy risk factors differed between elite and sub-elite male volleyball players. Nine elite and nine sub-elite male volleyball players performed a lateral stop-jump block movement. Maximum vertical jump, training history, muscle extensibility and strength, three-dimensional landing kinematics (250 Hz), along with lower limb neuromuscular activation patterns (1500 Hz), and patellar tendon loading were collected during each trial. Multivariate analyses of variance (P volleyball players. Interventions designed to reduce landing frequency and improve quadriceps extensibility are recommended to reduce patellar tendinopathy prevalence in volleyball players. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Tunneling of the blocked wave in a circular hydraulic jump

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Jayanta K., E-mail: jkb@hri.res.in

    2017-02-19

    The formation of a circular hydraulic jump in a thin liquid layer involves the creation of a horizon where the incoming wave (surface ripples) is blocked by the fast flowing fluid. That there is a jump at the horizon is due to the viscosity of the fluid which is not relevant for the horizon formation. By using a tunneling formalism developed for the study of the Hawking radiation from black holes, we explicitly show that there will be an exponentially small tunneling of the blocked wave across the horizons as anticipated in studies of “analog gravity”. - Highlights: • A thin layer of radially flowing fluid traveling at high speed sweeps away the incoming ripples. • The speed decreases as the flow spreads out. • At some radius the flow speed decreases to match the ripple speed creating a “horizon”. • The “horizon” blocks out the incoming ripples mimicking a white hole horizon. • The fluctuations around the steady state allows an exponentially small penetration inside the horizon analogous to the Hawking effect.

  13. Comparison of whole-body vibration exercise and plyometric exercise to improve isokinetic muscular strength, jumping performance and balance of female volleyball players.

    Science.gov (United States)

    Kim, Yong-Youn; Park, Si-Eun

    2016-11-01

    [Purpose] The purpose of this study was to assess the effect of whole-body vibration exercise and plyometric exercise on female volleyball players. [Subjects and Methods] Subjects were randomly allocated to two exercise groups (whole-body vibration exercise group and plyometric exercise group). The exercise was conducted three times each week for 8 weeks. Isokinetic muscular strength, jumping performance, and balance were measured before starting the exercise and after finishing the 8 weeks of exercise. [Results] Measurements of isokinetic muscular strength revealed that the whole-body vibration exercise group showed significant increase after the exercise. However, the plyometric exercise group had no significant increase in lumbar flexion, extension, and knee flexion. Measurements of vertical jumping revealed that, the whole-body vibration exercise group had no significant increase after the exercise. However, the plyometric exercise group showed significant increase. Measurements of balance revealed that, the whole-body vibration exercise group showed significant increase. However, the plyometric exercise group showed no significant increase. [Conclusion] Although both whole-body vibration and plyometric exercises are effective intervention methods, the two methods have different effects on the improvement of isokinetic muscular strength, jumping performance, and balance of female volleyball players.

  14. Efeito do Uso do Estabilizador Active Ankle System® na Altura do Salto Vertical em Jogadores de Voleibol Effect of the Use of the Active Ankle System Stabilizer in The Vertical Jump Height in Volleyball Players

    Directory of Open Access Journals (Sweden)

    Marco Túlio Saldanha dos Anjos

    2009-10-01

    performance or not. The aim of this study was to assess the effect of the Active Ankle System® (AAS DAB on the vertical jump height in volleyball players. METHODS: The sample consisted of 14 female athletes aged between 14 and 18 years. The sample was told to jump, simulating the sportive gesture of attack and block (with and without DAB, over contact plates plugged to a notebook computer that calculated the height of the jump using a software. Previously, a pilot study was performed to establish the Intraclass Correlation Coefficient at the four testing conditions (n=4, and the outcomes were: attack with DAB 0.95; attack without DAB 0.76; block with DAB 0.92 and block without DAB 0.89. The height data from each sort of vertical jump with or without DAB were matched using paired Student's t test samples. RESULTS: To a significance level of α=0.05, no significant difference was found between the attack jumps with DAB (0.41 + 0.073m and without DAB (0.41 + 0.086m, p=0.517. In addition, no significant difference was found between the block jumps with DAB (0.31 + 0.048m and without DAB (0.32 + 0.050m, p=0.06. CONCLUSION: Therefore, the results of the present study point out that the use of the AAS DAB does not influence volleyball players' vertical jumping performance.

  15. Training strategy of explosive strength in young female volleyball players

    Directory of Open Access Journals (Sweden)

    Ana Pereira

    2015-01-01

    Conclusions: The 8-week combined jump and ball throwing training can significantly improve muscular performance in young female volleyball players. These findings may be useful for all physical education teachers and volleyball coaches.

  16. Respostas neuromusculares dos membros inferiores durante protocolo intermitente de saltos verticais em voleibolistas Neuromuscular responses of the lower limb muscles during vertical jumping in volleyball athletes

    Directory of Open Access Journals (Sweden)

    Caroline Tosini Felicissimo

    2012-03-01

    Full Text Available O objetivo deste estudo foi analisar o desempenho e as respostas eletromiográficas dos músculos Reto Femoral, Bíceps Femoral e Gastrocnêmio Medial durante protocolo de saltos verticais. Participaram 13 voleibolistas do sexo feminino (15,6 ± 0,9 anos. Inicialmente foi realizado um protocolo de potência máxima (três saltos máximos, seguido do protocolo de resistência de saltos (ciclos de três saltos máximos em aproximadamente 10 segundos (s - um salto a cada três s, com recuperação de 15 s. O tempo de duração do protocolo de resistência foi de 20 minutos. Foi usada a técnica do salto com contramovimento sem ajuda dos braços, sobre tapete de contato. Para tratamento dos dados os saltos foram divididos em quatro períodos com 12 ciclos cada um. Os resultados mostraram queda na altura dos saltos de aproximadamente 1,3cm entre os períodos de 1 a 4, sendo que, essa queda foi mais significativa nos 3º e 4º períodos em comparação ao 1º e 2º. Entretanto, com relação às variáveis RMS e FM, não ocorreu alteração nas respostas eletromiográficas entre músculos e períodos. Concluiu-se, assim, que a fadiga pode depender de variáveis psicofisiológicas, ao nível do SNC, que também influem no desempenho.The purpose of this study was to analyze the performance and the electromyographic responses of the muscles Rectus Femoris, Biceps Femoris and Gastrocnemius Medialis during vertical jumping protocol. Participated 13 female volleyball players (15,6 ± 0,9 years. Initially was performed a protocol of maximum power (three maximum jumps, followed by resistance jumps protocol (cycles of three maximum jumps in about 10 seconds (s - one jump every three s, with recovery of 15s. The duration of resistance protocol was 20 minutes. Technique used was countermovement jump without the aid of arms on a mat of contact. The data collected during the jumps were divided into four periods containing 12 cycles each. The results showed a

  17. CHANGES IN DEVELOPMENT OF EHPLOSIVE POWER OF LEGS UNDER THE INFLUENCE OF PLYOMETRIC TRAINING METHOD BY VOLLEYBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Vladan Milić

    2009-11-01

    Full Text Available With goal to examine effects of plyometric training program on development of jumping strength for volleyball players, it was organized an experimental research on pattern of 23 volleyball players from cadet team and 23 students from high-school. For needs of this research four tests are valid for estimation, jump in block with left and right leg and jump in spike with left and right leg. Experiment has been realized in the second part on conditional preparations, and lasted for six weeks with two or three trainings per week. Control group had physical education lessons at their schools twice a week. On the results of research and discussion we can say that the model of training we used for development of jumping as a basic factor in experimental group brought statistically bigger difference in improving jumping that it brought in control group.

  18. The Effect of an Isometric Hip Muscle Strength Training Protocol on Valgus Angle During a Drop Vertical Jump in Competitive Female Volleyball Players

    Directory of Open Access Journals (Sweden)

    Kaitlin M. Jackson

    2017-10-01

    Full Text Available Background: Hip muscle weakness is associated with higher peak knee valgus angles (VA during drop vertical jumps (DVJ and linked to ACL injury risk. Objective: To determine if isometric strengthening (IST of the hip extensor, abductor, and external rotator muscle groups would reduce VA exhibited during a DVJ. Methodology:  Fourteen female volleyball players (7 training (TG, 7 control (CG, VA≥9˚ during DVJ participated. Pre- and post-test gluteal, quadriceps and hamstring strength were measured with a digital force gauge. Three-dimensional kinematics were collected during 15 DVJ trials. TG participated in a 6-week IST program that targeted the hip extensor, abductor, and external rotator muscle groups. Two-way mixed ANOVAs compared mean differences of VA and strength. Single-participant analyses examined if athlete-specific adaptations went undetected in the analyses of aggregated data. Results: TG hip extension, abduction, and knee flexion strength increased, respectively, by 20.5%, 27.5% and 23.5% (P<0.05. No group-level changes in VA were detected. Unilateral VA decreased for 5 TG participants, and bilateral VA decreased in 2 TG participants. Conclusions: IST increased isometric hip muscle strength, but its effect on VA is inconclusive based on group-level analyses. Using single-participant designs, future studies should assess IST and/or dynamic resistance/neuromuscular training in a larger sample to determine its effect on ACL injury risk factors.

  19. Study of some significant parameters about the dynamic of the arms to evaluate the vertical jump in volleyball athletes, category 13-15 from the sport school Ormani Arenado Llonch

    Directory of Open Access Journals (Sweden)

    Enrique Henríquez Hernández

    2016-04-01

    Full Text Available To improve the yield in the vertical jump for many scientists, trainers and athletes has been and it continues being a polemic objective in the training for the volleyball players keeping in mind the participation that has this task motorboat in question, without doubts the Cuban School of Volleyball keeping in mind the characteristics of our players it has potentialized the saltabilidad of the jugadoras there is inclination of the years for it becomes it necessary to study and to evaluate the capacity miodinámica of the musculature of the inferior members to give continuity to this problem takes like sample in our study the athletes of the category 13-15 years of the EIDE of Pinegrove of the River to which you/they were carried out a traverse study in the stage of general physical preparation where you study the restored miodinámica of the inferior members in different laboratory test Squat Jump and I jump with against movements starting from a contact doormat built in Pinegrove of the River, field test like long jump without impulse, test of Power of Lewis, test of relative force for inferior members, being significant securities of correlation. Starting from the results individual suggestions were offered for the training of this athletes.

  20. LANDING TECHNIQUES IN BEACH VOLLEYBALL

    Directory of Open Access Journals (Sweden)

    Markus Tilp

    2013-09-01

    Full Text Available The aims of the present study were to establish a detailed and representative record of landing techniques (two-, left-, and right-footed landings in professional beach volleyball and compare the data with those of indoor volleyball. Beach volleyball data was retrieved from videos taken at FIVB World Tour tournaments. Landing techniques were compared in the different beach and indoor volleyball skills serve, set, attack, and block with regard to sex, playing technique, and court position. Significant differences were observed between men and women in landings following block actions (χ²(2 = 18.19, p < 0.01 but not following serve, set, and attack actions. Following blocking, men landed more often on one foot than women. Further differences in landings following serve and attack with regard to playing technique and position were mainly observed in men. The comparison with landing techniques in indoor volleyball revealed overall differences both in men (χ²(2 = 161.4, p < 0.01 and women (χ²(2 = 84.91, p < 0.01. Beach volleyball players land more often on both feet than indoor volleyball players. Besides the softer surface in beach volleyball, and therefore resulting lower loads, these results might be another reason for fewer injuries and overuse conditions compared to indoor volleyball

  1. Relationship between sitting volleyball performance and field fitness of sitting volleyball players in Korea

    Science.gov (United States)

    Jeoung, Bogja

    2017-01-01

    The purpose of this study was to evaluate the relationship between sitting volleyball performance and the field fitness of sitting volleyball players. Forty-five elite sitting volleyball players participated in 10 field fitness tests. Additionally, the players’ head coach and coach assessed their volleyball performance (receive and defense, block, attack, and serve). Data were analyzed with SPSS software version 21 by using correlation and regression analyses, and the significance level was set at Pvolleyball performance. PMID:29326896

  2. Drop Jumping as a Training Method for Jumping Ability

    NARCIS (Netherlands)

    Bobbert, Maarten F.

    1990-01-01

    Vertical jumping ability is of importance for good performance in sports such as basketball and volleyball. Coaches are in need of exercises that consume only little time and still help to improve their players’ jumping ability, without involving a high risk of injury. Drop jumping is assumed to

  3. Choice of jumping strategy in two standard jumps, squat and countermovement jump--effect of training background or inherited preference?

    DEFF Research Database (Denmark)

    Ravn, Susanne; Voigt, M; Simonsen, Erik Bruun

    1999-01-01

    . The jumps were recorded on highspeed film (500 Hz) combined with registration of ground reaction forces, and net joint moments were calculated by inverse dynamics. The purpose was to investigate the choice of strategy in two standard jumps, squat jump and countermovement jump. The volleyball jump...... was performed with a sequential strategy and the ballet jump was performed with a simultaneous strategy. In the two standard jumps, the choice of strategy was individual and not related to training background. This was additionally confirmed in a test of seven ballet dancers and seven volleyball players....

  4. JUMP KINETIC DETERMINANTS OF SPRINT ACCELERATION PERFORMANCE FROM STARTING BLOCKS IN MALE SPRINTERS

    Directory of Open Access Journals (Sweden)

    Peter S. Maulder

    2006-06-01

    Full Text Available The purpose of this research was to identify the jump kinetic determinants of sprint acceleration performance from a block start. Ten male (mean ± SD: age 20 ± 3 years; height 1.82 ± 0.06 m; weight 76.7 ± 7.9 kg; 100 m personal best: 10.87 + 0.36 s {10.37 - 11.42} track sprinters at a national and regional competitive level performed 10 m sprints from a block start. Anthropometric dimensions along with squat jump (SJ, countermovement jump (CMJ, continuous straight legged jump (SLJ, single leg hop for distance, and single leg triple hop for distance measures of power were also tested. Stepwise multiple regression analysis identified CMJ average power (W/kg as a predictor of 10 m sprint performance from a block start (r = 0.79, r2 = 0.63, p<0.01, SEE = 0.04 (s, %SEE = 2.0. Pearson correlation analysis revealed CMJ force and power (r = -0.70 to -0.79; p = 0.011 - 0.035 and SJ power (r = -0.72 to -0.73; p = 0.026 - 0.028 generating capabilities to be strongly related to sprint performance. Further linear regression analysis predicted an increase in CMJ average and peak take-off power of 1 W/kg (3% & 1.5% respectively to both result in a decrease of 0.01 s (0.5% in 10 m sprint performance. Further, an increase in SJ average and peak take-off power of 1 W/kg (3.5% & 1.5% respectively was predicted to result in a 0.01 s (0.5% reduction in 10 m sprint time. The results of this study seem to suggest that the ability to generate power both elastically during a CMJ and concentrically during a SJ to be good indicators of predicting sprint performance over 10 m from a block start

  5. Relationship between landing strategy and patellar tendinopathy in volleyball

    NARCIS (Netherlands)

    Bisseling, Rob W.; Hof, At L.; Bredeweg, Steef W.; Zwerver, Johannes; Mulder, Theo

    Objective: The aetiology of patellar tendinopathy ( jumper's knee) remains unclear. To see whether landing strategy might be a risk factor for the development of this injury, this study examined whether landing dynamics from drop jumps differed among healthy volleyball players ( CON) and volleyball

  6. Avaliação da resistência de força explosiva em voleibolistas através de testes de saltos verticais Assessment of explosive strength-endurance in volleyball players through vertical jumping test

    Directory of Open Access Journals (Sweden)

    Jefferson Eduardo Hespanhol

    2007-06-01

    Full Text Available O propósito deste estudo foi verificar a existência de diferenças entre o teste de salto vertical com natureza contínua de 60 segundos (TSVC e o teste de salto vertical com natureza intermitente de quatro séries de 15 segundos (TSVI. Os dados foram obtidos através de amostra composta por 10 voleibolistas do sexo masculino (19,01 ± 1,36 anos; 191,5 ± 5,36cm; e 81,74 ± 7,45kg, todos com participação voluntária. As variáveis estudadas foram: as estimativas do pico de potência (PP, potência média (PM e o índice de fadiga (IF. O desempenho estimado através dos testes TSVC, com duração de 60 segundos, e o TSVI foi determinado em quatro séries de 15 segundos, com 10 segundos de recuperação entre cada série. Os dados foram determinados através da estatística descritiva e do teste de Wilcoxon; o nível de significância utilizado foi de p The aim of this study was to verify the differences between the continuous jump test of 60 seconds (CJ60 sec and the intermittent jump test of 4 sets of 15 seconds (IJ4x15 sec. The sample was composed of 10 male volleyball players with 19.01 ± 1.36 years, 191.5 ± 5.36 cm height and 81.74 ± 7.45 of body mass, who participated in this research as volunteers. The variables studied were estimated as the peak power (PP, mean power (MP and fatigue index (FI. These performances were measured through tests of vertical jump with duration the 60 seconds and with the performance of 4 sets of 15 seconds with 10 seconds of recovery between the sets. The data were analyzed through descriptive statistics and the Wilcoxon test. The significance level was of p < 0.05. It was possible to analyze that the continuous and the intermittent jump test presented significant differences in MP (p < 0.05, FI (p < 0.01, and in the number of the vertical jump in 60 seconds (p < 0.01, and the height in 60 seconds exercise (p < 0.05. The MP found in IJ4x15sec was significantly higher than in the CJ60 sec in volleyball

  7. Physics of volleyball: Spiking with a purpose

    Science.gov (United States)

    Behroozi, F.

    1998-05-01

    A few weeks ago our volleyball coach telephoned me with a problem: How high should a player jump to "spike" a "set" ball so it would clear the net and land at a known distance on the other side of the net?

  8. Evaluation of the Effect of Core Training on the Leap Power and Motor Characteristics of the 14-16 Years Old Female Volleyball Players

    Science.gov (United States)

    Bilici, Ömer Faruk; Selçuk, Muzaffer

    2018-01-01

    In this study, it was aimed to assess the effects of core training on the vertical jump strength and some motor characteristics of 14-16 aged female volleyball players. Thirty-four female athletes playing volleyball in Van province participated in the study voluntarily. The average age of volleyball players is 15.47, the weight average is 53.66 kg…

  9. Strategies for Competitive Volleyball.

    Science.gov (United States)

    Fraser, Stephen D.

    This book deals with strategies and team tactics involved in the game of volleyball. It is not intended to be an instructional book on how to execute the various skills required to play volleyball but instead endeavors to detail and explain basic tactics and strategies involved in volleyball team play. Each chapter deals with major areas of team…

  10. Sports injuries in Plus League volleyball players.

    Science.gov (United States)

    Cieśla, E; Dutkiewicz, R; Mgłosiek, M; Nowak-Starz, G; Markowska, M; Jasiński, P; Dudek, J

    2015-06-01

    features, jumping parameters and the length of professional volleyball career.

  11. Volleyball. August 1975 - August 1977.

    Science.gov (United States)

    Polvino, Geri, Ed.

    This guide is part of a series published by the National Association for Girls and Women in Sport. It contains 16 articles written on various aspects of volleyball, such as (1) volleyball visual aids, (2) a volleyball bibliography, (3) training for volleyball, (4) key visual cues in volleyball, (5) basic agility for beginners, and (6) solving…

  12. Physical actions and work-rest time in men's beach volleyball

    Directory of Open Access Journals (Sweden)

    José Manuel Palao

    2014-09-01

    Full Text Available The purpose of this study was to assess the ball contacts, jumps, hits, work time, and rest ratio in male beach volleyball players in relation to their tactical roles. The sample of this study included 6970 rallies played by 91 beach volleyball players, which corresponded to 179 sets of the 2008 Men's Beach Volleyball World Tour (FIVB. We analyzed: ball contacts, jumps, hits, work time, rest time, set (first, second or third, and player's tactical role (e.g., defense specialist, blocker, or no specialization. A significantly higher number of jumps were executed by blockers. No differences were found in the third set for any of the physical variables studied. This paper provides references about the physical demands (e.g., contacts, jumps, and hits for blockers and defense specialists and temporal patterns of the beach volleyball game (i.e., work and rest time for two-set matches and three-set matches.

  13. Evaluation of Game Performance in Elite Male Sitting Volleyball Players.

    Science.gov (United States)

    Molik, Bartosz; Morgulec-Adamowicz, Natalia; Marszałek, Jolanta; Kosmol, Andrzej; Rutkowska, Izabela; Jakubicka, Alicja; Kaliszewska, Ewelina; Kozłowski, Robert; Kurowska, Monika; Ploch, Elwira; Mustafins, Pavel; Gómez, Miguel-Ángel

    2017-04-01

    The aims of the current study were (a) to analyze the differences in game performances of sitting volleyball athletes representing the different types of disabilities and (b) to assess whether the seated position vertical reach is one of the crucial factors in the game performance level of sitting volleyball athletes. One hundred male athletes from various national teams participating in the European Championships in Sitting Volleyball (2009) took part in this study. The athletes were categorized according to type of disability and the results of the vertical reach in a seated position. Thirtysix games were analyzed using the Game Performance Sheet for Sitting Volleyball. Twenty-three game performance parameters were studied. In addition, the sum and effectiveness of attacks, blocks, block services, services, ball receiving, and defensive actions were calculated. The main results indicated significant differences between athletes with minimal disability and athletes with single amputations from above the knee in the level of defensive performances and the summation of defensive actions. There was also a significant difference between athletes in relation to their vertical reach during activity and attacking actions, blocks, and ball receiving. In addition, there were strong relationships between the players' vertical reach scores and their activity and effectiveness in sitting volleyball. In conclusion, the accuracy of the World Organization Volleyball for Disabled classification systems for sitting volleyball players was confirmed. There is a strong relationship between players' vertical reach and their effectiveness in sitting volleyball.

  14. Physical and physiological attributes of female volleyball players--a review.

    Science.gov (United States)

    Lidor, Ronnie; Ziv, Gal

    2010-07-01

    The main objective of this article was to review a series of studies (n = 31) on physical attributes, physiological attributes, and on-court performances of female volleyball players. Empirical and practical knowledge emerging from studies on training-related issues in volleyball, such as body mass, fat-free mass, aerobic profile, strength, and agility and speed, should be integrated and applied when planning annual training programs for volleyball players. Based on our review, it was found that (a) players of a higher skill level are taller, somewhat heavier, and have higher vertical jump values than players of a lower level; (b) the aerobic profile of female volleyball players is similar to that of female basketball players; (c) ballistic resistance training can increase vertical jump values in female volleyball players; and (d) preseason conditioning should be conducted to prevent fatigue and reduced performance at the beginning of the season. Among the research concerns discussed in the article are that there is a lack data for on-court performance and time-motion analysis in female volleyball players and that more experimental/manipulative studies are needed to examine the effectiveness of different training programs on physiological attributes of female volleyball players. Two practical implications are suggested for volleyball and strength and conditioning coaches: (a) functional and nonfunctional overreaching should be carefully monitored when planning strength and conditioning programs, and (b) volleyball programs should include ballistic-type training.

  15. Usefulness of the jump-and-reach test in assessment of vertical jump performance.

    Science.gov (United States)

    Menzel, Hans-Joachim; Chagas, Mauro H; Szmuchrowski, Leszek A; Araujo, Silvia R; Campos, Carlos E; Giannetti, Marcus R

    2010-02-01

    The objective was to estimate the reliability and criterion-related validity of the Jump-and-Reach Test for the assessment of squat, countermovement, and drop jump performance of 32 male Brazilian professional volleyball players. Performance of squat, countermovement, and drop jumps with different dropping heights was assessed on the Jump-and-Reach Test and the measurement of flight time, then compared across different jump trials. The very high reliability coefficients of both assessment methods and the lower correlation coefficients between scores on the assessments indicate a very high consistency of each method but only moderate covariation, which means that they measure partly different items. As a consequence, the Jump-and-Reach Test has good ecological validity in situations when reaching height during the flight phase is critical for performance (e.g., basketball and volleyball) but only limited accuracy for the assessment of vertical impulse production with different jump techniques and conditions.

  16. Analysis of Severe Injuries Associated with Volleyball Activities.

    Science.gov (United States)

    Gerberich, Susan Goodwin; And Others

    1987-01-01

    Evaluation of 106 persons treated for injuries related to volleyball revealed that nearly 90 percent of injuries were concentrated in the lower extremities. Knee injuries accounted for 59 percent of injuries and ankle injuries accounted for about 23 percent of injuries. The mechanisms of jumping, landing, or twisting upon impact were highly…

  17. Modeling attacking of high skills volleyball players

    Directory of Open Access Journals (Sweden)

    Vladimir Gamaliy

    2014-12-01

    Full Text Available Purpose: to determine the model indicators of technical and tactical actions in the attack highly skilled volleyball players. Material and Methods: the study used statistical data of major international competitions: Olympic Games – 2012 World Championships – 2010, World League – 2010–2014 European Championship – 2010–2014. A total of 130 analyzed games. Methods were used: analysis and generalization of scientific and methodological literature, analysis of competitive activity highly skilled volleyball players, teacher observation, modeling technical and tactical actions in attacking highly skilled volleyball players. Results: it was found that the largest volume application of technical and tactical actions in the attack belongs to the group tactics «supple movement», whose indicator is 21,3%. The smallest amount of application belongs to the group tactics «flight level» model whose indicators is 5,4%, the efficiency of 3,4%, respectively. It is found that the power service in the jump from model parameters used in 51,6% of cases, the planning targets – 21,7% and 4,4% planning to reduce. Attacks performed with the back line, on model parameters used in the amount of 20,8% efficiency –13,7%. Conclusions: we prove that the performance of technical and tactical actions in the attack can be used as model in the control system of training and competitive process highly skilled volleyball players

  18. Enhancing physical performance in male volleyball players with a caffeine-containing energy drink.

    Science.gov (United States)

    Del Coso, Juan; Pérez-López, Alberto; Abian-Vicen, Javier; Salinero, Juan Jose; Lara, Beatriz; Valadés, David

    2014-11-01

    There are no scientific data about the effects of caffeine intake on volleyball performance. The aim of this study was to investigate the effect of a caffeine-containing energy drink to enhance physical performance in male volleyball players. A double-blind, placebo-controlled, randomized experimental design was used. In 2 different sessions separated by 1 wk, 15 college volleyball players ingested 3 mg of caffeine per kg of body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed volleyball-specific tests: standing spike test, maximal squat jump (SJ), maximal countermovement jump (CMJ), 15-s rebound jump test (15RJ), and agility T-test. Later, a simulated volleyball match was played and recorded. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased ball velocity in the spike test (73 ± 9 vs 75 ± 10 km/h, P volleyball actions more frequently (24.6% ± 14.3% vs 34.3% ± 16.5%, P volleyball players.

  19. Training strategy of explosive strength in young female volleyball players.

    Science.gov (United States)

    Pereira, Ana; Costa, Aldo M; Santos, Patricia; Figueiredo, Teresa; João, Paulo Vicente

    2015-01-01

    The aim of this study was to examine the effect of an 8-week combined jump and ball throwing training program in the performance of upper and lower extremities among young female volleyball players of the high school. A total of 20 young female volleyball players playing at Scholar Sport in High School at the district level were divided in two groups: the experimental group (n=10; 14.0±0.0 years; 1.6±0.1 m; 52.0±7.0 kg and 20.7±2.4% body mass) and the control group (n=10; 13.8±0.4 years, 1.6±0.1 m; 53.5±4.7 kg and 20.3±1.7% body mass). The experimental group received additional plyometric and ball throwing exercises besides their normal volleyball practice. The control group underwent only their regular session of training. Strength performance in the experimental group significantly improved (medicine ball and volleyball ball throwing: P=0.00; and counter movement jump: P=0.05), with the improvement ranging from 5.3% to 20.1%. No significant changes in strength performance were observed in the control group (P>0.05). The 8-week combined jump and ball throwing training can significantly improve muscular performance in young female volleyball players. These findings may be useful for all physical education teachers and volleyball coaches. Copyright © 2015 Lithuanian University of Health Sciences. Production and hosting by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  20. Sport skill level and gender with relation to age, physical development and special fitness of the participants of Olympic volleyball tournament Beijing 2008.

    Science.gov (United States)

    Sterkowicz-Przybycien, Katarzyna; Sterkowicz, Stanislaw; Zak, Stanislaw

    2014-06-01

    The aim of this study was to provide an answer to the question whether and how age, body height, body mass, body mass index and results from fitness tests are related to sport skill level and gender of the participants of the Olympic volleyball tournament. Two-Way ANOVA was used to find the dependency of the variables on the factor of sport skill level (A--teams which took places 1 to 4, B--places from 5 to 8; C--places from 9 to 12) and gender (F--female; M--male). Statistical significance was set at p sports level and gender on the height of attack jump (F = 4.13; p = 0.02) and block jump (F = 9.22; p differences between the men and women. A significant advantage over the groups B and C was found for attack height and block height. In the group A, the differences between the results obtained for women and men in the ranges of attack and block with respect to the net height were not significant. Mean range of block jump did not match up to attack jump, particularly in women. The application of PNN network showed that age, BMI, relative attack jump and block jump are good predictors of sport results. The percentage of properly classified players in the group of men was lower than in women (42.4 vs. 56.3%). In this regard, big differences were found at the lower level of sport results: A (77.1 vs. 79.2%), B (25.0 vs. 25.0%) and C (25.0 vs. 64.6%). In conclusion, selection for national teams should take into consideration the players with long competitive experience with adequate weight/height ratios, who exhibit good training adaptations to jumping exercise.

  1. Volleyball Scoring Systems.

    Science.gov (United States)

    Calhoun, William; Dargahi-Noubary, G. R.; Shi, Yixun

    2002-01-01

    The widespread interest in sports in our culture provides an excellent opportunity to catch students' attention in mathematics and statistics classes. One mathematically interesting aspect of volleyball, which can be used to motivate students, is the scoring system. (MM)

  2. Neuromechanical evidence of improved neuromuscular control around knee joint in volleyball players.

    Science.gov (United States)

    Masci, Ilaria; Vannozzi, Giuseppe; Gizzi, Leonardo; Bellotti, Pasquale; Felici, Francesco

    2010-02-01

    The aim of the present work was to verify that skilled volleyball players present specific adaptations in both neuromuscular control and movement biomechanics, showing an improved neuromuscular control around the knee joint than in non-jumper athletes. Seven male volleyball players and seven male non-jumper athletes were recruited for this study. The following tests were performed in a random order: single countermovement jump (CMJ), single squat jump. At the end of the series, subjects performed a repetitive CMJ test. Electromyographic signals were recorded from vastus lateralis and biceps femoris muscles on both sides. Ground reaction forces and moments were measured with a force plate. Volleyball athletes performed better in all tests and were more resistant to fatigue than non-jumper athletes. Furthermore, volleyball athletes showed a reduced co-activation of knee flexor/extensor muscles. The present results seem to stand for a neural adaptation of the motor control scheme to training.

  3. Rotational Angles and Velocities During Down the Line and Diagonal Across Court Volleyball Spikes

    OpenAIRE

    Justin R. Brown; Bader J. Alsarraf; Mike Waller; Patricia Eisenman; Charlie A. Hicks-Little

    2014-01-01

    The volleyball spike is an explosive movement that is frequently used to end a rally and earn a point. High velocity spikes are an important skill for a successful volleyball offense. Although the influence of vertical jump height and arm velocity on spiked ball velocity (SBV) have been investigated, little is known about the relationship of shoulder and hip angular kinematics with SBV. Other sport skills, like the baseball pitch share similar movement patterns and suggest trunk rotation is i...

  4. Lower Limb Neuromuscular Asymmetry in Volleyball and Basketball Players.

    Science.gov (United States)

    Fort-Vanmeerhaeghe, Azahara; Gual, Gabriel; Romero-Rodriguez, Daniel; Unnitha, Viswanath

    2016-04-01

    The primary objective of the present study was to evaluate the agreement between the dominant leg (DL) (determined subjectively) and the stronger leg (SL) (determined via a functional test) in a group of basketball and volleyball players. The secondary objective was to calculate lower limb neuromuscular asymmetry when comparing the DL vs the non-dominant leg (NDL) and the SL vs the weaker (WL) leg in the whole group and when differentiating by sex. Seventy-nine male and female volleyball and basketball players (age: 23.7 ± 4.5 years) performed three single-leg vertical countermovement jumps (SLVCJ) on a contact mat. Vertical jump height and an inter-limb asymmetry index (ASI) were determined. Only 32 (40%) of the subjects had a concordance between the perception of their dominant leg and the limb reaching the highest jump height. Using the DL as the discriminating variable, significant (pjump performance. Vertical jump asymmetry of 10-15% exists and this can be considered as a reference value for male and female basketball and volleyball players.

  5. The effects of 6 weeks of preseason skill-based conditioning on physical performance in male volleyball players.

    Science.gov (United States)

    Trajković, Nebojša; Milanović, Zoran; Sporis, Goran; Milić, Vladan; Stanković, Ratko

    2012-06-01

    The purpose of this study was to determine the changes in physical performance after a 6-week skill-based conditioning training program in male competitive volleyball players. Sixteen male volleyball players (mean ± SD: age 22.3 ± 3.7 years, body height 190.7 ± 4.2 cm, and body mass 78.4 ± 4.5 kg) participated in this study. The players were tested for sprinting (5- and 10-m sprint), agility, and jumping performance (the vertical-jump test, the spike-jump test, and the standing broad jump [SBJ]). Compared with pretraining, there was a significant improvement in the 5- and 10-m speed. There were no significant differences between pretraining and posttraining for lower-body muscular power (vertical-jump height, spike-jump height, and SBJ) and agility. Based on our results, it could be concluded that a preseason skill-based conditioning program does not offer a sufficient stimulus for volleyball players. Therefore, a general conditioning and hypertrophy training along with specific volleyball conditioning is necessary in the preseason period for the development of the lower-body strength, agility and speed performance in volleyball players.

  6. HAND INJURIES IN VOLLEYBALL

    NARCIS (Netherlands)

    BHAIRO, NH; NIJSTEN, MWN; VANDALEN, KC; TENDUIS, HJ

    We studied the long-term sequelae of hand injuries as a result of playing volleyball. In a retrospective study, 226 patients with injuries of the hand who were seen over a 5-year period at our Trauma Department, were investigated. Females accounted for 66 % of all injuries. The mean age was 26

  7. Biomotor status and kinesiological education of girls aged 10 to 12 years--example: volleyball.

    Science.gov (United States)

    Milić, Mirjana; Grgantov, Zoran; Katić, Ratko

    2012-09-01

    The aim of this study was to define processes of orientation and/or selection towards sports game of volleyball in schoolgirls of Kastela, aged 10-12, by examining the relations between regular classes of physical education (PE) and extracurricular sport activities. For this purpose, two morphological measures were used (body height and body mass) and a set of 11 motor tests (6 basic motor abilities tests and 5 motor achievement tests) on a sample of 242 girls aged 10-12 was used, divided into a subsample of 42 girls participating in volleyball training (Volleyball players) and a subsample of 200 girls who do not participate in volleyball training (volleyball non-players). Based on the comparison of test results of schoolgirls from Kastela and Croatian norms, factor analysis of applied variables and discriminant analysis of these variables between volleyball players and non-players, processes and/or phases of selection in forming quality volleyball players were defined. Selection processes are preceded by orientation processes in physical education classes, i.e. choosing those sport activities which are in accordance with the biomotor status of students. Results have shown that orientation and initial selection in female volleyball needs to be executed based on the motor set of psychomotor speed, repetitive strength of the trunk and flexibility (muscle tone regulation), and body height. Volleyball training has affected the muscle mass development and the development of strength factors, so that explosive strength of jumping and/or takeoff along with body height, has predominantly differentiated female volleyball players from non-players, aged 10 to 12, and serve and spike quality will have dominant influence on the match outcome.

  8. Lower Limb Neuromuscular Asymmetry in Volleyball and Basketball Players

    Directory of Open Access Journals (Sweden)

    Fort-Vanmeerhaeghe Azahara

    2016-04-01

    Full Text Available The primary objective of the present study was to evaluate the agreement between the dominant leg (DL (determined subjectively and the stronger leg (SL (determined via a functional test in a group of basketball and volleyball players. The secondary objective was to calculate lower limb neuromuscular asymmetry when comparing the DL vs the non-dominant leg (NDL and the SL vs the weaker (WL leg in the whole group and when differentiating by sex. Seventy-nine male and female volleyball and basketball players (age: 23.7 ± 4.5 years performed three single-leg vertical countermovement jumps (SLVCJ on a contact mat. Vertical jump height and an inter-limb asymmetry index (ASI were determined. Only 32 (40% of the subjects had a concordance between the perception of their dominant leg and the limb reaching the highest jump height. Using the DL as the discriminating variable, significant (p<0.05 inter-limb differences were found in the total group of players. When comparing between sexes, significant differences (p<0.05 arose in the female group only. With regard to the WL vs. the SL, significant (p<0.05 differences were noted in the whole group and when stratified into males and females. The mean ASI ranged from 9.31% (males to 12.84% (females and from 10.49% (males to 14.26% (females, when comparing the DL vs. the NDL and the SL vs. the WL, respectively. Subjective expression of leg dominance cannot be used as a predictor of limb jump performance. Vertical jump asymmetry of 10-15% exists and this can be considered as a reference value for male and female basketball and volleyball players.

  9. Physical parameters and performance values in starters and non-starters volleyball players: A brief research note

    OpenAIRE

    Marques, M.C.; Marinho, D.A.

    2009-01-01

    The aim of this paper was to investigate the anthropometric and strength characteristics of elite male volleyball athletes and determines if differences exist in these characteristics between starters (S) and non-starters players (NS). A group of 22 professional male team volleyball players participated in the study and the players were categorized as S (n= 13) and NS (n= 9). Anthropometric characteristics, countermovement jump, overhead medicine ball throwing and maximal dynamic strength wer...

  10. Physiologic performance test differences in female volleyball athletes by competition level and player position.

    Science.gov (United States)

    Schaal, Monique; Ransdell, Lynda B; Simonson, Shawn R; Gao, Yong

    2013-07-01

    The purpose of this study was to examine physiologic performance test differences by competition level (high school and Division-I collegiate athletes) and player position (hitter, setter, defensive specialist) in 4 volleyball-related tests. A secondary purpose was to establish whether a 150-yd shuttle could be used as a field test to assess anaerobic capacity. Female participants from 4 varsity high school volleyball teams (n = 27) and 2 Division-I collegiate volleyball teams (n = 26) were recruited for the study. Participants completed 4 performance-based field tests (vertical jump, agility T-test, and 150- and 300-yd shuttle runs) after completing a standardized dynamic warm-up. A 2-way multivariate analysis of variance with Bonferroni post hoc adjustments (when appropriate) and effect sizes were used for the analyses. The most important findings of this study were that (a) college volleyball athletes were older, heavier, and taller than high school athletes; (b) high school athletes had performance deficiencies in vertical jump/lower-body power, agility, and anaerobic fitness; (c) lower-body power was the only statistically significant difference in the performance test measures by player position; and (d) the correlation between the 150- and 300-yd shuttle was moderate (r = 0.488). Female high school volleyball players may enhance their ability to play collegiate volleyball by improving their vertical jump, lower-body power, agility, and anaerobic fitness. Furthermore, all player positions should emphasize lower-body power conditioning. These physical test scores provide baseline performance scores that should help strength and conditioning coaches create programs that will address deficits in female volleyball player performance, especially as they transition from high school to college.

  11. QUANTITATIVE AND QUALITATIVE DIFFERENCES OF MORPHOLOGICAL CHARACTERISTICS AND EXPLOSIVE STRENGTH OF LEGS IN UNDER-16 FEMALE AND MALE VOLLEYBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Slobodan Andrašić

    2015-05-01

    Full Text Available In order to achieve an advantage over the opponent, all the game elements, for which it is possible, are tended to be performed by jumping (Ziv & Lidor, 2010. This is supported by the fact that research of vertical jumping ability of volleyball players of different levels, found that players at a higher level of competition also achieve better results on tests of the assessment of vertical jumping ability (Forthomme, Croisier, Ciccarone, Crielaard, & Cloes, 2005. The research subject was aimed at detecting the difference between male and female volleyball players in morphological characteristics and explosive strength of legs, as well as determining the size of the impact of morphological characteristics of the explosive power of the lower limbs between groups formed on the basis of gender dimorphism. Method: The sample in this study was derived from a population of volleyball players of OK “RFU” from Futog, N=27 and female volleyball players of ŽOK “Futog” from Futog, N=38. For the purposes of this research morphological characteristics were measured. By using MANOVA and ANOVA differences were determined between the two sub-samples of respondents formed on the basis of gender dimorphism regarding the analyzed morphological and motor variables. In order to determine effects of the system of predictor variables on the criteria variables we used Linear Regression Analysis. Results: Statistically significant differences were observed for the variables Body height, Legs length and Lower-leg circumference, as well as for all three motor variables: Spike jump, Standing triple jump and Standing vertical jump in favor of volleyball players. Linear Regression Analysis revealed the impact of the predictor system of morphological characteristics on the criterion Spike jump in both subsamples. It was found that Body height gives the highest contribution to achieving better results regarding the height reached during spike jump in both groups

  12. Physical performance and positional differences among young female volleyball players.

    Science.gov (United States)

    Paz, Gabriel A; Gabbett, Tim J; Maia, Marianna F; Santana, Haroldo; Miranda, Humberto; Lima, Vicente

    2017-10-01

    The purpose of this study was to investigate the association among anthropometric, physical performance parameters, and dynamic postural control attributes of young female volleyball athletes, and to determine if differences exist in these attributes according to playing position. Forty-three young female volleyball players participated in this study. Players were divided by position into hitters (N.=17), middle blockers (N.=8), setters (N.=10), and liberos (N.=8). Stature, body mass, vertical jump (VJ), peak power, horizontal jump (HJ), sit-and-reach (SRT), star excursion balance (SEBT), and agility (e.g. shuttle run and Illinois agility test) tests were assessed on non-consecutive days in randomized order. No difference was found between groups for SRT, peak power, VJ, and HJ (P≤0.05). Middle blockers and hitters were taller than setters (P≤0.05). Middle blockers were also taller than liberos (P=0.017). Significant differences were observed among groups for agility tests, with hitters significantly faster than setters (P=0.023) and middle blockers (P=0.037). In addition, liberos were significantly faster than setters (P=0.032) and middle blockers (P=0.046), during the Illinois agility test. No difference was observed between groups for reach distance scores in the SEBT. These results demonstrate important positional differences in agility measures of young female volleyball players. Coaches can use this information to determine the type of physical profile that is needed for specific positions and to design training programs to maximize strength, power, and neuromuscular development of young female volleyball athletes.

  13. Relationships Among Two Repeated Activity Tests and Aerobic Fitness of Volleyball Players.

    Science.gov (United States)

    Meckel, Yoav; May-Rom, Moran; Ekshtien, Aya; Eisenstein, Tamir; Nemet, Dan; Eliakim, Alon

    2015-08-01

    The purpose of the study was to determine performance indices of a repeated sprint test (RST) and to examine their relationships with performance indices of a repeated jump test (RJT) and with aerobic fitness among trained volleyball players. Sixteen male volleyball players performed RST (6 × 30 m sprints), RJT (6 sets of 6 consecutive jumps), and an aerobic power test (20-m Shuttle Run Test). Performance indices for the RST and the RJT were (a) the ideal 30-m run time (IS), the total run time (TS) of the 6 sprints, and the performance decrement (PD) during the test and (b) the ideal jump height (IJ), the total jump height (TJ) of all the jumps, and the PD during the test, respectively. No significant correlations were found between performance indices of the RST and RJT. Significant correlations were found between PD, IS, and TS in the RST protocol and predicted peak V[Combining Dot Above]O2 (r = -0.60, -0.75, -0.77, respectively). No significant correlations were found between performance indices of the RJT (IJ, TJ, and PD) and peak V[Combining Dot Above]O2. The findings suggest that a selection of repeated activity test protocols should acknowledge the specific technique used in the sport, and that a distinct RJT, rather than the classic RST, is more appropriate for assessing the anaerobic capabilities of volleyball players. The findings also suggest that aerobic fitness plays only a minor role in performance maintenance throughout characteristic repeated jumping activity of a volleyball game.

  14. Validation of an inertial measurement unit for the measurement of jump count and height.

    Science.gov (United States)

    MacDonald, Kerry; Bahr, Roald; Baltich, Jennifer; Whittaker, Jackie L; Meeuwisse, Willem H

    2017-05-01

    To validate the use of an inertial measurement unit (IMU) for the collection of total jump count and assess the validity of an IMU for the measurement of jump height against 3-D motion analysis. Cross sectional validation study. 3D motion-capture laboratory and field based settings. Thirteen elite adolescent volleyball players. Participants performed structured drills, played a 4 set volleyball match and performed twelve counter movement jumps. Jump counts from structured drills and match play were validated against visual count from recorded video. Jump height during the counter movement jumps was validated against concurrent 3-D motion-capture data. The IMU device captured more total jumps (1032) than visual inspection (977) during match play. During structured practice, device jump count sensitivity was strong (96.8%) while specificity was perfect (100%). The IMU underestimated jump height compared to 3D motion-capture with mean differences for maximal and submaximal jumps of 2.5 cm (95%CI: 1.3 to 3.8) and 4.1 cm (3.1-5.1), respectively. The IMU offers a valid measuring tool for jump count. Although the IMU underestimates maximal and submaximal jump height, our findings demonstrate its practical utility for field-based measurement of jump load. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Kinetic parameters as determinants of vertical jump performance. DOI: 10.5007/1980-0037.2012v14n1p41

    Directory of Open Access Journals (Sweden)

    Saray Giovana dos Santos

    2012-01-01

    Full Text Available The aim of this study was to identify force and velocity parameters related to vertical jump performance in counter movement jump (CMJ and squat jump (SJ, and to compare these parameters between sprint runners and volleyball players. Twenty-four male athletes (12 regional/national-level sprint runners and 12 national-level volleyball players participated in this study. The athletes performed CMJ and SJ on a force platform. The following variables were analyzed: jump performance (jump height and power, peak velocity (PV, absolute and relative maximum force (Fmax, rate of force development (RFD, and time to reach maximum force (TFmax. In CMJ, jump height was correlated with PV (r=0.97 and normalized Fmax (r=0.47, whereas jump power was significantly correlated with all variables, except for Fmax (r=0.12. In SJ, PV and normalized Fmax were significantly correlated with jump height (r=0.95 and r=0.51, respectively and power (r=0.80 and r=0.87, respectively. In addition, TFmax was inversely correlated with power (r=-0.49. Runners presented higher performance variables (height and power, normalized Fmax and PV than volleyball players in both CMJ and SJ. In conclusion, velocity and maximum force were the main determinants of height and power in the two types of vertical jump. However, explosive force (RFD and TFmax was also important for power production in vertical jumps. Finally, runners presented a better vertical jump performance than volleyball players.

  16. The Changing Rules of the Game, Volleyball Player Systematic Structure and Effects in Applying

    Directory of Open Access Journals (Sweden)

    Özgür DİNÇER

    2015-08-01

    Full Text Available Purpose: We the purpose of this study, ranging from past to present and play volleyball rule changes that occur related to industry structure, how structure affects in applying with a systematic trial. Method: Volleyball, starting from the date of the present day sports entertainment, sport has become a subject performance. . As regards; the changing rules of the game, in terms of volleyball player systematic structure and effects on performance. The changing rules of the game, volleyball player systematic structure and effects the exhibition of the game, tactical understanding of the game is to combine the implementation of different systems to meet the needs of training and competition has created situations. Volleyball to purpose of changing the rules of the game, service, location and block combinations to improve defense, reducing the effect of conditions of service coverage and attack the ball to extend the duration of stay in the game. Thus, the visuals might volleyball, in terms of spectators and media will become attractive. While this study, scan was used during the research literature. Results: According to the data obtained from the literature, that the structural changes in the volleyball is thought to cause the positive and negative impact in the volleyball. Conclusion: Result of this research, the changing rules of the game affected the players' and the exhibition of the game and the diversity of training, volleyball game speed has increased, and became the focus of visual winning. The conclusion of every move made in the field with a number of players has increased and with it the responsibility of the importance of individual tactical exercises may have gained more importance.

  17. 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…

  18. Performance indicators analysis at Brazilian and Italian women's volleyball leagues according to game location, game outcome, and set number.

    Science.gov (United States)

    Campos, Fabio A D; Stanganélli, Luiz C R; Campos, Leandra C B; Pasquarelli, Bruno N; Gómez, Miguel-Angel

    2014-04-01

    This study was done to investigate the advantage of playing at home in elite women's volleyball leagues and the influence of performance indicators in the game score according to set number. The sample consisted of 240 games of the Brazilian Volleyball League (n = 132 games) and the Italian Volleyball League (n = 108 games) from the 2011-2012 season. The relationship of performance indicators (including serve, attack, block, and opponents' errors) with the game outcome (win or lose) was assessed. The results showed that there was a home advantage effect in women's volleyball leagues, with a higher prevalence of victory for the home teams in Brazilian and Italian leagues (58 and 56%, respectively). When related to the performance indicators and among the aspects that were most highly correlated with victory, the attack was the technical indicator that explained most of the results of volleyball games.

  19. Physical and technical demands of elite beach volleyball according to playing position and gender.

    Science.gov (United States)

    Natali, Simone; Ferioli, Davide; LA Torre, Antonio; Bonato, Matteo

    2017-12-01

    Beach volleyball is a team sport played by two teams of two players on a sand court divided by a net. To date, research has mainly focused on male beach volleyball players. Therefore, the aim of this study was to assess work-rest ratio and physical actions between males and females according to their role. Forty-two elite beach volley players (24 males and 18 females) were filmed during 12 beach volleyball matches of the Swatch Major Series 2016 of the beach volleyball World Tour in Poreč in (Croatia). Duration of point rallies, work rest ratio and the number of jumps and hits performed by the players according to their role (blockers and defenders) were recorded. Twenty-one teams (12 males and 9 females) were recorded during a total of 12 matches comprising 11 sets for males and 9 sets for females. Males scored a total of 428 points whereas females scored 440 points. Un-paired t-test did not show significant differences between males and females. Two-way analysis of variance showed a significant difference in the jumps performed between blockers and defenders and not between males and females. No significant differences in the other variables were detected. The present study provides new inside into female beach volleyball matches, giving preliminary normative data. Technical and physical aspects of beach volleyball performance appear not to be influenced by gender and to be only partially different according to playing positions. These results should be considered during the daily training scheduling.

  20. Comparison of Angiotensin Converting Enzyme (ACE gene polymorphisms elite basketball players and volleyball players

    Directory of Open Access Journals (Sweden)

    Emin Süel

    2015-09-01

    Full Text Available Aim: The purpose of this study is to research the differences of genotype polymorphism between the elite male and elite female basketball player, volleyball player and control group. Material and Methods: 58 basketball players (ages 24.25±4.99 years, height 188.22±12.31 cm and weight 80.62±16.34 kg, 64 volleyball players (ages 22.82±5.40 years, height 188.67±9.69 cm and weight 77.82±12.14 kg and 122 sedentary subjects (control group were participated randomly in the study. 5cc blood was taken control and control groups for measuring the ACE gene polymorphism. Chi-square and analysis of variance (ANOVA, Levene’s Tests, and frequencies of allele were used for statistical evaluation at significance level p0.05, basketball, volleyball and control group (p>0.05, male basketball, volleyball and control group (p>0.05, female basketball, volleyball and control group (p>0.05 and male and female athletes (p>0.05 respectively. There were no significance differences in male athletes between the genotype distribution and physical performance tests, such as 20m shuttle-run (F=1.31, vertical jump (F=0.22, and 20m sprint test (F=0.44. There were also no significance differences in female athletes between the genotype distribution and physical performance tests, such as 20m shuttle-run (F=2.03, vertical jump (F=0.10, and 20m sprint test (F=1.17. Conclusion: ACE polymorphism genotype distribution in terms of elite female and male volleyball players with elite female and male basketball players are the same.

  1. Jumping Dynamics

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2013-01-01

    paradigm the physical scale and henceforth also the massive spectrum of the theory jump at the lower boundary of the conformal window. In particular we propose that a theory can suddenly jump from a Quantum Chromodynamics type spectrum, at the lower boundary of the conformal window, to a conformal one...... without particle interpretation. The jumping scenario, therefore, does not support a near-conformal dynamics of walking type. We will also discuss the impact of jumping dynamics on the construction of models of dynamical electroweak symmetry breaking....

  2. Measurement of talent in volleyball: 15-month follow-up of elite adolescent players.

    Science.gov (United States)

    Lidor, R; Hershko, Y; Bilkevitz, A; Arnon, M; Falk, B

    2007-06-01

    The purpose of this study was two-fold: first, to examine the contribution of a battery of physical and motor tests to early phases of talent detection and early development in volleyball, and second, to differentiate between and compare the motor ability of 16-year-old starter (S) and non-starter (NS) volleyball players. Fifteen male adolescent volleyball players underwent assessment of physical and motor ability 6 times during a 15-month training program; however, not all of them took part in each testing phase. The battery was composed of 8 physical and motor tests and 2 skill tests. The physical and motor tests included 2 speed tests, an agility run, 4 explosive power tests, and an endurance test. The skill tests evaluated service accuracy at rest and following effort. All participants improved their results in all but 2 tests (endurance and skill tests) across testing phases. Comparisons between the S (n=8) and NS (n=7) revealed that only one physical explosive power test (vertical jump with approach), was found to be a good indicator for distinguishing between the 2 groups of players. It was concluded that the volleyball battery of tests was not sensitive enough to distinguish between the ''good'' and ''very good'' players suggesting that physical and motor tests do not reflect open skill ability in volleyball.

  3. Effect of Age Group on Technical-Tactical Performance Profile of the Serve in Men's Volleyball.

    Science.gov (United States)

    García-de-Alcaraz, Antonio; Ortega, Enrique; Palao, José M

    2016-10-01

    The aim of this study was to analyze the technical-tactical performance profile of the serve for various age groups and categories of competition in men's volleyball. The sample comprised 13,262 serves performed by 986 players in 299 sets observed in various categories of competition (U-14, U-16, U-19, national senior, and international senior). An observational design was used. The variables studied were category of competition, type of execution, and serve performance. The results showed that for higher age groups (senior categories), there were significantly fewer jump serves and poorer serve performance, regardless of players' maturity and training development. The use of the jump serves increased the serve risk while attempting to hinder the organization of the opponent attack. This paper discusses the serve evolution and the implications on the training process at the different age groups in men's volleyball. © The Author(s) 2016.

  4. Anthropometric and fitness profile of high-level basketball, handball and volleyball players

    OpenAIRE

    J. Peña; D. Moreno-Doutres; J. Coma; M. Cook; B. Buscà

    2018-01-01

    Objective: The aim of this study was to compare several anthropometric and physiological variables between high-level basketball, handball and volleyball players. Method: Forty-six Spanish first division professional players took part in our study. Height, standing reach, body weight, body fat percentages (by using Jackson & Pollock equation), vertical jumps (assessed by Bosco tests), 4 m × 5 m agility test and maximal power output in a bench press exercise were assessed. Results: A one...

  5. Predicting Volleyball Serve-Reception

    NARCIS (Netherlands)

    Paulo, Ana; Zaal, Frank T J M; Fonseca, Sofia; Araujo, Duarte

    2016-01-01

    Serve and serve-reception performance have predicted success in volleyball. Given the impact of serve-reception on the game, we aimed at understanding what it is in the serve and receiver's actions that determines the selection of the type of pass used in serve-reception and its efficacy. Four

  6. MOTIVES OF JUNIOR VOLLEYBALL PLAYERS TO START AND CONTINUE VOLLEYBALL AND THEIR EXPECTATIONS FOR THE FUTURE

    OpenAIRE

    BİNBOĞA, Meltem; KILIÇ, İbrahim; GÖKDEMİR, Kadir

    2013-01-01

    ABSTRACT The goal of this research is to analyze the reasons why junior volleyball players start and continue volleyball and their expectations from future. The study sample includes 359 sportsmen that have participated in the finals of Turkey Junior Volleyball championship in 2010-2011 volleyball seasons in Afyonkarahisar and Isparta cities. Data collection tool of the research is a survey made of three scales and personal features. Reliability analysis, frequency and percenta...

  7. Shaping decisions in volleyball An ecological approach to decision-making in volleyball passing

    NARCIS (Netherlands)

    Barsingerhorn, Annemiek D.; Zaal, Frank T. J. M.; De Poel, Harjo J.; Pepping, Gert-Jan

    2013-01-01

    To extend research on decision-making in sport we addressed the choices volleyball-players are faced with in a simple volleyball pass-return task. We manipulated the distance that eight experienced volleyball players had to cover for successful ball passing, and mapped their passing technique (i.e.,

  8. Training reduces catabolic and inflammatory response to a single practice in female volleyball players.

    Science.gov (United States)

    Eliakim, Alon; Portal, Shawn; Zadik, Zvi; Meckel, Yoav; Nemet, Dan

    2013-11-01

    We examined the effect of training on hormonal and inflammatory response to a single volleyball practice in elite adolescent players. Thirteen female, national team level, Israeli volleyball players (age 16.0 ± 1.4 years, Tanner stage 4-5) participated in the study. Blood samples were collected before and immediately after a typical 60 minutes of volleyball practice, before and after 7 weeks of training during the initial phase of the season. Training involved tactic and technical drills (20% of time), power and speed drills (25% of time), interval sessions (25% of time), endurance-type training (15% of time), and resistance training (15% of time). To achieve greater training responses, the study was performed during the early phase (first 7 weeks) of the volleyball season. Hormonal measurements included the anabolic hormones growth hormone (GH), insulin-like growth factor-I (IGF-I) and IGF-binding protein-3, the catabolic hormone cortisol, the proinflammatory marker interleukin-6 (IL-6), and the anti-inflammatory marker IL-1 receptor antagonist. Training led to a significant improvement of vertical jump, anaerobic properties (peak and mean power by the Wingate Anaerobic Test), and predicted VO2max (by the 20-m shuttle run). Volleyball practice, both before and after the training intervention, was associated with a significant increase of serum lactate, GH, and IL-6. Training resulted in a significantly reduced cortisol response ([INCREMENT]cortisol: 4.2 ± 13.7 vs. -4.4 ± 12.3 ng · ml, before and after training, respectively; p volleyball practice. The results suggest that along with the improvement of power and anaerobic and aerobic characteristics, training reduces the catabolic and inflammatory response to exercise.

  9. THE DIFFERENCE BETWEEN TWO VOLLEYBALL TEAMS IN SOME ANTHROPOMETERIC AND MOTOR ABILITIS

    Directory of Open Access Journals (Sweden)

    Bahri Gjinovci

    2014-06-01

    Full Text Available Introduction: In this research we are deal with two teams of the super league of Kosovo in volleyball. The goal of this study is to verify the differences between the two teams in volleyball in some anthropometric characteristics, basic motor skills and situational tests. Methods: For the realization of this research, there were included 12 volleyball player from the team KV “Prishtina" and 12 from the team KV "Universiteti AAB". There are applied 4 anthropometric variables (body weight, body height, arm length, forearm length, 5 basic motor variables (long jump from place, high jump from the place taping hand, taping feet, jogging with 20 meters with a fast start, and 7 situational tests (pass the ball with the fingers on target vertical expulsion of the ball with the forearm ("hammer" in vertical target, passing the ball with the fingers in a horizontal target, the expulsion of the ball with the forearm ("hammer" in horizontal target, pass the ball with fingers to jump in the horizontal target, tennis service in horizontal target, the target service with the horizontal jump. For processing the obtained results from the measurements and proving the difference between the teams in anthrop motored parameters, was used the discriminatory analysis using the t-test for independent variables. Results: The results obtained show that the players of the two volleyball teams, involved in research do not distinguish between them in anthropometric characteristics (p> 0:05. The team KV "Prishtina" has had better results in some explosive force motor variables and situational tests (p 1.97, at the statistical significance level of p < 0.05. Results from our sample showed that between VC. "Pristina" and VC. "AAB", important statistical changes were in those motoric tests. High jumping, foot taping, Passing the ball with hammer to the wall, Tactical accurate Service, Accuracy of service with jump and Standing long jump length. References: Strahonja A

  10. Does the adolescent patellar tendon respond to 5 days of cumulative load during a volleyball tournament?

    Science.gov (United States)

    van Ark, M; Docking, S I; van den Akker-Scheek, I; Rudavsky, A; Rio, E; Zwerver, J; Cook, J L

    2016-02-01

    Patellar tendinopathy (jumper's knee) has a high prevalence in jumping athletes. Excessive load on the patellar tendon through high volumes of training and competition is an important risk factor. Structural changes in the tendon are related to a higher risk of developing patellar tendinopathy. The critical tendon load that affects tendon structure is unknown. The aim of this study was to investigate patellar tendon structure on each day of a 5-day volleyball tournament in an adolescent population (16-18 years). The right patellar tendon of 41 players in the Australian Volleyball Schools Cup was scanned with ultrasound tissue characterization (UTC) on every day of the tournament (Monday to Friday). UTC can quantify structure of a tendon into four echo types based on the stability of the echo pattern. Generalized estimating equations (GEE) were used to test for change of echo type I and II over the tournament days. Participants played between eight and nine matches during the tournament. GEE analysis showed no significant change of echo type percentages of echo type I (Wald chi-square = 4.603, d.f. = 4, P = 0.331) and echo type II (Wald chi-square = 6.070, d.f. = 4, P = 0.194) over time. This study shows that patellar tendon structure of 16-18-year-old volleyball players is not affected during 5 days of cumulative loading during a volleyball tournament. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Rehabilitation protocol for patellar tendinopathy applied among 16- to 19-year old volleyball players.

    Science.gov (United States)

    Biernat, Ryszard; Trzaskoma, Zbigniew; Trzaskoma, Lukasz; Czaprowski, Dariusz

    2014-01-01

    The aim of the study was to investigate the efficacy of rehabilitation protocol applied during competitive period for the treatment of patellar tendinopathy. A total of 28 male volleyball players were divided into two groups. Fifteen from experimental group (E) and 13 from control group (C) fulfilled the same tests 3 times: before the training program started (first measurement), after 12 weeks (second measurement) and after 24 weeks (third measurement). The above-mentioned protocol included the following: USG imagining with color Doppler function, clinical testing, pain intensity evaluation with VISA-P questionnaire, leg muscle strength and power and jumping ability measurements. The key element of the rehabilitation program was eccentric squat on decline board with additional unstable surface. The essential factor of the protocol was a set of preventive functional exercises, with focus on eccentric exercises of hamstrings. Patellar tendinopathy was observed in 18% of the tested young volleyball players. Implementation of the presented rehabilitation protocol with eccentric squat on decline board applied during sports season lowered the pain level of the young volleyball players. Presented rehabilitation protocol applied without interrupting the competitive period among young volleyball players together with functional exercises could be an effective method for the treatment of patellar tendinopathy.

  12. Postural Variables in Girls Practicing Volleyball

    Science.gov (United States)

    Grabara, Malgorzata; Hadzik, Andrzej

    2009-01-01

    Study aim: To assess body posture of young female volleyball players in relation to their untrained mates. Material and methods: A group of 42 volleyball players and another of 43 untrained girls, all aged 13-16 years were studied with respect to their body posture indices by using computer posturography. Spinal angles and curvatures were…

  13. Differentiating experts’ anticipatory skills in beach volleyball

    NARCIS (Netherlands)

    Canal Bruland, R.; Mooren, M.; Savelsbergh, G.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

  14. Jumping together

    DEFF Research Database (Denmark)

    Lund, Ole; Ravn, Susanne; Christensen, Mette Krogh

    2014-01-01

    , in order to reach a deeper understanding of how practice facilitates learning. Results: We encircle the athletes’ interrelated learning processes by introducing the training environment of the national team and situations in which the athletes guide each other verbally or by jumping together. Discussion...

  15. Menstrual cycle disorders in female volleyball players.

    Science.gov (United States)

    Wodarska, M; Witkoś, J; Drosdzol-Cop, A; Dąbrowska, J; Dąbrowska-Galas, M; Hartman, M; Plinta, R; Skrzypulec-Plinta, V

    2013-07-01

    The aim of this study was to examine the relation between increased physical activity and menstrual disorders in adolescent female volleyball players. The study was conducted on 210 Polish female volleyball players, aged 13-17 years, the authorship questionnaire was used. The results of the study showed that irregular menstruation occurred in 19% of girls, spotting between menstrual periods in 27% and heavy menstruation was reported in 33% of girls. Out of all volleyball female players participating in the study, 94 girls (45%) declared absence of menstrual periods after regular cycles. Statistical analysis showed that the more training hours per week, the bigger probability of the occurrence of irregular menstruation. It was concluded that the number of hours of volleyball training per week affects regularity of menstrual cycles in female volleyball players. The absence of menstruation might be caused by the duration of training per week or years of training.

  16. Evidence for ˜80-75 Ma subduction jump during Anatolide-Tauride-Armenian block accretion and ˜48 Ma Arabia-Eurasia collision in Lesser Caucasus-East Anatolia

    Science.gov (United States)

    Rolland, Yann; Perincek, Dogan; Kaymakci, Nuretdin; Sosson, Marc; Barrier, Eric; Avagyan, Ara

    2012-05-01

    Orogens formed by a combination of subduction and accretion are featured by a short-lived collisional history. They preserve crustal geometries acquired prior to the collisional event. These geometries comprise obducted oceanic crust sequences that may propagate somewhat far away from the suture zone, preserved accretionary prism and subduction channel at the interplate boundary. The cessation of deformation is ascribed to rapid jump of the subduction zone at the passive margin rim of the opposite side of the accreted block. Geological investigation and 40Ar/39Ar dating on the main tectonic boundaries of the Anatolide-Tauride-Armenian (ATA) block in Eastern Turkey, Armenia and Georgia provide temporal constraints of subduction and accretion on both sides of this small continental block, and final collisional history of Eurasian and Arabian plates. On the northern side, 40Ar/39Ar ages give insights for the subduction and collage from the Middle to Upper Cretaceous (95-80 Ma). To the south, younger magmatic and metamorphic ages exhibit subduction of Neotethys and accretion of the Bitlis-Pütürge block during the Upper Cretaceous (74-71 Ma). These data are interpreted as a subduction jump from the northern to the southern boundary of the ATA continental block at 80-75 Ma. Similar back-arc type geochemistry of obducted ophiolites in the two subduction-accretion domains point to a similar intra-oceanic evolution prior to accretion, featured by slab steepening and roll-back as for the current Mediterranean domain. Final closure of Neotethys and initiation of collision with Arabian Plate occurred in the Middle-Upper Eocene as featured by the development of a Himalayan-type thrust sheet exhuming amphibolite facies rocks in its hanging-wall at c. 48 Ma.

  17. Using Microsensor Technology to Quantify Match Demands in Collegiate Women's Volleyball.

    Science.gov (United States)

    Vlantes, Travis G; Readdy, Tucker

    2017-12-01

    Vlantes, TG and Readdy, T. Using microsensor technology to quantify match demands in collegiate women's volleyball. J Strength Cond Res 31(12): 3266-3278, 2017-The purpose of this study was to quantify internal and external load demands of women's NCAA Division I collegiate volleyball competitions using microsensor technology and session rating of perceived exertion (S-RPE). Eleven collegiate volleyball players wore microsensor technology (Optimeye S5; Catapult Sports, Chicago, IL, USA) during 15 matches played throughout the 2016 season. Parameters examined include player load (PL), high impact PL, percentage of HI PL, explosive efforts (EEs), and jumps. Session rating of perceived exertion was collected 20 minutes postmatch using a modified Borg scale. The relationship between internal and external load was explored, comparing S-RPE data with the microsensor metrics (PL, HI PL, % HI PL, EEs, and jumps). The setter had the greatest mean PL and highest number of jumps of all positions in a 5-1 system, playing all 6 rotations. Playing 4 sets yielded a mean PL increase of 25.1% over 3 sets, whereas playing 5 sets showed a 31.0% increase in PL. A multivariate analysis of variance revealed significant differences (p < 0.01) across all position groups when examining % HI PL and jumps. Cohen's d analysis revealed large (≥0.8) effect sizes for these differences. Defensive specialists recorded the greatest mean S-RPE values over all 15 matches (886 ± 384.6). Establishing positional load demands allows coaches, trainers, and strength and conditioning professionals to implement training programs for position-specific demands, creating consistent peak performance, and reducing injury risk.

  18. DIFFERENCES IN MOTOR STATUS OF CHILDREN OF DIFFERENT SEX IN SCHOOL VOLLEYBALL

    Directory of Open Access Journals (Sweden)

    Maja Batez

    2013-07-01

    Full Text Available On a sample of 45 children (25 girls and 20 boys age of 9 to 11, who have been training volleyball (one to three years in the club "Sportisimo pajp" in Novi Sad, were applied four motor tests. The aim of this research was to determine differences in the motor status of children of different sex in the school volleyball. Multivariate analysis of variance (MANOVA determined a statistically significant difference in the whole system of analyzed motor variables depending on the sex on studied sample of child¬ren. Univariate analysis of variance (ANOVA showed that girls had better results in va¬riables of flexibility and agility. Boys are better in standing long jump, while sta¬tistically significant differences between means in the speed of alternative movements between girls and boys the not found.

  19. THE IMPACT OF ANTHROPOMETRIC CHARACTERISTICS ON MANIFESTATION OF EXPLOSIVE STRENGTH IN VOLLEYBALL PLAYERS AGED 13 YEARS

    Directory of Open Access Journals (Sweden)

    Goran Nesic

    2006-04-01

    Full Text Available With the aim to investigate the plyometric training model used for the increase of explosive strength type (the vertical jump, an experimental research was carried out, drawing a sample of 40 volleyball players at the cadet level. For the purpose of this research, we applied nine anthropometric characteristics, which made the predictor system of variables. For the assessment of explosive strength, three tests were performed. The data were processed by descriptive and regression analyses. Based on the findings of the research and the discussion, one could unfailingly conclude that the applied system of anthropometric characteristics, as a predictor, has a significant impact on manifestation of explosive strength in volleyball players, aged 13 years, that is, it is possible to predict results of the tests of explosive strength based on the measures of anthropometric status of examinees.

  20. Supersonic Jump

    Science.gov (United States)

    Muller, Andreas

    2013-01-01

    On October 14,2012, Felix Baumgartner, an Austrian sky-diver, set some new world records for his discipline. Jumping from a height of about 39 km, he reached a top speed of 1342 km/h, becoming the first human being to break the sound barrier in free fall. In order to understand some essential physics aspects of this remarkable feat, we wonder why…

  1. Effects of habitual loading on patellar tendon mechanical and morphological properties in basketball and volleyball players.

    Science.gov (United States)

    Zhang, Z J; Ng, G Y F; Fu, S N

    2015-11-01

    Tendon mechanical properties are linked to sports performance and tendon-related injuries, such as tendinopathy. Whether habitual loading, such as participation in regular jumping activities, would induce adaptation on tendon mechanical properties remains unclear. Forty healthy subjects (10 sedentary, 15 volleyball players, and 15 basketball players) aged between 18 and 35 years were recruited. Supersonic shearwave imaging was used to measure the shear elastic modulus and thickness and cross-sectional area (CSA) of the proximal patellar tendons of both knees at 30° of flexion. Significant group differences in tendon shear elastic modulus were found among the three groups. In the dominant leg, reduction in tendon shear elastic modulus by 18.9 % (p = 0.018) and 48.7 % (p = 0.000) were observed in the basketball and volleyball players, respectively, when compared with sedentary subjects. In the non-dominant leg, reduction in tendon shear elastic modulus were 27.3 % (p = 0.034) and 47.1 % (p = 0.02) in the basketball and volleyball players, respectively. The athlete groups were found to have larger CSA but with similar tendon thickness than sedentary group. The CSA were larger by 24-29 % and by 22-24 % in the basketball players and volleyball players, for the dominant and non-dominant legs, respectively (all p < 0.05). Age and body mass are related to tendon stiffness and CSA, particularly in the sedentary subjects. The proximal patellar tendon can undergo substantial adaptation on tendon mechanical and morphological properties when exposed in jumping sports. Intrinsic factors such as age and body mass could influence tendon properties.

  2. Principal component structure and sport-specific differences in the running one-leg vertical jump.

    Science.gov (United States)

    Laffaye, G; Bardy, B G; Durey, A

    2007-05-01

    The aim of this study is to identify the kinetic principal components involved in one-leg running vertical jumps, as well as the potential differences between specialists from different sports. The sample was composed of 25 regional skilled athletes who play different jumping sports (volleyball players, handball players, basketball players, high jumpers and novices), who performed a running one-leg jump. A principal component analysis was performed on the data obtained from the 200 tested jumps in order to identify the principal components summarizing the six variables extracted from the force-time curve. Two principal components including six variables accounted for 78 % of the variance in jump height. Running one-leg vertical jump performance was predicted by a temporal component (that brings together impulse time, eccentric time and vertical displacement of the center of mass) and a force component (who brings together relative peak of force and power, and rate of force development). A comparison made among athletes revealed a temporal-prevailing profile for volleyball players, and a force-dominant profile for Fosbury high jumpers. Novices showed an ineffective utilization of the force component, while handball and basketball players showed heterogeneous and neutral component profiles. Participants will use a jumping strategy in which variables related to either the magnitude or timing of force production will be closely coupled; athletes from different sporting backgrounds will use a jumping strategy that reflects the inherent demands of their chosen sport.

  3. Correlation between toe flexor strength and ankle dorsiflexion ROM during the countermovement jump.

    Science.gov (United States)

    Yun, Sung Joon; Kim, Moon-Hwan; Weon, Jong-Hyuck; Kim, Young; Jung, Sung-Hoon; Kwon, Oh-Yun

    2016-08-01

    [Purpose] This study assessed the relationships between peak toe flexor muscle strength, ankle dorsiflexion range of motion, and countermovement jump height. [Subjects and Methods] Eighteen healthy volunteers participated in the study. Each participant completed tests for peak toe flexor muscle strength, ankle dorsiflexion range of motion, and countermovement jump height. [Results] The results showed (1) a moderate correlation between ankle dorsiflexion range of motion and countermovement jump height and (2) a high correlation between peak first toe flexor muscle strength and countermovement jump height. Peak first toe flexor muscle strength and ankle dorsiflexion range of motion are the main contributors to countermovement jump performance. [Conclusion] These findings indicate that the measurement of peak first toe flexor muscle strength and ankle dorsiflexion range of motion may be useful in clinical practice for improving jump performance in athletes training for sports such as volleyball and basketball.

  4. Coordination in vertical jumping

    NARCIS (Netherlands)

    Bobbert, Maarten F.; van Ingen Schenau, Gerrit Jan

    1988-01-01

    The present study was designed to investigate for vertical jumping the relationships between muscle actions, movement pattern and jumping achievement. Ten skilled jumpers performed jumps with preparatory countermovement. Ground reaction forces and cinematographic data were recorded. In addition,

  5. Psycho-social attributes of elite African women volleyball players ...

    African Journals Online (AJOL)

    Psycho-social attributes of elite African women volleyball players. ... 78% of them were influenced by family members to play volleyball, 81% continued to play the game due to success, and 64% envisaged that ... AJOL African Journals Online.

  6. Conditioning exercises in ski jumping: biomechanical relationship of squat jumps, imitation jumps, and hill jumps.

    Science.gov (United States)

    Lorenzetti, Silvio; Ammann, Fabian; Windmüller, Sabrina; Häberle, Ramona; Müller, Sören; Gross, Micah; Plüss, Michael; Plüss, Stefan; Schödler, Berni; Hübner, Klaus

    2017-11-22

    As hill jumps are very time-consuming, ski jumping athletes often perform various imitation jumps during training. The performed jumps should be similar to hill jumps, but a direct comparison of the kinetic and kinematic parameters has not been performed yet. Therefore, this study aimed to correlate 11 common parameters during hill jumps (Oberstdorf Germany), squat jumps (wearing indoor shoes), and various imitation jumps (rolling 4°, rolling flat, static; jumping equipment or indoor shoes) on a custom-built instrumented vehicle with a catch by the coach. During the performed jumps, force and video data of the take-off of 10 athletes were measured. The imitation and squat jumps were then ranked. The main difference between the hill jumps and the imitation and squat jumps is the higher maximal force loading rate during the hill jumps. Imitation jumps performed on a rolling platform, on flat ground were the most similar to hill jumps in terms of the force-time, and leg joint kinematic properties. Thus, non-hill jumps with a technical focus should be performed from a rolling platform with a flat inrun with normal indoor shoes or jumping equipment, and high normal force loading rates should be the main focus of imitation training.

  7. Which skills and factors better predict winning and losing in high-level men's volleyball?

    Science.gov (United States)

    Peña, Javier; Rodríguez-Guerra, Jorge; Buscà, Bernat; Serra, Núria

    2013-09-01

    The aim of this study was to determine which skills and factors better predicted the outcomes of regular season volleyball matches in the Spanish "Superliga" and were significant for obtaining positive results in the game. The study sample consisted of 125 matches played during the 2010-11 Spanish men's first division volleyball championship. Matches were played by 12 teams composed of 148 players from 17 different nations from October 2010 to March 2011. The variables analyzed were the result of the game, team category, home/away court factors, points obtained in the break point phase, number of service errors, number of service aces, number of reception errors, percentage of positive receptions, percentage of perfect receptions, reception efficiency, number of attack errors, number of blocked attacks, attack points, percentage of attack points, attack efficiency, and number of blocks performed by both teams participating in the match. The results showed that the variables of team category, points obtained in the break point phase, number of reception errors, and number of blocked attacks by the opponent were significant predictors of winning or losing the matches. Odds ratios indicated that the odds of winning a volleyball match were 6.7 times greater for the teams belonging to higher rankings and that every additional point in Complex II increased the odds of winning a match by 1.5 times. Every reception and blocked ball error decreased the possibility of winning by 0.6 and 0.7 times, respectively.

  8. NAGWS Volleyball Rulebook, 1993. Official Rules & Interpretations/Officiating.

    Science.gov (United States)

    1993

    The National Association for Girls and Women in Sport (NAGWS) Volleyball Rules are based on the United States Volleyball Rules, which in turn are adopted from the rules and interpretations of the International Volleyball Federation Rules. Following a foreword by Robertha Abney, NAGWS President, the publication is organized into six sections as…

  9. Volleyball Guide with Official Rules. July 1971 - July 1973.

    Science.gov (United States)

    Wilde, Jackie, Ed.

    This guide for playing women's volleyball dated July 1971 - July 1973 details rules and standards as well as the Division for Girls and Women's Sports (DGWS) statement of beliefs. Specific articles dealing with teamwork, basic fundamentals, suggestions for beginners, a volleyball mini unit, and volleyball visual aids are included. The booklet…

  10. Physical parameters and performance values in starters and non-starters volleyball players: A brief research note

    Directory of Open Access Journals (Sweden)

    M.C. Marques

    2009-09-01

    Full Text Available The aim of this paper was to investigate the anthropometric and strength characteristics of elite male volleyball athletes and determines if differences exist in these characteristics between starters (S and non-starters players (NS. A group of 22 professional male team volleyball players participated in the study and the players were categorized as S (n= 13 and NS (n= 9. Anthropometric characteristics, countermovement jump, overhead medicine ball throwing and maximal dynamic strength were evaluated in all the subjects. Significant diferences in age, hight and weight were noticed between S and NS. There were no significant differences between the two groups in strength and power values, except for squat performance, where S were significant strong than NS. These findings provide normative data for elite male volleyball players competing in specific playing status. From a practical perspective, sport scientists and conditioning professionals should take specicif lower body strength characteristics of volleyball players into account when designing individualized training stauts specific training programmes.

  11. Physical parameters and performance values in starters and non-starters volleyball players: A brief research note

    Directory of Open Access Journals (Sweden)

    M.C. Marques

    2009-01-01

    Full Text Available The aim of this paper was to investigate the anthropometric and strength characteristics of elite male volleyball athletes and determines if differences exist in these characteristics between starters (S and non-starters players (NS. A group of 22 professional male team volleyball players participated in the study and the players were categorized as S (n= 13 and NS (n= 9. Anthropometric characteristics, countermovement jump, overhead medicine ball throwing and maximal dynamic strength were evaluated in all the subjects. Significant diferences in age, hight and weight were noticed between S and NS. There were no significant differences between the two groups in strength and power values, except for squat performance, where S were significant strong than NS. These findings provide normative data for elite male volleyball players competing in specific playing status. From a practical perspective, sport scientists and conditioning professionals should take specicif lower body strength characteristics of volleyball players into account when designing individualized training stauts specific training programmes.

  12. The Effects of 3-Month Skill-Based and Plyometric Conditioning on Fitness Parameters in Junior Female Volleyball Players.

    Science.gov (United States)

    Idrizovic, Kemal; Gjinovci, Bahri; Sekulic, Damir; Uljevic, Ognjen; João, Paulo Vicente; Spasic, Miodrag; Sattler, Tine

    2018-02-24

    This study compared the effects of skill-based and plyometric conditioning (both performed in addition to regular volleyball training twice a week for 12 wk) on fitness parameters in female junior volleyball players. The participants [n = 47; age: 16.6 (0.6) y; mass: 59.4 (8.1) kg; height: 175.1 (3.0) cm] were randomized into a plyometric (n = 13), a skill-based (n = 17), and a control (n = 17) groups. The variables included body height, body mass, calf girth, calf skinfold, corrected calf girth, countermovement jump, 20-m-sprint, medicine ball toss, and sit-and-reach test. Two-way analysis of variance (time × group) effects for time were significant (P plyometric group, and sit-and-reach (η 2  = .35; large ES), with greater gains in plyometric and skill-based groups. The magnitude-based inference indicated positive changes in 1) medicine ball toss and countermovement jump for all groups; 2) sit-and-reach for the plyometric and skill-based groups; and 3) 20-m sprint, calf girth, calf skinfold, and corrected calf girth for plyometric group only. Selected variables can be improved by adding 2 plyometric training sessions throughout the period of 12 weeks. Additional skill-based conditioning did not contribute to improvement in the studied variables compared with regular volleyball training.

  13. Rotational Angles and Velocities During Down the Line and Diagonal Across Court Volleyball Spikes

    Directory of Open Access Journals (Sweden)

    Justin R. Brown

    2014-05-01

    Full Text Available The volleyball spike is an explosive movement that is frequently used to end a rally and earn a point. High velocity spikes are an important skill for a successful volleyball offense. Although the influence of vertical jump height and arm velocity on spiked ball velocity (SBV have been investigated, little is known about the relationship of shoulder and hip angular kinematics with SBV. Other sport skills, like the baseball pitch share similar movement patterns and suggest trunk rotation is important for such movements. The purpose of this study was to examine the relationship of both shoulder and hip angular kinematics with ball velocity during the volleyball spike. Methods: Fourteen Division I collegiate female volleyball players executed down the line (DL and diagonally across-court (DAC spikes in a laboratory setting to measure shoulder and hip angular kinematics and velocities. Each spike was analyzed using a 10 Camera Raptor-E Digital Real Time Camera System.  Results: DL SBV was significantly greater than for DAC, respectively (17.54±2.35 vs. 15.97±2.36 m/s, p<0.05.  The Shoulder Hip Separation Angle (S-HSA, Shoulder Angular Velocity (SAV, and Hip Angular Velocity (HAV were all significantly correlated with DAC SBV. S-HSA was the most significant predictor of DAC SBV as determined by regression analysis.  Conclusions: This study provides support for a relationship between a greater S-HSA and SBV. Future research should continue to 1 examine the influence of core training exercise and rotational skill drills on SBV and 2 examine trunk angular velocities during various types of spikes during play.

  14. Word play, ritual insult, and volleyball in Peru.

    Science.gov (United States)

    Perez, Justin

    2011-01-01

    Many gay men in the popular sectors of Lima, Peru participate in vóley callejero, or street volleyball. The ethnographic data presented in this article describes verbal and corporal mechanisms through which gay identity emerges within the particular context of the street volleyball game, ultimately highlighting the contextual nature of identity. The volleyball players are not just hitting a ball back and forth, they are engaging in a meaningful activity that illuminates intersections of language, sexuality, and identity. Through the manipulation of the street into a volleyball court, the volleyball players create a space conducive to the articulation of particular verbal and embodied practices that index gay identity. The challenge to the regulations of "proper" volleyball through the practice of ritual insulting and the cultivation of gay volleyball technique are playful reconfigurations of gendered practices prominent in the sites where fieldwork was carried out.

  15. Anterior cruciate ligament injury profile in Italian Serie A1-A2 women's volleyball league.

    Science.gov (United States)

    Devetag, Francesca; Mazzilli, Massimiliano; Benis, Roberto; LA Torre, Antonio; Bonato, Matteo

    2018-01-01

    The aim of this study was to assess how anterior cruciate ligament (ACL) ruptures with subsequent surgery reconstruction impact on the professional career of A1-A2 Italian women's volleyball league players. Using an observational study with a retrospective case-series design for ACL ruptures, 125 teams with 1488 players were monitored. Subjects had to report level, role, injury modality, lower limb injured, laterality, period of the season and age. A total of 34 ACL ruptures were reported. Thirty-three (97%) were non-contact and 1 (3%) with contact. Twenty-one (61.7%) occurred in landing from a jump attack, 3 (8.8%) in landing from wall jump, 1 (3%) with apparent contact and 9 (26.5%) in other landing conditions. The most injured knee was the left limb (22, 64.7%) respect to the right limb (12, 35.3%). Fourteen (41.2%) ruptures occurred in spikers, 10 (29.4%) in middle blockers, 6 (17.6%) in setters, 3 (8.8%) in liberos and 1 (3%) in opposite hitters. Nine (26.5%) occurred in pre-season period, 16 (47%) in the first round, 4 (11.8%) in the second round, and 5 (14.7%) during play-off. The average age of the first ACL rupture was 23±3 years. We observed that female volleyball players of A1-A2 Italian volleyball league occurred mostly in a left non-contact ACL rupture during a landing condition and the spikers were the players most at risk. Therefore, it is desirable that coaches teach players variations of landing in order to avoid possible chronic overloading of ACL.

  16. A Comparison of Isokinetic Knee Strength and Power Output Ratios Between Female Basketball and Volleyball Players

    Directory of Open Access Journals (Sweden)

    Kabaciński Jarosław

    2017-09-01

    Full Text Available Purpose. Tests such as the counter movement jump (CMJ and squat jump (SJ allow for determining the ratio of maximal power output generated during SJ to CMJ (S/C. The isokinetic peak torque ratio of the hamstrings contracting eccentrically to the quadriceps contracting concentrically (H/Q is defined as functional H/Q. The purpose of this study was to compare the S/C and functional H/Q between female basketball and volleyball players. Methods. The total of 14 female basketball players (age, 19.8 ± 1.4 years and 12 female volleyball players (age, 22.3 ± 4.2 years participated in the study. A piezoelectric force platform was used for the CMJ and SJ. Moreover, isokinetic tests of the hamstrings and quadriceps muscle torque during eccentric and concentric contraction were performed. Results. The results of the S/C and functional H/Q at 90 deg · s-1/60 deg · s-1 velocities were higher in basketball players (87.3 ± 9.1% and 91.4 ± 9.3%, respectively than in volleyball players (83.1 ± 9.8% and 83.6 ± 16.5%, respectively. No significant differences in S/C or functional H/Q values between the two groups were found (p > 0.05. Conclusions. Decreasing the S/C may result from an improvement in the power output during CMJ and a better utilization of the stretch-shortening cycle effect. Balancing the functional H/Q through increasing the eccentric hamstrings strength can provide dynamic knee joint stabilization.

  17. [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

  18. Risk, Jumps, and Diversification

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Law, Tzuo Hann; Tauchen, George

    We test for price discontinuities, or jumps, in a panel of high-frequency intraday returns for forty large-cap stocks and an equiweighted index from these same stocks. Jumps are naturally classified into two types: common and idiosyncratic. Common jumps affect all stocks, albeit to varying degrees......, while idiosyncratic jumps are stock-specific. Despite the fact that each of the stocks has a of about unity with respect to the index, common jumps are virtually never detected in the individual stocks. This is truly puzzling, as an index can jump only if one or more of its components jump. To resolve...... this puzzle, we propose a new test for cojumps. Using this new test we find strong evidence for many modest-sized common jumps that simply pass through the standard jump detection statistic, while they appear highly significant in the cross section based on the new cojump identification scheme. Our results...

  19. Relationships Between Anaerobic Performance, Field Tests and Game Performance of Sitting Volleyball Players

    Directory of Open Access Journals (Sweden)

    Marszalek Jolanta

    2015-12-01

    Full Text Available The aim of this study was to evaluate relationships between anaerobic performance, field tests, game performance and anthropometric variables of sitting volleyball players. Twenty elite Polish sitting volleyball players were tested using the 30 s Wingate Anaerobic Test for arm crank ergometer and participated in six physical field tests. Heights in position to block and to spike, as well as arm reach were measured. Players were observed during the game on the court in terms of effectiveness of the serve, block, attack, receive and defense. Pearson analysis and the Spearman's rank correlation coefficient were used. The strongest correlations were found between the chest pass test and mean power and peak power (r=.846; p=.001 and r=.708; p=.0005, respectively, and also between the T-test and peak power (r= −.718; p=.001. Mean power correlated with the 3 m test (r= −.540; p=.014, the 5 m test (r= −.592; p=.006, and the T-test (r= −.582; p=.007. Peak power correlated with the 3 m test (r= −.632; p=.003, the 5 m test (r= −.613; p=.004, speed & agility (r= −.552; p=.012 and speed & endurance (r=−.546; p=.013. Significant correlations were observed between anthropometric parameters and anaerobic performance variables (p≤.001, and also between anthropometric parameters and field tests (p≤.05. Game performance and physical fitness of sitting volleyball players depended on their anthropometric variables: reach of arms, the position to block and to spike. The chest pass test could be used as a non-laboratory field test of anaerobic performance of sitting volleyball players.

  20. ANÁLISIS DE LAS VARIABLES ANTROPOMÉTRICAS Y FÍSICO TÉCNICAS EN VOLEIBOL FEMENINO [Analysis of anthropometric and physical techniques in women´s volleyball

    Directory of Open Access Journals (Sweden)

    Natalia Valladares Iglesias

    2016-12-01

    Volleyball has been considered a highly complex sport because of their technical, tactical, physical, psychological and anthropometric factors requirements. Over the years there has been an increase in the homogeneity of the characteristics of volleyball players in high performance due to talent acquisition with similar skills. The main interest of this study was to determine the performance of a sample of 53 volleyball players participating in different official women's volleyball competition. The variables studied are: category, anthropometric variables (body mass, height, endomorphy, mesomorphy, ectomorphy, upper body strength (throwing ball, measure the speed hitting without jump and with jump spike and lower body strength (CMJ, ABK, DJ and jump spike. Statistical analysis consisted of a Shapiro-Wilks test, to determine the normality of the sample. The comparative analysis between categories was performed using an analysis of variance (ANOVA a factor. The results showed a significant positive increase in physical, technical and anthropometric characteristics of the players with the increased level of competition, and a better use of technical gestures, reflecting an increase in performance thereof.

  1. A comparison of two landing styles in a two-foot vertical jump.

    Science.gov (United States)

    Gutiérrez-Davila, Marcos; Campos, José; Navarro, Enrique

    2009-01-01

    In team sports, such as basketball and volleyball, the players use different takeoff styles to make the vertical jump. The two-foot vertical jump styles have been classified according to the landing style and identified as hop style, when both feet touch the ground at the same time, and step-close style, when there is a slight delay between the first and second foot making contact with the ground. The aim of this research is to identify the differences between the two styles. Twenty-three subjects participated in the study, of whom 14 were volleyball players and 9 were basketball players. The jumps were video recorded and synchronized with two force platforms at 250 Hz. Two temporal periods of the takeoff were defined according to the reduction or increase in the radial distance between the center of gravity (CG) and the foot support (T - RDCG and T + RDCG, respectively). The findings produced no specific advantages when both styles were compared with respect to takeoff velocity and, consequently, to jump height, but takeoff time was significantly shorter (p vertical velocity of CG at the beginning of the takeoff is significantly lower. Moreover, the mean vertical force developed during T - RDCG was reduced by -627.7 +/- 251.1 N, thus lessening impact on landing. Horizontal velocity at the end of the takeoff is less when the step-close style is used (p jumps where it is necessary to move horizontally during the flight against an opponent.

  2. Jumping in Arithmetic

    NARCIS (Netherlands)

    Visser, Albert

    In this paper we study a new relation between sentences: the jump relation. The idea of the jump relation is based on an analysis of Feferman's Theorem that the inconsistency of a theory U is interpretable over U. The jump relation is based on a converse of Feferman's Theorem: if a sentence is

  3. Jumping in Arithmetic

    NARCIS (Netherlands)

    Visser, Albert

    2014-01-01

    In this paper we study a new relation between sentences: the jump relation. The idea of the jump relation is based on an analysis of Feferman's Theorem that the inconsistency of a theory U is interpretable over U. The jump relation is based on a converse of Feferman's Theorem: if a sentence is

  4. SPORTS SHOES PURCHASE INTENTION AMONG MALAYSIAN VOLLEYBALL PLAYERS VS. NON-VOLLEYBALL PLAYERS: A CONCEPTUAL PAPER

    Directory of Open Access Journals (Sweden)

    GOH PIN SIANG

    2013-12-01

    Full Text Available The purpose of this study is to advance the understanding of volleyball players’ purchase intention toward sport shoes by investigating the relationship between the independent variables (endorsement, advertising, pricing and electronic word-of-mouth and purchase intention. Descriptive research and causal research will be used as the research design, thus questionnaire and experimentation will be used to obtain data. Primary data in this study is attained by distributing the questionnaire to the Malaysian volleyball players throughout several volleyball tournament venues in Malaysia. The experiment will be conducted by comparing two groups of respondents, including volleyball players and non-volleyball players. This study is limited to several independent variables such as endorsement, advertising, pricing and electronic word-of-mouth. This study is significant for marketers for solving the challenges faced in the sport industry. It also helps to identify consumers’ purchase preferences for sport shoes. The marketer would understand more about their targeted customers’ intentions to purchase, thus the sport industry related with sport marketing in Malaysia might gain more profit.

  5. Effect of different knee starting angles on intersegmental coordination and performance in vertical jumps.

    Science.gov (United States)

    Gheller, Rodrigo G; Dal Pupo, Juliano; Ache-Dias, Jonathan; Detanico, Daniele; Padulo, Johnny; dos Santos, Saray G

    2015-08-01

    This study aimed to analyze the effect of different knee starting angles on jump performance, kinetic parameters, and intersegmental coupling coordination during a squat jump (SJ) and a countermovement jump (CMJ). Twenty male volleyball and basketball players volunteered to participate in this study. The CMJ was performed with knee flexion at the end of the countermovement phase smaller than 90° (CMJ(90)), and in a preferred position (CMJ(PREF)), while the SJ was performed from a knee angle of 70° (SJ(70)), 90° (SJ(90)), 110° (SJ(110)), and in a preferred position (SJ(PREF)). The best jump performance was observed in jumps that started from a higher squat depth (CMJ(90). Analysis of continuous relative phase showed that thigh-trunk coupling was more in-phase in the jumps (CMJ and SJ) performed with a higher squat depth, while the leg-thigh coupling was more in-phase in the CMJ(>90) and SJ(PREF). Jumping from a position with knees more flexed seems to be the best strategy to achieve the best performance. Intersegmental coordination and jump performance (CMJ and SJ) were affected by different knee starting angles. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Design and validation of an observational instrument for technical and tactical actions in beach volleyball

    Directory of Open Access Journals (Sweden)

    José Manuel Palao

    2015-06-01

    Full Text Available Technical and tactical actions determine performance in beach volleyball. This research develops and tests an instrument to monitor and evaluate the manner of execution and efficacy of the actions in beach volleyball. The purpose of this paper was to design and validate an observational instrument to analyze technical and tactical actions in beach volleyball. The instrument collects information regarding: a information about the match (context, b information about game situations, c information about technical situations (serve, reception, set, attack, block, and court defense in relation to player execution, role, manner of execution, execution zone, and efficacy, and d information about the result of the play (win-lose and way point is obtained. Instrument design and validation was done in seven stages: a review of literature and consultation of experts; b pilot observation and data analysis; c expert review of instrument (qualitative and quantitative evaluation; d observer training test; e expert review of instrument (content validity; f measurement of the ability of the instrument to discriminate the result of the set; and g measurement of the ability of the instrument to differentiate between competition age groups. The results show that the instrument allows for obtaining objective and valid information about the players and team from offensive and defensive technical and tactical actions, as well as indirectly from physical actions. The instrument can be used, in its entirety or partially, for researching and coaching purposes.

  7. Game-Related Performance Factors in four European Men's Professional Volleyball Championships.

    Science.gov (United States)

    Peña, Javier; Casals, Martí

    2016-12-01

    The present study was designed to assess the relevance of game-related performance factors as outcome predictors in high-level volleyball. To carry out the analysis, the official box scores of 399 matches played by 47 different teams in four different European male professional volleyball leagues (Italy, Poland, Germany and Turkey) during the 2013-14 regular season were analyzed. A logistic mixed model was performed to determine the effects of different variables in matches' outcomes. According to the multivariate analysis the following factors were significantly associated with winning matches: the number of scorers (OR = 1.32; CI: 1.09 - 1.59), service errors (OR = 0.91; CI: 0.87 - 0.95), service points (OR = 1.25; CI: 1.15 -1.36), reception errors (OR = 0.79; CI: 0.74 - 0.84), the percentage of positive receptions (OR = 1.02; CI: 1.00 -1.04) and blocked balls (OR = 1.17; CI: 1.11 - 1.26). Team category 2 (OR = 0.39; CI: 0.24 - 0.63) and team category 3 (OR = 0.15; CI: 0.09 - 0.25) were significantly associated with losing matches. These findings can contribute to a better understanding of performance indicators in professional volleyball, helping coaches and decision makers to better determine the importance of particular game factors.

  8. Game-Related Performance Factors in four European Men’s Professional Volleyball Championships

    Directory of Open Access Journals (Sweden)

    Peña Javier

    2016-12-01

    Full Text Available The present study was designed to assess the relevance of game-related performance factors as outcome predictors in high-level volleyball. To carry out the analysis, the official box scores of 399 matches played by 47 different teams in four different European male professional volleyball leagues (Italy, Poland, Germany and Turkey during the 2013-14 regular season were analyzed. A logistic mixed model was performed to determine the effects of different variables in matches’ outcomes. According to the multivariate analysis the following factors were significantly associated with winning matches: the number of scorers (OR = 1.32; CI: 1.09 – 1.59, service errors (OR = 0.91; CI: 0.87 – 0.95, service points (OR = 1.25; CI: 1.15 -1.36, reception errors (OR = 0.79; CI: 0.74 – 0.84, the percentage of positive receptions (OR = 1.02; CI: 1.00 -1.04 and blocked balls (OR = 1.17; CI: 1.11 – 1.26. Team category 2 (OR = 0.39; CI: 0.24 – 0.63 and team category 3 (OR = 0.15; CI: 0.09 – 0.25 were significantly associated with losing matches. These findings can contribute to a better understanding of performance indicators in professional volleyball, helping coaches and decision makers to better determine the importance of particular game factors.

  9. Effect of a Volleyball Course on Health-Related Fitness Components of University Students

    Directory of Open Access Journals (Sweden)

    Mohammed Hamdan Hashem Mohammed

    2018-02-01

    Full Text Available Physical educators need to evaluate the physical education (PE curriculum they provide to their students. One way is through regular health-related fi tness assessments. Physical education programs have improved fi tness levels of schoolchildren, but such data is rare for university students. The aim of this study was to determine the eff ect of a volleyball course on the health-related fi tness of male university students. The participants were non-PE majors from King Fahd University of Petroleum & Minerals. They registered for a volleyball course which was done twice a week for eight weeks (31 October-29 December 2016, 50 minutes per session. The parameters assessed were as follows: 1 body composition through body mass index (BMI, 2 muscular endurance through the 60s curl-up test, 3 fl exibility through the sit and reach test, 4 leg explosive strength through standing long jump, and 5 cardiovascular endurance through a 1.6 km run. Pre and post measurements were taken and the data were analyzed using descriptive statistics and paired t-test with SPSS 16. P-values for statistical signifi cance was set at0.2 was considered of practical signifi cance. Data from 145 students were analyzed (mean (SD age=20.8 (0.64 years. There were improvements from pre to post in all variables except body mass and BMI. The data shows evidence that the volleyball course improved the health-related fi tness variables of the students. This shows a course designed for non-PE majors may improve their fi tness levels if well designed.

  10. Match Analysis in Volleyball: a systematic review

    Directory of Open Access Journals (Sweden)

    Miguel Silva

    2016-03-01

    Full Text Available The present article aims to review the available literature on match analysis in adult male Volleyball. Specific key words "performance analysis", "match analysis", "game analysis", "notational analysis", "tactical analysis", "technical analysis", "outcome" and "skills" were used to search relevant databases (PubMed, Web of Science, SportDiscus, Academic Search Complete and the International Journal of Performance Analysis in Sport. The research was conducted according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta analyses guidelines. Of 3407 studies initially identified, only 34 were fully reviewed, and their outcome measures extracted and analyzed. Studies that fit all inclusion criteria were organized into two levels of analysis, according to their research design (comparative or predictive and depending on the type of variables analyzed (skills and their relationship with success, play position and match phase. Results show that from a methodological point of view, comparative studies where currently complemented with some predictive studies. This predictive approach emerged with the aim to identify the relationship between variables, considering their possible interactions and consequently its effect on team performance, contributing to a better understanding of Volleyball game performance through match analysis. Taking into account the limitations of the reviewed studies, future research should provide comprehensive operational definitions for the studied variables, using more recent samples, and consider integrating the player positions and match phase contexts into the analysis of Volleyball.

  11. Study of attack in college volleyball

    Directory of Open Access Journals (Sweden)

    Yordan Portela Pozo

    2014-03-01

    This work is done in order to analyze the positive and negative aspects that affected the performance of the auction action in volleyball players performing this action (in this case male in the Provincial University Games in 2012 in Havana , for which I take as a case study to the players of the University of Information Sciences and its opponents in those games, completing a total of 268 shares auctions in 7 games with a total of 15 September analyzed taking account of changes in the sport of Volleyball university in Cuba, data recorded by an observation sheet previously completed by the authors. The main results in this paper show that the greatest amount of shots that were done in these games were diagonal and a good percentage of positive linear auctions however were few and with very poor results. The primary role of the auction for the game's success is fully confirmed in this work because this action is achieved through many points in the game of volleyball and thus leads to a better result.

  12. Estimation of Jump Tails

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Todorov, Victor

    We propose a new and flexible non-parametric framework for estimating the jump tails of Itô semimartingale processes. The approach is based on a relatively simple-to-implement set of estimating equations associated with the compensator for the jump measure, or its "intensity", that only utilizes...... the weak assumption of regular variation in the jump tails, along with in-fill asymptotic arguments for uniquely identifying the "large" jumps from the data. The estimation allows for very general dynamic dependencies in the jump tails, and does not restrict the continuous part of the process...... and the temporal variation in the stochastic volatility. On implementing the new estimation procedure with actual high-frequency data for the S&P 500 aggregate market portfolio, we find strong evidence for richer and more complex dynamic dependencies in the jump tails than hitherto entertained in the literature....

  13. Physical and Temporal Characteristics of Under 19, Under 21 and Senior Male Beach Volleyball Players

    Directory of Open Access Journals (Sweden)

    Alexandre Medeiros, Rui Marcelino, Isabel Mesquita, José Manuel Palao

    2014-09-01

    Full Text Available This study aimed to assess the effects of age groups and players’ role (blocker vs. defender specialist in beach volleyball in relation to physical and temporal variables, considering quality of opposition. 1101 rallies from Under 19 (U19, 933 rallies from Under 21 (U21, and 1480 rallies from senior (senior (Men’s Swatch World Championships, 2010-2011 were observed using video match analysis. Cluster analysis was used to set teams’ competitive levels and establish quality of opposition as “balanced”, “moderate balanced” and “unbalanced” games. The analyzed variables were: temporal (duration of set, total rest time, total work time, duration of rallies, rest time between rallies and physical (number of jumps and number of hits done by defenders and blockers characteristics. A one-way ANOVA, independent samples t-test and multinomial logistic regression were performed to analyze the variables studied. The analysis of temporal and physical characteristics showed differences considering age group, player’s role and quality of opposition. The duration of set, total rest time, and number of jumps done by defenders significantly increased from the U19 to senior category. Multinomial logistic regression showed that in: a balanced games, rest time between rallies was higher in seniors than in U19 or U21; number of jumps done by defenders was higher in seniors than in U19 and U21; b moderate balanced games, number of jumps done by defenders was higher in seniors than in U21 and number of jumps done by blockers was smaller in U19 than U21 or seniors; c unbalanced games, no significant findings were shown. This study suggests differences in players’ performances according to age group and players’ role in different qualities of opposition. The article provides reference values that can be useful to guide training and create scenarios that resemble a competition, taking into account physical and temporal characteristics.

  14. Evaluation of strength and conditioning measures with game success in Division I collegiate volleyball: A retrospective study.

    Science.gov (United States)

    Bunn, Jennifer A; Ryan, Greg A; Button, Gabriel R; Zhang, S

    2017-08-04

    The purpose of this study was to retrospectively assess relationships between strength and conditioning (SC) measures and game performance in Division I volleyball. Five years of SC and game data were collected from one women's Division I collegiate team, n = 76. SC measures included: T-drill, 18.3 m sprint, back squat, hang clean, vertical jump, and broad jump. All game and SC stats were normalized to Z-scores. Analyses included assessing SC differences by position, and multiple stepwise regression to assess relationships between game and SC stats. There was a significant difference by position for broad jump (p =.002), 18.3 m sprint (p =.036), vertical (p game performance and SC measures were significantly correlated (r = .439, p game success by position as follows: defensive specialist stats with squat and total strength; setters game stats with hang cleans, T-drill, and broad jump; pin hitter game stats with vertical, squat, and total strength; middle blockers game stats with broad jump. These data indicate that SC measures correlate well with game performance and are specific by position. These data could help SC coaches create a more precise training approach to focus on improving specific measures by position, which could then translate to improved game performance. These data could also help coaches with talent identification to determine playing time and rotations to maximize player ability and achieve success.

  15. Anthropometric and performance measures to study talent detection in youth volleyball.

    Science.gov (United States)

    Melchiorri, Giovanni; Viero, Valerio; Triossi, Tamara; Annino, Giuseppe; Padua, Elvira; Tancredi, Virginia

    2017-12-01

    The aim of this work was to study anthropometric and performance measurements in 60 young male volleyball players (YV) and 60 youth not active in the sport (YNA) to assess which of these would be more useful to study the characteristics of potential performers. Eight measures to assess anthropometric characteristics, six performance measures and two tests for joint mobility were used. Also relative age and level of maturation were assessed. The anthropometric variables, relative age and level of maturation measured did not show statistically significant differences between groups. The YV and YNA groups showed differences in the performance measures. YV group was characterized by a better performance of the ability to repeat short sprints, of the upper limbs, abdominal muscles and lower limbs, with a medium effect size (Shuttle Running Test: 0.6; Push-Up: 0.5; Sit-Up: 0.4; counter movement jump: 0.4). These performance variables were very sensitive and specific: the SRT measurement had the best positive likelihood ratio that indicates the utility of the test in identifying type of players (YV and YNA). In talent detection in youth volleyball, in the 11-13 age range, performance variables should be preferred to anthropometric ones.

  16. Analysis of Setting Efficacy in Young Male and Female Volleyball Players.

    Science.gov (United States)

    González-Silva, Jara; Domínguez, Alberto Moreno; Fernández-Echeverría, Carmen; Rabaz, Fernando Claver; Arroyo, M Perla Moreno

    2016-12-01

    The main objective of this study was to analyse the variables that predicted setting efficacy in complex I (KI) in volleyball, in formative categories and depending on gender. The study sample was comprised of 5842 game actions carried out by the 16 male category and the 18 female category teams that participated in the Under-16 Spanish Championship. The dependent variable was setting efficacy. The independent variables were grouped into: serve variables (a serve zone, the type of serve, striking technique, an in-game role of the server and serve direction), reception variables (a reception zone, a receiver player and reception efficacy) and setting variables (a setter's position, a setting zone, the type of a set, setting technique, a set's area and tempo of a set). Multinomial logistic regression showed that the best predictive variables of setting efficacy, both in female and male categories, were reception efficacy, setting technique and tempo of a set. In the male category, the jump serve was the greatest predictor of setting efficacy, while in the female category, it was the set's area. Therefore, in the male category, it was not only the preceding action that affected setting efficacy, but also the serve. On the contrary, in the female category, only variables of the action itself and of the previous action, reception, affected setting efficacy. The results obtained in the present study should be taken into account in the training process of both male and female volleyball players in formative stages.

  17. Analysis of Setting Efficacy in Young Male and Female Volleyball Players

    Directory of Open Access Journals (Sweden)

    González-Silva Jara

    2016-12-01

    Full Text Available The main objective of this study was to analyse the variables that predicted setting efficacy in complex I (KI in volleyball, in formative categories and depending on gender. The study sample was comprised of 5842 game actions carried out by the 16 male category and the 18 female category teams that participated in the Under-16 Spanish Championship. The dependent variable was setting efficacy. The independent variables were grouped into: serve variables (a serve zone, the type of serve, striking technique, an in-game role of the server and serve direction, reception variables (a reception zone, a receiver player and reception efficacy and setting variables (a setter‘s position, a setting zone, the type of a set, setting technique, a set’s area and tempo of a set. Multinomial logistic regression showed that the best predictive variables of setting efficacy, both in female and male categories, were reception efficacy, setting technique and tempo of a set. In the male category, the jump serve was the greatest predictor of setting efficacy, while in the female category, it was the set’s area. Therefore, in the male category, it was not only the preceding action that affected setting efficacy, but also the serve. On the contrary, in the female category, only variables of the action itself and of the previous action, reception, affected setting efficacy. The results obtained in the present study should be taken into account in the training process of both male and female volleyball players in formative stages.

  18. What are quantum jumps?

    International Nuclear Information System (INIS)

    Cook, R.J.

    1988-01-01

    This paper answers the title question by giving an operational definition of quantum jumps based on measurement theory. This definition forms the basis of a theory of quantum jumps which leads to a number of testable predictions. Experiments are proposed to test the theory. The suggested experiments also test the quantum Zeno paradox, i.e., they test the proposition that frequent observation of a quantum system inhibits quantum jumps in that system. (orig.)

  19. A one season prospective cohort study of volleyball injuries

    NARCIS (Netherlands)

    Verhagen, E.A.L.M.; van der Beek, A.J.; Bouter, L.M.; Bahr, R.; van Mechelen, W.

    2004-01-01

    Objective: To estimate the overall incidence of acute and overuse volleyball injuries, and to describe factors associated with ankle sprains. Methods: 486 players from the second and third Dutch national volleyball divisions participated in the study and were followed prospectively during a whole

  20. Improved safety in ski jumping.

    Science.gov (United States)

    Wester, K

    1988-01-01

    Among approximately 2,600 licensed Norwegian ski jumpers, only three injuries that caused a permanent medical disability of at least 10% were incurred during the 5 year period from 1982 through 1986. When compared to the previous 5 year period (1977 to 1981), a dramatic improvement in safety is seen, as both number and severity of such injuries were markedly reduced. There are several probable reasons for this improved safety record: better preparation of the jumps, the return to using only one standard heel block, and the fact that coaches are being more responsible, especially with younger jumpers.

  1. Countermovement jump height: gender and sport-specific differences in the force-time variables.

    Science.gov (United States)

    Laffaye, Guillaume; Wagner, Phillip P; Tombleson, Tom I L

    2014-04-01

    The goal of this study was to assess (a) the eccentric rate of force development, the concentric force, and selected time variables on vertical performance during countermovement jump, (b) the existence of gender differences in these variables, and (c) the sport-specific differences. The sample was composed of 189 males and 84 females, all elite athletes involved in college and professional sports (primarily football, basketball, baseball, and volleyball). The subjects performed a series of 6 countermovement jumps on a force plate (500 Hz). Average eccentric rate of force development (ECC-RFD), total time (TIME), eccentric time (ECC-T), Ratio between eccentric and total time (ECC-T:T) and average force (CON-F) were extracted from force-time curves and the vertical jumping performance, measured by impulse momentum. Results show that CON-F (r = 0.57; p differ between both sexes (p differ, showing a similar temporal structure. The best way to jump high is to increase CON-F and ECC-RFD thus minimizing the ECC-T. Principal component analysis (PCA) accounted for 76.8% of the JH variance and revealed that JH is predicted by a temporal and a force component. Furthermore, the PCA comparison made among athletes revealed sport-specific signatures: volleyball players revealed a temporal-prevailing profile, a weak-force with large ECC-T:T for basketball players and explosive and powerful profiles for football and baseball players.

  2. Training Load, Physical Performance, Biochemical Markers, and Psychological Stress During A Short Preparatory Period in Brazilian Elite Male Volleyball Players.

    Science.gov (United States)

    Horta, Thiago A G; Bara Filho, Maurício G; Coimbra, Danilo R; Miranda, R; Werneck, Francisco Z

    2017-12-11

    The aim of this study was to assess the relationship between training load (TL) and physical performance, biochemical markers, and psychological stress during a short preparatory period (PP) in Brazilian elite male volleyball players. Twelve volleyball players from a team competing in the Brazilian Men's Volleyball Super League were enrolled (26.9 ± 4.6 years). Countermovement Jump (CMJ), Creatine Kinase (CK), Testosterone (T), Cortisol (Cr), T/Cr ratio, and Recovery and Stress Questionnaire for Athletes (RESTQ-Sport) were collected at baseline, after 2, 4, and 6 week. TL was quantified daily using the Rating of Perceived Exertion (RPE). Differences were noted between Total Weekly TL (TWTL) (F3,33 = 50.907; p = 0.0001), CK (F3,33 = 16.157; p = 0.0001), and T (F3,33 = 3.283; p = 0.03). No differences were seen in CMJ (F3,33 = 1.821; p = 0.16), Cr (F3,33 = 2.409; p = 0.08), or T/Cr ratio (F3,33 = 1.527; p = 0.23). The RESTQ-Sport demonstrated differences between moments in Social Stress (F3,33 = 2.297; p = 0.04; Eta = 0.25), Success (F3,33 = 4.350; p = 0.01; Eta = 0.19), General Well-being (F3,33 = 4.465; p = 0.01; Eta = 0.36), and Injury (F3,33 = 2.792; p = 0.05; Eta = 0.62). The results showed a significant correlations of small to moderate magnitude between TWTL and CK (r = 0.32; p = 0.05). In conclusion, a short PP in volleyball leads to increased TL, CK level, and psychological stress. TL was related with the increase of CK, suggesting muscle damage without increased of physical performance.

  3. Comparative analysis of the physique of volleyball players selected from different volleyball clubs

    Directory of Open Access Journals (Sweden)

    Adrian Sieroń

    2017-12-01

    Full Text Available In recent years we have seen a steady increase in interest in sport among the public. This is due primarily to the deepening of knowledge about the health-promoting aspects for people who practice it regularly. Considerable interest primarily characterized by team games, which due to their accessibility, clearly defined rules, the variety of forms of movement, or finally, the interaction between human are the most popular sport disciplines. In Poland, one of the most popular team sports of football is next to volleyball. From year to year, this form of recreation is more and more supporters.  For many years, extremely important for researchers from around the world was to find the factors that determine the achievement of high results volleyball. This problem is steadily gaining in importance, because modern training methods contribute to maximizing the potential of each player. Many researchers believe that making attempts to find factors that are of potential players is one of the few areas where you can find the reserves to increase results. The aim of this study is to compare intergroup somatic athletes practicing volleyball, playing and trainees in four different teams in Lower Silesia. The study enrolled 54 men aged 12-15 years with a group of four volleyball players representing the same level of sports preparation. The study used data measuring 17 somatic features. The results show that the somatic features of individual players in all four teams are similar and homogeneous.

  4. Drop jumping. I. The influence of jumping technique on the biomechanics of jumping

    NARCIS (Netherlands)

    Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

    In the literature, drop jumping is advocated as an effective exercise for athletes who prepare themselves for explosive activities. When executing drop jumps, different jumping techniques can be used. In this study, the influence of jumping technique on the biomechanics of jumping is investigated.

  5. Modification of Knee Flexion Angle Has Patient-Specific Effects on Anterior Cruciate Ligament Injury Risk Factors During Jump Landing.

    Science.gov (United States)

    Favre, Julien; Clancy, Caitlin; Dowling, Ariel V; Andriacchi, Thomas P

    2016-06-01

    The incidence of anterior cruciate ligament (ACL) injuries may be decreased through the use of intervention programs that focus on increasing the knee flexion angle during jump landing, which decreases strain on the ACL. To investigate whether intervention training designed to change the knee flexion angle during landing causes secondary changes in other known measures associated with the risk of ACL injuries and to examine the time points when these secondary measures change. Controlled laboratory study. A total of 39 healthy recreational athletes performed a volleyball block jump task in an instrumented gait laboratory. The participants first completed the jumps without any modification to their normal landing technique. They were then given oral instruction to land softly and to increase their knee flexion angle during landing. Lower body kinematics and kinetics were measured before and after the modification using an optoelectronic motion capture system. The knee flexion angle after the modification significantly increased from 11.2° to 15.2° at initial contact and from 67.8° to 100.7° at maximum flexion, and the time between initial contact and maximum flexion increased from 177.4 to 399.4 milliseconds. The flexion modification produced a substantial reduction in vertical ground-reaction force (243.1 to 187.8 %BW) with a concomitant reduction in the maximum flexion moment. Interestingly, the flexion modification only affected the abduction angle and abduction moment for the group of participants that landed in an initial adducted position before the modification and had no significant effect on the group that landed in an abducted position. Increasing the knee flexion angle during jump landing may be an effective intervention to improve knee biomechanical risk factors associated with an ACL injury. However, the fact that the flexion modification only influenced critical risk factors (the abduction angle and abduction moment) in participants who initially

  6. Optimal Ski Jump

    Science.gov (United States)

    Rebilas, Krzysztof

    2013-01-01

    Consider a skier who goes down a takeoff ramp, attains a speed "V", and jumps, attempting to land as far as possible down the hill below (Fig. 1). At the moment of takeoff the angle between the skier's velocity and the horizontal is [alpha]. What is the optimal angle [alpha] that makes the jump the longest possible for the fixed magnitude of the…

  7. Physical therapists' role in prevention and management of patellar tendinopathy injuries in youth, collegiate, and middle-aged indoor volleyball athletes

    Science.gov (United States)

    Kulig, Kornelia; Noceti-DeWit, Lisa M.; Reischl, Stephen F.; Landel, Rob F.

    2015-01-01

    Patellar tendinopathy is highly prevalent in all ages and skill levels of volleyball athletes. To illustrate this, we discuss the clinical, biomechanical, and ultrasound imaging presentation and the intervention strategies of three volleyball athletes at different stages of their athletic career: youth, middle-aged, and collegiate. We present our examination strategies and interpret the data collected, including visual movement analysis and dynamics, relating these findings to the probable causes of their pain and dysfunction. Using the framework of the EdUReP concept, incorporating Education, Unloading, Reloading, and Prevention, we propose intervention strategies that target each athlete's specific issues in terms of education, rehabilitation, training, and return to sport. This framework can be generalized to manage patellar tendinopathy in other sports requiring jumping, from youth to middle age, and from recreational to elite competitive levels. PMID:26537811

  8. [Muscular trunk stability in professional and amateur volleyball players].

    Science.gov (United States)

    Miltner, O; Siebert, C; Tschaepe, R; Maus, U; Kieffer, O

    2010-03-01

    The aim of this study was to analyse the efficiency of muscular activity in the trunk stabilisation of professional volleyball players compared to a group of amateur hobby players. The results were compared amongst the groups as well as with a reference group consisting of asymptomatic individuals. The question to be answered was whether or not professional volleyball players possess a characteristic strength profile in their trunk musculature and if differences exist with regard to the individuals' competitive playing level. In this comparative study 12 professional volleyball players (German Bundesliga) and 18 non-professional volleyball players were analysed with regard to their isometric strength profile in all three planes. The reference group was provided by the Proxomed company, which had previously analysed healthy untrained individuals (n = 1045) of various age groups. A sports-specific profile for the musculature of volleyball players revealed a significant reduction in the flexion and rotation strength as well as a well-developed lateral flexion strength (highly significant when compared to the reference group). With reference to the level played, better strength values in flexion and lateral flexion were found among the professional athletes. Professional volleyball players present with a characteristic trunk musculature strength profile. A detailed analysis of the muscle strength of the spine as part of a sports medicine work-up could prove helpful in preventing injuries and overuse problems in professional and hobby volleyball players.

  9. Strength asymmetry of the shoulders in elite volleyball players.

    Science.gov (United States)

    Hadzic, Vedran; Sattler, Tine; Veselko, Matjaž; Markovic, Goran; Dervisevic, Edvin

    2014-01-01

    Volleyball players are reported to have shoulder strength imbalances. Previous authors have primarily investigated small samples of male players at a single skill level, without considering playing position, and with inconsistent findings. To evaluate shoulder strength asymmetry and a history of shoulder injury in a large sample of professional volleyball players of both sexes across different playing positions and skill levels. Descriptive laboratory study. A sample of 183 volleyball players (99 men, 84 women). We assessed shoulder internal-rotator and external-rotator concentric strength at 60°/s using an isokinetic dynamometer and dominant-nondominant differences in shoulder strength and strength ratios using repeated-measures analyses of variance. Peak torque was normalized for body mass and external-rotation/internal-rotation concentric strength. Internal-rotation strength was asymmetric in favor of the dominant side in both sexes, regardless of previous shoulder injury status. Male volleyball players had a lower shoulder strength ratio on the dominant side, regardless of previous shoulder injury status. However, this finding was valid only when hand dominance was taken into account. Female volleyball players playing at a higher level (ie, first versus second division) were 3.43 times more likely to have an abnormal strength ratio. Playing position was not associated with an abnormal shoulder strength ratio or strength asymmetry. In male volleyball players, the external-rotation/internal-rotation strength ratio of the dominant shoulder was lower, regardless of playing position, skill level, or a previous shoulder injury. In female players, the ratio was less only in those at a higher skill level. Although speculative, these findings generally suggest that female volleyball players could have a lower risk of developing shoulder-related problems than male volleyball players. Isokinetic shoulder testing may reveal important information about the possible risk

  10. ACUTE EFFECTS OF A RESISTED DYNAMIC WARM-UP PROTOCOL ON JUMPING PERFORMANCE

    Science.gov (United States)

    Cilli, M; Yildiz, S; Saglam, T; Camur, MH

    2014-01-01

    This study aimed to investigate the kinematic and kinetic changes when resistance is applied in horizontal and vertical directions, produced by using different percentages of body weight, caused by jumping movements during a dynamic warm-up. The group of subjects consisted of 35 voluntary male athletes (19 basketball and 16 volleyball players; age: 23.4 ± 1.4 years, training experience: 9.6 ± 2.7 years; height: 177.2 ± 5.7 cm, body weight: 69.9 ± 6.9 kg) studying Physical Education, who had a jump training background and who were training for 2 hours, on 4 days in a week. A dynamic warm-up protocol containing seven specific resistance movements with specific resistance corresponding to different percentages of body weight (2%, 4%, 6%, 8%, 10%) was applied randomly on non consecutive days. Effects of different warm-up protocols were assessed by pre-/post- exercise changes in jump height in the countermovement jump (CMJ) and the squat jump (SJ) measured using a force platform and changes in hip and knee joint angles at the end of the eccentric phase measured using a video camera. A significant increase in jump height was observed in the dynamic resistance warm-up conducted with different percentages of body weight (p 0.05). In jump movements before and after the warm-up, while no significant difference between the vertical ground reaction forces applied by athletes was observed (p > 0.05), in some cases of resistance, a significant reduction was observed in hip and knee joint angles (p jumping movements, as well as an increase in jump height values. As a result, dynamic warm-up exercises could be applicable in cases of resistance corresponding to 6-10% of body weight applied in horizontal and vertical directions in order to increase the jump performance acutely. PMID:25435670

  11. Validity, Reliability, and Sensitivity of a Volleyball Intermittent Endurance Test.

    Science.gov (United States)

    Rodríguez-Marroyo, Jose A; Medina-Carrillo, Javier; García-López, Juan; Morante, Juan C; Villa, José G; Foster, Carl

    2017-03-01

    To analyze the concurrent and construct validity of a volleyball intermittent endurance test (VIET). The VIET's test-retest reliability and sensitivity to assess seasonal changes was also studied. During the preseason, 71 volleyball players of different competitive levels took part in this study. All performed the VIET and a graded treadmill test with gas-exchange measurement (GXT). Thirty-one of the players performed an additional VIET to analyze the test-retest reliability. To test the VIET's sensitivity, 28 players repeated the VIET and GXT at the end of their season. Significant (P volleyball players.

  12. Serious ski jumping injuries in Norway.

    Science.gov (United States)

    Wester, K

    1985-01-01

    Injuries caused by ski jumping have been poorly investigated. Among approximately 2,200 licensed jumpers in Norway, there occurred at least 12 injuries with a permanent medical disability of greater than or equal to 10%. The risk of being seriously injured is approximately 5% in a 5 year period (1977 to 1981); it is higher in the age group 15 to 17 years. Seven injuries were very serious [four central nervous system (CNS) lesions, two leg amputations, and one blindness of one eye], and five were less serious (sequelae to fractures of the lower extremities). The first jump of the day is particularly dangerous, and so is the beginning and end of the season. It seems dangerous to use more than one standard heel block. Poor preparation of the jump may have contributed to the accidents. Based on the findings, several prophylactic measures are suggested.

  13. Methodological alternative for volleyball technic tactical preparation

    Directory of Open Access Journals (Sweden)

    Tania Rosa García Hernández

    2014-12-01

    Full Text Available At the moment, the humanity has travelled an impressive road. The man, that thousands of years ago used to obtain the existence means with primitive stone instruments that horrified him and used to invoke to God before any natural phenomenon, has penetrated in the world of the micro and macrocosms, and has created admirable works in all the aspects of the life. Besides, he has built and transformed many things in search of the truth and through the development of the science; however, the most important thing is that he has demonstrated that his creative possibilities and intellectuals are unlimited. The sport and the physical culture as part of the human creation have also to travel long road influenced by the development of the technology and the science. In order to contextualize these aspects we will go into the concepts of science and technology given by different authors. The present article offers a methodological alternative proposal for the improvement of the technical tactical evaluation of the volleyball base practitioners' during the process of training starting from a reorganization of the technical tactical indicators of the game, it has implicit the understanding of the structural elements of the volleyball game that allow to readjust in an integrated way the technical tactical elements for its evaluation during the process of training and its behaviour in the competition.

  14. Efeitos de um programa de treinamento neuromuscular sobre o consumo máximo de oxigênio e salto vertical em atletas iniciantes de voleibol Los efectos de un programa de entrenamiento neuromuscular nel consumo máximo de oxígeno y salto vertical en atletas principiantes de voleyball Effects of a neuromuscular training program on the maximal Oxygen consumption and vertical jump in beginning volleyball players

    Directory of Open Access Journals (Sweden)

    Alexandre Altini Neto

    2006-02-01

    logro de las pruebas, de alcance de ataque y asedio y la prueba de 1.000 metros, con el objetivo de evaluar, en tres momentos diferentes, el programa de entrenamiento sugerido. Cuatro colecciones de datos fueron realizadas; la primera: en la presentación de las atletas, la segunda en el final de la etapa general, la tercera en el final de la etapa especial y la última en el final del período competitivo. Los ejercicios del período preparatorio se usaron con el objetivo de mejorar la acción de las atletas en el logro de las acciones motoras del juego. Los ejercicios competitivos fueron cumplidos con el objetivo de mantener los índices del desempeño alcanzado previamente, mientras se priorizaban los ejercicios colectivos que involucran la técnica y las tácticas de la modalidad. Con base en el análisis estadístico de los datos, que se obtuvo a través del cálculo del promedio, la desviación típica, nivel de significancia (p The alterations that occur in the motor performance of young athletes involved in specialized trainings are not yet quite clear. That is a highly important knowledge to the appropriate prescription of the trainings. The purpose of this paper was to verify the influence of the training on the neuromotor and organic variables in young volleyball athletes in different moments of the program. Nine female athletes of the child team from Clube de Campo Piracicaba/SP were selected to perform the tests: the attack and blocking range, and the 1,000 meters test, with the purpose to assess the suggested training program in three different moments of the suggested training program. Four data collection were performed: the first on the athletes' presentation, the second one at the end of the general phase, and the third at the end of the special phase, and the last one at the end of the competitive period. In the preparatory period, the exercises were used aiming to improve the athletes' performance to accomplish the motor actions of the game. During

  15. Competitive activity analysis in play-off stage of 'Wiener Stadtische' Serbian volleyball league for men in 2012/2013 season

    Directory of Open Access Journals (Sweden)

    Majstorović Nikola

    2015-01-01

    Full Text Available Sport is defined as an activity that involves competition, specific preparation for the competition, specific relationships and connections in that area of activity taken as a whole. Analysis of competitive activity is the basis for a rational approach to the planning, programming, implementation and evaluation of the effects of systematic training process. Subject to this study was to analyze competitive activities of volleyball players in the play-off stage of 'Wiener Statische' Serbian league in season 2012/2013. The aim of the research is to determine characteristics of the volleyball game structure in competitive activity, to determine the technical-tactical elements with a statistically significant contribution to the achievement of positive results in the competition and to perform certain conclusions, with the help of research results, regarding the design of the training process. Description of elements was performed in the research, the contents that describe competitive activity in men's volleyball were explored, and then comparative analysis of these elements was performed for different levels of team performance. We can conclude that, based on these results, there is a statistically significant difference between successful and less successful men volleyball teams in only three variables, namely: the efficiency coefficient of serve, efficiency coefficient of block, efficiency coefficient of attack. This data is absolutely correspond to considerations in practice, which is that these three elements directly bring a point in the field, and therefore by observing them we can determine the winner of the match, with the highest certainty. Other elements, though necessary may influence the final outcome in men's volleyball to a lesser extent. Data from this study should be used primarily for modeling volleyball players training, with the ultimate projection on training improvement and game efficiency increase.

  16. Close set in volleyball. Differences and discriminatory power of final game actions in formative stages

    Directory of Open Access Journals (Sweden)

    Dávila Romero, Carlos

    2012-01-01

    Full Text Available The aim of this study was to establish which final game actions discriminate final victories and defeats in women volleyball formative stages during ended sets, which are solved by regulation with a minimal advantage of two points. A total of 57 sets were analyzed in infantile category and 69 sets in cadet category during the national volleyball championship at school age (12-16, Valladolid 2008 and Huelva 2009. Statistics analysis shows differences between the condition of both the winner and the loser teams in sets in the positive attack in infantile category and in positive block and error in cadet category. Discriminative analysis, statistical test that determines those most significant game actions when establishing the differences existing between the winner and loser teams, shows how to predict victory and defeat in the ended sets regarding the positive attack, negative service and error in infantile category and positive block and error in cadet category. These ones suggest that during decisive set moments in both categories, either technical gestures control or errors which arise from a regulation infraction may predict their final performance.

  17. A harmonic oscillator having “volleyball damping”

    Science.gov (United States)

    Mickens, R. E.; Oyedeji, K.; Rucker, S. A.

    2006-05-01

    Volleyball damping corresponds to linear damping up to a certain critical velocity, with zero damping above this value. The dynamics of a linear harmonic oscillator is investigated with this damping mechanism.

  18. SPORTS SHOES PURCHASE INTENTION AMONG MALAYSIAN VOLLEYBALL PLAYERS VS. NON-VOLLEYBALL PLAYERS: A CONCEPTUAL PAPER

    OpenAIRE

    GOH PIN SIANG; ZURAIDAH SULAIMAN

    2013-01-01

    The purpose of this study is to advance the understanding of volleyball players’ purchase intention toward sport shoes by investigating the relationship between the independent variables (endorsement, advertising, pricing and electronic word-of-mouth) and purchase intention. Descriptive research and causal research will be used as the research design, thus questionnaire and experimentation will be used to obtain data. Primary data in this study is attained by distributing the questionnaire to...

  19. Jumping on water

    Science.gov (United States)

    Kim, Ho-Young

    2016-11-01

    Water striders can jump on water as high as they can jump on land. Quick jumps allow them to avoid sudden dangers such as predators' attacks, and therefore understanding how they make such a dramatic motion for survival can shed light on the ultimate level of semi-aquatic motility achievable through evolution. However, the mechanism of their vertical jumping from a water surface has eluded hydrodynamic explanations so far. By observing movements of water strider legs and theoretically analyzing their dynamic interactions with deforming liquid-air interface, we have recently found that different species of jumping striders always tune their leg rotation speed with a force just below that required to break the water surface to reach the maximum take-off velocity. Here, we start with discussing the fundamental theories of dynamics of floating and sinking of small objects. The theories then enable us to analyze forces acting on a water strider while it presses down the water surface to fully exploit the capillary force. We further introduce a 68-milligram at-scale robotic insect capable of jumping on water without splash, strikingly similar to the real strider, by utilizing the water surface just as a trampoline.

  20. Physical and temporal characteristics of under 19, under 21 and senior male beach volleyball players.

    Science.gov (United States)

    Medeiros, Alexandre; Marcelino, Rui; Mesquita, Isabel; Palao, José Manuel

    2014-09-01

    This study aimed to assess the effects of age groups and players' role (blocker vs. defender specialist) in beach volleyball in relation to physical and temporal variables, considering quality of opposition. 1101 rallies from Under 19 (U19), 933 rallies from Under 21 (U21), and 1480 rallies from senior (senior) (Men's Swatch World Championships, 2010-2011) were observed using video match analysis. Cluster analysis was used to set teams' competitive levels and establish quality of opposition as "balanced", "moderate balanced" and "unbalanced" games. The analyzed variables were: temporal (duration of set, total rest time, total work time, duration of rallies, rest time between rallies) and physical (number of jumps and number of hits done by defenders and blockers) characteristics. A one-way ANOVA, independent samples t-test and multinomial logistic regression were performed to analyze the variables studied. The analysis of temporal and physical characteristics showed differences considering age group, player's role and quality of opposition. The duration of set, total rest time, and number of jumps done by defenders significantly increased from the U19 to senior category. Multinomial logistic regression showed that in: a) balanced games, rest time between rallies was higher in seniors than in U19 or U21; number of jumps done by defenders was higher in seniors than in U19) and U21; b) moderate balanced games, number of jumps done by defenders was higher in seniors than in U21 and number of jumps done by blockers was smaller in U19 than U21 or seniors; c) unbalanced games, no significant findings were shown. This study suggests differences in players' performances according to age group and players' role in different qualities of opposition. The article provides reference values that can be useful to guide training and create scenarios that resemble a competition, taking into account physical and temporal characteristics. Key PointsPlayer roles, quality of opposition

  1. Agreement Between Visual Assessment and 2-Dimensional Analysis During Jump Landing Among Healthy Female Athletes.

    Science.gov (United States)

    Rabin, Alon; Einstein, Ofira; Kozol, Zvi

    2018-04-01

      Altered movement patterns, including increased frontal-plane knee movement and decreased sagittal-plane hip and knee movement, have been associated with several knee disorders. Nevertheless, the ability of clinicians to visually detect such altered movement patterns during high-speed athletic tasks is relatively unknown.   To explore the association between visual assessment and 2-dimensional (2D) analysis of frontal-plane knee movement and sagittal-plane hip and knee movement during a jump-landing task among healthy female athletes.   Cross-sectional study.   Gymnasiums of participating volleyball teams.   A total of 39 healthy female volleyball players (age = 21.0 ± 5.2 years, height = 172.0 ± 8.6 cm, mass = 64.2 ± 7.2 kg) from Divisions I and II of the Israeli Volleyball Association.   Frontal-plane knee movement and sagittal-plane hip and knee movement during jump landing were visually rated as good, moderate, or poor based on previously established criteria. Frontal-plane knee excursion and sagittal-plane hip and knee excursions were measured using free motion-analysis software and compared among athletes with different visual ratings of the corresponding movements.   Participants with different visual ratings of frontal-plane knee movement displayed differences in 2D frontal-plane knee excursion ( P < .01), whereas participants with different visual ratings of sagittal-plane hip and knee movement displayed differences in 2D sagittal-plane hip and knee excursions ( P < .01).   Visual ratings of frontal-plane knee movement and sagittal-plane hip and knee movement were associated with differences in the corresponding 2D hip and knee excursions. Visual rating of these movements may serve as an initial screening tool for detecting altered movement patterns during jump landings.

  2. Relationships Between Countermovement Jump Ground Reaction Forces and Jump Height, Reactive Strength Index, and Jump Time.

    Science.gov (United States)

    Barker, Leland A; Harry, John R; Mercer, John A

    2018-01-01

    Barker, LA, Harry, JR, and Mercer, JA. Relationships between countermovement jump ground reaction forces and jump height, reactive strength index, and jump time. J Strength Cond Res 32(1): 248-254, 2018-The purpose of this study was to determine the relationship between ground reaction force (GRF) variables to jump height, jump time, and the reactive strength index (RSI). Twenty-six, Division-I, male, soccer players performed 3 maximum effort countermovement jumps (CMJs) on a dual-force platform system that measured 3-dimensional kinetic data. The trial producing peak jump height was used for analysis. Vertical GRF (Fz) variables were divided into unloading, eccentric, amortization, and concentric phases and correlated with jump height, RSI (RSI = jump height/jump time), and jump time (from start to takeoff). Significant correlations were observed between jump height and RSI, concentric kinetic energy, peak power, concentric work, and concentric displacement. Significant correlations were observed between RSI and jump time, peak power, unload Fz, eccentric work, eccentric rate of force development (RFD), amortization Fz, amortization time, second Fz peak, average concentric Fz, and concentric displacement. Significant correlations were observed between jump time and unload Fz, eccentric work, eccentric RFD, amortization Fz, amortization time, average concentric Fz, and concentric work. In conclusion, jump height correlated with variables derived from the concentric phase only (work, power, and displacement), whereas Fz variables from the unloading, eccentric, amortization, and concentric phases correlated highly with RSI and jump time. These observations demonstrate the importance of countermovement Fz characteristics for time-sensitive CMJ performance measures. Researchers and practitioners should include RSI and jump time with jump height to improve their assessment of jump performance.

  3. Incidence, aetiology and prevention of musculoskeletal injuries in volleyball : A systematic review of the literature

    NARCIS (Netherlands)

    Kilic, O.; Maas, M.; Verhagen, E.; Zwerver, J.; Gouttebarge, V.

    2017-01-01

    Currently, there is no overview of the incidence and (volleyball-specific) risk factors of musculoskeletal injuries among volleyball players, nor any insight into the effect of preventive measures on the incidence of injuries in volleyball. This study aimed to review systematically the scientific

  4. Bridging the Gap in Volleyball. From Basic Instruction to Game Play.

    Science.gov (United States)

    Dawson, Linda; Polvino, Geri

    1982-01-01

    Using volleyball "mini games," which emphasize, one at a time, skills needed to play volleyball, helps students to develop skills needed to play. Mini games described are: (1) forearm pass; (2) overhand pass; (3) overhand pass; (4) overhand serve; (5) mini volleyball; and (6) alternate court set-up. (CJ)

  5. Incidence, aetiology and prevention of musculoskeletal injuries in volleyball: A systematic review of the literature

    NARCIS (Netherlands)

    Kilic, O.; Maas, M.; Verhagen, E.; Zwerver, J.; Gouttebarge, V.

    2017-01-01

    Currently, there is no overview of the incidence and (volleyball-specific) risk factors of musculoskeletal injuries among volleyball players, nor any insight into the effect of preventive measures on the incidence of injuries in volleyball. This study aimed to review systematically the scientific

  6. Why is countermovement jump height greater than squat jump height?

    NARCIS (Netherlands)

    Bobbert, Maarten F.; Gerritsen, Karin G M; Litjens, Maria C A; Van Soest, Arthur J.

    1996-01-01

    In the literature, it is well established that subjects are able to jump higher in a countermovement jump (CMJ) than in a squat jump (SJ). The purpose of this study was to estimate the relative contribution of the time available for force development and the storage and reutilization of elastic

  7. Jump into Action

    Science.gov (United States)

    Ball, Stephen; Cohen, Ann; Meyer, Margaret

    2012-01-01

    Jump Into Action (JIA) is a school-based team-taught program to help fifth-grade students make healthy food choices and be more active. The JIA team (physical education teacher, classroom teacher, school nurse, and parent) work together to provide a supportive environment as students set goals to improve food choices and increase activity.…

  8. Egg Bungee Jump!

    Science.gov (United States)

    Fitzgerald, Mike; Brand, Lance

    2004-01-01

    In this article, the authors present an egg bungee jumping activity. This activity introduces students to ways that engineers might apply calculations of failure to meet a challenge. Students are required to use common, everyday materials such as rubber bands, string, plastic bags, and eggs. They will apply technological problem solving, material…

  9. Prospective study of injury in volleyball players: 6 year results.

    Science.gov (United States)

    Pastor, M F; Ezechieli, M; Classen, L; Kieffer, O; Miltner, O

    2015-01-01

    The volleyball game has a high complexity and thus entails a lot of strain to the players. Due to this high and different training and competition strain comprehensive and individual training plans should be developed with competing training objectives in order to prevent injuries. The aim of the study was to analyse prospectively over six seasons the acute and overuse injuries of a German male professional volleyball team. The study included 34 male national league players from season the 2007/08 to 2012/13. All players received a sport medicine examination and a functional diagnosis before each season. Based on the results the players received an individual training plan. The players suffered 186 injuries. The prevalence of acute injuries was 1.94 per player and overuse injuries 0.64 per player. The incidence of acute injuries was 3.3/1000 h volleyball and overuse injuries 1.08/1000 h volleyball. The largest number of injuries was found in the spine. The players had most likely minor injuries. The players had significantly fewer injuries in their second season (1.92) than in their first season (3.25; p= 0.004). It could be concluded that volleyball is a sport with a relative low prevalence of injuries compared to other team sports. The prevalence of injury is 2.58 per player. Due to an injury a player dropped out 16.91 days per season. An individual training program seems to reduce the incidence of injury.

  10. The volleyball athlete's shoulder: biomechanical adaptations and injury associations.

    Science.gov (United States)

    Challoumas, Dimitrios; Stavrou, Antonio; Dimitrakakis, Georgios

    2017-06-01

    In volleyball, the dominant shoulder of the athlete undergoes biomechanical and morphological adaptations; however, definitive conclusions about their exact nature, aetiology, purpose and associations with shoulder injury have not been reached. We present a systematic review of the existing literature describing biomechanical adaptations in the dominant shoulders of volleyball players and factors that may predispose to shoulder pain/injury. A thorough literature search via Medline, EMBASE and SCOPUS was conducted for original studies of volleyball players and 15 eligible articles were identified. Assessment of study quality was performed using the STROBE statement. The reviewed literature supports the existence of a glenohumeral internal rotation deficit (GIRD) and a possible (and less pronounced) external rotation gain in the dominant vs. the non-dominant shoulder of volleyball athletes. Unlike other overhead sports, the GIRD in volleyball athletes appears to be anatomical as a response to the repetitive overhead movements and not to be associated with shoulder pain/injury. Additionally, the dominant shoulder exhibits muscular imbalance, which appears to be a significant risk factor for shoulder pain. Strengthening of the external rotators should be used alongside shoulder stretching and joint mobilisations, core strengthening and optimisation of spike technique as part of injury management and prevention programmes.

  11. Experiences of returning to elite beach volleyball after shoulder injury.

    Science.gov (United States)

    Bele, Sofie; Östenberg, Anna Hafsteinsson; Sjöström, Rita; Alricsson, Marie

    2015-08-01

    The purpose of this study was to examine beach volleyball players' experience regarding shoulder injury and how it affects their return to play. To achieve the research aims a qualitative design with semi-structured interviews had been conducted, five elite beach volleyball players, four men and one woman aged 27-42 participated in the study. All participants had suffered a severe shoulder injury, with absence from training and competing for at least 28 days. The findings of this study indicate that it is the individual's inner motivation, together with a clear goal and support from the community, family, teammate and coach that are the most important factors when going through rehabilitation and getting back to playing beach volleyball after a shoulder injury. All participants had been affected by their injury in some way; some of the participants had been affected in a positive way since they had become mentally stronger and had developed better volleyball technique after rehabilitation. The conclusions of this study indicate that there are three distinct factors that increase the chances of getting back to playing beach volleyball after shoulder injury; it is the players' self motivation, together with a clear goal and support from the community.

  12. SARS – virus jumps species

    Indian Academy of Sciences (India)

    SARS – virus jumps species. Coronavirus reshuffles genes; Rotteir et al, Rotterdam showed the virus to jump from cats to mouse cells after single gene mutation ? Human disease due to virus jumping from wild or domestic animals; Present favourite animal - the cat; - edible or domestic.

  13. Accuracy of Jump-Mat Systems for Measuring Jump Height.

    Science.gov (United States)

    Pueo, Basilio; Lipinska, Patrycja; Jiménez-Olmedo, José M; Zmijewski, Piotr; Hopkins, Will G

    2017-08-01

    Vertical-jump tests are commonly used to evaluate lower-limb power of athletes and nonathletes. Several types of equipment are available for this purpose. To compare the error of measurement of 2 jump-mat systems (Chronojump-Boscosystem and Globus Ergo Tester) with that of a motion-capture system as a criterion and to determine the modifying effect of foot length on jump height. Thirty-one young adult men alternated 4 countermovement jumps with 4 squat jumps. Mean jump height and standard deviations representing technical error of measurement arising from each device and variability arising from the subjects themselves were estimated with a novel mixed model and evaluated via standardization and magnitude-based inference. The jump-mat systems produced nearly identical measures of jump height (differences in means and in technical errors of measurement ≤1 mm). Countermovement and squat-jump height were both 13.6 cm higher with motion capture (90% confidence limits ±0.3 cm), but this very large difference was reduced to small unclear differences when adjusted to a foot length of zero. Variability in countermovement and squat-jump height arising from the subjects was small (1.1 and 1.5 cm, respectively, 90% confidence limits ±0.3 cm); technical error of motion capture was similar in magnitude (1.7 and 1.6 cm, ±0.3 and ±0.4 cm), and that of the jump mats was similar or smaller (1.2 and 0.3 cm, ±0.5 and ±0.9 cm). The jump-mat systems provide trustworthy measurements for monitoring changes in jump height. Foot length can explain the substantially higher jump height observed with motion capture.

  14. Relationship of long-term macronutrients intake on anabolic-catabolic hormones in female elite volleyball players.

    Science.gov (United States)

    Mielgo Ayuso, Juan; Zourdos, Michael C; Urdampilleta, Aritz; Calleja González, Julio; Seco, Jesús; Córdova, Alfredo

    2017-10-24

    Specific macronutrient distribution and training can alter acute and chronic hormone behavior and, subsequently, sport performance. The main aim was to examine relationships between dietary intake and anabolic/catabolic hormone response in elite female volleyball players during a 29-week season. Twenty-two elite female volleyballers (26.4 ± 5.6 years; 178 ± 9 cm; 67.1 ± 7.5 kg) had dietary intake (seven-day dietary recall and food frequency questionnaire), blood concentration of anabolic/catabolic hormones concentration, physical performance, and body composition assessed at four time points: a) T1: baseline/pre-testing; b) T2: eleven weeks after T1; c) T3: ten weeks after T2; and d) T4: eight weeks after T3. Hormones evaluated were: total testosterone (TT), free testosterone (FT) adrenocorticotropic hormone (ACTH), and cortisol (C), along with hormone ratios. Positive correlations were observed between carbohydrate/protein ratio with ΔFT (r = 0.955; p 0.05) in body mass or body mass index at any time point, and the sum of six skinfolds improved (p < 0.05) from T1 (86.5 ± 6.9 mm) to T4 (75.2 ± 5.6 mm) as did muscle mass (T1: 28.9 ± 0.7 kg vsT4: 30.1 ± 0.8 kg). Vertical jump, spike-jump and speed improved (p < 0.05) from T1 to T4. A high carbohydrate/protein ratio was associated with positive changes in anabolism, while high protein and low carbohydrates (CHO) were associated with an attenuated anabolic response.

  15. The acute effects of manipulating volume and load of back squats on countermovement vertical jump performance.

    Science.gov (United States)

    Moir, Gavin L; Mergy, David; Witmer, Ca; Davis, Shala E

    2011-06-01

    The acute effects of manipulating the volume and load of back squats on subsequent countermovement vertical jump performance were investigated in the present study. Eleven National Collegiate Athletic Association division II female volleyball players performed 10 countermovement vertical jumps (CMJs) on a force platform 2 minutes after the last squat repetition of a high-load (HL) or high-volume (HV) squat protocol. Two minutes of rest was provided between each CMJ. The HL protocol culminated in the subjects having to perform 3 repetitions with a load equivalent to 90% 1 repetition maximum (1RM) back squat, whereas 12 repetitions with a load equivalent to 37% 1RM were performed in the HV protocol. During an initial familiarization session, knee angles were recorded during a series of CMJs, and these angles were used to control the depth of descent during all subsequent back squats. Jump height (JH) and vertical stiffness (VStiff) were calculated during each of the 10 CMJ, and the change in these variables after the 2 squat protocols was assessed using an analysis of variance model with repeated measures on 2 factors (Protocol [2-levels]; Time [2-levels]). There was no significant difference in JH after the HL and HV protocols (p > 0.05). A significant Protocol × Time interaction for VStiff resulted from the increase after the HL protocol being greater than that after the HV protocol (p = 0.03). The knee angles before the HL and HV protocols were significantly greater than those measured during the initial familiarization session (p = 0.001). Although neither squat protocol provided any benefit in improving JH, the heavy squat protocol produced greater increases in VStiff during the CMJ. Because of the increased VStiff caused by the HL protocol, volleyball coaches may consider using such protocols with their players to improve performance in jumps performed from a run such as the spike and on-court agility.

  16. Discriminant effect of morphology and range of attack on the performance level of volleyball players. DOI: 10.5007/1980-0037.2011v13n3p223

    Directory of Open Access Journals (Sweden)

    Victor Machado Reis

    2011-04-01

    Full Text Available The aim of this study was to identify the discriminant effect of morphology and range of attack-related variables on the performance level of under-17 female volleyball players. The sample consisted of young volleyball players (n=40 divided into two groups: players of the Brazilian national team (n=21 aged 15.86 ± 0.36 years, body weight of 68.11 ± 8.73 kg, and height of 181.61 ± 6.11 cm, and players of the state team of Rio Grande do Norte (n=19 aged 15.16 ± 0.88 years, body weight of 60.54 ± 7.60 kg, and height of 170.52 ± 7.97 cm. The somatotype was assessed using the Heath & Carter method. A modified Sargent test was used to assess vertical jump height and maximum attack height. The measures were compared between the two groups using the Student t-test for independent samples. Discriminant function analysis was applied to predict group allocation using the measures obtained as independent variables. The two groups differed significantly in terms of body weight, fat mass, height, maximum attack height, range of attack, and somatotype. Discriminant function analysis identified the somato-type measures (endomorphy, ectomorphy, and mesomorphy with correlation coefficients below 0.30. The canonical correlation coefficient obtained with this function was 0.856. In conclusion, somatotype or vertical jump ability does not seem to distinguish elite athletes from non-elite athletes in under-17 female volleyball players, and height is the main morphological determinant to achieve elite level performance.

  17. A Profile of Fitness Parameters and Performance of Volleyball Players

    Directory of Open Access Journals (Sweden)

    Govind B. Taware

    2013-07-01

    Full Text Available Background: Ball games require comprehen-sive ability including physical, technical, men-tal and tactical abilities. Among them, physicalabilities of players exert marked effects on theskill of the players themselves and the tacticsof the team. Therefore players must have thephysical abilities to meet the demand of thesport. Volleyball is one of the most popularlyplayed games in the world. Unfortunately, thelevel of performance of the Indian volleyballplayers lags far behind the international stan-dards. Aim of the Study: The present study wasaimed to assess flexibility, muscular endurance,power and cardio-respiratory endurance of vol-leyball players and to compare the results withage matched controls. Also, to compare thefindings of the volleyball players with that ofthe international norms from the available lit-erature and to make some suggestions for theimprovement in their performance level. Ma-terial and Methods: The study was carried outin 40 male volleyball players aged between 17to 26 years and 40 ages matched male controls.Physical fitness parameters namely flexibility,muscular endurance, power and cardio-respi-ratory endurance were measured, data was ana-lyzed using unpaired ‘t’-test. Results: It was ob-served that all physical fitness parameters weresignificantly more in players as compared totheir aged-matched controls but when values ofthe subjects were compared to internationalstandards; our subjects were behind the recom-mended norms for the elite volleyball players.Conclusion: The volleyball players have moreadvantage of flexibility muscular endurance,power and cardio-respiratory endurance.

  18. Upgrading model for the Volleyball teachers

    Directory of Open Access Journals (Sweden)

    Tania Rosa García Hernández

    2017-07-01

    Full Text Available The nowadays society in this XXI century influenced by the progressive development of technologies of information and communication and the knowledge management demands a creative man, transformer of the context in which he takes place, an individual who accepts the challenges of the modern society and that at the same time takes the best of this development. Meeting this goal, the higher education holds the mission of preparing in a continuous and permanent way to the professionals according to the activity they carry out, updating the knowledge in the science they work on. The sport professionals are not the exception in this endeavor due to the formative role they play in the society, it is also caused by the dynamics and the current competitions, the steady changes of the sport rules and the gradual improvement of the athlete’s performance, the venues equipment and the competition itself worldwide. This work is aimed at proposing an upgrading course for the Volleyball professionals in the sport formation school (EIDE Ormani Arenado Llonchimplemented through a strategy based on the difficulties taken from the application of the scientific methods which facilitate a viable, flexible and feasible outcome and with a high social meaning, as it contributes to rise the professional profile of the individuals involved in the study.

  19. Optimal Ski Jump

    Science.gov (United States)

    Rebilas, Krzysztof

    2013-02-01

    Consider a skier who goes down a takeoff ramp, attains a speed V, and jumps, attempting to land as far as possible down the hill below (Fig. 1). At the moment of takeoff the angle between the skier's velocity and the horizontal is α. What is the optimal angle α that makes the jump the longest possible for the fixed magnitude of the velocity V? Of course, in practice, this is a very sophisticated problem; the skier's range depends on a variety of complex factors in addition to V and α. However, if we ignore these and assume the jumper is in free fall between the takeoff ramp and the landing point below, the problem becomes an exercise in kinematics that is suitable for introductory-level students. The solution is presented here.

  20. Jumping hoops on water

    Science.gov (United States)

    Yang, Eunjin; Kim, Ho-Young

    2015-11-01

    Small aquatic arthropods, such as water striders and fishing spiders, are able to jump off water to a height several times their body length. Inspired by the unique biological motility on water, we study a simple model using a flexible hoop to provide fundamental understanding and a mimicking principle of small jumpers on water. Behavior of a hoop on water, which is coated with superhydrophobic particles and initially bent into an ellipse from an equilibrium circular shape, is visualized with a high speed camera upon launching it into air by releasing its initial elastic strain energy. We observe that jumping of our hoops is dominated by the dynamic pressure of water rather than surface tension, and thus it corresponds to the dynamic condition experienced by fishing spiders. We calculate the reaction forces provided by water adopting the unsteady Bernoulli equation as well as the momentum loss into liquid inertia and viscous friction. Our analysis allows us to predict the jumping efficiency of the hoop on water in comparison to that on ground, and to discuss the evolutionary pressure rendering fishing spiders select such dynamic behavior.

  1. Undular Hydraulic Jump

    Directory of Open Access Journals (Sweden)

    Oscar Castro-Orgaz

    2015-04-01

    Full Text Available The transition from subcritical to supercritical flow when the inflow Froude number Fo is close to unity appears in the form of steady state waves called undular hydraulic jump. The characterization of the undular hydraulic jump is complex due to the existence of a non-hydrostatic pressure distribution that invalidates the gradually-varied flow theory, and supercritical shock waves. The objective of this work is to present a mathematical model for the undular hydraulic jump obtained from an approximate integration of the Reynolds equations for turbulent flow assuming that the Reynolds number R is high. Simple analytical solutions are presented to reveal the physics of the theory, and a numerical model is used to integrate the complete equations. The limit of application of the theory is discussed using a wave breaking condition for the inception of a surface roller. The validity of the mathematical predictions is critically assessed using physical data, thereby revealing aspects on which more research is needed

  2. Ankle Bracing, Fatigue, and Time to Stabilization in Collegiate Volleyball Athletes

    Science.gov (United States)

    Shaw, Megan Y; Gribble, Phillip A; Frye, Jamie L

    2008-01-01

    Context: Fatigue has been shown to disrupt dynamic stability in healthy volunteers. It is not known if wearing prophylactic ankle supports can improve dynamic stability in fatigued athletes. Objective: To determine the type of ankle brace that may be more effective at providing dynamic stability after a jump-landing task during normal and fatigued conditions. Design: Two separate repeated-measures analyses of variance with 2 within-subjects factors (condition and time) were performed for each dependent variable. Setting: Research laboratory. Patients or Other Participants: Ten healthy female collegiate volleyball athletes participated (age  =  19.5 ± 1.27 years, height  =  179.07 ± 7.6 cm, mass  =  69.86 ± 5.42 kg). Intervention(s): Athletes participated in 3 separate testing sessions, applying a different bracing condition at each session: no brace (NB), Swede-O Universal lace-up ankle brace (AB), and Active Ankle brace (AA). Three trials of a jump-landing task were performed under each condition before and after induced functional fatigue. The jump-landing task consisted of a single-leg landing onto a force plate from a height equivalent to 50% of each participant's maximal jump height and from a starting position 70 cm from the center of the force plate. Main Outcome Measure(s): Time to stabilization in the anterior-posterior (APTTS) and medial-lateral (MLTTS) directions. Results: For APTTS, a condition-by-time interaction existed (F2,18  =  5.55, P  =  .013). For the AA condition, Tukey post hoc testing revealed faster pretest (2.734 ± 0.331 seconds) APTTS than posttest (3.817 ± 0.263 seconds). Post hoc testing also revealed that the AB condition provided faster APTTS (2.492 ± 0.271 seconds) than AA (3.817 ± 0.263 seconds) and NB (3.341 ± 0.339 seconds) conditions during posttesting. No statistically significant findings were associated with MLTTS. Conclusions: Fatigue increased APTTS for the AA condition. Because the

  3. Training-induced changes in physical performance can be achieved without body mass reduction after eight week of strength and injury prevention oriented programme in volleyball female players

    Directory of Open Access Journals (Sweden)

    M Lehnert

    2017-04-01

    Full Text Available The purpose of the study was to analyse the changes in muscle strength, power, and somatic parameters in elite volleyball players after a specific pre-season training programme aimed at improving jumping and strength performance and injury prevention. Twelve junior female volleyball players participated in an 8-week training programme. Anthropometric characteristics, isokinetic peak torque (PT single-joint knee flexion (H and extension (Q at 60º/s and 180º/s, counter movement jump (CMJ, squat jump (SJ, and reactive strength index (RSI were measured before and after intervention. Significant moderate effects were found in flexor concentric PT at 60º/s and at 180 º/s in the dominant leg (DL (18.3±15.1%, likely; 17.8±11.2%, very likely and in extensor concentric PT at 180º/s (7.4%±7.8%, very likely in the DL. In the non-dominant leg (NL significant moderate effects were found in flexor concentric PT at 60º/s and at 180º/s (13.7±11.3%, likely; 13.4±8.0%, very likely and in extensor concentric PT at 180º/s (10.7±11.5%, very likely. Small to moderate changes were observed for H/QCONV in the DL at 60º/s and 180º/s (15.9±14.1%; 9.6±10.4%, both likely and in the NL at 60º/s (moderate change, 9.6±11.8%, likely, and small to moderate decreases were detected for H/QFUNC at 180º/s, in both the DL and NL (-7.0±8.3%, likely; -9.5±10.0%, likely. Training-induced changes in jumping performance were trivial (for RSI to small (for CMJ and SJ. The applied pre-season training programme induced a number of positive changes in physical performance and risk of injury, despite a lack of changes in body mass and composition. CITATION: Lehnert M, Sigmund M, Lipinska P et al. Training-induced changes in physical performance can be achieved without body mass reduction after eight week of strength and injury prevention oriented programme in volleyball female players. Biol Sport. 2017;34(2:205-213.

  4. Considerations on the constitutional type of the central hitter in volleyball

    Directory of Open Access Journals (Sweden)

    Sorin GRĂDINARU

    2017-03-01

    Full Text Available The last major volleyball men competition was within the London 2012 Summer Olympics, which gathered 12 volleyball teams thoroughly selected during trial tournaments. On this occasion, they recorded the evolution of all participants and supplied volleyball methodologists and technicians with data on the various aspects of volleyball game (physical, technical, and tactical. We aimed at establishing the defining elements of a central hitter parameter dynamics in this competition. The subjects of our research were central hitters of all the participating volleyball teams. We also identified central hitters of the “Universitatea” Timişoara men volleyball team. The mean central hitter is, according to the data collected by the specialists of the London 2012 Summer Olympics, 27.93 years old and 203.8 cm tall, and weighs 94 kg. The central hitters of the volleyball team of Russia had particular values in all studied parameters: this position is relevant for the potential of the team and for the high level of the game. The mean values of the studied parameters are relevant in establishing the final hierarchy (Russia, Brazil, and Italy. We found obvious differences between the mean values of these parameters in the men volleyball players participating in the London 2012 Summer Olympics and the men volleyball players of the “Universitatea” Timişoara volleyball team.

  5. Foot Posture and Patellar Tendon Pain Among Adult Volleyball Players

    NARCIS (Netherlands)

    de Groot, Reinier; Malliaras, Peter; Munteanu, Shannon; Payne, Craig; Morrissey, Dylan; Maffulli, Nicola

    Objective: We hypothesized that individuals with a normal foot posture would be less likely to experience patellar tendon pain and pathology than those with a pronated or supinated foot. Design: Observational study. Setting: Field-based study among competing athletes. Participants: Volleyball

  6. TRAUMATISM IN TRAINING PROCESS OF STUDENTS - VOLLEYBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    V.Ya. Kovalchuk

    2017-01-01

    Full Text Available Purpose: to analyze traumas in training process of students-volleyball players. Material: 42 students participated in the research. Students’ medical records were analyzed in the research. Results: with every year of study in university the quantity of traumas decreased. In 1st year students we found 10 traumas, in 4th year - 5. Ligament sprains are the most frequent kinds of traumas. In total we found 33.3%. Their main part covers ankle joint traumas. The reasons of them are bursts, stops, changes of movements’ direction. Rather frequents (30% are maims of knee and elbow joints, caused by falling down. The degree of joints’ injury is, as usually, negligible. The highest quantity of moderate and heavy traumas was among 1st year students (9 from 10 and 2nd year students (8 from 8. Conclusions: prophylaxis complex for prevention of volleyball traumas has been offered. Volleyball traumas’ prevention implies improvement methodic and technique of students-volleyball players’ training. The main reasons of traumatism are the following: non observation of sports training principles; poor organizational and logistical support of training process.

  7. Teaching Strategies for the Forearm Pass in Volleyball

    Science.gov (United States)

    Casebolt, Kevin; Zhang, Peng; Brett, Christine

    2014-01-01

    This article shares teaching strategies for the forearm pass in the game of volleyball and identifies how they will help students improve their performance and development of forearm passing skills. The article also provides an assessment rubric to facilitate student understanding of the skill.

  8. Tales of the Unexpected: Coping among Female Collegiate Volleyball Players

    Science.gov (United States)

    Holt, Nicholas L.; Berg, Kylie-Joy; Tamminen, Katherine A.

    2007-01-01

    The purpose of this study was to examine patterns of appraisal, coping, and coping effectiveness in sport. Ten players from a collegiate female volleyball team were interviewed on two occasions, first in the week before a provincial final playoff tournament and in the week following the tournament. Data were transcribed verbatim and subjected to…

  9. Effectiveness of the Call in Beach Volleyball Attacking Play

    Directory of Open Access Journals (Sweden)

    Künzell Stefan

    2014-12-01

    Full Text Available In beach volleyball the setter has the opportunity to give her or his hitter a “call”. The call intends that the setter suggests to her or his partner where to place the attack in the opponent’s court. The effectiveness of a call is still unknown. We investigated the women’s and men’s Swiss National Beach Volleyball Championships in 2011 and analyzed 2185 attacks. We found large differences between female and male players. While men called in only 38.4% of attacks, women used calls in 85.5% of attacks. If the male players followed a given call, 63% of the attacks were successful. The success rate of attacks without any call was 55.8% and 47.6% when the call was ignored. These differences were not significant (χ2(2 = 4.55, p = 0.103. In women’s beach volleyball, the rate of successful attacks was 61.5% when a call was followed, 35% for attacks without a call, and 42.6% when a call was ignored. The differences were highly significant (χ2(2 = 23.42, p < 0.0005. Taking into account the findings of the present study, we suggested that the call was effective in women’s beach volleyball, while its effect in men’s game was unclear. Considering the quality of calls we indicate that there is a significant potential to increase the effectiveness of a call.

  10. Foot posture and patellar tendon pain among adult volleyball players.

    NARCIS (Netherlands)

    Groot, R. de; Malliaras, P.; Munteanu, S.; Payne, C.; Morrissey, D.; Maffulli, N.

    2012-01-01

    OBJECTIVE: We hypothesized that individuals with a normal foot posture would be less likely to experience patellar tendon pain and pathology than those with a pronated or supinated foot. DESIGN: Observational study. SETTING: Field-based study among competing athletes. PARTICIPANTS: Volleyball

  11. Predicting stay/leave behavior among volleyball referees

    NARCIS (Netherlands)

    Van Yperen, N.W.

    1998-01-01

    This study aimed to predict stay/leave behavior among volleyball referees. The predictor variables reflect commitment aspects from the literature: attraction, perceived lack of alternatives, personal investments, and feelings of obligation to remain. Intent to quit was assumed to mediate the link

  12. Effect of squat depth on performance and biomechanical parameters of countermovement vertical jump

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    Rodrigo Ghedini Gheller

    2014-10-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2014v16n6p658   The aim of this study was to analyze the effect of different squat depths in the performance and biomechanical parameters at counter movement jump (CMJ. Twenty-two male volleyball or basketball players volunteered to participate in this study and all were currently competing at the college level. The CMJ was performed in three different conditions: 1 with relative knee flexion at the end of counter movement phase smaller than 90° (90°, and; 3 preferred position (PREF. During the CMJ, kinematic, kinetic, and electromyography parameters were assessed. ANOVA for repeated measures with post-hoc Bonferroni´s test was used for variables comparison, with a significance level set at p≤0.05. The higher performance was on PREF and 90°. Average and peak power, as well as absolute and normalized peak forces, were higher in >90° CMJ. The peak velocity of CG and angular velocities of hip and knee were higher in the 90°. Recuts femoris and biceps femoris did not show difference in any jump phases. In conclusion, the knee flexion interferes the performance and the biomechanical variables at the CMJ. The highest jumps were got at a deeper squat, so this technique could be used for athletes in order to optimize the vertical jump performance in the training and competitions.

  13. BPS Jumping Loci are Automorphic

    Science.gov (United States)

    Kachru, Shamit; Tripathy, Arnav

    2018-06-01

    We show that BPS jumping loci-loci in the moduli space of string compactifications where the number of BPS states jumps in an upper semi-continuous manner—naturally appear as Fourier coefficients of (vector space-valued) automorphic forms. For the case of T 2 compactification, the jumping loci are governed by a modular form studied by Hirzebruch and Zagier, while the jumping loci in K3 compactification appear in a story developed by Oda and Kudla-Millson in arithmetic geometry. We also comment on some curious related automorphy in the physics of black hole attractors and flux vacua.

  14. Volleyball and Basketball Enhanced Bone Mass in Prepubescent Boys.

    Science.gov (United States)

    Zouch, Mohamed; Chaari, Hamada; Zribi, Anis; Bouajina, Elyès; Vico, Laurence; Alexandre, Christian; Zaouali, Monia; Ben Nasr, Hela; Masmoudi, Liwa; Tabka, Zouhair

    2016-01-01

    The aim of this study was to examine the effect of volleyball and basketball practice on bone acquisition and to determine which of these 2 high-impact sports is more osteogenic in prepubertal period. We investigated 170 boys (aged 10-12 yr, Tanner stage I): 50 volleyball players (VB), 50 basketball players (BB), and 70 controls. Bone mineral content (BMC, g) and bone area (BA, cm(2)) were measured by dual-energy X-ray absorptiometry at different sites. We found that, both VB and BB have a higher BMC at whole body and most weight-bearing and nonweight-bearing sites than controls, except the BMC in head which was lower in VB and BB than controls. Moreover, only VB exhibited greater BMC in right and left ultra-distal radius than controls. No significant differences were observed between the 3 groups in lumbar spine, femoral neck, and left third D radius BMC. Athletes also exhibited a higher BA in whole body, limbs, lumbar spine, and femoral region than controls. In addition, they have a similar BA in head and left third D radius with controls. The VB exhibited a greater BA in most radius region than controls and a greater femoral neck BA than BB. A significant positive correlation was reported between total lean mass and both BMC and BA in whole body, lumbar spine, total hip, and right whole radius among VB and BB. In summary, we suggest that volleyball and basketball have an osteogenic effect BMC and BA in loaded sites in prepubescent boys. The increased bone mass induced by both volleyball and basketball training in the stressed sites was associated to a decreased skull BMC. Moreover, volleyball practice produces a more sensitive mechanical stress in loaded bones than basketball. This effect seems translated by femoral neck expansion. Copyright © 2016 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  15. Defence tactic in volleyball: the analysis of the results of the pedagogic supervising. The competitive activity of the volleyball players

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    A A Lobanov

    2009-06-01

    Full Text Available The article analyses the technical and tactical actions that are used by volleyball players of high qualification during the competition. Taking into account this information in the studying and training process contributes to the increase of its effectiveness.

  16. Landing-related ankle injuries do not occur in plantarflexion as once thought: a systematic video analysis of ankle injuries in world-class volleyball.

    Science.gov (United States)

    Skazalski, Christopher; Kruczynski, Jacek; Bahr, Martin Aase; Bere, Tone; Whiteley, Rod; Bahr, Roald

    2018-01-01

    Ankle injuries are prevalent in elite volleyball and suggested to result from player contact at the net. Traditionally, ankle sprains are thought to happen in a plantarflexed position, but case studies suggest plantarflexion may not be involved. Describe the injury situations and mechanisms of ankle injuries in world-class volleyball based on systematic video analysis of injuries reported through the Fédération Internationale de Volleyball (FIVB) Injury Surveillance System. Videos of 24 injuries from major FIVB tournaments were included for analysis (14 men, 10 women). Five analysts reviewed the videos to determine specific situations and mechanisms leading to injuries. The majority of injuries occurred during two volleyball situations, blocking (n=15) and attacking (n=6). Injuries to blockers were the result of landing on an opponent (n=11) or teammate (n=4). Attacking injuries most frequently occurred when a back-row player landed on a front-row teammate (n=4 of 6). When landing on an opponent under the net, the attacker landed into the opponent's court in 11 of 12 situations but without violating the centre line rule. Injuries mostly resulted from rapid inversion without any substantial plantarflexion. The majority of injuries occur while blocking, often landing on an opponent. The attacker is overwhelmingly to blame for injuries at the net secondary to crossing the centre line. Injuries while attacking often result from a back-row player landing on a front-row teammate. Landing-related injuries mostly result from rapid inversion with the absence of plantarflexion. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  17. Pediatric volleyball-related injuries treated in US emergency departments, 1990-2009.

    Science.gov (United States)

    Pollard, Katherine A; Shields, Brenda J; Smith, Gary A

    2011-09-01

    This study describes the epidemiology of pediatric volleyball-related injuries treated in US hospital emergency departments. Data for children younger than 18 years obtained from the National Electronic Injury Surveillance System of the US Consumer Product Safety Commission from 1990 through 2009 were analyzed. An estimated 692 024 volleyball-related injuries to children younger than 18 years occurred during the study period. The annual number of injuries declined significantly by 23% during the study period; however, the annual injury rate remained unchanged, and the number of volleyball-related concussions/closed head injuries increased significantly. Upper (48%) and lower (39%) extremity injuries occurred most frequently, as did strains/sprains (54%). Contact with the net/pole was associated with concussions/closed head injury our findings indicate opportunities for making volleyball an even safer sport for children. Protective padding, complying with US volleyball standards, should cover all volleyball poles and protruding hardware to prevent impact-related injuries.

  18. Exploring Lightning Jump Characteristics

    Science.gov (United States)

    Chronis, Themis; Carey, Larry D.; Schultz, Christopher J.; Schultz, Elise; Calhoun, Kristin; Goodman, Steven J.

    2014-01-01

    This study is concerned with the characteristics of storms exhibiting an abrupt temporal increase in the total lightning flash rate (i.e., lightning jump, LJ). An automated storm tracking method is used to identify storm "clusters" and total lightning activity from three different lightning detection systems over Oklahoma, northern Alabama and Washington, D.C. On average and for different employed thresholds, the clusters that encompass at least one LJ (LJ1) last longer, relate to higher Maximum Expected Size of Hail, Vertical Integrated Liquid and lightning flash rates (area-normalized) than the clusters that did not exhibit any LJ (LJ0). The respective mean values for LJ1 (LJ0) clusters are 80 min (35 min), 14 mm (8 mm), 25 kg per square meter (18 kg per square meter) and 0.05 flash per min per square kilometer (0.01 flash per min per square kilometer). Furthermore, the LJ1 clusters are also characterized by slower decaying autocorrelation functions, a result that implies a less "random" behavior in the temporal flash rate evolution. In addition, the temporal occurrence of the last LJ provides an estimate of the time remaining to the storm's dissipation. Depending of the LJ strength (i.e., varying thresholds), these values typically range between 20-60 min, with stronger jumps indicating more time until storm decay. This study's results support the hypothesis that the LJ is a proxy for the storm's kinematic and microphysical state rather than a coincidental value.

  19. THE DIFFERENCE BETWEEN TWO VOLLEYBALL TEAMS IN SOME ANTHROPOMETERIC AND MOTOR ABILITIS

    OpenAIRE

    Bahri Gjinovci; Valon Nikqi; Florian Miftari

    2014-01-01

    Introduction: In this research we are deal with two teams of the super league of Kosovo in volleyball. The goal of this study is to verify the differences between the two teams in volleyball in some anthropometric characteristics, basic motor skills and situational tests. Methods: For the realization of this research, there were included 12 volleyball player from the team KV “Prishtina" and 12 from the team KV "Universiteti AAB". There are applied 4 anthropometric variables (body weight, body...

  20. Jump conditions in transonic equilibria

    International Nuclear Information System (INIS)

    Guazzotto, L.; Betti, R.; Jardin, S. C.

    2013-01-01

    In the present paper, the numerical calculation of transonic equilibria, first introduced with the FLOW code in Guazzotto et al.[Phys. Plasmas 11, 604 (2004)], is critically reviewed. In particular, the necessity and effect of imposing explicit jump conditions at the transonic discontinuity are investigated. It is found that “standard” (low-β, large aspect ratio) transonic equilibria satisfy the correct jump condition with very good approximation even if the jump condition is not explicitly imposed. On the other hand, it is also found that high-β, low aspect ratio equilibria require the correct jump condition to be explicitly imposed. Various numerical approaches are described to modify FLOW to include the jump condition. It is proved that the new methods converge to the correct solution even in extreme cases of very large β, while they agree with the results obtained with the old implementation of FLOW in lower-β equilibria.

  1. Mechanics of jumping on water

    Science.gov (United States)

    Kim, Ho-Young; Amauger, Juliette; Jeong, Han-Bi; Lee, Duck-Gyu; Yang, Eunjin; Jablonski, Piotr G.

    2017-10-01

    Some species of semiaquatic arthropods including water striders and springtails can jump from the water surface to avoid sudden dangers like predator attacks. It was reported recently that the jump of medium-sized water striders is a result of surface-tension-dominated interaction of thin cylindrical legs and water, with the leg movement speed nearly optimized to achieve the maximum takeoff velocity. Here we describe the mathematical theories to analyze this exquisite feat of nature by combining the review of existing models for floating and jumping and the introduction of the hitherto neglected capillary forces at the cylinder tips. The theoretically predicted dependence of body height on time is shown to match the observations of the jumps of the water striders and springtails regardless of the length of locomotory appendages. The theoretical framework can be used to understand the design principle of small jumping animals living on water and to develop biomimetic locomotion technology in semiaquatic environments.

  2. Kinanthropometric profile of Cuban women Olympic volleyball champions.

    Science.gov (United States)

    Carvajal, Wiliam; Betancourt, Hamlet; León, Sofia; Deturnel, Yanel; Martínez, Miriam; Echevarría, Ivis; Castillo, María Eugenia; Serviat, Noemí

    2012-04-01

    Athletes' kinanthropometric profiles are widely addressed in the scientific literature. Such profiles are particularly important in volleyball because absolute size contributes a significant percentage of total variance associated with athletic success. As in other team sports, volleyball players' kinanthropometric attributes correlate with the game's tactical demands. From 1992 through 2000, the Cuban women's volleyball team achieved top global performance, winning first place in three successive Summer Olympic Games. Describe the kinanthropometric profiles of Cuban women Olympic volleyball champions during 1992-2000 and compare these by position played. Measurements were taken of body composition, somatotype, proportionality and several anthropometric indicators in 41 Cuban women volleyball players, grouped by playing position. All were members of the national team that participated in the Summer Olympic Games in Barcelona (1992), Atlanta (1996) and Sydney (2000). Mean and standard deviations were calculated for all study variables. Analysis of variance was used to compare means for different positions for the variables weight; height; percent adipose, muscle and bone mass; body mass index; and muscle-to-bone ratio. Discriminant analysis was performed to identify anthropometric dimensions differentiating playing positions (center, spiker and setter), using pvolleyball players was balanced mesomorphic (2.7-3.6-2.9). Classified by position, centers (2.9-3.4-3.4) and spikers (2.8-3.6-2.9) presented an average mesomorphic-ectomorphic somatotype, and setters (2.6-3.7-2.6) were balanced mesomorphic. On assessing Somatotype Attitudinal Mean (SAM), centers and spikers showed more intrapositional homogeneity than that of setters. Centers were significantly taller (187.1±2.5 cm) than players in other positions. Centers' percent adipose tissue mass (28.9±2.7%) was significantly higher than that of setters (24.3±2.7%), who were leanest of all positions. The

  3. Thersites: a `jumping' Trojan?

    Science.gov (United States)

    Tsiganis, K.; Dvorak, R.; Pilat-Lohinger, E.

    2000-02-01

    In this paper, we examine the dynamical evolution of the asteroid (1868) Thersites, a member of the Trojan belt. Thersites is librating around the Lagrangian point L_4, following, however, a chaotic orbit. The equations of motion for Thersites as well as for a distribution of neighboring initial conditions are integrated numerically for 50 million years in the Outer Solar System model (OSS), which consists of the Sun and the four giant planets. Our results indicate that the probability that this asteroid will eventually escape from the Trojan swarm is rather high. In fact, 20% from our initial distribution escaped within the integration time. Many of the remaining ones also show characteristic `jumps' in the orbital elements, especially the inclination. Secular resonances involving the nodes of the outer planets are found to be responsible for this chaotic behavior. The width of libration and eccentricity values that lead to grossly unstable orbits are calculated and compared with previously known results on the stability of the Trojans. Finally, a very interesting behavior has been observed for one of the escaping asteroids as he `jumped' from L_4 to L_5 where he remained performing a highly inclined libration for ~ 2 Myrs before escaping from the Trojan swarm. According to Homer, Thersites was not only the ugliest of all Greeks that took part in the Trojan war, but also had the most intolerable personality. His nasty habit of making fun of everybody cost him his life, as the last person for whom he spoke ironically about was Achilles, the mightiest warrior of all Greeks, who killed Thersites with just one punch!

  4. Transition I efficiency and victory in volleyball matches

    Directory of Open Access Journals (Sweden)

    Herbert Ugrinowitsch

    2014-03-01

    Full Text Available The present study investigated the correlation between Transition Iwith victory in volleyball matches. The 2002 South-American Youth Men's Championship was recorded and the Transition I was analyzed and classified as negative, null or positive. Results of the efficiency in Transition I was calculated using t test for independent samples and compared to the efficiency between teams during each set and matches. Spearman correlation assessed the relationship between efficiency in each set and results of the matches with the final ranking in the championship. The results showed that the winning teams exhibited higher efficiency in Transition I, as well as a positive relationship of higher efficiency in Transition I with all of their results. The higher efficiency in Transition I is related to victory in volleyball matches.

  5. Predicting Factors of Zone 4 Attack in Volleyball.

    Science.gov (United States)

    Costa, Gustavo C; Castro, Henrique O; Evangelista, Breno F; Malheiros, Laura M; Greco, Pablo J; Ugrinowitsch, Herbert

    2017-06-01

    This study examined 142 volleyball games of the Men's Super League 2014/2015 seasons in Brazil from which we analyzed 24-26 games of each participating team, identifying 5,267 Zone 4 attacks for further analysis. Within these Zone 4 attacks, we analyzed the association between the effect of the attack carried out and the separate effects of serve reception, tempo and type of attack. We found that the reception, tempo of attack, second tempo of attack, and power of diagonal attack were predictors of the attack effect in Zone 4. Moreover, placed attacks showed a tendency to not yield a score. In conclusion, winning points in high-level men's volleyball requires excellent receptions, a fast attack tempo and powerfully executed of attacks.

  6. Volleyball and emotional health of students of pedagogical university

    Directory of Open Access Journals (Sweden)

    Y.Y. Muskharina

    2013-07-01

    Full Text Available The features of valueological pedagogical influence of volleyball lessons on the emotional state of pedagogical university students. In the experiment involved 96 students aged 18-20 years. It was found that 72% of students feel the satisfaction of most emotional needs during the game, 86.4% indicate a bright splash of feelings and a sense of mutual aid during the game, 24% of students met the best friends among the players section. 89.3% of students say that skill, sense of humor, energy, example and support of teacher (trainer during exercise can affect the emotional state of the team and each student. Professional and personal qualities of the coach, to encourage students to employment volleyball positive impact on the physical, mental performance, improve attention, ability to work in a team, to overcome emotional stress, feelings of fatigue, improves emotional state of students.

  7. Assessment of mental training in improving performance serve in volleyball

    Directory of Open Access Journals (Sweden)

    José Maria Montiel

    2013-09-01

    Full Text Available This article aimed to investigate the effects of mental training on volleyball players service performance. Six male volleyball players aged from 18 to 25 years old of a team from the interior of São Paulo’s state were studied. The service performance was evaluated in three different championships of the same season. The services were scored in game situations at the same time of the intervention process. The measure means indicated service performance increased with the mental training practice, with more services performed correctly and less mistakes at the end of the intervention process. The mistakes dimished significantly from the baseline to the final of the intervention process and from the start of the intervention process to its final.

  8. Volleyball and emotional health of students of pedagogical university

    Directory of Open Access Journals (Sweden)

    Muskharina Y.Y.

    2013-06-01

    Full Text Available The features of valueological pedagogical influence of volleyball lessons on the emotional state of pedagogical university students. In the experiment involved 96 students aged 18-20 years. It was found that 72% of students feel the satisfaction of most emotional needs during the game, 86.4% indicate a bright splash of feelings and a sense of mutual aid during the game, 24% of students met the best friends among the players section. 89.3% of students say that skill, sense of humor, energy, example and support of teacher (trainer during exercise can affect the emotional state of the team and each student. Professional and personal qualities of the coach, to encourage students to employment volleyball positive impact on the physical, mental performance, improve attention, ability to work in a team, to overcome emotional stress, feelings of fatigue, improves emotional state of students.

  9. Morphological classification of novice female volleyball players

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    José António Ribeiro Maia

    2003-12-01

    Full Text Available The characteristics of physique have been the subject of several studies in sport sciences because high-level competitive sports place maximum demands on the physical constitution of players. Furthermore, the specifi c function performed by a player in a game may be related to a particular modality. The goals of this study were: (1 to describe and to compare, from a somatic point of view, the physiques of 71 female volleyball players at beginner levels A and B (aged 12-14 years; and (2 to identify the components of somatic structure that best differentiate the athletics by level of experience. In order to evaluate the players’ somatic structure,we performed 21 measurements including: weight and height, diameters, circumferences, upper and lower limb measurements and skinfolds thicknesses. Discriminant function analysis (DFA was used to identify the power of variables classifi cation. No difference was found in physique between level A and level B players. They were classifi ed by somatotype as mesomorphic endomorphs (A = 4.76 - 3.78 - 1.85; and B = 4.37 - 4.02 - 1.88. RESUMO As características morfológicas têm sido objeto de vários estudos em Ciências Desporto, pelo fato de o fenômeno do desporto de alta competição exigir o máximo da estrutura física dos atletas e pela expectativa da função que o atleta desempenha em jogo. O presente estudo teve como objetivo: (1 descrever e comparar, do ponto de vista somático, a estrutura morfológica de 71 atletas de voleibol do sexo feminino dos escalões de formação A e B (entre os 12 e 14 anos de idade; (2 identifi car os componentes da estrutura somática que melhor diferenciam as atletas de níveis distintos. Para a avaliação da estrutura somática das atletas foram efetuadas 21 avaliações, incluindo além do peso e altura, comprimento dos membros, perímetros, diâmetros e pregas de adiposidade subcutâneas. Com o intuito de verifi car o poder discriminatório das variáveis na

  10. Self-reported symptoms and risk factors for digital ischaemia among international world-class beach volleyball players

    NARCIS (Netherlands)

    van de Pol, Daan; Alaeikhanehshir, Sena; Maas, Mario; Kuijer, P. Paul F. M.

    2016-01-01

    The prevalence of ischaemia-related symptoms is remarkably high among elite indoor volleyball players. Since the exposure to sport-specific demands may be higher in beach volleyball compared to indoor volleyball, the aim of this study was to assess the prevalence of ischaemia-related symptoms and

  11. An economic evaluation of a proprioceptive balance board training programme for the prevention of ankle sprains in volleyball

    NARCIS (Netherlands)

    Verhagen, E.A.L.M.; van Tulder, M.; van der Beek, A.J.; Bouter, L.M.; van Mechelen, W.

    2005-01-01

    OBJECTIVES: To evaluate the cost effectiveness of a proprioceptive balance board training programme for the prevention of ankle sprains in volleyball. METHODS: A total of 116 volleyball teams participated in this study which was carried out during the 2001-2002 volleyball season. Teams were randomly

  12. Cardiovascular and Musculoskeletal Assessment of Elite US Volleyball Players.

    Science.gov (United States)

    Davis, Christopher K; Dyar, Dan A; Vargas, Lisa A; Grossfeld, Paul D

    2015-11-01

    The aim of this study was to characterize the cardiovascular and musculoskeletal systems of elite volleyball players, including aortic dimensions. Previous studies have shown that the upper limit of normal aortic sinus diameter for male and female athletes is 4 and 3.4 cm, respectively. Cross-sectional analysis. United States Olympic Volleyball Training Facility and Rady Children's Hospital San Diego. Seventy (37 male) members of the US national volleyball team. Athletes underwent evaluation that included medical and family histories, targeted physical examinations specifically focusing on abnormalities present in Marfan syndrome (MFS), and transthoracic echocardiograms. Cardiac chamber and great artery size, valve function, and coronary artery origins were assessed. Three male athletes (8%) had an aortic sinus diameter ≥4 cm, one of whom also had an ascending aorta >4 cm. Two female athletes (6%) had aortic sinus diameter ≥3.4 cm, and another had an ascending aorta of 3.4 cm. There were no other intracardiac or arterial abnormalities. Individual musculoskeletal characteristics of MFS were common among the athletes but not more frequent or numerous in those with aortic dilation. The prevalence of aortic root dilation in this population of athletes was higher than what has previously been reported in other similar populations. Further study is needed to determine whether these represent pathological changes or normal variations in tall athletes. This study adds to the existing knowledge base of athlete's heart, with specific attention to aortic dimensions in elite volleyball players. The data are relevant to similar athletes' medical care and to preparticipation cardiac screening in general.

  13. Body mass index and body fat percentage are associated with decreased physical fitness in adolescent and adult female volleyball players

    Directory of Open Access Journals (Sweden)

    Pantelis Theo Nikolaidis

    2013-01-01

    Full Text Available Background: The objectives of this study were to examine (a the prevalence of overweight/obesity, and (b the relationship between body mass index (BMI, body fat percentage (BF and physical fitness in adolescent and adult female volleyball players. Materials and Methods: Adolescent (n = 102, aged 15.2 ± 2.0 year and adult (n = 57, 25.9 ± 5.0 year players were examined for anthropometric characteristics and body composition, and performed the physical working capacity in heart rate 170 min -1 test, a force-velocity test, the Wingate anaerobic test (WAnT, sit-and-reach test (SAR, handgrip strength test (HST and countermovement vertical jump (CVJ. Results: Based on international BMI cut-off points, 27.5% (n = 28 of adolescent and 12.3% (n = 7 of adult participants were classified as overweight, with the prevalence of overweight being higher in girls than in women (χ2 = 4.90, P = 0.027. BMI was correlated with BF in both age groups (r = 0.72, P < 0.001 in girls; r = 0.75, P < 0.001 in women. Normal participants had superior certain physical and physiological characteristics than those who were overweight. For instance, normal girls and women had higher mean power during WAnT than their overweight counterparts (P = 0.003 and P = 0.009 respectively. Except for flexibility, BMI and BF were inversely related with physical fitness (e.g., BMI vs. HST r = -0.39, P < 0.001 in girls; BF vs. CVJ r = -0.45, P < 0.001 in women. Conclusion: The findings confirmed the negative effect of overweight and fatness on selected parameters of physical fitness. The prevalence of overweight in adolescent volleyball players was higher than in general population, which was a novel finding, suggesting that proper exercise interventions should be developed to target the excess of body mass in youth volleyball clubs.

  14. Y-balance normative data for female collegiate volleyball players.

    Science.gov (United States)

    Hudson, Christy; Garrison, J Craig; Pollard, Kalyssa

    2016-11-01

    The Lower Quarter Y Balance (YBT-LQ) Test performance varies depending on competitive level, sport, gender, and age; therefore, determining normative scores specific to a population may be helpful in identifying injury-risk thresholds and return-to-play criteria following an injury. The purpose of this study was to determine normative YBT-LQ scores by assessing a subset of female, Division I volleyball players. A descriptive analysis cohort study. Ninety healthy (19.6 ± 1.2 y/o), collegiate female volleyball players. YBT-LQ was measured in 3 distinct directions of anterior (ANT), posteromedial (PM) and posterolateral (PL) on both the dominant and non-dominant limbs. In addition, a one way ANOVA was performed to determine mean group differences of YBT-LQ dominant and non-dominant limb composite score across position. Baseline values for this population were 94.1 ± 6.6% on the dominant limb and 93.9 ± 6.2% on the non-dominant limb. There were no significant differences for YBT-LQ composite scores on dominant (P = 0.867) and non-dominant (P = 0.989) limbs between position. This study identified normative YBT-LQ composite scores for healthy, female, collegiate volleyball players. Participants performed similarly despite their position. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Jump probabilities in the non-Markovian quantum jump method

    International Nuclear Information System (INIS)

    Haerkoenen, Kari

    2010-01-01

    The dynamics of a non-Markovian open quantum system described by a general time-local master equation is studied. The propagation of the density operator is constructed in terms of two processes: (i) deterministic evolution and (ii) evolution of a probability density functional in the projective Hilbert space. The analysis provides a derivation for the jump probabilities used in the recently developed non-Markovian quantum jump (NMQJ) method (Piilo et al 2008 Phys. Rev. Lett. 100 180402).

  16. The impact of physically demanding work of basketball and volleyball players on the risk for patellar tendinopathy and on work limitations.

    Science.gov (United States)

    van der Worp, H; Zwerver, J; Kuijer, P P F M; Frings-Dresen, M H W; van den Akker-Scheek, I

    2011-01-01

    Patellar tendinopathy is a common injury in jumping athletes. Little is known about work-related etiological factors for patellar tendinopathy and related work limitations. The aim of this study was to identify work-related etiological factors for patellar tendinopathy and to determine the relation between patellar tendinopathy and work limitations. Basketball and volleyball players between 18 and 35 years were invited to complete an online-questionnaire concerning knee complaints, etiological risk factors for patellar tendinopathy and related work limitations. A total of 1505 subjects were included in the analysis. Risk factors for patellar tendinopathy were gender and heavy physically demanding work. The odds for having patellar tendinopathy were significantly higher for heavy physically demanding occupations compared to mentally demanding occupations. 30% of subjects with patellar tendinopathy with a physically demanding job reported to be impaired in their work and 17% reported to be less productive. Basketball and volleyball players with heavy physically demanding work seem to have an increased risk for developing patellar tendinopathy. This finding has important clinical relevance in the treatment of this injury. Working activities should be adjusted in order to reduce the total load on the patellar tendon and help prevention and recovery.

  17. Contribution of Leg Muscle Explosive Power and Eye-Hand Coordination to The Accuracy Smash of Athletes in Volleyball Club of Universitas Islam Riau

    Directory of Open Access Journals (Sweden)

    Mimi Yulianti

    2017-11-01

    Full Text Available The purpose of this study was to determine the contribution of leg muscle explosive power and eye-hand coordination. The type of research was correlational. The population in this study was all athletes who actively follow the training as many as 20 people and using total sampling technique. Thus the sample in this study amounted to 20 men athletes. The data were collected using the measurement test on the three variables: the leg muscle explosive power data was using vertical jump test, eyehand coordination was using ballwerfen und fangen test and smash accuracy was using smash accuracy test. The data were analyzed by product moment correlation and double correlation and then continued with contribution of the determinant formula. Based on data analysis found that there was contribution of leg muscle explosive power equal to 35,52%, eye-hand coordination equal to 20,79%, and both equal to 40,70% regarding to the accuracy smash of volleyball atletes of Universitas Islam Riau. It was concluded that there was contribution of leg muscle explosive power and eye-hand coordination to the smash accuracy of volleyball athlete of Universitas Islam Riau.

  18. Students' Game Performance Improvements during a Hybrid Sport Education-Step-Game-Approach Volleyball Unit

    Science.gov (United States)

    Araújo, Rui; Mesquita, Isabel; Hastie, Peter; Pereira, Cristiana

    2016-01-01

    The purpose of this study was to examine a hybrid combination of sport education and the step-game-approach (SGA) on students' gameplay performance in volleyball, taking into account their sex and skill-level. Seventeen seventh-grade students (seven girls, 10 boys, average age 11.8) participated in a 25-lesson volleyball season, in which the…

  19. High intensity training improves exercise performance in elite women volleyball players during a competitive season

    DEFF Research Database (Denmark)

    Purkhús, Elisabeth; Krustrup, Peter; Mohr, Magni

    2016-01-01

    Elite women volleyball players (n=25; age; 19±5 yrs, height; 171±7 cm, weight; 63±10 kg; means±SD) volunteered to participate in the study. They were randomized into a high intensity training group (HIT; n=13) and a control group (CON; n=12). In addition to the normal team training and games, HIT...... women volleyball players....

  20. Collaboration with Sport Psychologists as Viewed by Female Volleyball Junior Teams

    Science.gov (United States)

    Otrebski, Wojciech; Rutkowska, Katarzyna

    2008-01-01

    Study aim: To determine the need of female junior volleyball players to collaborate with a psychologist, considering previous sport career of those players. Material and methods: A group of 78 female volleyball players aged 14-17 years from 7 top Polish junior teams participated in the study. They were requested to fill questionnaires on their…

  1. Physical Fitness Profiles of Sitting Volleyball Players of the Turkish National Team

    Science.gov (United States)

    Yüksel, Mehmet Fatih; Sevindi, Tarik

    2018-01-01

    This research is conducted to determine the physical profiles of sitting volleyball players of the Turkish National Team. 12 male players from Turkish Sitting Volleyball National Team volunteered to participate in the study. The anthropometric measurements were taken over dominant extremity. In order to determine the physical features of the…

  2. Hydraulic jumps in a channel

    DEFF Research Database (Denmark)

    Bonn, D.; Andersen, Anders Peter; Bohr, Tomas

    2009-01-01

    We present a study of hydraulic jumps with flow predominantly in one direction, created either by confining the flow to a narrow channel with parallel walls or by providing an inflow in the form of a narrow sheet. In the channel flow, we find a linear height profile upstream of the jump as expected......'s mixing-length theory with a mixing length that is proportional to the height of the fluid layer. Using averaged boundary-layer equations, taking into account the friction with the channel walls and the eddy viscosity, the flow both upstream and downstream of the jump can be understood. For the downstream...... subcritical flow, we assume that the critical height is attained close to the channel outlet. We use mass and momentum conservation to determine the position of the jump and obtain an estimate which is in rough agreement with our experiment. We show that the averaging method with a varying velocity profile...

  3. Jump Landing Characteristics Predict Lower Extremity Injuries in Indoor Team Sports.

    Science.gov (United States)

    van der Does, H T D; Brink, M S; Benjaminse, A; Visscher, C; Lemmink, K A P M

    2016-03-01

    The aim of this study is to investigate the predictive value of landing stability and technique to gain insight into risk factors for ankle and knee injuries in indoor team sport players. Seventy-five male and female basketball, volleyball or korfball players were screened by measuring landing stability after a single-leg jump landing and landing technique during a repeated counter movement jump by detailed 3-dimensional kinematics and kinetics. During the season 11 acute ankle injuries were reported along with 6 acute and 7 overuse knee injuries by the teams' physical therapist. Logistic regression analysis showed less landing stability in the forward and diagonal jump direction (OR 1.01-1.10, p≤0.05) in players who sustained an acute ankle injury. Furthermore landing technique with a greater ankle dorsiflexion moment increased the risk for acute ankle injury (OR 2.16, p≤0.05). A smaller knee flexion moment and greater vertical ground reaction force increased the risk of an overuse knee injury (OR 0.29 and 1.13 respectively, p≤0.05). Less one-legged landing stability and suboptimal landing technique were shown in players sustaining an acute ankle and overuse knee injury compared to healthy players. Determining both landing stability and technique may further guide injury prevention programs. © Georg Thieme Verlag KG Stuttgart · New York.

  4. How do we learn to "kill" in volleyball?: The role of working memory capacity and expertise in volleyball motor learning.

    Science.gov (United States)

    Bisagno, Elisa; Morra, Sergio

    2018-03-01

    This study examines young volleyball players' learning of increasingly complex attack gestures. The main purpose of the study was to examine the predictive role of a cognitive variable, working memory capacity (or "M capacity"), in the acquisition and development of motor skills in a structured sport. Pascual-Leone's theory of constructive operators (TCO) was used as a framework; it defines working memory capacity as the maximum number of schemes that can be simultaneously activated by attentional resources. The role of expertise in motor learning was also considered. The expertise of each athlete was assessed in terms of years of practice and number of training sessions per week. The participants were 120 volleyball players, aged between 6 and 26 years, who performed both working memory tests and practical tests of volleyball involving the execution of the "third touch" by means of technical gestures of varying difficulty. We proposed a task analysis of these different gestures framed within the TCO. The results pointed to a very clear dissociation. On the one hand, M capacity was the best predictor of correct motor performance, and a specific capacity threshold was found for learning each attack gesture. On the other hand, experience was the key for the precision of the athletic gestures. This evidence could underline the existence of two different cognitive mechanisms in motor learning. The first one, relying on attentional resources, is required to learn a gesture. The second one, based on repeated experience, leads to its automatization. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. How players exploit variability and regularity of game actions in female volleyball teams.

    Science.gov (United States)

    Ramos, Ana; Coutinho, Patrícia; Silva, Pedro; Davids, Keith; Mesquita, Isabel

    2017-05-01

    Variability analysis has been used to understand how competitive constraints shape different behaviours in team sports. In this study, we analysed and compared variability of tactical performance indices in players within complex I at two different competitive levels in volleyball. We also examined whether variability was influenced by set type and period. Eight matches from the 2012 Olympics competition and from the Portuguese national league in the 2014-2015 season were analysed (1496 rallies). Variability of setting conditions, attack zone, attack tempo and block opposition was assessed using Shannon entropy measures. Magnitude-based inferences were used to analyse the practical significance of compared values of selected variables. Results showed differences between elite and national teams for all variables, which were co-adapted to the competitive constraints of set type and set periods. Elite teams exploited system stability in setting conditions and block opposition, but greater unpredictability in zone and tempo of attack. These findings suggest that uncertainty in attacking actions was a key factor that could only be achieved with greater performance stability in other game actions. Data suggested how coaches could help setters develop the capacity to play at faster tempos, diversifying attack zones, especially at critical moments in competition.

  6. Contributing factors to performance of a medicine ball explosive power test: a comparison between jump and nonjump athletes.

    Science.gov (United States)

    Stockbrugger, Barry A; Haennel, Robert G

    2003-11-01

    The present study examined the factors contributing to performance of a backward overhead medicine ball throw (B-MBT) across 2 types of athletes. Twenty male volleyball players (jump athletes) and 20 wrestlers (nonjump athletes) were evaluated on 4 measures of power, including B-MBT, chest medicine ball throw (C-MBT), countermovement vertical jump (CMJ), and power index (PI). The athletes also completed 3 measures of strength: a 1-repetition-maximum (1RM) bench press (BP), a 1RM leg press (LP), and combined BP + LP strength. Jump athletes demonstrated greater absolute scores for CMJ, C-MBT, and B-MBT (p < 0.05), whereas nonjump athletes demonstrated greater strength scores for BP and for BP + LP (p < 0.05). When performances were examined on a relative basis, jump athletes achieved superior scores for C-MBT (p < 0.05), whereas nonjump athletes had greater scores for BP, LP, and BP + LP (p < 0.05). For both groups, B-MBT had strong correlations with PI (r = 0.817 [jump] and 0.917 [nonjump]), whereas for C-MBT, only nonjump athletes demonstrated a strong correlation (r = 0.842). When expressed in relative terms, B-MBT was strongly correlated with C-MBT (r = 0.762 [jump] and 0.835 [nonjump]) and CMJ (r = 0.899 [jump] and 0.945 [nonjump]). Only nonjump athletes demonstrated strong correlations with strength for absolute LP (r = 0.801) and BP + LP (r = 0.810) strength. The interaction of upper- and lower-body strength and power in the performance of a B-MBT appears complex, with the contributing factors differing for athletes with divergent skill sets and performance demands.

  7. Vortex-induced dynamic loads on a non-spinning volleyball

    Science.gov (United States)

    Qing-ding, Wei; Rong-sheng, Lin; Zhi-jie, Liu

    1988-09-01

    An experiment on vortex-induced dynamic loads on a non-spinning Volleyball was conducted in a wind tunnel. The flow past the Volleyball was visualized, and the aerodynamic load was measured by use of a strain gauge balance. The separation on the Volleyball was measured with hot-film. The experimental results suggest that under the action of an unstable tail vortex system the separation region is changeable, and that the fluctuation of drag and lateral forces is the same order of magnitude as the mean drag, no matter whether the seam of the Volleyball is symmetric or asymmetric, with regard to the flow. Based on the experimental data a numerical simulation of Volleyball swerve motion was made.

  8. Birth of a hydraulic jump

    Science.gov (United States)

    Duchesne, Alexis; Bohr, Tomas; Andersen, Anders

    2017-11-01

    The hydraulic jump, i.e., the sharp transition between a supercritical and a subcritical free-surface flow, has been extensively studied in the past centuries. However, ever since Leonardo da Vinci asked it for the first time, an important question has been left unanswered: How does a hydraulic jump form? We present an experimental and theoretical study of the formation of stationary hydraulic jumps in centimeter wide channels. Two starting situations are considered: The channel is, respectively, empty or filled with liquid, the liquid level being fixed by the wetting properties and the boundary conditions. We then change the flow-rate abruptly from zero to a constant value. In an empty channel, we observe the formation of a stationary hydraulic jump in a two-stage process: First, the channel fills by the advancing liquid front, which undergoes a transition from supercritical to subcritical at some position in the channel. Later the influence of the downstream boundary conditions makes the jump move slowly upstream to its final position. In the pre-filled channel, the hydraulic jump forms at the injector edge and then moves downstream to its final position.

  9. Variation in free jumping technique within and among horses with little experience in show jumping

    NARCIS (Netherlands)

    Santamaria, S.; Bobbert, M.F.; Back, W.; Barneveld, A.; van Weeren, P.R.

    2004-01-01

    Objective - To quantify variation in the jumping technique within and among young horses with little jumping experience, establish relationships between kinetic and kinematic variables, and identify a limited set of variables characteristic for detecting differences in jumping performance among

  10. Comparison of dynamic postural stability scores between athletes with and without chronic ankle instability during lateral jump landing.

    Science.gov (United States)

    Shiravi, Zeinab; Shadmehr, Azadeh; Moghadam, Saeed Talebian; Moghadam, Behrouz Attarbashi

    2017-01-01

    Many ankle injuries occur while participating in sports that require jumping and landing such as basketball, volleyball and soccer. Most recent studies have investigated dynamic postural stability of patients with chronic ankle instability after landing from a forward jump. The present study aimed to investigate the dynamic postural stability of the athletes who suffer from chronic ankle sprain while landing from a lateral jump. Twelve athletes with self-reported unilateral chronic ankle instability (4 females and 8 males) and 12 matched controls (3 females and 9 males) voluntarily participated in the study. Dynamic postural stability index and its directional indices were measured while performing lateral jump landing test. No differences were found between athletes with and without chronic ankle instability during our landing protocol by means of the dynamic postural stability index and its directional indices. Findings showed that in each group, medial/lateral stability index is significantly higher than anterior/posterior and vertical stability indexes. Findings showed that dynamic postural stability was not significantly different between the two groups. Future studies should examine chronic ankle instability patients with more severe disabilities and expose them to more challenging dynamic balance conditions to further explore postural stability. IIIa.

  11. Nerve Blocks

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Nerve Blocks A nerve block is an injection to ... the limitations of Nerve Block? What is a Nerve Block? A nerve block is an anesthetic and/ ...

  12. Superolateral Hoffa's Fat Pad Edema in Collegiate Volleyball Players.

    Science.gov (United States)

    Mehta, Kaushal; Wissman, Robert; England, Eric; Dʼheurle, Albert; Newton, Keith; Kenter, Keith

    2015-01-01

    Superolateral Hoffa's fat pad (SHFP) edema is a previously described magnetic resonance (MR) finding located between the patellar tendon and the lateral femoral condyle. The purpose of our study was to determine the prevalence and clinical significance of SHFP edema in female collegiate volleyball players. Sixteen female collegiate volleyball players were consented for bilateral knee evaluations which consisted of history, physical examination and MR imaging. Each MR study was reviewed for the presence of SHFP edema, and 6 patellar maltracking measurements were done. These were tibial tuberosity-trochlear groove distance, patellar translation, lateral patellofemoral angle, trochlear depth, trochlear sulcus angle, and lateral trochlear inclination angle. A total of 16 athletes, 32 knees (16 girls; age range, 18-22 years; mean, 19.9) were enrolled in the study. Sixteen knees (50%) in 8 athletes had SHFP edema, with 100% bilaterality; 16 knees in 8 athletes had no evidence of SHFP edema (50%). Functional outcomes and physical examination findings were within normal limits for all athletes with no difference noted between SHFP edema-positive and -negative individuals. There was a statistically significant difference in the tibial tuberosity-trochlear groove distance, patellar translation, and patellofemoral angle (P value of volleyball athletes have a very high prevalence of SHFP edema, which is always bilateral. Although the exact etiology of SHFP edema remains inconclusive, it could potentially be a sensitive indicator of subtle patellar maltracking which cannot be distinguished by history and physical examination findings. Given the very high prevalence of SHFP edema and this being an asymptomatic finding, there is likely little clinical significance of this in majority of high-performance athletes.

  13. Comparison of posture among adolescent male volleyball players and non-athletes

    Science.gov (United States)

    2014-01-01

    Due to high training loads and frequently repeated unilateral exercises, several types of sports training can have an impact on the process of posture development in young athletes. The objective of the study was to assess and compare the postures of adolescent male volleyball players and their non-training peers. The study group comprised 104 volleyball players while the control group consisted of 114 non-training individuals aged 14-16 years. Body posture was assessed by the Moiré method. The volleyball players were significantly taller, and had greater body weight and fat-free mass. The analysis of posture relative to symmetry in the frontal and transverse planes did not show any significant differences between the volleyball players and non-athletes. Postural asymmetries were observed in both the volleyball players and the control participants. Lumbar lordosis was significantly less defined in the volleyball players compared to non-training individuals while no difference was observed in thoracic kyphosis. All athletes demonstrated a loss of lumbar lordosis and an increase in thoracic kyphosis. Significant differences in anteroposterior curvature of the spine between the volleyball players and the non-athletes might be associated with both training and body height. Considering the asymmetric spine overloads which frequently occur in sports training, meticulous posture assessment in young athletes seems well justified. PMID:25729154

  14. Incidence, aetiology and prevention of musculoskeletal injuries in volleyball: A systematic review of the literature.

    Science.gov (United States)

    Kilic, O; Maas, M; Verhagen, E; Zwerver, J; Gouttebarge, V

    2017-07-01

    Currently, there is no overview of the incidence and (volleyball-specific) risk factors of musculoskeletal injuries among volleyball players, nor any insight into the effect of preventive measures on the incidence of injuries in volleyball. This study aimed to review systematically the scientific evidence on the incidence, prevalence, aetiology and preventive measures of volleyball injuries. To this end, a highly sensitive search strategy was built based on two groups of keywords (and their synonyms). Two electronic databases were searched, namely Medline (biomedical literature) via Pubmed, and SPORTDiscus (sports and sports medicine literature) via EBSCOhost. The results showed that ankle, knee and shoulder injuries are the most common injuries sustained while playing volleyball. Results are presented separately for acute and overuse injuries, as well as for contact and non-contact injuries. Measures to prevent musculoskeletal injuries, anterior knee injuries and ankle injuries were identified in the scientific literature. These preventive measures were found to have a significant effect on decreasing the occurrence of volleyball injuries (for instance on ankle injuries with a reduction from 0.9 to 0.5 injuries per 1000 player hours). Our systematic review showed that musculoskeletal injuries are common among volleyball players, while effective preventive measures remain scarce. Further epidemiological studies should focus on other specific injuries besides knee and ankle injuries, and should also report their prevalence and not only the incidence. Additionally, high-quality studies on the aetiology and prevention of shoulder injuries are lacking and should be a focus of future studies.

  15. Comparison of posture among adolescent male volleyball players and non-athlete

    Directory of Open Access Journals (Sweden)

    Małgorzata Grabara

    2014-10-01

    Full Text Available Due to high training loads and frequently repeated unilateral exercises, several types of sports training can have an impact on the process of posture development in young athletes. The objective of the study was to assess and compare the postures of adolescent male volleyball players and their non-training peers. The study group comprised 104 volleyball players while the control group consisted of 114 non-training individuals aged 14-16 years. Body posture was assessed by the Moiré method. The volleyball players were significantly taller, and had greater body weight and fat-free mass. The analysis of posture relative to symmetry in the frontal and transverse planes did not show any significant differences between the volleyball players and non-athletes. Postural asymmetries were observed in both the volleyball players and the control participants. Lumbar lordosis was significantly less defined in the volleyball players compared to non-training individuals while no difference was observed in thoracic kyphosis. All athletes demonstrated a loss of lumbar lordosis and an increase in thoracic kyphosis. Significant differences in anteroposterior curvature of the spine between the volleyball players and the non-athletes might be associated with both training and body height. Considering the asymmetric spine overloads which frequently occur in sports training, meticulous posture assessment in young athletes seems well justified.

  16. Comparison of posture among adolescent male volleyball players and non-athletes

    Directory of Open Access Journals (Sweden)

    Małgorzata Grabara

    2014-11-01

    Full Text Available Due to high training loads and frequently repeated unilateral exercises, several types of sports training can have an impact on the process of posture development in young athletes. The objective of the study was to assess and compare the postures of adolescent male volleyball players and their non-training peers. The study group comprised 104 volleyball players while the control group consisted of 114 non-training individuals aged 14-16 years. Body posture was assessed by the Moiré method. The volleyball players were significantly taller, and had greater body weight and fat-free mass. The analysis of posture relative to symmetry in the frontal and transverse planes did not show any significant differences between the volleyball players and non-athletes. Postural asymmetries were observed in both the volleyball players and the control participants. Lumbar lordosis was significantly less defined in the volleyball players compared to non-training individuals while no difference was observed in thoracic kyphosis. All athletes demonstrated a loss of lumbar lordosis and an increase in thoracic kyphosis. Significant differences in anteroposterior curvature of the spine between the volleyball players and the non-athletes might be associated with both training and body height. Considering the asymmetric spine overloads which frequently occur in sports training, meticulous posture assessment in young athletes seems well justified.

  17. Timeless Approach to Quantum Jumps

    Directory of Open Access Journals (Sweden)

    Ignazio Licata

    2015-10-01

    Full Text Available According to the usual quantum description, the time evolution of the quantum state is continuous and deterministic except when a discontinuous and indeterministic collapse of state vector occurs. The collapse has been a central topic since the origin of the theory, although there are remarkable theoretical proposals to understand its nature, such as the Ghirardi–Rimini–Weber. Another possibility could be the assimilation of collapse with the now experimentally well established phenomenon of quantum jump, postulated by Bohr already in 1913. The challenge of nonlocality offers an opportunity to reconsider the quantum jump as a fundamental element of the logic of the physical world, rather than a subsidiary accident. We propose here a simple preliminary model that considers quantum jumps as processes of entry to and exit from the usual temporal domain to a timeless vacuum, without contradicting the quantum relativistic formalism, and we present some potential connections with particle physics. Quanta 2015; 4: 10–26.

  18. Quantum jumps on Anderson attractors

    Science.gov (United States)

    Yusipov, I. I.; Laptyeva, T. V.; Ivanchenko, M. V.

    2018-01-01

    In a closed single-particle quantum system, spatial disorder induces Anderson localization of eigenstates and halts wave propagation. The phenomenon is vulnerable to interaction with environment and decoherence that is believed to restore normal diffusion. We demonstrate that for a class of experimentally feasible non-Hermitian dissipators, which admit signatures of localization in asymptotic states, quantum particle opts between diffusive and ballistic regimes, depending on the phase parameter of dissipators, with sticking about localization centers. In a diffusive regime, statistics of quantum jumps is non-Poissonian and has a power-law interval, a footprint of intermittent locking in Anderson modes. Ballistic propagation reflects dispersion of an ordered lattice and introduces the second timescale for jumps, resulting in non-nonmonotonous probability distribution. Hermitian dephasing dissipation makes localization features vanish, and Poissonian jump statistics along with normal diffusion are recovered.

  19. High Prevalence of Nontraumatic Shoulder Pain in a Regional Sample of Female High School Volleyball Athletes

    Science.gov (United States)

    Frisch, Kayt E.; Clark, Jacob; Hanson, Chad; Fagerness, Chris; Conway, Adam; Hoogendoorn, Lindsay

    2017-01-01

    Background: Shoulder pain is becoming increasingly problematic in young players as volleyball gains popularity. Associations between repetitive motion and pain and overuse injury have been observed in other overhand sports (most notably baseball). Studies of adult athletes suggest that there is a shoulder pain and overuse problem present in volleyball players, but minimal research has been done to establish rates and causes in juvenile participants. Purpose: To establish rates of shoulder pain, regardless of whether it resulted in a loss of playing time, in female high school volleyball players. A secondary goal was to determine whether high repetition volumes correlated with an increased likelihood of experiencing pain. Study Design: Descriptive epidemiology study. Methods: A self-report survey focusing on the prevalence of pain not associated with a traumatic event in female high school youth volleyball players was developed. Survey questions were formulated by certified athletic trainers, experienced volleyball coaches, and biomechanics experts. Surveys were received from 175 healthy, active high school volleyball players in Iowa, South Dakota, and Minnesota. Results: Forty percent (70/175) of active high school volleyball players remembered experiencing shoulder pain not related to traumatic injury, but only 33% (23/70) reported taking time off to recover from the pain. Based on these self-reported data, activities associated with significantly increased risk of nontraumatic shoulder pain included number of years playing competitive volleyball (P = .01) and lifting weights out of season (P = .001). Players who reported multiple risk factors were more likely to experience nontraumatic shoulder pain. Conclusion: When using time off for recovery as the primary injury criterion, we found that the incidence of shoulder pain is more than twice as high as the incidence of injury reported by previous studies. Findings also indicated that the incidence of shoulder pain

  20. Preventing musculoskeletal injuries among recreational adult volleyball players: design of a randomised prospective controlled trial.

    Science.gov (United States)

    Gouttebarge, Vincent; Zwerver, Johannes; Verhagen, Evert

    2017-08-02

    Both acute and overuse injuries are common among recreational volleyball players, especially finger/wrist, ankle, shoulder and knee injuries. Consequently, an intervention ('VolleyVeilig') was developed to prevent or reduce the occurrence of finger/wrist, shoulder, knee and ankle injuries among recreational volleyball players. This article describes the design of a study evaluating the effectiveness of the developed intervention on the one-season occurrence of finger/wrist, shoulder, knee and ankle injuries among recreational adult volleyball players. A randomized prospective controlled trial with a follow-up period of one volleyball season will be conducted. Participants will be healthy recreational adult volleyball players (18 years of age or older) practicing volleyball (training and/or match) at least twice a week. The intervention ('VolleyVeilig') consists of a warm-up program based on more than 50 distinct exercises (with different variations and levels). The effect of the intervention programme on the occurrence of injuries will be compared to volleyball as usual. Outcome measures will be incidence of acute injury (expressed as number of injuries per 1000 h of play) and prevalence of overuse injuries (expressed as percentage). This study will be one of the first randomized prospective controlled trials evaluating the effectiveness of an intervention on the occurrence of both acute and overuse injuries among recreational adult volleyball players. Outcome of this study could possibly lead to the nationwide implementation of the intervention in all volleyball clubs in The Netherlands, ultimately resulting in less injuries. Dutch Trial Registration NTR6202 , registered February 1st 2017. Version 3, February 2017.

  1. High Prevalence of Nontraumatic Shoulder Pain in a Regional Sample of Female High School Volleyball Athletes.

    Science.gov (United States)

    Frisch, Kayt E; Clark, Jacob; Hanson, Chad; Fagerness, Chris; Conway, Adam; Hoogendoorn, Lindsay

    2017-06-01

    Shoulder pain is becoming increasingly problematic in young players as volleyball gains popularity. Associations between repetitive motion and pain and overuse injury have been observed in other overhand sports (most notably baseball). Studies of adult athletes suggest that there is a shoulder pain and overuse problem present in volleyball players, but minimal research has been done to establish rates and causes in juvenile participants. To establish rates of shoulder pain, regardless of whether it resulted in a loss of playing time, in female high school volleyball players. A secondary goal was to determine whether high repetition volumes correlated with an increased likelihood of experiencing pain. Descriptive epidemiology study. A self-report survey focusing on the prevalence of pain not associated with a traumatic event in female high school youth volleyball players was developed. Survey questions were formulated by certified athletic trainers, experienced volleyball coaches, and biomechanics experts. Surveys were received from 175 healthy, active high school volleyball players in Iowa, South Dakota, and Minnesota. Forty percent (70/175) of active high school volleyball players remembered experiencing shoulder pain not related to traumatic injury, but only 33% (23/70) reported taking time off to recover from the pain. Based on these self-reported data, activities associated with significantly increased risk of nontraumatic shoulder pain included number of years playing competitive volleyball ( P = .01) and lifting weights out of season ( P = .001). Players who reported multiple risk factors were more likely to experience nontraumatic shoulder pain. When using time off for recovery as the primary injury criterion, we found that the incidence of shoulder pain is more than twice as high as the incidence of injury reported by previous studies. Findings also indicated that the incidence of shoulder pain may be correlated with volume of previous volleyball experience.

  2. Scaling of interfacial jump conditions

    International Nuclear Information System (INIS)

    Quezada G, S.; Vazquez R, A.; Espinosa P, G.

    2015-09-01

    To model the behavior of a nuclear reactor accurately is needed to have balance models that take into account the different phenomena occurring in the reactor. These balances have to be coupled together through boundary conditions. The boundary conditions have been studied and different treatments have been given to the interface. In this paper is a brief description of some of the interfacial jump conditions that have been proposed in recent years. Also, the scaling of an interfacial jump condition is proposed, for coupling the different materials that are in contact within a nuclear reactor. (Author)

  3. Structural and electronic stability of a volleyball-shaped B80 fullerene

    Science.gov (United States)

    Wang, Xiao-Qian

    2010-10-01

    We have studied the structural and electronic characteristics of a volleyball-shaped B80 cage using first-principles density-functional calculations. In contrast to the popularly ratified “magic” B80 buckyball with 20 hexagonal pyramids and 12 hollow pentagons, the volleyball-shaped B80 constitutes 12 pentagonal pyramids, 8 hexagonal pyramids, and 12 hollow hexagons. The B80 volleyball is markedly more stable than the previously assumed magic B80 buckyball, which is attributed to the improved aromaticity associated with the distinct configuration.

  4. Strength of the Shoulder Rotators in Second-League Volleyball Players

    Directory of Open Access Journals (Sweden)

    Popieluch Aneta

    2015-12-01

    Full Text Available Introduction. The main aim of the study was to assess the strength of the shoulder rotator muscles of a group of second-league volleyball players. These muscles are assumed to have a crucial impact on attack effectiveness in volleyball. Strength was assessed based on peak torque values obtained for the rotator muscles measured using the maximal voluntary contraction (MVC method. Torque was measured in both limbs and the differences between the two limbs were examined. The torque values obtained for the volleyball players were also compared against those measured in a group of students who had never trained any sports.

  5. Self-reported symptoms and risk factors for digital ischaemia among international world-class beach volleyball players.

    Science.gov (United States)

    Van De Pol, Daan; Alaeikhanehshir, Sena; Maas, Mario; Kuijer, P Paul F M

    2016-01-01

    The prevalence of ischaemia-related symptoms is remarkably high among elite indoor volleyball players. Since the exposure to sport-specific demands may be higher in beach volleyball compared to indoor volleyball, the aim of this study was to assess the prevalence of ischaemia-related symptoms and associated risk factors among world-class beach volleyball players. Therefore, a questionnaire survey was performed among beach volleyball players active during the 2013 Grand Slam Beach Volleyball in the Netherlands. In total, 60 of the 128 beach volleyball players (47%) participated: 26 males and 34 females from 17 countries. The self-reported prevalence of cold or blue or pale digits in the dominant hand during or immediately after practice or competition was 38% (n = 23). Two risk factors were independently associated with symptoms of blue or pale digits: more than 14 years playing volleyball (odds ratio (OR) 4.42, 90% confidence interval (90% CI) 1.30-15.07) and sex (female) (OR 4.62, 90% CI 1.15-18.57). In conclusion, the prevalence of symptoms associated with digital ischaemia is high among international world-class beach volleyball players. Female sex and the length of the volleyball career were independently associated with an increased risk of ischaemia-related symptoms. The high prevalence of these seemingly innocuous symptoms and possible associated risk factors warrant regular monitoring since early detection can potentially prevent thromboembolic complications and irreversible tissue damage.

  6. Risk factors for patellar tendinopathy in volleyball and basketball players: A survey-based prospective cohort study.

    Science.gov (United States)

    de Vries, A J; van der Worp, H; Diercks, R L; van den Akker-Scheek, I; Zwerver, J

    2015-10-01

    Patellar tendinopathy (PT) is a common overuse injury of the patellar tendon in jumping athletes. In a recent large cross-sectional study from 2008 several factors were identified that may be associated with the etiology of PT. However, because of the study design no conclusions could be drawn about causal relations. The primary aim of the current study is to investigate whether the factors identified in the previous 2008 study can also be prospectively recognized as predictors of symptomatic PT in 2011. Nine hundred twenty-six Dutch elite and non-elite basketball and volleyball players from the previous study were invited again to complete an online survey about knee complaints and risk factors for PT in 2011. The logistic regression included 385 athletes of which 51 (13%) developed PT since 2008. Male gender [odds ratio (OR) 2.0, 95% confidence interval (CI) 1.1-3.5] was found to be a risk factor for developing PT. No sports-related variables could be identified to increase the risk of developing PT, but some evidence was found for performing heavy physically demanding work, like being a nurse or a physical education teacher (OR 2.3, 95% CI 0.9-6.3). These findings indicate that, when considering preventive measures, it is important to take into account the total tendon load. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Overload and neovascularization of shoulder tendons in volleyball players

    Science.gov (United States)

    2012-01-01

    Background In overhead sports like volleyball, the onset of a rotator cuff tendinopathy due to functional overload is a common observation. An angiofibroblastic etiopathogenesis has been hypothesized, whereby a greater anaerobic metabolism occurs in critical zones of the tendon with a lower degree of vascularization; this would induce collagen and extracellular matrix degradation, that could then trigger a compensatory neovascularization response. We performed a clinical observational study of 80 elite volleyball players, monitoring the perfusion values of the supraspinatus tendons by oximetry. Results No statistically significant differences were found between the oximetry data and age, sex or years of sports activity, nor when comparing the right and left arm or the dominant and non-dominant arm. A statistically significant difference was found for the dominant arm values in relation to the competitive role, higher values being obtained in outside hitters (62.7%) than middle hitters (53.7%) (p = 0.01), opposite hitters (55.5%) (p = 0.02) and libero players (54.4%) (p = 0.008), whereas there were no differences in setters (56.2%) (p > 0.05). Conclusions The different tendon vascularization values found in players with different roles in the team may be attributed to a response to the specific biomechanical demands posed by the different overhead throwing roles. PMID:22853746

  8. ANTHROPOMETRIC AND MOTOR CHARACTERISTICS IN VOLLEYBALL AND BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Enver Tahiraj

    2011-09-01

    Full Text Available The purpose of this study is the morphological and motor status players for both teams, and then based on the results of anthropometric and motor status of this work can also do a comparative analysis between these two sports, volleyball and basketball. Therefore, the present study is in the results (achieved of the differences and their special achievement and to skills top players. In this research, we have participation 30 players (15 for each team volleyball and basketball, the teams is from Pristina. It should be noted that all players are fully able to follow regular exercise in their clubs. Those two clubs in Pristina, have the training five days a week, the clubs are in super league and the current champion in country. We as a coach interesed about the comparisons and differences of these two sports for anthropometric and motor characteristics, and in these sports, in those two sports players have a special that is characterized by height body and explosive power. We think, that this research work serves as a continuation of the way and further research on these two sports that have a significant increase from the psycho-physical and anthropometric aspects

  9. MEANING TO BE VOLLEYBALL PLAYER IN CAREER TRANSITION PHASE

    Directory of Open Access Journals (Sweden)

    Adriana Justino

    2016-09-01

    Full Text Available The objective of this study is to assess the meaning of being that a volleyball player for the under-19 players who are experiencing a transition in their in career. Sixteen male players aged 17 and 18 were evaluated, by being asked the triggering question “What does being a volleyball player mean to you?” The analysis of the discourses was carried out according to the procedures recommended by Miles & Huberman (2004. Four response categories resulted: psychoemotional and behavioral skills, emotions in sport, recognition and financial return, skills as an athlete/player. The athletes showed that the meaning of sport lies especially in the passion for practice, but also, in the improving of their tactics and techniques, in the development of psychoemotional and behavioral skills, in the professional recognition and, to a lesser degree, in the financial aspect. Most athletes state they intend to continue in the juvenile sports categories, therefore, understanding the meaning of this activity in their life can be the key to the elaboration of a plan of psychological preparation whose aim is to provide support to their needs in this moment of professional choice.

  10. Pressure Jumps during Drainage in Macroporous Soils

    DEFF Research Database (Denmark)

    Soto, Diego; Paradelo Pérez, Marcos; Corral, A

    2018-01-01

    Tensiometer readings obtained at high resolution during drainage of structured soil columns revealed pressure jumps with long range correlations and burst sequences with a hierarchical structure. The statistical properties of jumps are similar to Haines jumps described in invasion percolation...... processes at pore scale, but they are much larger in amplitude and duration. Pressure jumps can result from transient redistribution of water potential in internal regions of soil and can be triggered during drainage by capillary displacements at the scale of structural pores....

  11. The identification of price jumps

    Czech Academy of Sciences Publication Activity Database

    Hanousek, Jan; Kočenda, Evžen; Novotný, Jan

    2012-01-01

    Roč. 18, č. 1 (2012), s. 53-77 ISSN 0929-9629 R&D Projects: GA ČR(CZ) GAP403/11/0020; GA ČR(CZ) GBP402/12/G097 Institutional support: PRVOUK-P23 Keywords : price jumps * non-parametric testing * financial econometrics Subject RIV: AH - Economics

  12. Regime Jumps in Electricity Prices

    NARCIS (Netherlands)

    R. Huisman (Ronald); R.J. Mahieu (Ronald)

    2001-01-01

    textabstractElectricity prices are known to be very volatile and subject to frequent jumps due to system breakdown, demand shocks, and inelastic supply. As many international electricity markets are in some state of deregulation, more and more participants in these markets are exposed to these

  13. Mesopause Jumps: Observations and Explanation

    Science.gov (United States)

    Luebken, F. J.; Becker, E.; Höffner, J.; Viehl, T. P.; Latteck, R.

    2017-12-01

    Recent high resolution temperature measurements by resonance lidar at Davis (69°S) occasionally showed a sudden mesopause altitude increase by 5km and an associated mesopause temperature decrease by 10K. We present further observations which are closely related to this `mesopause jump', namely the increase of mean height of polar mesospheric summer echoes (PMSE) observed by a VHF radar, very strong westward winds in the upper mesosphere measured by an MF radar, and relatively large eastward winds in the stratosphere taken from reanalysis. We compare to similar observations in the Northern Hemisphere, namely at ALOMAR (69°N) where such mesopause jumps have never been observed. We present a detailed explanation of mesopause jumps. They occur only when stratospheric winds are moderately eastward and mesospheric winds are very large (westward). Under these conditions, gravity waves with comparatively large eastward phase speeds can pass the stratosphere and propagate to the lower thermosphere because their vertical wavelengths in the mesosphere are rather large which implies reduced dynamical stability. When finally breaking in the lower thermosphere, these waves drive an enhanced residual circulation that causes a cold and high-altitude mesopause. The conditions for a mesopause jump occur only in the Southern Hemisphere (SH) and are associated with the late breakdown of the polar vortex.Mesopause jumps are primarily, but not only, observed prior and close to solstice. We also show that during the onset of PMSE in the SH, stratospheric zonal winds are still eastward (up to 30m/s), and that the onset is not closely related to the transition of the stratospheric circulation.

  14. Sex differences in discriminative power of volleyball game-related statistics.

    Science.gov (United States)

    João, Paulo Vicente; Leite, Nuno; Mesquita, Isabel; Sampaio, Jaime

    2010-12-01

    To identify sex differences in volleyball game-related statistics, the game-related statistics of several World Championships in 2007 (N=132) were analyzed using the software VIS from the International Volleyball Federation. Discriminant analysis was used to identify the game-related statistics which better discriminated performances by sex. Analysis yielded an emphasis on fault serves (SC = -.40), shot spikes (SC = .40), and reception digs (SC = .31). Specific robust numbers represent that considerable variability was evident in the game-related statistics profile, as men's volleyball games were better associated with terminal actions (errors of service), and women's volleyball games were characterized by continuous actions (in defense and attack). These differences may be related to the anthropometric and physiological differences between women and men and their influence on performance profiles.

  15. Effects of timing of signal indicating jump directions on knee biomechanics in jump-landing-jump tasks.

    Science.gov (United States)

    Stephenson, Mitchell L; Hinshaw, Taylour J; Wadley, Haley A; Zhu, Qin; Wilson, Margaret A; Byra, Mark; Dai, Boyi

    2018-03-01

    A variety of the available time to react (ATR) has been utilised to study knee biomechanics during reactive jump-landing tasks. The purpose was to quantify knee kinematics and kinetics during a jump-land-jump task of three possible directions as the ATR was reduced. Thirty-four recreational athletes performed 45 trials of a jump-land-jump task, during which the direction of the second jump (lateral, medial or vertical) was indicated before they initiated the first jump, the instant they initiated the first jump, 300 ms before landing, 150 ms before landing or at the instant of landing. Knee joint angles and moments close to the instant of landing were significantly different when the ATR was equal to or more than 300 ms before landing, but became similar when the ATR was 150 ms or 0 ms before landing. As the ATR was decreased, knee moments decreased for the medial jump direction, but increased for the lateral jump direction. When the ATR is shorter than an individual's reaction time, the movement pattern cannot be pre-planned before landing. Knee biomechanics are dependent on the timing of the signal and the subsequent jump direction. Precise control of timing and screening athletes with low ATR are suggested.

  16. STRUCTURE OF ISOLATED PRECISION FACTORS OF THE MALE STUDENT ON VOLLEYBALL

    OpenAIRE

    Bahri Gjinovci; Malsor Gjonbalaj; Besnik Morina; Florian Miftari

    2015-01-01

    The aim of this study was to verify the current status of accuracy in volleyball for the students of the faculty of physical education and sports of the University of Prishtina, all the students have successfully passed the exam in volleyball. Also, another aim was to observe whether there are significant statistical differences between both generations of students. In the study were included 70 students (35 from the second academic year and 35 from the fourth academic year). To achieve the a...

  17. The patellar tendon in junior elite volleyball players and an Olympic elite weightlifter

    OpenAIRE

    Gisslén, Karl

    2006-01-01

    The principal aim of the present thesis was to prospectively follow (clinical status and ultrasound + Doppler findings) the patellar tendons in the young elite volleyball players at the Swedish National Centre for high school volleyball in Falköping. In an Olympic weightlifter with chronic painful jumper´s knee, the effects of treatment with sclerosing injections followed by early instituted very heavy weightlifting training, was also evaluated. First, in a prevalence study, we demonstrated t...

  18. High Prevalence of Nontraumatic Shoulder Pain in a Regional Sample of Female High School Volleyball Athletes

    OpenAIRE

    Frisch, Kayt E.; Clark, Jacob; Hanson, Chad; Fagerness, Chris; Conway, Adam; Hoogendoorn, Lindsay

    2017-01-01

    Background: Shoulder pain is becoming increasingly problematic in young players as volleyball gains popularity. Associations between repetitive motion and pain and overuse injury have been observed in other overhand sports (most notably baseball). Studies of adult athletes suggest that there is a shoulder pain and overuse problem present in volleyball players, but minimal research has been done to establish rates and causes in juvenile participants. Purpose: To establish rates of shoulder pai...

  19. Anthropometric characteristics and motor abilities in 13-15 year old female volleyball players

    OpenAIRE

    Nešić, Goran; Majstorović, Nikola; Sikimić, Milan; Marković, Srđan; Ilić, Dejan; Grbić, Vladimir; Osmankač, Nedžad; Savić, Zoran

    2014-01-01

    The goal of this research was to determine whether there is a difference in the manifestation of measured anthropometric characteristics and tested motor abilities of female volleyball players that are 13-15 years old. The sample of participants consists of 62 female volleyball players divided into three groups according to their age. The sample of variables has two sub-samples: 18 variables belonging to anthropometric space and 14 variables belonging to the space of motor skills. A variance ...

  20. The effect of ankle bracing on knee kinetics and kinematics during volleyball-specific tasks.

    Science.gov (United States)

    West, T; Ng, L; Campbell, A

    2014-12-01

    The purpose of this study was to examine the effects of ankle bracing on knee kinetics and kinematics during volleyball tasks. Fifteen healthy, elite, female volleyball players performed a series of straight-line and lateral volleyball tasks with no brace and when wearing an ankle brace. A 14-camera Vicon motion analysis system and AMTI force plate were used to capture the kinetic and kinematic data. Knee range of motion, peak knee anterior-posterior and medial-lateral shear forces, and peak ground reaction forces that occurred between initial contact with the force plate and toe off were compared using paired sample t-tests between the braced and non-braced conditions (P volleyball tasks. However, ankle bracing was demonstrated to reduce knee lateral shear forces during all of the lateral movement volleyball tasks. Wearing the Active Ankle T2 brace will not impact knee joint range of motion and may in fact reduce shear loading to the knee joint in volleyball players. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Risk factors for patellar tendinopathy in basketball and volleyball players: a cross-sectional study.

    Science.gov (United States)

    van der Worp, H; van Ark, M; Zwerver, J; van den Akker-Scheek, I

    2012-12-01

    Patellar tendinopathy (PT) has a multifactorial etiology, and many possible risk factors have been described in the literature. The findings are conflicting, though, and most research has been conducted on elite athletes. The aim of the current study is to determine the risk factors for PT in a large representative sample of basketball and volleyball players. Separate risk factors for men and women, basketball and volleyball players, and athletes with unilateral and bilateral PT were identified. All basketball and volleyball players between ages 18 and 35 from the Dutch Basketball Association and the Dutch Volleyball Association were invited to complete an online questionnaire on knee complaints and risk factors for PT. The logistic regression analyses included 2224 subjects. The risk factors for PT were age, playing at the national level, being male and playing volleyball (compared with playing basketball). The risk factors for men and women were comparable. Among volleyball players, outside hitters and middle blockers/hitters had an increased risk compared with setters. For basketball players, no risk factors could be identified. No differences in the risk factors were found between athletes with unilateral and bilateral PT. These findings should be taken into account for prevention and rehabilitation purposes. © 2011 John Wiley & Sons A/S.

  2. Level of Transformation of Motor Skills in Female Volleyball Players Influenced by Training Operators

    Directory of Open Access Journals (Sweden)

    Ifet Mahmutović

    2016-06-01

    Full Text Available The aim of this paper is to determine the level of improvement of motor skills of female volleyball players influenced by kinesiology operators in a period of 6 months. Research was conducted on sample subject of 130 female volleyball players aged from 13±0.6 (mean±SD. Sample variables are divided in two groups: 9 variables of assessment of basic motor skills and 5 variables of assessment of situational motor skills. Analysing difference of arithmetic means between of initial and final measures of treated variables it is determined that there is statistically significant difference on the level Sig=0.001, except for variables of Jelka test which determinates speed duration of female volleyball players. Analysis of quantity changes of basic motor skills, shows that the most important projections on selected discriminative function of basic motor skills have the following variables: body lifting in 30 sec; dynamometry of a hand, hand tapping; pull-up; throwing a 1 kg ball from lying position; side defence movement; push-up on bars and situational motor skill are the variables: precision of tactic serving; consecutive bumping; wall-spikes. Comprehensive development of female volleyball players and diversity in the level of volleyball specialization of the development will depend on systematic work on treated motor skills. This program appeared to be efficient. However, it is necessary to gradually increase the demands for the female volleyball players and to put the accent on performance of acquired situational motor skills in future work.

  3. Pedagogical characteristics of the systems for assessing the technical and tactical skills of qualified volleyball players

    Directory of Open Access Journals (Sweden)

    Мykhailo Oliinyk

    2017-12-01

    Full Text Available Purpose: on the basis of the analysis of the special literature and their own experimental studies, to determine the characteristics of the systems for assessing the technical and tactical skills of qualified volleyball players. Material & Methods: study was conducted on the basis of the material of the national team of Zaporozhye State Medical University on volleyball. Analysis and generalization of the data of scientific and methodical literature are used; registration, analysis and interpretation of indicators of technical and tactical actions of qualified volleyball players in training and competitive processes; pedagogical observations; algorithms for calculating the quantitative and qualitative indicators of technical and tactical skill in volleyball; methods of mathematical statistics. Results: data on the existence of a strong statistical relationship between the systems of assessment of technical and tactical skills of qualified volleyball players, taking into account the specificity of the game role. Conclusion: shows the specifics of the application of various systems for assessing the technical and tactical skills of qualified volleyball players, taking into account the factors of the game role, noted the methodological features of special analysis and interpretation of indicators of technical and tactical actions in the adversarial process.

  4. Locomotion of Mexican jumping beans

    International Nuclear Information System (INIS)

    West, Daniel M; K Lal, Ishan; Leamy, Michael J; Hu, David L

    2012-01-01

    The Mexican jumping bean, Laspeyresia saltitans, consists of a hollow seed housing a moth larva. Heating by the sun induces movements by the larva which appear as rolls, jumps and flips by the bean. In this combined experimental, numerical and robotic study, we investigate this unique means of rolling locomotion. Time-lapse videography is used to record bean trajectories across a series of terrain types, including one-dimensional channels and planar surfaces of varying inclination. We find that the shell encumbers the larva's locomotion, decreasing its speed on flat surfaces by threefold. We also observe that the two-dimensional search algorithm of the bean resembles the run-and-tumble search of bacteria. We test this search algorithm using both an agent-based simulation and a wheeled Scribbler robot. The algorithm succeeds in propelling the robot away from regions of high temperature and may have application in biomimetic micro-scale navigation systems. (paper)

  5. Model for polygonal hydraulic jumps

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Watanabe, Shinya; Bohr, Tomas

    2012-01-01

    We propose a phenomenological model for the polygonal hydraulic jumps discovered by Ellegaard and co-workers [Nature (London) 392, 767 (1998); Nonlinearity 12, 1 (1999); Physica B 228, 1 (1996)], based on the known flow structure for the type-II hydraulic jumps with a "roller" (separation eddy...... nonhydrostatic pressure contributions from surface tension in light of recent observations by Bush and co-workers [J. Fluid Mech. 558, 33 (2006); Phys. Fluids 16, S4 (2004)]. The model can be analyzed by linearization around the circular state, resulting in a parameter relationship for nearly circular polygonal...... states. A truncated but fully nonlinear version of the model can be solved analytically. This simpler model gives rise to polygonal shapes that are very similar to those observed in experiments, even though surface tension is neglected, and the condition for the existence of a polygon with N corners...

  6. Lateral Scapular Slide Test and Scapular Mobility in Volleyball Players

    Science.gov (United States)

    Ozunlu, Nihan; Tekeli, Hatice; Baltaci, Gul

    2011-01-01

    Context: The stability of the scapula in relation to the entire moving upper extremity is the key in the throwing sequence. The importance of scapular positioning in volleyball players has been well documented in the literature, but no one has compared scapular positioning between volleyball players and sedentary people. Objective: To compare measurements of scapular mobility obtained using the lateral scapular slide test between volleyball players and sedentary participants without shoulder impairments and to compare changes in scapular mobility in players according to the number of years of sport participation. Design: Cross-sectional study. Setting: University research laboratory. Patients or Other Participants: A total of 121 people at a single university volunteered. Of these, 67 were sedentary (age = 24.3 ± 2.34 years, height = 1.69 ± 0.09 m, mass = 65.1 ± 11.91 kg); 54 were volleyball players from 4 professional teams and were separated into 2 groups according to their years of sport participation. The first group was named young players (n = 31; age = 17.7 ± 2.58 years, height = 1.83 ± 0.10 m, mass = 68.3 ± 12.21 kg, sport participation ≤ 9 years), and the second group was named old players (n = 23; age = 26.9 ± 3.39 years, height = 1.95 ± 4.38 m, mass = 90.7 ± 5.75 kg, sport participation ≥ 10 years). Main Outcome Measure(s): Study participants completed a rating scale for pain and a questionnaire about demographic and shoulder problems. One assessor performed the lateral scapular slide test and additional flexibility measurements around the shoulder girdle. Flexibility (external rotation, internal rotation) and scapular position (1, 2, 3) were compared among groups (young players, old players, sedentary people) and between sides (dominant, nondominant). Results: In sedentary participants, we found differences for position 1 (t66 = 3.327, P = .002), position 2 (t66 = 2.491, P = .004), position 3 (t66 = 2.512, P = .006), and internal rotation

  7. Data-Driven Jump Detection Thresholds for Application in Jump Regressions

    Directory of Open Access Journals (Sweden)

    Robert Davies

    2018-03-01

    Full Text Available This paper develops a method to select the threshold in threshold-based jump detection methods. The method is motivated by an analysis of threshold-based jump detection methods in the context of jump-diffusion models. We show that over the range of sampling frequencies a researcher is most likely to encounter that the usual in-fill asymptotics provide a poor guide for selecting the jump threshold. Because of this we develop a sample-based method. Our method estimates the number of jumps over a grid of thresholds and selects the optimal threshold at what we term the ‘take-off’ point in the estimated number of jumps. We show that this method consistently estimates the jumps and their indices as the sampling interval goes to zero. In several Monte Carlo studies we evaluate the performance of our method based on its ability to accurately locate jumps and its ability to distinguish between true jumps and large diffusive moves. In one of these Monte Carlo studies we evaluate the performance of our method in a jump regression context. Finally, we apply our method in two empirical studies. In one we estimate the number of jumps and report the jump threshold our method selects for three commonly used market indices. In the other empirical application we perform a series of jump regressions using our method to select the jump threshold.

  8. Are Tendinopathies really a common injury in volleyball?

    Science.gov (United States)

    Bustos, Aldo; Locaso, Fernando

    2017-01-01

    Objectives: To perform a description of tendinopathies as an injury in volleyball high performance. Methods: An observational and prospective study was conducted from 2014-2016 in the senior Argentinian volleyball team. The same was held by two observers. Moreover, 78 athletes were evaluated. We support Dvorak’s claims that an injury is determined by the loss of at least one training session or a match. Results: 78 players were exposed to 21812 hours of training and matches. As a result 37 injuries were evaluated in 31 players. Taking into account tendinopathies, it can be said that 34 players consulted 412 times, showing a prevalence of 43.5% of the whole enquires but when we refer to the same pathology as injury the average lowers, presenting 8 lesions in 6 players and showing a prevalence of 7.6% as injuries. Incidence of tendon injuries is 0.32 per 1000 hours of exposure Tendon Injuries: 5 were patellar, 2 supraspinatus, 1 aquiles. 5 Slight, 2 moderate, 1 severe. Conclusion: Clearly, tendinopathy is a common problem in this sport but it is not a common cause of injury. This is demonstrated in prevalence rates whereas 43.5 % just consulted and 7,6 % suffer from real injuries. We think this might be due to several factors such as, advances in medical therapy, preventive protocols and increase in thresholds of pain that high-performance athletes can bear. In our experience this pathology was shown to be the third leading cause of injuries. In 2016 we did not deal with any case of injury for tendinopathy.

  9. Block ground interaction of rockfalls

    Science.gov (United States)

    Volkwein, Axel; Gerber, Werner; Kummer, Peter

    2016-04-01

    During a rockfall the interaction of the falling block with the ground is one of the most important factors that define the evolution of a rockfall trajectory. It steers the rebound, the rotational movement, possibly brake effects, friction losses and damping effects. Therefore, if most reliable rockfall /trajectory simulation software is sought a good understanding of the block ground interaction is necessary. Today's rockfall codes enable the simulation of a fully 3D modelled block within a full 3D surface . However, the details during the contact, i.e. the contact duration, the penetration depth or the dimension of the marks in the ground are usually not part of the simulation. Recent field tests with rocks between 20 and 80 kg have been conducted on a grassy slope in 2014 [1]. A special rockfall sensor [2] within the blocks measured the rotational velocity and the acting accelerations during the tests. External video records and a so-called LocalPositioningSystem deliver information on the travel velocity. With these data not only the flight phases of the trajectories but also the contacts with the ground can be analysed. During the single jumps of a block the flight time, jump length, the velocity, and the rotation are known. During the single impacts their duration and the acting accelerations are visible. Further, the changes of rotational and translational velocity influence the next jump of the block. The change of the rotational velocity over the whole trajectory nicely visualizes the different phases of a rockfall regarding general acceleration and deceleration in respect to the inclination and the topography of the field. References: [1] Volkwein A, Krummenacher B, Gerber W, Lardon J, Gees F, Brügger L, Ott T (2015) Repeated controlled rockfall trajectory testing. [Abstract] Geophys. Res. Abstr. 17: EGU2015-9779. [2] Volkwein A, Klette J (2014) Semi-Automatic Determination of Rockfall Trajectories. Sensors 14: 18187-18210.

  10. Effect of A 16 Week Combined Strength and Plyometric Training Program Followed by A Detraining Period on Athletic Performance in Pubertal Volleyball Players.

    Science.gov (United States)

    Fathi, Abed; Hammami, Raouf; Moran, Jason; Borji, Rihab; Sahli, Sonia; Rebai, Haithem

    2018-02-01

    The purpose of this study was to determine the effects of 16 weeks of combined strength and plyometric training or plyometric training alone, and how a detraining program can modify adaptations in response to the training stimulus. Sixty male volleyball players (circa PHV:-1 to +1 years from PHV) were assigned to a Combined Training group (CTG) (n=20), a Plyometric Training group (PTG) (n=20) or a control group (CG) (n=20). The experimental groups (CTG and PTG) participated in training twice weekly for 16 weeks. Thigh muscle volume, body fat, flexibility, sprint, jump height and medicine ball throw were measured at pre-training, post-training and detraining. Respectively, the CTG and PTG showed increases in thigh muscle volume (Effect size: 0.71 and 0.42), and decreases in body fat (-0.42 and -0.34) as well as improvements in 5 m sprint (-0.69 and -0.46) 10 m sprint (-0.31 and -0.3), lower body muscle power (0.44 and 0.36) and upper body muscle power (1.32 and 0.7). After the detraining period, all groups maintained previously attained muscle power (6.79% to 9.87%; pplyometric training provided better improvements than plyometric training only. The combination of strength and plyometric training is a time-effective training modality that confers improvements in physical performance measures, muscle size and body fat. A temporary period of detraining may not undermine performance gains in pubertal volleyball players.

  11. Fast Regulation of Vertical Squat Jump during Push-Off in Skilled Jumpers

    Science.gov (United States)

    Fargier, Patrick; Massarelli, Raphael; Rabahi, Tahar; Gemignani, Angelo; Fargier, Emile

    2016-01-01

    The height of a maximum Vertical Squat Jump (VSJ) reflects the useful power produced by a jumper during the push-off phase. In turn this partly depends on the coordination of the jumper's segmental rotations at each instant. The physical system constituted by the jumper has been shown to be very sensitive to perturbations and furthermore the movement is realized in a very short time (ca. 300 ms), compared to the timing of known feedback loops. However, the dynamics of the segmental coordination and its efficiency in relation to energetics at each instant of the push-off phase still remained to be clarified. Their study was the main purpose of the present research. Eight young adult volunteers (males) performed maximal VSJ. They were skilled in jumping according to their sport activities (track and field or volleyball). A video analysis on the kinematics of the jump determined the influence of the jumpers' segments rotation on the vertical velocity and acceleration of the body mass center (MC). The efficiency in the production of useful power at the jumpers' MC level, by the rotation of the segments, was measured in consequence. The results showed a great variability in the segmental movements of the eight jumpers, but homogeneity in the overall evolution of these movements with three consecutive types of coordination in the second part of the push-off (lasting roughly 0.16 s). Further analyses gave insights on the regulation of the push-off, suggesting that very fast regulation(s) of the VSJ may be supported by: (a) the adaptation of the motor cerebral programming to the jumper's physical characteristics; (b) the control of the initial posture; and (c) the jumper's perception of the position of his MC relative to the ground reaction force, during push-off, to reduce energetic losses. PMID:27486404

  12. Fast Regulation of Vertical Squat Jump during push-off in skilled jumpers

    Directory of Open Access Journals (Sweden)

    Patrick FARGIER

    2016-07-01

    Full Text Available The height of a maximum Vertical Squat Jump (VSJ reflects the useful power produced by a jumper during the push-off phase. In turn this partly depends on the coordination of the jumper's segmental rotations at each instant. The physical system constituted by the jumper has been shown to be very sensitive to perturbations and furthermore the movement is realised in a very short time (ca. 300ms, compared to the timing of known feedback loops. However, the dynamics of the segmental coordination and its efficiency in relation to energetics at each instant of the push-off phase still remained to be clarified. Their study was the main purpose of the present research.Eight young adult volunteers (males performed maximal VSJ. They were skilled in jumping according to their sport activities (track and field or volleyball. A video analysis on the kinematics of the jump determined the influence of the jumpers’ segments rotation on the vertical velocity and acceleration of the body mass center (MC. The efficiency in the production of useful power at the jumpers’ MC level, by the rotation of the segments, was measured in consequence. The results showed a great variability in the segmental movements of the eight jumpers, but homogeneity in the overall evolution of these movements with three consecutive types of coordination in the second part of the push-off (lasting roughly 0.16 s.Further analyses gave insights on the regulation of the push-off, suggesting that very fast regulation(s of the VSJ may be supported by: (a the adaptation of the motor cerebral programming to the jumper’s physical characteristics; (b the control of the initial posture; and (c the jumper’s perception of the position of his MC relative to the ground reaction force during push-off to reduce energetic losses.

  13. Fast Regulation of Vertical Squat Jump during Push-Off in Skilled Jumpers.

    Science.gov (United States)

    Fargier, Patrick; Massarelli, Raphael; Rabahi, Tahar; Gemignani, Angelo; Fargier, Emile

    2016-01-01

    The height of a maximum Vertical Squat Jump (VSJ) reflects the useful power produced by a jumper during the push-off phase. In turn this partly depends on the coordination of the jumper's segmental rotations at each instant. The physical system constituted by the jumper has been shown to be very sensitive to perturbations and furthermore the movement is realized in a very short time (ca. 300 ms), compared to the timing of known feedback loops. However, the dynamics of the segmental coordination and its efficiency in relation to energetics at each instant of the push-off phase still remained to be clarified. Their study was the main purpose of the present research. Eight young adult volunteers (males) performed maximal VSJ. They were skilled in jumping according to their sport activities (track and field or volleyball). A video analysis on the kinematics of the jump determined the influence of the jumpers' segments rotation on the vertical velocity and acceleration of the body mass center (MC). The efficiency in the production of useful power at the jumpers' MC level, by the rotation of the segments, was measured in consequence. The results showed a great variability in the segmental movements of the eight jumpers, but homogeneity in the overall evolution of these movements with three consecutive types of coordination in the second part of the push-off (lasting roughly 0.16 s). Further analyses gave insights on the regulation of the push-off, suggesting that very fast regulation(s) of the VSJ may be supported by: (a) the adaptation of the motor cerebral programming to the jumper's physical characteristics; (b) the control of the initial posture; and (c) the jumper's perception of the position of his MC relative to the ground reaction force, during push-off, to reduce energetic losses.

  14. Relations of competitive state anxiety and efficacy of young volleyball players.

    Science.gov (United States)

    Milavić, Boris; Jurko, Damir; Grgantov, Zoran

    2013-05-01

    With the aim of validating the Competitive State Anxiety Inventory on a population of young Croatian volleyball players, 286 examinees, 106 male and 180 female volleyball players (average age of 16.09+/-1.83), filled out the CSAI-2, constructed by Martens, Vealey, Burton, Bump and Smith (1990)1. Given the fact that all scales of the Competitive State Anxiety Inventory have good homogeneity, reliability and sensitivity, it can be concluded that they represent high-quality measuring instruments for measuring psychological characteristics of young volleyball players. Young male and female volleyball players generally have a moderate level of self-confidence, and their cognitive anxiety is more prominent that somatic anxiety. In order to determine the age and gender differences in somatic and cognitive anxiety and self-confidence, parametric analysis of differences was performed and coefficients of the independent samples t-test were calculated. By analysis of differences according to age, it has been established that female junior players, in relation to female youth players, express a significantly lower level of somatic and cognitive anxiety and a significantly higher level of self-confidence. As opposed to female players, male youth and junior players do not differ in any of the analysed variables. By analysis of differences according to gender, it has been established that male youth players have a significantly higher level of self-confidence in comparison to female youth players. No significant differences were found in the level of competitive anxiety and self-confidence by analysis of variance between different player roles. No significant differences were found by discriminant analysis in somatic and cognitive anxiety, and self-confidence of female volleyball players of different situational efficacy. The group of least efficient male volleyball players is characterized by a very low level of self-confidence, while the most efficient group of volleyball

  15. Psychophysiological response in parachute jumps, the effect of experience and type of jump.

    Science.gov (United States)

    Clemente-Suárez, Vicente Javier; Robles-Pérez, José Juan; Fernández-Lucas, Jesús

    2017-10-01

    We aimed to analyse the effect of experience and type of parachute jump on the psychophysiological responses of jumpers. We analysed blood oxygen saturation, heart rate, blood glucose, lactate and creatinkinase, leg strength, isometric hand strength, cortical arousal, specific fine motor skills, self-confidence and cognition, and somatic and state anxiety, before and after four different parachute jumps: a sport parachute jump, a manual tactical parachute jump, tandem pilots, and tandem passengers. Independently of the parachute jump, the psychophysiological responses of experienced paratroopers were not affected by the jumps, except for an increase in anaerobic metabolism. Novice parachute jumpers presented a higher psychophysiological stress response than the experienced jumpers, together with a large anticipatory anxiety response before the jump; however, this decreased after the jump, although the high physiological activation was maintained. This information could be used by civil and military paratroopers' instructors to improve their training programmes. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Pre-Activity and Post-Activity Stretching Perceptions and Practices in NCAA Division I Volleyball Programs

    Science.gov (United States)

    Judge, Lawrence W.; Bodey, Kimberly J.; Bellar, David; Bottone, Adam; Wanless, Elizabeth

    2010-01-01

    The purpose of this study was to determine if NCAA Division I women's volleyball programs were in compliance with suggested current pre- and post-activity stretching protocols. Questionnaires were sent to NCAA division I women's volleyball programs in the United States. Fifty six coaches (23 males & 33 females) participated in the study. Some…

  17. Risk factors associated with self-reported symptoms of digital ischemia in elite male volleyball players in the Netherlands

    NARCIS (Netherlands)

    van de pol, D.; Kuijer, P. P. F. M.; Langenhorst, T.; Maas, M.

    2014-01-01

    One in every four elite male volleyball players in the Netherlands reported blue or pale digits in the dominant hand. Little is known about risk factors. To assess whether personal-, sports-, and work-related risk factors are associated with these symptoms in these volleyball players, a survey was

  18. Examination of the Relationship between Coach-Athlete Communication Levels and Perceived Motivational Climate for Volleyball Players

    Science.gov (United States)

    Avci, Kübra Seden; Çepikkurt, Fatma; Kale, Esen Kizildag

    2018-01-01

    The aim of this study was to reveal the relationship between the athlete-coach relationship and the motivational climate created by the coach. In this study, relational survey model was used. The study sample included 96 female volleyball players who are active players at Turkey Women Volleyball 3rd League. "The Coach-Athlete Relationship…

  19. Dynamic jump intensities and risk premiums

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Ornthanalai, Chayawat; Jacobs, Kris

    2012-01-01

    We build a new class of discrete-time models that are relatively easy to estimate using returns and/or options. The distribution of returns is driven by two factors: dynamic volatility and dynamic jump intensity. Each factor has its own risk premium. The models significantly outperform standard...... models without jumps when estimated on S&P500 returns. We find very strong support for time-varying jump intensities. Compared to the risk premium on dynamic volatility, the risk premium on the dynamic jump intensity has a much larger impact on option prices. We confirm these findings using joint...

  20. Characteristics of Air Entrainment in Hydraulic Jump

    Science.gov (United States)

    Albarkani, M. S. S.; Tan, L. W.; Al-Gheethi, A.

    2018-04-01

    The characteristics of hydraulic jump, especially the air entrainment within jump is still not properly understood. Therefore, the current work aimed to determine the size and number of air entrainment formed in hydraulic jump at three different Froude numbers and to obtain the relationship between Froude number with the size and number of air entrainment in hydraulic jump. Experiments of hydraulic jump were conducted in a 10 m long and 0.3 m wide Armfield S6MKII glass-sided tilting flume. Hydraulic jumps were produced by flow under sluice gate with varying Froude number. The air entrainment of the hydraulic jump was captured with a Canon Power Shot SX40 HS digital camera in video format at 24 frames per second. Three discharges have been considered, i.e. 0.010 m3/s, 0.011 m3/s, and 0.013 m3/s. For hydraulic jump formed in each discharge, 32 frames were selected for the purpose of analysing the size and number of air entrainment in hydraulic jump. The results revealed that that there is a tendency to have greater range in sizes of air bubbles as Fr1 increases. Experiments with Fr1 = 7.547. 7.707, and 7.924 shown that the number of air bubbles increases exponentially with Fr1 at a relationship of N = 1.3814 e 0.9795Fr1.

  1. Como pensar o voleibol de praia sociologicamente How to think beach volleyball sociologicaly

    Directory of Open Access Journals (Sweden)

    Gilmar Francisco Afonso

    2012-03-01

    Full Text Available Este artigo trata de uma análise sociológica da história do Voleibol de Praia. Aqui procuramos responder: por que o desenvolvimento internacional da modalidade ocorreu no Brasil e não nos EUA? Como hipótese apresentamos que a estrutura do campo Voleibol de Praia vem sendo determinada pela disputa de duas instituições, a Federação Internacional de Voleibol (FIVB e a Association of Volleyball Professionals (AVP. Os objetivos foram investigar por que o Brasil foi o local onde o Voleibol de Praia se transformou em show business internacional e analisar as configurações entre os agentes/estruturas que compõem o campo. O recorte compreendeu o intervalo de 1985 a 2004. Como referencial teórico metodológico de análise, buscamos na teoria dos campos de Pierre Bourdieu o instrumental capaz de explicitar as relações que se estabelecem no contexto socioeconômico contemporâneo, aplicando-o na leitura do desenvolvimento do Voleibol de Praia. Constatamos que a FIVB assumiu o controle do campo e o Brasil passou a ser uma estrutura estruturante da modalidade.This study carried out a sociological analysis of the history of Beach Volleyball. The problem was: why has the development of Beach Volleyball as an international sport occurred in Brazil rather than in the USA? The hypothesis proposed that the framework of the field of Beach Volleyball has been defined by the dispute between two institutions, the Fèdèration Internationale de Volleyball (FIVB and the Association of Volleyball Professionals (AVP. The outlined goals were to investigate why Brazil came to be where Beach Volleyball was transformed into International Show Business and analyze the structure of the interdependent relationships among the sub components that make up the field. The proposed period included the years 1985 to 2004. The instrument capable of expounding the relationships that are established in the contemporary socioeconomic context was found in the 'theory of fields

  2. Home advantage in high-level volleyball varies according to set number.

    Science.gov (United States)

    Marcelino, Rui; Mesquita, Isabel; Palao Andrés, José Manuel; Sampaio, Jaime

    2009-01-01

    The aim of the present study was to identify the probability of winning each Volleyball set according to game location (home, away). Archival data was obtained from 275 sets in the 2005 Men's Senior World League and 65,949 actions were analysed. Set result (win, loss), game location (home, away), set number (first, second, third, fourth and fifth) and performance indicators (serve, reception, set, attack, dig and block) were the variables considered in this study. In a first moment, performance indicators were used in a logistic model of set result, by binary logistic regression analysis. After finding the adjusted logistic model, the log-odds of winning the set were analysed according to game location and set number. The results showed that winning a set is significantly related to performance indicators (Chisquare(18)=660.97, padvantage at the beginning of the game (first set) and in the two last sets of the game (fourth and fifth sets), probably due to facilities familiarity and crowd effects. Different game actions explain these advantages and showed that to win the first set is more important to take risk, through a better performance in the attack and block, and to win the final set is important to manage the risk through a better performance on the reception. These results may suggest intra-game variation in home advantage and can be most useful to better prepare and direct the competition. Key pointsHome teams always have more probability of winning the game than away teams.Home teams have higher performance in reception, set and attack in the total of the sets.The advantage of home teams is more pronounced at the beginning of the game (first set) and in two last sets of the game (fourth and fifth sets) suggesting intra-game variation in home advantage.Analysis by sets showed that home teams have a better performance in the attack and block in the first set and in the reception in the third and fifth sets.

  3. A tale of quantum jumps

    International Nuclear Information System (INIS)

    Carmichael, H.J.

    2015-01-01

    This paper cannot provide anything like a complete overview of quantum optics in New Zealand. The scope over 40 years is far too broad and the number of players far too large. Nevertheless, the story of quantum jumps, from the days of the Old Quantum Theory up to the present, serves to highlight some small part of the New Zealand experience. It also offers an encounter with the oddities of light as a quantum mechanical 'something', oddities that the gallant proposers of technologies for the future aim to exploit. (author).

  4. Dynamic trunk stabilization: a conceptual back injury prevention program for volleyball athletes.

    Science.gov (United States)

    Smith, Chad E; Nyland, John; Caudill, Paul; Brosky, Joseph; Caborn, David N M

    2008-11-01

    The sport of volleyball creates considerable dynamic trunk stability demands. Back injury occurs all too frequently in volleyball, particularly among female athletes. The purpose of this clinical commentary is to review functional anatomy, muscle coactivation strategies, assessment of trunk muscle performance, and the characteristics of effective exercises for the trunk or core. From this information, a conceptual progressive 3-phase volleyball-specific training program is presented to improve dynamic trunk stability and to potentially reduce the incidence of back injury among volleyball athletes. Phase 1 addresses low-velocity motor control, kinesthetic awareness, and endurance, with the clinician providing cues to teach achievement of biomechanically neutral spine alignment. Phase 2 focuses on progressively higher velocity dynamic multiplanar endurance, coordination, and strength-power challenges integrating upper and lower extremity movements, while maintaining neutral spine alignment. Phase 3 integrates volleyball-specific skill simulations by breaking down composite movement patterns into their component parts, with differing dynamic trunk stability requirements, while maintaining neutral spine alignment. Prospective research is needed to validate the efficacy of this program.

  5. Kinematics and Kinetics of Squats, Drop Jumps and Imitation Jumps of Ski Jumpers.

    Science.gov (United States)

    Pauli, Carole A; Keller, Melanie; Ammann, Fabian; Hübner, Klaus; Lindorfer, Julia; Taylor, William R; Lorenzetti, Silvio

    2016-03-01

    Squats, drop jumps, and imitation jumps are commonly used training exercises in ski jumping to enhance maximum force, explosive force, and sport-specific skills. The purpose of this study was to evaluate the kinetics and kinematics of training exercises in ski jumping and to find objective parameters in training exercises that most correlate with the competition performance of ski jumpers. To this end, barbell squats, drop jumps, and imitation jumps were measured in a laboratory environment for 10 elite ski jumpers. Force and motion data were captured, and the influence of maximum vertical force, force difference, vertical take-off velocity, knee moments, knee joint power, and a knee valgus/varus index was evaluated and correlated with their season jump performance. The results indicate that, especially for the imitation jumps, a good correlation exists between the vertical take-off velocity and the personal jump performance on the hill (R = 0.718). Importantly, however, the more the athletes tended toward a valgus knee alignment during the measured movements, the worse their performance (R = 0.729 imitation jumps; R = 0.685 squats). Although an evaluation of the athletes' lower limb alignment during competitive jumping on the hill is still required, these preliminary data suggest that performance training should additionally concentrate on improving knee alignment to increase ski jumping performance.

  6. Influence of the level of speed-strength preparedness on the agility of volleyball players 12–13 years old

    Directory of Open Access Journals (Sweden)

    Oleg Shevchenko

    2018-02-01

    Full Text Available Purpose: determine the impact level of indicators of speed-strength preparedness for the agility of young volleyball players 12–13 years. Material & Methods: analysis of scientific and methodological literature, pedagogical testing of speed-strength qualities and agility, pedagogical experiment, methods of mathematical statistics. The study involved 25 volleyball players aged 12–13 years, training in the basic training group of the second year of training of the sports club "Lokomotiv" in Kharkov. Young athletes were divided into an experimental – 13 people and a control –12 volleyball team. Results: after the introduction of the experimental methodology, a link was found between the level of speed-strength abilities and the agility of volleyball players. Conclusion: the positive influence of development of speed-strength qualities on indicators of agility of volleyball players that is necessary for selection of means and methods in training process of young athletes is proved.

  7. Cognitive and somatic anxiety and self-confidence in athletic performance of beach volleyball.

    Science.gov (United States)

    Kais, Kristjan; Raudsepp, Lennart

    2004-04-01

    This study considered the influence of competitive anxiety and self-confidence state responses upon athletic performance. 66 male beach volleyball players completed the translated and modified Competitive State Anxiety Inventory-2 which included the original intensity scale and a direction scale of Jones and Swain. Players' performance was scored from the video records using a standard rating scales. Correlations indicated scores on Direction subscale of modified Competitive State Anxiety Inventory-2 and Self-confidence were moderately positively (r=.27 to .51) correlated with different skill components and sum of skill components of beach volleyball. Stepwise multiple regressions indicated that, as anticipated, directional perceptions of cognitive and somatic anxiety and self-confidence were significant predictors of beach volleyball performance but accounted for only 42% of variance. Original Intensity subscales of somatic and cognitive anxiety did not predict performance. Findings support the notion that direction of anxiety responses must be taken into consideration when examining anxiety-performance association in sport.

  8. Factors associated to performance efficacy of technical-tactical actions in volleyball

    Directory of Open Access Journals (Sweden)

    William das Neves Salles

    2017-05-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2017v19n1p74   The aim of the study was to investigate the factors associated to performance efficacy of technical-tactical actions in volleyball. Based on the protocol of the Instrument for Technical and Tactical Performance Assessment in Volleyball (IAD-VB, 44.025 match actions performed by male and female athletes from u-15, u-16 and u-17 finalist teams of the 2010 Santa Catarina Volleyball Championship in Brazil were observed. Data were analyzed on SPPS 21 software using the logistic regression technique, adopting 5% significance level for the interpretation of results. Adjusted model explained 51.40% efficacy variance, and the factors associated with this variable were decision making, adjustment, efficiency, and competition level.

  9. Isolated and painless (? atrophy of the infraspinatus muscle: left handed versus right handed volleyball players

    Directory of Open Access Journals (Sweden)

    Thiago D. Gonçalves Côelho

    1994-12-01

    Full Text Available The suprascapular nerve originates from the upper trunk of the brachial plexus or less frequently from the root of C5. It runs a short way and crosses the suprascapular notch. It innervates the supraspinatus muscle and the acromioclavicular and glenohumeral joints. Then, it crosses the lateral edge of the spine of the scapula passing through the spinoglenoid notch, and innervates the infraspinatus muscle. These are potential sites of injury to the suprascapular nerve. Three cases of suprascapular nerve entrapment causing an isolated infraspinatus muscle atrophy in volleyball players were studied. It is suggested the hypothesis that the nature of the smash, in which the athlete uses the arm violently, more than does in volleyball service or in the art of reception, is the key to the pathogenesis of the lesion in volleyball players.

  10. Contact psychophysiological and neural functions with technical and tactical readiness volleyball

    Directory of Open Access Journals (Sweden)

    I.D. Glazyrin

    2013-06-01

    Full Text Available Set the level of neural development, psycho-physiological functions in highly skilled volleyball players. Defined technical and tactical preparedness highly skilled volleyball players in the competitive period of the annual cycle of training. The study involved six masters of sport and 8 candidates for the master of sports. That the quality of play activities and the successful execution of technical elements depend on functional mobility, strength and reactivity of nerve processes, associative thinking, memory and attention. The results, which may have a prognostic value. It is shown that the neurodynamic functions are genetically determined. It is recommended to use them for the initial recruitment and selection stages for sports improvement. The necessity influence the types of thinking, memory and attention in the training process of volleyball players.

  11. Separation and pattern formation in hydraulic jumps

    DEFF Research Database (Denmark)

    Bohr, Tomas; Ellegaard, C.; Hansen, A. Espe

    1998-01-01

    We present theory and experiments on the circular hydraulic jump in the stationary regime. The theory can handle the situation in which the fluid flows over an edge far away from the jump. In the experiments the external height is controlled, and a series of transitions in the flow structure appe...

  12. Biomechanical analysis of drop and countermovement jumps

    NARCIS (Netherlands)

    Bobbert, M. F.; Mackay, M.T.; Schinkelshoek, D.; Huijing, P. A.; van Ingen Schenau, G. J.

    For 13 subjects the performance of drop jumps from a height of 40 cm (DJ) and of countermovement jumps (CMJ) was analysed and compared. From force plate and cine data biomechanical variables including forces, moments, power output and amount of work done were calculated for hip, knee and ankle

  13. Jump Detection in the Danish Stock Market

    DEFF Research Database (Denmark)

    Høg, Esben

    2002-01-01

    It is well known in financial economics that stock market return data are often modelled by a diffusion process with some regular drift function. Occasionally, however, sudden changes or jumps occur in the return data. Wavelet scaling methods are used to detect jumps and cusps in stock market...

  14. You Say Jump, I Say How High?

    DEFF Research Database (Denmark)

    Fasterhold, Martin; Pichlmair, Martin; Holmgård, Christoffer

    This paper explores the design of jumping in 2D platform games. Through creating a method for measuring existing games, applying this method to a selection of different platformer games, and analysing the results, the paper arrives at a comprehensive data model for jumping. The model supports the...

  15. Modified Tuck Jump Assessment: Reliability and Training of Raters

    Directory of Open Access Journals (Sweden)

    Craig A. Smith, Nicole J. Chimera, Monica R. Lininger, Meghan Warren

    2017-09-01

    Full Text Available We are writing with regard to “Intra- and inter-rater reliability of the modified tuck jump assessment,” by Fort-Vanmeerhaeghe et al. (2017 published in the Journal of Sports Science & Medicine. The authors reported on the reliability of the modified Tuck Jump Assessment (TJA. The purpose of the article was twofold: to introduce a new scoring methodology and to report on the interrater and intrarater reliability. The authors found the modified TJA to have excellent interrater reliability (ICC = 0.94, 95% CI = 0.88-0.97 and intrarater reliability (rater 1 ICC = 0.94, 95% CI = 0.88-0.9; rater 2 ICC = 0.96, 95% CI = 0.92-0.98 with experienced raters (n = 2 in a sample of 24 elite volleyball athletes. Overall, we found the study to be well conducted and valuable to the field of injury screening; however, the study did not adequately explain how the raters were trained in the modified TJA to improve consistency of scoring, or the modifications of the individual flaw “excessive contact noise at landing.” This information is necessary to improve the clinical utility of the TJA and direct future reliability studies. The TJA has been changed at least three times in the literature: from the initial introduction (Myer et al., 2006 to the most referenced and detailed protocol (Myer et al., 2011 to the publication under discussion (Fort-Vanmeerhaeghe et al., 2017. The initial test protocol was based upon clinical expertise and has evolved over time as new research emerged and problems arose with the original TJA. Initially, the TJA was scored on a visual analog scale (Myer et al., 2006, changed to a dichotomous scale (0 for no flaw or 1 for flaw present (Myer et al., 2011 and most recently modified using an ordinal scale (Fort-Vanmeerhaeghe et al., 2017. A significant disparity in the reported interrater and intrarater reliability arose with the dichotomously scored TJA, between those involved in the development of the TJA (Herrington et al., 2013

  16. Analysis of male volleyball players' motor activities during a top level match.

    Science.gov (United States)

    Mroczek, Dariusz; Januszkiewicz, Aleksander; Kawczyński, Adam S; Borysiuk, Zbigniew; Chmura, Jan

    2014-08-01

    The present study aims to assess motor activity of volleyball players using an original video recording method developed by the authors. Twenty-eight volleyball players taking part in 4 matches of the Polish Volleyball League were examined. The recorded data were analyzed in view of the mean total distance covered by volleyball players on different court positions during a match, set, and rally. The results showed that volleyball players cover the mean total distance of 1221 ± 327 m (mean ± SD) in a 3-set match, and 1757 ± 462 m in a 4-set match. A statistically significant difference (p ≤ 0.005) was found between the distance covered by the middle blockers and setters, defenders, spikers, and libero players in a match and in a set. The study revealed a tendency to lengthen the distance by the players in the final sets, which is indicative of the extended time of individual rallies. The mean distance covered in a single rally amounted to 10.92 ± 0.9 m in 4 matches (between 9.12 and 12.56 m). Considering the limited size of the field of play, volleyball players cover relatively long distances during a match and individual sets, with the shortest distance covered by middle blockers, and the longest by setters. From a practical application point of view, detailed topographic analysis of a player's movements on the court as well as precise data on the time of activity and rest breaks provide the coach with valuable information on the ways of development of arrhythmic, changing and dynamic training loads.

  17. Tracking of ball and players in beach volleyball videos.

    Directory of Open Access Journals (Sweden)

    Gabriel Gomez

    Full Text Available This paper presents methods for the determination of players' positions and contact time points by tracking the players and the ball in beach volleyball videos. Two player tracking methods are compared, a classical particle filter and a rigid grid integral histogram tracker. Due to mutual occlusion of the players and the camera perspective, results are best for the front players, with 74,6% and 82,6% of correctly tracked frames for the particle method and the integral histogram method, respectively. Results suggest an improved robustness against player confusion between different particle sets when tracking with a rigid grid approach. Faster processing and less player confusions make this method superior to the classical particle filter. Two different ball tracking methods are used that detect ball candidates from movement difference images using a background subtraction algorithm. Ball trajectories are estimated and interpolated from parabolic flight equations. The tracking accuracy of the ball is 54,2% for the trajectory growth method and 42,1% for the Hough line detection method. Tracking results of over 90% from the literature could not be confirmed. Ball contact frames were estimated from parabolic trajectory intersection, resulting in 48,9% of correctly estimated ball contact points.

  18. Tracking of Ball and Players in Beach Volleyball Videos

    Science.gov (United States)

    Gomez, Gabriel; Herrera López, Patricia; Link, Daniel; Eskofier, Bjoern

    2014-01-01

    This paper presents methods for the determination of players' positions and contact time points by tracking the players and the ball in beach volleyball videos. Two player tracking methods are compared, a classical particle filter and a rigid grid integral histogram tracker. Due to mutual occlusion of the players and the camera perspective, results are best for the front players, with 74,6% and 82,6% of correctly tracked frames for the particle method and the integral histogram method, respectively. Results suggest an improved robustness against player confusion between different particle sets when tracking with a rigid grid approach. Faster processing and less player confusions make this method superior to the classical particle filter. Two different ball tracking methods are used that detect ball candidates from movement difference images using a background subtraction algorithm. Ball trajectories are estimated and interpolated from parabolic flight equations. The tracking accuracy of the ball is 54,2% for the trajectory growth method and 42,1% for the Hough line detection method. Tracking results of over 90% from the literature could not be confirmed. Ball contact frames were estimated from parabolic trajectory intersection, resulting in 48,9% of correctly estimated ball contact points. PMID:25426936

  19. [Eating habits of a group of professional volleyball players].

    Science.gov (United States)

    Gacek, Maria

    2011-01-01

    The aim of the research was an analysis of the eating habits of professional volleyball players according to their sex and age. The research has been carried out on a group of 210 men players and women players at the age of 13-25, representatives of sports clubs in Ostrołeka, Myślenice, Bydgoszcz and Warszawa. The research has revealed a limited realisation of rational diets by both men and women players. The most common mistakes made by them include a smaller number of meals during the day than recommended (especially among men), taking up training on empty stomach and insufficient frequency of consumption of dairy products, fish, vegetables and fruit. The research has also revealed excessive consumption of sweets, sweet sparkling drinks and fast food (mainly among men). The examined players to some extent only apply regular strategies of rehydration of their organisms. A high percentage of them do not pay attention to supplementation of liquids after an effort or they drink a lot of liquids at one time. The most frequently chosen drinks were mineral water and isotonic drinks. Supplementation was applied by a small percentage of the players, mainly men, who most often chose vitamins, Izostar, creatine, L-carnitine and HMB.

  20. A review on the basketball jump shot.

    Science.gov (United States)

    Okazaki, Victor H A; Rodacki, André L F; Satern, Miriam N

    2015-06-01

    The ability to shoot an effective jump shot in the sport of basketball is critical to a player's success. In an attempt to better understand the aspects related to expert performance, researchers have investigated successful free throws and jump shots of various basketball players and identified movement variables that contribute to their success. The purpose of this study was to complete a systematic review of the scientific literature on the basketball free throw and jump shot for the purpose of revealing the critical components of shooting that coaches, teachers, and players should focus on when teaching, learning, practising, and performing a jump shot. The results of this review are presented in three sections: (a) variables that affect ball trajectory, (b) phases of the jump shot, and (c) additional variables that influence shooting.

  1. Theory of boiling-up jump

    International Nuclear Information System (INIS)

    Labuntsov, D.A.; Avdeev, A.A.

    1981-01-01

    Concept of boiling-up jump representing a zone of intense volume boiling-up separating overtaking flow of overheated metastable liquid from an area of equilibrium flow located below along the flow is introduced. It is shown that boiling-up jump is a shock wave of rarefaction. It is concluded that entropy increment occurs on the jump. Characteristics of adiabatic shock wave curve of boiling- up in ''pressure-specific volume'' coordinates have been found and its form has been investigated. Stability of boiling-up jump has been analyzed as well. On the basis of approach developed analysis is carried out on the shock adiobatic curve of condensation. Concept of boiling-up jump may be applied to the analysis of boiling-up processes when flowing liquid through packings during emergency pressure drop etc [ru

  2. Evaluation of the body bearing of high performance female volleyball players

    Directory of Open Access Journals (Sweden)

    Stech M.

    2010-09-01

    Full Text Available In the present paper the results of the study of body bearing in 12 high performance female volleyball players of polish team (TPS Rumia are presented. To estimate body bearing the New-York's test of the body bearing classification was used. The results of the study have shown that asymmetrical positions of volleyball players in the time of services and attacks are contributed to formed some asymmetrical disturbances of body bearing. At the majority of sportsmen it is exhibited in omitting the left brachium and the left blade, in a right-hand scoliosis, in the tendency to a platypodia. It requires use of special preventive and adjusting exercises.

  3. Biomechanical Assessment of the Strength of Volleyball Players in Different Stages of the Training Macrocycle

    Directory of Open Access Journals (Sweden)

    Śliwa Marcin

    2015-09-01

    Full Text Available Introduction. In order to help volleyball players achieve superior results, their coaches are constantly seeking new training methods. One of the methods used to improve the effectiveness of the training that is being implemented is conducting tests which make it possible to assess the player’s locomotor system in terms of its motor and biomechanical functions. The aim of the study was to determine the torque of the knee flexor and extensor muscles of volleyball players in three stages of the annual macrocycle.

  4. Kinematics and Kinetics of Squats, Drop Jumps and Imitation Jumps of Ski Jumpers

    Science.gov (United States)

    Pauli, Carole A.; Keller, Melanie; Ammann, Fabian; Hübner, Klaus; Lindorfer, Julia; Taylor, William R.

    2016-01-01

    Abstract Pauli, CA, Keller, M, Ammann, F, Hübner, K, Lindorfer, J, Taylor, WR, and Lorenzetti, S. Kinematics and kinetics of squats, drop jumps and imitation jumps of ski jumpers. J Strength Cond Res 30(3): 643–652, 2016—Squats, drop jumps, and imitation jumps are commonly used training exercises in ski jumping to enhance maximum force, explosive force, and sport-specific skills. The purpose of this study was to evaluate the kinetics and kinematics of training exercises in ski jumping and to find objective parameters in training exercises that most correlate with the competition performance of ski jumpers. To this end, barbell squats, drop jumps, and imitation jumps were measured in a laboratory environment for 10 elite ski jumpers. Force and motion data were captured, and the influence of maximum vertical force, force difference, vertical take-off velocity, knee moments, knee joint power, and a knee valgus/varus index was evaluated and correlated with their season jump performance. The results indicate that, especially for the imitation jumps, a good correlation exists between the vertical take-off velocity and the personal jump performance on the hill (R = 0.718). Importantly, however, the more the athletes tended toward a valgus knee alignment during the measured movements, the worse their performance (R = 0.729 imitation jumps; R = 0.685 squats). Although an evaluation of the athletes' lower limb alignment during competitive jumping on the hill is still required, these preliminary data suggest that performance training should additionally concentrate on improving knee alignment to increase ski jumping performance. PMID:26418370

  5. Mobile Jump Assessment (mJump): A Descriptive and Inferential Study.

    Science.gov (United States)

    Mateos-Angulo, Alvaro; Galán-Mercant, Alejandro; Cuesta-Vargas, Antonio

    2015-08-26

    Vertical jump tests are used in athletics and rehabilitation to measure physical performance in people of different age ranges and fitness. Jumping ability can be analyzed through different variables, and the most commonly used are fly time and jump height. They can be obtained by a variety of measuring devices, but most are limited to laboratory use only. The current generation of smartphones contains inertial sensors that are able to record kinematic variables for human motion analysis, since they are tools for easy access and portability for clinical use. The aim of this study was to describe and analyze the kinematics characteristics using the inertial sensor incorporated in the iPhone 4S, the lower limbs strength through a manual dynamometer, and the jump variables obtained with a contact mat in the squat jump and countermovement jump tests (fly time and jump height) from a cohort of healthy people. A cross sectional study was conducted on a population of healthy young adults. Twenty-seven participants performed three trials (n=81 jumps) of squat jump and countermovement jump tests. Acceleration variables were measured through a smartphone's inertial sensor. Additionally, jump variables from a contact mat and lower limbs dynamometry were collected. In the present study, the kinematic variables derived from acceleration through the inertial sensor of a smartphone iPhone 4S, dynamometry of lower limbs with a handheld dynamometer, and the height and flight time with a contact mat have been described in vertical jump tests from a cohort of young healthy subjects. The development of the execution has been described, examined and identified in a squat jump test and countermovement jump test under acceleration variables that were obtained with the smartphone. The built-in iPhone 4S inertial sensor is able to measure acceleration variables while performing vertical jump tests for the squat jump and countermovement jump in healthy young adults. The acceleration

  6. Epidural block

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000484.htm Epidural block - pregnancy To use the sharing features on this page, please enable JavaScript. An epidural block is a numbing medicine given by injection (shot) ...

  7. Population Blocks.

    Science.gov (United States)

    Smith, Martin H.

    1992-01-01

    Describes an educational game called "Population Blocks" that is designed to illustrate the concept of exponential growth of the human population and some potential effects of overpopulation. The game material consists of wooden blocks; 18 blocks are painted green (representing land), 7 are painted blue (representing water); and the remaining…

  8. Risk factors associated with self-reported symptoms of digital ischemia in elite male volleyball players in the Netherlands.

    Science.gov (United States)

    van de Pol, D; Kuijer, P P F M; Langenhorst, T; Maas, M

    2014-08-01

    One in every four elite male volleyball players in the Netherlands reported blue or pale digits in the dominant hand. Little is known about risk factors. To assess whether personal-, sports-, and work-related risk factors are associated with these symptoms in these volleyball players, a survey was performed among elite male volleyball players in the Dutch national top league and in the Dutch beach volleyball team. The questionnaire assessed the presence of symptoms and risk factors. Binary logistic regression was performed to calculate odds ratios (ORs). A total of 99 of the 107 athletes participated - a response rate of 93%. Two sports-related risk factors were associated with symptoms of blue or pale digits: 18-30 years playing volleyball [OR = 6.70; 95% confidence interval (CI) 1.12-29.54] and often/always performing weight training to increase dominant limb strength (OR = 2.70; 95% CI 1.05-6.92). No significant other sports-, personal-, or work-related risk factors were found. Playing volleyball for more than 17 years and often/always performing weight training to increase dominant limb strength were independently associated with an increased risk on ischemia-related complaints of the dominant hand in elite male volleyball players. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Effects of prolonged intensive training on the resting levels of salivary immunoglobulin A and cortisol in adolescent volleyball players.

    Science.gov (United States)

    Li, T L; Lin, H C; Ko, M H; Chang, C K; Fang, S H

    2012-10-01

    Concerns have been raised regarding the effects of prolonged intensive training on adolescent athletes. This study investigated the differences in mucosal immune functions and stress responses between intensively trained male adolescent volleyball players and age-matched sedentary controls. Twelve male volleyball players (16.5 [0.7] years of age) and sixteen healthy sedentary male volunteers (17.1 [0.6] years of age) participated in this study. Volleyball players were engaged in regular and year-round training. Unstimulated saliva samples were collected from volleyball players during the high-intensity training period and from the counterparts at the same timepoints after at least 18 hours of rest. Concentrations of salivary total protein, secretory immunoglobulin A (SIgA), cortisol, and lactoferrin were measured. Results of this study revealed that the SIgA concentrations and the ratio of SIgA/total protein in volleyball players were significantly lower compared with those in sedentary controls. However, the salivary cortisol concentrations and the ratio of cortisol/total protein in volleyball players were markedly higher compared with those in sedentary controls. No significant difference was observed in lactoferrin levels between volleyball players and sedentary controls. The findings of this study suggest that the prolonged intensive training may elicit a sustained stress and induce a suppressive effect on mucosal immunity in regularly and intensively trained adolescent athletes.

  10. Relação saque, recepção e ataque no voleibol juvenil masculino Relation service, reception and attack in male junior volleyball

    Directory of Open Access Journals (Sweden)

    Gustavo De Conti Teixeira Costa

    2011-03-01

    Full Text Available Neste texto, O objetivo do presente estudo consistiu em analisar a relação do saque e da recepção com o efeito do ataque em seleções nacionais de voleibol juvenil masculino. Recorreu-se à observação e análise de onze jogos, totalizando 781 ações de ataque. Os resultados demonstraram que o ponto no ataque ocorreu mais do que o esperado após o saque suspensão colocado e após a recepção que permitiu todas as opções de ataque. Contrariamente, este ocorreu menos do que o esperado após o saque suspensão potente e a recepção que não permitiu ataque organizado. O presente estudo permitiu inferir que o saque potente e a recepção com baixos níveis de eficácia reduzem as possibilidades de pontuar no ataque. O fato do saque potente adversário induzir menor ocorrência de ponto no ataque, pode sugerir alguma debilidade na organização ofensiva da equipa perante as dificuldades acrescidas colocadas por este tipo de saque.Tal sugere a necessidade de, desde as categorias de base, ser dada maior atenção no treinamento à capacidade das equipas organizarem as manobras ofensivas em resposta a saques agressivos como é o caso do saque suspensão potente.The purpose of this study was to analyze the relationship between serve and serve reception on the effect of the offensive system in the national junior male volleyball teams. Eleven games were analyzes, totaling 781 attack actions. The results showed that the attack point occurred more than expected after the top spin placed jump serve from the opponent and after the reception that allowed all the attack options. In contrast, to this one and the reception that did not allowed an organized attack occurred less than expected after the power jump service. This study made it possible to infer that powerful service and the reception with low levels of efficiency reduce the chances of scoring in the attack. The fact that the opponent's powerful service results lesser occurrences of the

  11. Realized Jump Risk and Equity Return in China

    Directory of Open Access Journals (Sweden)

    Guojin Chen

    2014-01-01

    Full Text Available We utilize the realized jump components to explore a new jump (including nonsystematic jump and systematic jump risk factor model. After estimating daily realized jumps from high-frequency transaction data of the Chinese A-share stocks, we calculate monthly jump size, monthly jump standard deviation, and monthly jump arrival rate and then use those monthly jump factors to explain the return of the following month. Our empirical results show that the jump tail risk can explain the equity return. For the large capital-size stocks, large cap stock portfolios, and index, one-month lagged jump risk factor significantly explains the asset return variation. Our results remain the same even when we add the size and value factors in the robustness tests.

  12. Strength Determinants of Jump Height in the Jump Throw Movement in Women Handball Players.

    Science.gov (United States)

    McGhie, David; Østerås, Sindre; Ettema, Gertjan; Paulsen, Gøran; Sandbakk, Øyvind

    2018-06-08

    McGhie, D, Østerås, S, Ettema, G, Paulsen, G, and Sandbakk, Ø. Strength determinants of jump height in the jump throw movement in women handball players. J Strength Cond Res XX(X): 000-000, 2018-The purpose of the study was to improve the understanding of the strength demands of a handball-specific jump through examining the associations between jump height in a jump throw jump (JTJ) and measures of lower-body maximum strength and impulse in handball players. For comparison, whether the associations between jump height and strength differed between the JTJ and the customarily used countermovement jump (CMJ) was also examined. Twenty women handball players from a Norwegian top division club participated in the study. Jump height was measured in the JTJ and in unilateral and bilateral CMJ. Lower-body strength (maximum isometric force, one-repetition maximum [1RM], impulse at ∼60% and ∼35% 1RM) was measured in seated leg press. The associations between jump height and strength were assessed with correlation analyses and t-tests of dependent r's were performed to determine if correlations differed between jump tests. Only impulse at ∼35% 1RM correlated significantly with JTJ height (p jump height and strength were significantly weaker in the JTJ than in both CMJ tests for all strength measures (p = 0.001-0.044) except one. Maximum strength and impulse at ∼60% 1RM did not seem to sufficiently capture the capabilities associated with JTJ height, highlighting the importance of employing tests targeting performance-relevant neuromuscular characteristics when assessing jump-related strength in handball players. Further, CMJ height seemed to represent a wider range of strength capabilities and care should be taken when using it as a proxy for handball-specific movements.

  13. The AGS γt-jump system

    International Nuclear Information System (INIS)

    Syphers, M.J.; Ahrens, L.; van Asselt, W.; Brennan, J.M.

    1994-01-01

    In an attempt to generate a lossless crossing of an accelerator's transition energy, one procedure is to alter the transition energy of the accelerator quickly as the beam passes through this energy region by changing the optics of the lattice -- a so-called ''transition jump,'' or '' γt -jump'' scheme. Such a system was first implemented at CERN and later adopted at other accelerator laboratories. A scheme for the AGS was developed in 1986. A description of the AGS γt -jump system, and recent results from its commissioning are presented in this report

  14. Predicting vertical jump height from bar velocity.

    Science.gov (United States)

    García-Ramos, Amador; Štirn, Igor; Padial, Paulino; Argüelles-Cienfuegos, Javier; De la Fuente, Blanca; Strojnik, Vojko; Feriche, Belén

    2015-06-01

    The objective of the study was to assess the use of maximum (Vmax) and final propulsive phase (FPV) bar velocity to predict jump height in the weighted jump squat. FPV was defined as the velocity reached just before bar acceleration was lower than gravity (-9.81 m·s(-2)). Vertical jump height was calculated from the take-off velocity (Vtake-off) provided by a force platform. Thirty swimmers belonging to the National Slovenian swimming team performed a jump squat incremental loading test, lifting 25%, 50%, 75% and 100% of body weight in a Smith machine. Jump performance was simultaneously monitored using an AMTI portable force platform and a linear velocity transducer attached to the barbell. Simple linear regression was used to estimate jump height from the Vmax and FPV recorded by the linear velocity transducer. Vmax (y = 16.577x - 16.384) was able to explain 93% of jump height variance with a standard error of the estimate of 1.47 cm. FPV (y = 12.828x - 6.504) was able to explain 91% of jump height variance with a standard error of the estimate of 1.66 cm. Despite that both variables resulted to be good predictors, heteroscedasticity in the differences between FPV and Vtake-off was observed (r(2) = 0.307), while the differences between Vmax and Vtake-off were homogenously distributed (r(2) = 0.071). These results suggest that Vmax is a valid tool for estimating vertical jump height in a loaded jump squat test performed in a Smith machine. Key pointsVertical jump height in the loaded jump squat can be estimated with acceptable precision from the maximum bar velocity recorded by a linear velocity transducer.The relationship between the point at which bar acceleration is less than -9.81 m·s(-2) and the real take-off is affected by the velocity of movement.Mean propulsive velocity recorded by a linear velocity transducer does not appear to be optimal to monitor ballistic exercise performance.

  15. Management of Sport Injuries with Korean Medicine: A Survey of Korean National Volleyball Team

    Directory of Open Access Journals (Sweden)

    Changsop Yang

    2016-01-01

    Full Text Available The purpose of this study was to report the current state of Korean medicine (KM treatment on sports injury by implementing survey with volleyball team medical doctors participating in 2013-2014 season. Six KM doctors completed a questionnaire that includes injury parameters: type, location, situation, and pain scores. We collected 166 injury cases from 94 Korean male and female national volleyball players. Knee (25.9%, low back (13.3%, elbow, and ankle (8.4% injuries were most common. Joint (41.6% and muscle (30.7% were major injured tissues. KM team medical doctors utilized acupuncture (40.4%, chuna manual therapy (16.0%, physical therapy (15.2%, taping (9.0%, and cupping (7.8% to treat volleyball injuries. Any types of medications were used infrequently. Additional physical and exercise therapy were preferred after receiving acupuncture (both 46.9%. This study presented the preliminary injury profile of Korean elite volleyball players. Injury and treatment parameters could be useful to build advanced KM model in sport medicine.

  16. Technical player profiles related to the physical fitness of young female volleyball players predict team performance.

    Science.gov (United States)

    Dávila-Romero, C; Hernández-Mocholí, M A; García-Hermoso, A

    2015-03-01

    This study is divided into three sequential stages: identification of fitness and game performance profiles (individual player performance), an assessment of the relationship between these profiles, and an assessment of the relationship between individual player profiles and team performance during play (in championship performance). The overall study sample comprised 525 (19 teams) female volleyball players aged 12-16 years and a subsample (N.=43) used to examine study aims one and two was selected from overall sample. Anthropometric, fitness and individual player performance (actual game) data were collected in the subsample. These data were analyzed through clustering methods, ANOVA and independence chi-square test. Then, we investigated whether the proportion of players with the highest individual player performance profile might predict a team's results in the championship. Cluster analysis identified three volleyball fitness profiles (high, medium, and low) and two individual player performance profiles (high and low). The results showed a relationship between both types of profile (fitness and individual player performance). Then, linear regression revealed a moderate relationship between the number of players with a high volleyball fitness profile and a team's results in the championship (R2=0.23). The current study findings may enable coaches and trainers to manage training programs more efficiently in order to obtain tailor-made training, identify volleyball-specific physical fitness training requirements and reach better results during competitions.

  17. The prevention of musculoskeletal injuries in volleyball : the systematic development of an intervention and its feasibility

    NARCIS (Netherlands)

    Gouttebarge, Vincent; van Sluis, Marije; Verhagen, Evert; Zwerver, Johannes

    2017-01-01

    BACKGROUND: A scientific research project has started in the Netherlands with the aim of developing and implementing an evidence-based intervention to prevent the occurrence of musculoskeletal injuries among young and adult recreational volleyball players. This article describes (i) the systematic

  18. Different temporal bases for body and arm movements in volleyball serve reception

    NARCIS (Netherlands)

    Benerink, N. H.; Bootsma, R. J.; Zaal, F. T. J. M.

    2015-01-01

    In many sports, successfully intercepting a ball requires players to move both their body and their arms. Yet, studies of interception typically focus on one or the other. We performed an analysis of the moments of first foot and arm movements of elite-level volleyball players during serve

  19. Effects of Classwide Peer Tutoring on the Performance of Sixth Grade Students during a Volleyball Unit

    Science.gov (United States)

    Ayvazo, Shiri; Ward, Phillip

    2009-01-01

    This investigation examined the effects of Classwide Peer Tutoring (CWPT), a variation of peer tutoring on the volleyball skills of four 6th grade middle school students purposefully selected from an intact class of 21 students. Participants were average to low skilled males and females. A single subject A-B-A-B withdrawal design was used to…

  20. Role of Uniforms in the Body Image of Female College Volleyball Players

    Science.gov (United States)

    Steinfeldt, Jesse A.; Zakrajsek, Rebecca A.; Bodey, Kimberly J.; Middendorf, Katharine G.; Martin, Scott B.

    2013-01-01

    Female student athletes often desire a muscular body to be successful in sport, but this body type does not conform to traditional cultural norms of femininity. In this study, the authors qualitatively examined the experiences of female intercollegiate volleyball players to better understand their beliefs about their bodies--both as athletes and…

  1. Preventing musculoskeletal injuries among recreational adult volleyball players : design of a randomised prospective controlled trial

    NARCIS (Netherlands)

    Gouttebarge, Vincent; Zwerver, Johannes; Verhagen, Evert

    2017-01-01

    BACKGROUND: Both acute and overuse injuries are common among recreational volleyball players, especially finger/wrist, ankle, shoulder and knee injuries. Consequently, an intervention ('VolleyVeilig') was developed to prevent or reduce the occurrence of finger/wrist, shoulder, knee and ankle

  2. The prevention of musculoskeletal injuries in volleyball: the systematic development of an intervention and its feasibility

    NARCIS (Netherlands)

    Gouttebarge, Vincent; van Sluis, Marije; Verhagen, Evert; Zwerver, Johannes

    2017-01-01

    A scientific research project has started in the Netherlands with the aim of developing and implementing an evidence-based intervention to prevent the occurrence of musculoskeletal injuries among young and adult recreational volleyball players. This article describes (i) the systematic development

  3. Shoulder pain among high-level volleyball players and preseason features.

    Science.gov (United States)

    Forthomme, Benedicte; Wieczorek, Valerie; Frisch, Anne; Crielaard, Jean-Michel; Croisier, Jean-Louis

    2013-10-01

    The main goal of this prospective study was to identify the most significant intrinsic risk factors for shoulder pain by measuring strength developed by shoulder rotators and by carrying out various morphostatic assessments. Sixty-six players (mean ± SD age = 24 ± 5 yr) were recruited from nine volleyball teams from the first and second divisions (34 men and 32 women) to participate in the study. Before the start of the volleyball season, all the participants completed a preseason questionnaire and underwent both a bilateral isokinetic evaluation of the shoulders and morphostatic measurements. During the subsequent 6 months of the competition period, the players reported through a weekly questionnaire any shoulder pain experienced. During the ongoing season, 23% (15 of 66 players) of the volleyball players experienced dominant shoulder pain. Interestingly, participants who reported a history of dominant shoulder pain were found to have nine times higher risk of suffering further pain in their dominant shoulder. The eccentric maximal strength developed by the internal and external rotators was found to represent a protective factor in the volleyball players (respective odds ratios = 0.946, P = 0.01 and 0.94, P = 0.05). No risk factors were found among the shoulder morphostatic measurements. In our study, the evaluation of shoulder rotator muscle strength through isokinetic assessment, especially eccentric mode, appeared to be the most contributing parameter to identify risk factors for shoulder pain. This evaluation should allow to better identify players at risk.

  4. A COMPARATIVE STUDY OF PERSONALITY OF INTERNATIONAL VOLLEYBALL PLAYERS OF BRAZIL AND INDIA

    Directory of Open Access Journals (Sweden)

    Govind Kadam

    2010-06-01

    Full Text Available The main objective was to study the personality of the volleyball players of India. All the players of Indian team and the players of Brazil team, who came for FIVB Men Volleyball World Championship held at Pune in August 2009, were selected for the study. They were administered the Cattell’s 16 PF questionnaire. The results wereanalyzed with the help of ‘t’ test which showed that there are significant differences found between Indian volleyball players and Brazilian Volleyball players on seven factors but not on nine factors of 16 PF Questionnaire. Indian players scored high on factor ‘F’, factor ‘I’ and factor ‘M’ whereas Brazilian players have scored high on factor ‘B’, factor ‘G’, factor ‘H’ and factor ‘L’. Indian players scored low on Factor B which means that they tend to be slow to learn and grasp and they were dull as compared with Brazilian team, and gives concrete and literal interpretation. This dullness simply represents poor functioning.

  5. Preventing musculoskeletal injuries among recreational adult volleyball players: design of a randomised prospective controlled trial

    NARCIS (Netherlands)

    Gouttebarge, Vincent; Zwerver, Johannes; Verhagen, Evert

    2017-01-01

    Background: Both acute and overuse injuries are common among recreational volleyball players, especially finger/wrist, ankle, shoulder and knee injuries. Consequently, an intervention ('VolleyVeilig') was developed to prevent or reduce the occurrence of finger/wrist, shoulder, knee and ankle

  6. Exploring Changes to a Teacher's Teaching Practices and Student Learning through a Volleyball Content Knowledge Workshop

    Science.gov (United States)

    Kim, Insook

    2016-01-01

    This paper describes how improving a teacher's content knowledge changes his teaching practices and its subsequent effects on student learning during a middle school volleyball instructional unit. The study was designed to challenge teacher educators' thinking about the importance of in-depth content knowledge for effective teaching by…

  7. Spike the PCHA! Overuse injury of the Posterior Circumflex Humeral Artery in elite volleyball

    NARCIS (Netherlands)

    van de Pol, D.

    2016-01-01

    In 1993, professor Reekers of the Academic Medical Center (AMC) Radiology department was the first to describe a traumatic aneurysm of the posterior circumflex humeral artery (PCHA) in a volleyball player, suggesting a causal relationship. Fifteen years later, between 2008 and 2010, several elite

  8. The Effect of Movement Imagery Training on Learning Forearm Pass in Volleyball

    Science.gov (United States)

    Ay, Khitam Mousa; Halaweh, Rami Saleh; Al-Taieb, Mohammad Abu

    2013-01-01

    This study investigates the effect of movement imagery on learning the forearm pass in volleyball. Twenty four mail students from Physical Education Factuly at Jordan University (19 ± 0.5) years of age. After Completed the Movement Imagery Questionnaire-Revised (MIQ-R; Hall & Martin, 1997) the subjects randomly divided into two groups,…

  9. Comparison of Total Antioxidant Capacity Oxidative Stress and Blood Lipoprotein Parameters in Volleyball Players and Sedentary

    Science.gov (United States)

    Gokhan, Ismail

    2013-01-01

    This study aims to measure, then compare sedentary blood lipoproteins, oxidant- antioxidant state and oxidative stress index in volleyball players. The experimental group of the research consists of regularly practising 20 boys between the ages of 12 and 17, and the control group comprises 32 children practising no particular sports branch, 12 of…

  10. Comparison of Three Instructional Approaches to Enhance Tactical Knowledge in Volleyball among University Students

    Science.gov (United States)

    Vande Broek, Gert; Boen, Filip; Claessens, Manu; Feys, Jos; Ceux, Tanja

    2011-01-01

    This study investigated the decision-making process of three instructional groups (i.e., teacher-centered, student-centered with tactical questioning and student-centered without tactical questioning) in practical courses in volleyball among university students. All students (N = 122) performed a Tactical Awareness task on the correctness of the…

  11. Cohesion and Trauma: An Examination of a Collegiate Women's Volleyball Team

    Science.gov (United States)

    Fletcher, Teresa B.; Meyer, Barbara B.

    2009-01-01

    This study examined the effects of Adventure Based Counseling (i.e., a low-element challenge program) on the cohesion of a collegiate women's volleyball team. Results suggest postintervention improvements in team cohesion. The support created in the challenge experience also transferred to the players helping one another to grieve the untimely…

  12. Features of use of combinational circuits play in attack during volleyball matches

    Directory of Open Access Journals (Sweden)

    B. O. Artemenko

    2013-12-01

    Full Text Available Purpose : To characterize tactical formation game action in the attack and the frequency of execution of power and tactical (planning innings volleyball players of different skill levels. Material and methods: The analyzed video recordings of volleyball matches with the strongest teams of the world: Brazil, Russia, USA, Cuba, Italy, the leading volleyball championship teams of Russia and Ukraine. The features of tactical formation game. Results: It was established that the binders players strongest teams and club teams in the world is used in the organization of attack more variety of tactical combinations. So almost equally, the following combinations: Rise, Pipe and Zone (13.4 % 12.6 % 11.5%. Ukrainian binders players prefer only combinations Rise - 23%; Pipe - 2%; Zone - 2.5%, respectively. Distribution innings for planning and power for Ukrainian teams: 59.7 % versus 40.3% and 27.5 % versus 72.5 %, respectively, the strongest national teams in the world. Conclusions: The features of tactical formation attack suggest the best technical - tactical training players tie the strongest teams in the world and the whole team. Also leading the team to the world is much more likely to use the power supply, which indicates the nature of the power of world volleyball.

  13. Nonoperative Management and Novel Imaging for Posterior Circumflex Humeral Artery Injury in Volleyball

    NARCIS (Netherlands)

    van de Pol, Daan; Planken, R. Nils; Terpstra, Aart; Pannekoek-Hekman, Marja; Kuijer, P. Paul F. M.; Maas, Mario

    2017-01-01

    We report on a 34-yr-old male elite volleyball player with symptomatic emboli in the spiking hand from a partially thrombosed aneurysm of the posterior circumflex humeral artery (PCHA) in his dominant shoulder. At initial diagnosis and follow-up, a combination of time-resolved and high-resolution

  14. Identification of a effective cooperation model in the game positioning in a volleyball game

    Directory of Open Access Journals (Sweden)

    Leszek Mazur

    2017-06-01

    Full Text Available Purpose: The paper is aimed at identification of a model which shows the effective cooperation in the game positioning (exactly in receiving-passing the ball in a volleyball game. Design/methodology/approach: The original research method is used in this thesis which is called pragmatic unique case study. The research is aimed at observation USA team playing volleyball during The Olympic Games in Rio de Janeiro 2016.  Findings: There is a cooperation model in receiving and passing the ball among USA volleyball team players found, based on the observation. There are also other cooperation models used by teams.                     Research and practical limitations/implications: Based in the research I can tell that there are different models of cooperation in the game positioning in volleyball. The teams which are the most effective use different models of cooperation while playing.                     Originality/value: The paper is original and leads to think about the identification of the process of cooperation in team games. More research in this field is recommended.

  15. Comparative study of anthropometric variables in female classical ballet dancers, volleyball players and physically active subjects

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Vaz

    2009-01-01

    Full Text Available The objective of this study was to compare anthropometric variables (body weight, height, and percent body fat and plantarflexion and dorsiflexion range of motion (ROM between three different groups of women: classical ballet dancers (n=14, volleyball players (n=22 and physically active subjects (n=13. The assumption was that different functional requirements should produce differences in the anthropometric variables and ROM between the three groups. Body weight and height were higher in volleyball players (66.42 ± 5.8 kg; 174.77 ± 5.6 cm, followed by physically active women (59.93 ±10.3 kg; 164 ± 7.5 cm and ballet dancers (49.25 ± 4.5 kg; 157.03 ± 3.6 cm (p<0.05. Percent body fat was higher in physically active women (30.67 ± 4.6% compared to theother two groups, which showed similar percentages (volleyball players: 24.93 ± 4.1%; ballet dancers: 21.94 ± 4.3%. The three groups were similar in terms of total ankle ROM and active dorsiflexion ROM between the right and left sides. However, plantarflexion ROM was higher in ballet dancers (~83°, followed by physically active women (~68° and volleyball players who presented the smallest ROM (~60°. The different requirements imposed by the three distinct physical activities seem to be responsible for changes in some of the anthropometric variables and ankle joint ROM.

  16. Measurements of K shell absorption jump factors and jump ratios using EDXRF technique

    Science.gov (United States)

    Kacal, Mustafa Recep; Han, İbrahim; Akman, Ferdi

    2015-04-01

    In the present work, the K-shell absorption jump factors and jump ratios for 30 elements between Ti ( Z = 22) and Er ( Z = 68) were measured by energy dispersive X-ray fluorescence (EDXRF) technique. The jump factors and jump ratios for these elements were determined by measuring the K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to- Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using an Am-241 radioactive point source and a Si (Li) detector in direct excitation and transmission experimental geometry. The results for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature.

  17. The Effects of Aquatic Plyometric Training on Repeated Jumps, Drop Jumps and Muscle Damage.

    Science.gov (United States)

    Jurado-Lavanant, A; Alvero-Cruz, J R; Pareja-Blanco, F; Melero-Romero, C; Rodríguez-Rosell, D; Fernandez-Garcia, J C

    2015-09-22

    The purpose of this study was to compare the effects of land- vs. aquatic based plyometric training programs on the drop jump, repeated jump performance and muscle damage. Sixty-five male students were randomly assigned to one of 3 groups: aquatic plyometric training group (APT), plyometric training group (PT) and control group (CG). Both experimental groups trained twice a week for 10 weeks performing the same number of sets and total jumps. The following variables were measured prior to, halfway through and after the training programs: creatine kinase (CK) concentration, maximal height during a drop jump from the height of 30 (DJ30) and 50 cm (DJ50), and mean height during a repeated vertical jump test (RJ). The training program resulted in a significant increase (Pplyometric training, PT produced greater gains on reactive jumps performance than APT. © Georg Thieme Verlag KG Stuttgart · New York.

  18. Estimation of hydraulic jump characteristics of channels with sudden diverging side walls via SVM.

    Science.gov (United States)

    Roushangar, Kiyoumars; Valizadeh, Reyhaneh; Ghasempour, Roghayeh

    2017-10-01

    Sudden diverging channels are one of the energy dissipaters which can dissipate most of the kinetic energy of the flow through a hydraulic jump. An accurate prediction of hydraulic jump characteristics is an important step in designing hydraulic structures. This paper focuses on the capability of the support vector machine (SVM) as a meta-model approach for predicting hydraulic jump characteristics in different sudden diverging stilling basins (i.e. basins with and without appurtenances). In this regard, different models were developed and tested using 1,018 experimental data. The obtained results proved the capability of the SVM technique in predicting hydraulic jump characteristics and it was found that the developed models for a channel with a central block performed more successfully than models for channels without appurtenances or with a negative step. The superior performance for the length of hydraulic jump was obtained for the model with parameters F 1 (Froude number) and (h 2- h 1 )/h 1 (h 1 and h 2 are sequent depth of upstream and downstream respectively). Concerning the relative energy dissipation and sequent depth ratio, the model with parameters F 1 and h 1 /B (B is expansion ratio) led to the best results. According to the outcome of sensitivity analysis, Froude number had the most significant effect on the modeling. Also comparison between SVM and empirical equations indicated the great performance of the SVM.

  19. Salmon jumping: behavior, kinematics and optimal conditions, with possible implications for fish passageway design

    Energy Technology Data Exchange (ETDEWEB)

    Lauritzen, D V; Jordan, L K; Gordon, M S [Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095-1606 (United States); Hertel, F S, E-mail: dlauritz@ccsf.ed, E-mail: fritz.hertel@csun.ed, E-mail: msgordon@ucla.ed, E-mail: ljordan@ucla.ed [Department of Biology, California State University-Northridge, Northridge, CA 91330 (United States)

    2010-09-15

    Behavioral and kinematic properties and capacities of wild migratory salmonid fishes swimming upstream and jumping up waterfalls generally have played only minor roles in the design and construction of passageways intended to help these fishes get past dams and other human-made obstacles blocking their movements. This paper reports the results of an experimental study of relevant behavioral and kinematic properties of adult kokanee salmon (Oncorhynchus nerka) jumping up waterfalls as they migrate upstream. We used a portable, adjustable apparatus to study in the field fish responding to artificial waterfalls under a range of flow conditions. We observed fish under conditions of varying water flow rates, pool depths, fall heights and fall angles. We analyzed digital video recordings of their behaviors. Kokanee salmon spontaneously jump up waterfalls within a relatively narrow range of conditions, including low flow speeds, near vertical angles and pool depth to fall height ratios near 1.0. Preferred values for each parameter are, to some extent, dependent on other parameters. In contrast to previous misconceptions, jumping behavior is initiated by running S-start accelerations from beneath the boils formed in the plunge pools below waterfalls, as opposed to C-start standing jumps from the surface. S-starts are immediately followed by burst swimming to the point of takeoff at the surface. These results can contribute to an improved basis for developing designs of fish passageways that may ultimately make them more effective and efficient.

  20. Salmon jumping: behavior, kinematics and optimal conditions, with possible implications for fish passageway design

    International Nuclear Information System (INIS)

    Lauritzen, D V; Jordan, L K; Gordon, M S; Hertel, F S

    2010-01-01

    Behavioral and kinematic properties and capacities of wild migratory salmonid fishes swimming upstream and jumping up waterfalls generally have played only minor roles in the design and construction of passageways intended to help these fishes get past dams and other human-made obstacles blocking their movements. This paper reports the results of an experimental study of relevant behavioral and kinematic properties of adult kokanee salmon (Oncorhynchus nerka) jumping up waterfalls as they migrate upstream. We used a portable, adjustable apparatus to study in the field fish responding to artificial waterfalls under a range of flow conditions. We observed fish under conditions of varying water flow rates, pool depths, fall heights and fall angles. We analyzed digital video recordings of their behaviors. Kokanee salmon spontaneously jump up waterfalls within a relatively narrow range of conditions, including low flow speeds, near vertical angles and pool depth to fall height ratios near 1.0. Preferred values for each parameter are, to some extent, dependent on other parameters. In contrast to previous misconceptions, jumping behavior is initiated by running S-start accelerations from beneath the boils formed in the plunge pools below waterfalls, as opposed to C-start standing jumps from the surface. S-starts are immediately followed by burst swimming to the point of takeoff at the surface. These results can contribute to an improved basis for developing designs of fish passageways that may ultimately make them more effective and efficient.

  1. Option Panels in Pure-Jump Settings

    DEFF Research Database (Denmark)

    Andersen, Torben Gustav; Fusari, Nicola; Todorov, Viktor

    We develop parametric inference procedures for large panels of noisy option data in the setting where the underlying process is of pure-jump type, i.e., evolve only through a sequence of jumps. The panel consists of options written on the underlying asset with a (different) set of strikes...... specification for the risk-neutral asset return dynamics, the option prices are nonlinear functions of a time-invariant parameter vector and a time-varying latent state vector (or factors). Furthermore, no-arbitrage restrictions impose a direct link between some of the quantities that may be identified from...... the return and option data. These include the so-called jump activity index as well as the time-varying jump intensity. We propose penalized least squares estimation in which we minimize L_2 distance between observed and model-implied options and further penalize for the deviation of model-implied quantities...

  2. Microscopic models of quantum-jump superoperators

    International Nuclear Information System (INIS)

    Dodonov, A.V.; Mizrahi, S.S.; Dodonov, V.V.

    2005-01-01

    We discuss the quantum-jump operation in an open system and show that jump superoperators related to a system under measurement can be derived from the interaction of that system with a quantum measurement apparatus. We give two examples for the interaction of a monochromatic electromagnetic field in a cavity (the system) with two-level atoms and with a harmonic oscillator (representing two different kinds of detectors). We show that the derived quantum-jump superoperators have a 'nonlinear' form Jρ=γ diag[F(n)aρa † F(n)], where the concrete form of the function F(n) depends on assumptions made about the interaction between the system and detector. Under certain conditions the asymptotical power-law dependence F(n)=(n+1) -β is obtained. A continuous transition to the standard Srinivas-Davies form of the quantum-jump superoperator (corresponding to β=0) is shown

  3. Human Long Jump — A Deductive Approach

    Directory of Open Access Journals (Sweden)

    Miloš Jovanović

    2012-10-01

    Full Text Available This paper presents a useful application of a generalized approach to the modelling of human and humanoid motion using the deductive approach. It starts with formulating a completely general problem and deriving different real situations as special cases. The concept and the software realization are verified by comparing the results with the ones obtained using “classical” software for one well-known particular problem – biped walking. New applicability and potentials of the proposed method are demonstrated by simulation of a selected example – the long jump. The simulated motion included jumping and landing on the feet (after a jump. Additional analysis is done in the paper regarding the joint torque and joint angle during the jumping. Separate stages of the simulation are defined and explained.

  4. Volatility jumps and their economic determinants

    DEFF Research Database (Denmark)

    Caporin, Massimiliano; Rossi, Eduardo; Santucci de Magistris, Paolo

    that there is a positive probability of jumps in volatility. A common factor in the volatility jumps is shown to be related to a set of financial covariates (such as variance risk premium, S&P500 volume, credit-default swap, and federal fund rates). The credit-default swap on US banks and variance risk premium have...... predictive power on expected jump moves, thus confirming the common interpretation that sudden and large increases in equity volatility can be anticipated by credit deterioration of the US bank sector as well as changes in the market expectations of future risks. Finally, the model is extended to incorporate...... the credit-default swap and the variance risk premium in the dynamics of the jump size and intensity....

  5. A simple strategy for jumping straight up.

    Science.gov (United States)

    Hemami, Hooshang; Wyman, Bostwick F

    2012-05-01

    Jumping from a stationary standing position into the air is a transition from a constrained motion in contact with the ground to an unconstrained system not in contact with the ground. A simple case of the jump, as it applies to humans, robots and humanoids, is studied in this paper. The dynamics of the constrained rigid body are expanded to define a larger system that accommodates the jump. The formulation is applied to a four-link, three-dimensional system in order to articulate the ballistic motion involved. The activity of the muscular system and the role of the major sagittal muscle groups are demonstrated. The control strategy, involving state feedback and central feed forward signals, is formulated and computer simulations are presented to assess the feasibility of the formulations, the strategy and the jump. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. How quick is a quantum jump?

    International Nuclear Information System (INIS)

    Schulman, L.S.

    1997-01-01

    Although the only time scale one ordinarily associates with a quantum transition is its lifetime, observations of ''quantum jumps'' in recent years show that the actual transition time is much shorter. I define a ''jump time'' as the time scale such that perturbations occurring at intervals of this duration affect the decay. In terms of the ''Zeno time'' (related to the second moment of the Hamiltonian) the jump time is τ J is identical to τ 2 Z /τ L . Corroboration is given. I also show that observing the ''jumping'' will not seriously affect the system lifetime, but will affect the linewidth. This is consistent with Bohr's ideas on measurement as well as with a heuristic time-energy uncertainty principle. (author)

  7. A Correction Equation for Jump Height Measured Using the Just Jump System.

    Science.gov (United States)

    McMahon, John J; Jones, Paul A; Comfort, Paul

    2016-05-01

    To determine the concurrent validity and reliability of the popular Just Jump system (JJS) for determining jump height and, if necessary, provide a correction equation for future reference. Eighteen male college athletes performed 3 bilateral countermovement jumps (CMJs) on 2 JJSs (alternative method) that were placed on top of a force platform (criterion method). Two JJSs were used to establish consistency between systems. Jump height was calculated from flight time obtained from the JJS and force platform. Intraclass correlation coefficients (ICCs) demonstrated excellent within-session reliability of the CMJ height measurement derived from both the JJS (ICC = .96, P jump height (0.46 ± 0.09 m vs 0.33 ± 0.08 m) than the force platform (P jump height = (0.8747 × alternative jump height) - 0.0666. The JJS provides a reliable but overestimated measure of jump height. It is suggested, therefore, that practitioners who use the JJS as part of future work apply the correction equation presented in this study to resultant jump-height values.

  8. Jump Horse Safety: Reconciling Public Debate and Australian Thoroughbred Jump Racing Data, 2012–2014

    Directory of Open Access Journals (Sweden)

    Karen Ruse

    2015-10-01

    Full Text Available Thoroughbred jump racing sits in the spotlight of contemporary welfare and ethical debates about horse racing. In Australia, jump racing comprises hurdle and steeplechase races and has ceased in all but two states, Victoria and South Australia. This paper documents the size, geography, composition, and dynamics of Australian jump racing for the 2012, 2013, and 2014 seasons with a focus on debate about risks to horses. We found that the majority of Australian jump racing is regional, based in Victoria, and involves a small group of experienced trainers and jockeys. Australian jump horses are on average 6.4 years of age. The jump career of the majority of horses involves participating in three or less hurdle races and over one season. Almost one quarter of Australian jump horses race only once. There were ten horse fatalities in races over the study period, with an overall fatality rate of 5.1 fatalities per 1000 horses starting in a jump race (0.51%. There was significant disparity between the fatality rate for hurdles, 0.75 fatalities per 1000 starts (0.075% and steeplechases, 14 fatalities per 1000 starts (1.4%. Safety initiatives introduced by regulators in 2010 appear to have significantly decreased risks to horses in hurdles but have had little or no effect in steeplechases. Our discussion considers these Animals 2015, 5 1073 data in light of public controversy, political debate, and industry regulation related to jump horse safety.

  9. Jump Horse Safety: Reconciling Public Debate and Australian Thoroughbred Jump Racing Data, 2012-2014.

    Science.gov (United States)

    Ruse, Karen; Davison, Aidan; Bridle, Kerry

    2015-10-22

    Thoroughbred jump racing sits in the spotlight of contemporary welfare and ethical debates about horse racing. In Australia, jump racing comprises hurdle and steeplechase races and has ceased in all but two states, Victoria and South Australia. This paper documents the size, geography, composition, and dynamics of Australian jump racing for the 2012, 2013, and 2014 seasons with a focus on debate about risks to horses. We found that the majority of Australian jump racing is regional, based in Victoria, and involves a small group of experienced trainers and jockeys. Australian jump horses are on average 6.4 years of age. The jump career of the majority of horses involves participating in three or less hurdle races and over one season. Almost one quarter of Australian jump horses race only once. There were ten horse fatalities in races over the study period, with an overall fatality rate of 5.1 fatalities per 1000 horses starting in a jump race (0.51%). There was significant disparity between the fatality rate for hurdles, 0.75 fatalities per 1000 starts (0.075%) and steeplechases, 14 fatalities per 1000 starts (1.4%). Safety initiatives introduced by regulators in 2010 appear to have significantly decreased risks to horses in hurdles but have had little or no effect in steeplechases. Our discussion considers these Animals 2015, 5 1073 data in light of public controversy, political debate, and industry regulation related to jump horse safety.

  10. "Ballistic Six" Upper-Extremity Plyometric Training for the Pediatric Volleyball Players.

    Science.gov (United States)

    Turgut, Elif; Cinar-Medeni, Ozge; Colakoglu, Filiz F; Baltaci, Gul

    2017-09-19

    The Ballistic Six exercise program includes commonly used upper-body exercises, and the program is recommended for overhead throwing athletes. The purpose of the current study was to investigate the effects of a 12-week the Ballistic Six upper-extremity plyometric training program on upper-body explosive power, endurance, and reaction time in pediatric overhead athletes. Twenty-eight female pediatric volleyball players participated in the study. The participants were randomly divided into 2 study groups: an intervention group (upper-extremity plyometric training in addition to the volleyball training; n = 14) and a control group (the volleyball training only; n = 14). All the participants were assessed before and after a 12-week training program for upper-body power, strength and endurance, and reaction time. Statistical comparison was performed using an analysis of variance test. Comparisons showed that after a 12-week training program, the Ballistic Six upper-body plyometric training program resulted in more improvements in an overhead medicine ball throwing distance and a push-up performance, as well as greater improvements in the reaction time in the nonthrowing arm when compared with control training. In addition, a 12-week training program was found to be effective in achieving improvements in the reaction time in the throwing arm for both groups similarly. Compared with regular training, upper-body plyometric training resulted in additional improvements in upper-body power and strength and endurance among pediatric volleyball players. The findings of the study provide a basis for developing training protocols for pediatric volleyball players.

  11. Jump spillover between oil prices and exchange rates

    Science.gov (United States)

    Li, Xiao-Ping; Zhou, Chun-Yang; Wu, Chong-Feng

    2017-11-01

    In this paper, we investigate the jump spillover effects between oil prices and exchange rates. To identify the latent historical jumps for exchange rates and oil prices, we use a Bayesian MCMC approach to estimate the stochastic volatility model with correlated jumps in both returns and volatilities for each. We examine the simultaneous jump intensities and the conditional jump spillover probabilities between oil prices and exchange rates, finding strong evidence of jump spillover effects. Further analysis shows that the jump spillovers are mainly due to exogenous events such as financial crises and geopolitical events. Thus, the findings have important implications for financial risk management.

  12. A multiplicity jump trigger using silicon planes

    International Nuclear Information System (INIS)

    Alexopoulos, T.; Erwin, A.R.

    1993-01-01

    Since silicon tracking planes are already present in a B decay experiment, it is an attractive idea to use these as part of a multiplicity jump detector. Two average B decays would produce a multiplicity jump of around 10 in the final state. Such a trigger has been tried for a fixed target Charm experiment with disappointing success. The failure was attributed to the difficulty in adequately controlling the gains of a large number of microstrip amplifies

  13. Portfolio Selection with Jumps under Regime Switching

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2010-01-01

    Full Text Available We investigate a continuous-time version of the mean-variance portfolio selection model with jumps under regime switching. The portfolio selection is proposed and analyzed for a market consisting of one bank account and multiple stocks. The random regime switching is assumed to be independent of the underlying Brownian motion and jump processes. A Markov chain modulated diffusion formulation is employed to model the problem.

  14. Jumps in binomial AR(1) processes

    OpenAIRE

    Weiß , Christian H.

    2009-01-01

    Abstract We consider the binomial AR(1) model for serially dependent processes of binomial counts. After a review of its definition and known properties, we investigate marginal and serial properties of jumps in such processes. Based on these results, we propose the jumps control chart for monitoring a binomial AR(1) process. We show how to evaluate the performance of this control chart and give design recommendations. correspondance: Tel.: +49 931 31 84968; ...

  15. Tests for nonrandomness in quantum jumps

    International Nuclear Information System (INIS)

    Berkeland, D.J.; Raymondson, D.A.; Tassin, V.M.

    2004-01-01

    In a fundamental test of quantum mechanics, we have observed 228 000 quantum jumps of a single trapped and laser cooled 88 Sr + ion. This represents a statistical increase of two orders of magnitude over previous similar analyses of quantum jumps. Compared to other searches for nonrandomness in quantum-mechanical processes, using quantum jumps simplifies the interpretation of data by eliminated multiparticle effects and providing near-unit detection efficiency of transitions. We measure the fractional reduction in the entropy of information to be -4 when the value of any interval between quantum jumps is known. We also find that the number of runs of successively increasing or decreasing interval times agrees with the theoretically expected values. Furthermore, we analyze 238 000 quantum jumps from two simultaneously confined ions and find that the number of apparently coincidental transitions is as expected. Finally, we observe 8400 spontaneous decays of two simultaneously trapped ions and find that the number of apparently coincidental decays from the metastable state agrees with the expected value. We find no evidence for short- or long-term correlations in the intervals of the quantum jumps or in the decay of the quantum states, in agreement with quantum theory

  16. Hydrodynamics of vertical jumping in Archer fish

    Science.gov (United States)

    Techet, Alexandra H.; Mendelson, Leah

    2017-11-01

    Vertical jumping for aerial prey from an aquatic environment requires both propulsive power and precise aim to succeed. Rapid acceleration to a ballistic velocity sufficient for reaching the prey height occurs before the fish leaves the water completely and experiences a thousandfold drop in force-producing ability. In addition to speed, accuracy and stability are crucial for successful feeding by jumping. This talk examines the physics of jumping using the archer fish as a model. Better known for their spitting abilities, archer fish will jump multiple body lengths out of the water for prey capture, from a stationary position just below the free surface. Modulation of oscillatory body kinematics and use of multiple fins for force production are identified as methods through which the fish can meet requirements for both acceleration and stabilization in limited space. Quantitative 3D PIV wake measurements reveal how variations in tail kinematics relate to thrust production throughout the course of a jumping maneuver and over a range of jump heights. By performing measurements in 3D, the timing, interactions, and relative contributions to thrust and lateral forces from each fin can be evaluated, elucidating the complex hydrodynamics that enable archer fish water exit.

  17. High prevalence of jumper's knee and sonographic changes in Swedish elite junior volleyball players compared to matched controls

    OpenAIRE

    Gisslen, K; Gyulai, C; Soderman, K; Alfredson, H

    2005-01-01

    Background: Jumper's knee is a common and troublesome condition among senior volleyball players, but its prevalence among elite junior players compared to matched non-sports active controls is not known.

  18. Performance analysis of jump-gliding locomotion for miniature robotics.

    Science.gov (United States)

    Vidyasagar, A; Zufferey, Jean-Christohphe; Floreano, Dario; Kovač, M

    2015-03-26

    Recent work suggests that jumping locomotion in combination with a gliding phase can be used as an effective mobility principle in robotics. Compared to pure jumping without a gliding phase, the potential benefits of hybrid jump-gliding locomotion includes the ability to extend the distance travelled and reduce the potentially damaging impact forces upon landing. This publication evaluates the performance of jump-gliding locomotion and provides models for the analysis of the relevant dynamics of flight. It also defines a jump-gliding envelope that encompasses the range that can be achieved with jump-gliding robots and that can be used to evaluate the performance and improvement potential of jump-gliding robots. We present first a planar dynamic model and then a simplified closed form model, which allow for quantification of the distance travelled and the impact energy on landing. In order to validate the prediction of these models, we validate the model with experiments using a novel jump-gliding robot, named the 'EPFL jump-glider'. It has a mass of 16.5 g and is able to perform jumps from elevated positions, perform steered gliding flight, land safely and traverse on the ground by repetitive jumping. The experiments indicate that the developed jump-gliding model fits very well with the measured flight data using the EPFL jump-glider, confirming the benefits of jump-gliding locomotion to mobile robotics. The jump-glide envelope considerations indicate that the EPFL jump-glider, when traversing from a 2 m height, reaches 74.3% of optimal jump-gliding distance compared to pure jumping without a gliding phase which only reaches 33.4% of the optimal jump-gliding distance. Methods of further improving flight performance based on the models and inspiration from biological systems are presented providing mechanical design pathways to future jump-gliding robot designs.

  19. Jump Horse Safety: Reconciling Public Debate and Australian Thoroughbred Jump Racing Data, 2012–2014

    Science.gov (United States)

    Ruse, Karen; Davison, Aidan; Bridle, Kerry

    2015-01-01

    Simple Summary This paper documents the dynamics of Australian thoroughbred jump racing in the 2012, 2013, and 2014 seasons with the aim of informing debate about risks to horses and the future of this activity. We conclude that the safety of Australian jump racing has improved in recent years but that steeplechases are considerably riskier for horses than hurdle races. Abstract Thoroughbred jump racing sits in the spotlight of contemporary welfare and ethical debates about horse racing. In Australia, jump racing comprises hurdle and steeplechase races and has ceased in all but two states, Victoria and South Australia. This paper documents the size, geography, composition, and dynamics of Australian jump racing for the 2012, 2013, and 2014 seasons with a focus on debate about risks to horses. We found that the majority of Australian jump racing is regional, based in Victoria, and involves a small group of experienced trainers and jockeys. Australian jump horses are on average 6.4 years of age. The jump career of the majority of horses involves participating in three or less hurdle races and over one season. Almost one quarter of Australian jump horses race only once. There were ten horse fatalities in races over the study period, with an overall fatality rate of 5.1 fatalities per 1000 horses starting in a jump race (0.51%). There was significant disparity between the fatality rate for hurdles, 0.75 fatalities per 1000 starts (0.075%) and steeplechases, 14 fatalities per 1000 starts (1.4%). Safety initiatives introduced by regulators in 2010 appear to have significantly decreased risks to horses in hurdles but have had little or no effect in steeplechases. Our discussion considers these data in light of public controversy, political debate, and industry regulation related to jump horse safety. PMID:26506396

  20. Evaluation of the impact of the filing on the match results in qualifying for ME 2017 men's volleyball.

    OpenAIRE

    Dopita, Michal

    2017-01-01

    Title of the thesis Evaluation of the impact of service on the match result in qualification for Men's European Volleyball Championship 2017 Abstract The aim of this thesis is to evaluate the influence of service on the match result in qualification for the 2017 Men's Volleyball European Championship, using indirect video monitoring, and trace the success rate and frequency of individual types of services. Our intention is to show the importance of this individual game activity in a match wit...

  1. Verbal Instructions Acutely Affect Drop Vertical Jump Biomechanics--Implications for Athletic Performance and Injury Risk Assessments.

    Science.gov (United States)

    Khuu, Steven; Musalem, Lindsay L; Beach, Tyson A C

    2015-10-01

    Biomechanical quantities acquired during the drop vertical jump (DVJ) are used in the assessment of athletic performance and injury risk. The objective was to examine the impact of different verbal instructions on spatiotemporal, kinematic, and kinetic variables commonly included in such assessments. Ten men and 10 women from local varsity and club volleyball, basketball, figure skating, and track and field teams volunteered to participate. The athletes performed DVJs after given instructions to minimize ground contact time (CT), maximize jump height (HT), and synchronously extend the lower extremity joints (EX). Between the CT, HT, and EX conditions, body segment and joint angles were compared together with characteristics of vertical ground reaction force (GRF), whole-body power output, stiffness, and center-of-mass displacement time histories. Verbal instructions were found to influence nearly all of the spatiotemporal, body segment and joint kinematic, and kinetic variables that were statistically analyzed. Particularly noteworthy was the finding that athletic performance indices (e.g., jump height, power output, vertical stiffness, and reactive strength index) and lower extremity injury risk markers (e.g., peak vertical GRF and frontal plane knee angle) were significantly different (p ≤ 0.05) between the CT, HT, and EX conditions. The findings of this study suggest that verbal instructions should be controlled and/or clearly documented when using the DVJ to assess athletic performance potential and injury risk. Moreover, practitioners who devise performance enhancement and injury prevention strategies based on DVJ assessments are advised to consider that "coaching" or "cueing" during the task execution could impact conclusions drawn.

  2. Jumping to conclusions in schizophrenia

    Directory of Open Access Journals (Sweden)

    Evans SL

    2015-07-01

    Full Text Available Simon L Evans,1 Bruno B Averbeck,2 Nicholas Furl31School of Psychology, University of Sussex, Brighton, East Sussex, UK; 2Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA; 3Department of Psychology, Royal Holloway, University of London, Egham, Surrey, UKAbstract: Schizophrenia is a mental disorder associated with a variety of symptoms, including hallucinations, delusions, social withdrawal, and cognitive dysfunction. Impairments on decision-making tasks are routinely reported: evidence points to a particular deficit in learning from and revising behavior following feedback. In addition, patients tend to make hasty decisions when probabilistic judgments are required. This is known as “jumping to conclusions” (JTC and has typically been demonstrated by presenting participants with colored beads drawn from one of two “urns” until they claim to be sure which urn the beads are being drawn from (the proportions of colors vary in each urn. Patients tend to make early decisions on this task, and there is evidence to suggest that a hasty decision-making style might be linked to delusion formation and thus be of clinical relevance. Various accounts have been proposed regarding what underlies this behavior. In this review, we briefly introduce the disorder and the decision-making deficits associated with it. We then explore the evidence for each account of JTC in the context of a wider decision-making deficit and then go on to summarize work exploring JTC in healthy controls using pharmacological manipulations and functional imaging. Finally, we assess whether JTC might have a role in therapy.Keywords: ketamine, decision making, delusions, fMRI, urn task

  3. The reliability of vertical jump tests between the Vertec and My Jump phone application.

    Science.gov (United States)

    Yingling, Vanessa R; Castro, Dimitri A; Duong, Justin T; Malpartida, Fiorella J; Usher, Justin R; O, Jenny

    2018-01-01

    The vertical jump is used to estimate sports performance capabilities and physical fitness in children, elderly, non-athletic and injured individuals. Different jump techniques and measurement tools are available to assess vertical jump height and peak power; however, their use is limited by access to laboratory settings, excessive cost and/or time constraints thus making these tools oftentimes unsuitable for field assessment. A popular field test uses the Vertec and the Sargent vertical jump with countermovement; however, new low cost, easy to use tools are becoming available, including the My Jump iOS mobile application (app). The purpose of this study was to assess the reliability of the My Jump relative to values obtained by the Vertec for the Sargent stand and reach vertical jump (VJ) test. One hundred and thirty-five healthy participants aged 18-39 years (94 males, 41 females) completed three maximal Sargent VJ with countermovement that were simultaneously measured using the Vertec and the My Jump . Jump heights were quantified for each jump and peak power was calculated using the Sayers equation. Four separate ICC estimates and their 95% confidence intervals were used to assess reliability. Two analyses (with jump height and calculated peak power as the dependent variables, respectively) were based on a single rater, consistency, two-way mixed-effects model, while two others (with jump height and calculated peak power as the dependent variables, respectively) were based on a single rater, absolute agreement, two-way mixed-effects model. Moderate to excellent reliability relative to the degree of consistency between the Vertec and My Jump values was found for jump height (ICC = 0.813; 95% CI [0.747-0.863]) and calculated peak power (ICC = 0.926; 95% CI [0.897-0.947]). However, poor to good reliability relative to absolute agreement for VJ height (ICC = 0.665; 95% CI [0.050-0.859]) and poor to excellent reliability relative to absolute agreement for peak power

  4. Jump locations of jump-diffusion processes with state-dependent rates

    International Nuclear Information System (INIS)

    Miles, Christopher E; Keener, James P

    2017-01-01

    We propose a general framework for studying statistics of jump-diffusion systems driven by both Brownian noise (diffusion) and a jump process with state-dependent intensity. Of particular natural interest in many physical systems are the jump locations: the system evaluated at the jump times. As an example, this could be the voltage at which a neuron fires, or the so-called ‘threshold voltage’. However, the state-dependence of the jump rate provides direct coupling between the diffusion and jump components, making it difficult to disentangle the two to study individually. In this work, we provide an iterative map formulation of the sequence of distributions of jump locations. The distributions computed by this map can be used to elucidate other interesting quantities about the process, including statistics of the interjump times. Ultimately, the limit of the map reveals that knowledge of the stationary distribution of the full process is sufficient to recover (but not necessarily equal to) the distribution of jump locations. We propose two biophysical examples to illustrate the use of this framework to provide insight about a system. We find that a sharp threshold voltage emerges robustly in a simple stochastic integrate-and-fire neuronal model. The interplay between the two sources of noise is also investigated in a stepping model of molecular motor in intracellular transport pulling a diffusive cargo. (paper)

  5. Experimental study of the hydraulic jump in a hydraulic jump in a ...

    African Journals Online (AJOL)

    The hydraulic jump in a sloped rectangular channel is theoretically and experimentally examined. The study aims to determine the effect of the channel's slope on the sequent depth ratio of the jump. A theoretical relation is proposed for the inflow Froude number as function of the sequent depth ratio and the channel slope.

  6. Drop jumping. II. The influence of dropping height on the biomechanics of drop jumping

    NARCIS (Netherlands)

    Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

    In the literature, athletes preparing for explosive activities are recommended to include drop jumping in their training programs. For the execution of drop jumps, different techniques and different dropping heights can be used. This study was designed to investigate for the performance of bounce

  7. Increase in Jumping Height Associated with Maximal Effort Vertical Depth Jumps.

    Science.gov (United States)

    Bedi, John F.; And Others

    1987-01-01

    In order to assess if there existed a statistically significant increase in jumping performance when dropping from different heights, 32 males, aged 19 to 26, performed a series of maximal effort vertical jumps after dropping from eight heights onto a force plate. Results are analyzed. (Author/MT)

  8. The effect of wind on jumping distance in ski jumping--fairness assessed.

    Science.gov (United States)

    Virmavirta, Mikko; Kivekäs, Juha

    2012-09-01

    The special wind compensation system recently adopted by Fédération Internationale de Ski (FIS; International Ski Federation) to consider the effects of changing wind conditions has caused some controversy. Here, the effect of wind on jumping distance in ski jumping was studied by means of computer simulation and compared with the wind compensation factors used by FIS during the World Cup season 2009/2010. The results showed clearly that the effect of increasing head/tail wind on jumping distance is not linear: +17.4 m/-29.1 m, respectively, for a wind speed of 3 m/s. The linear formula used in the trial period of the wind compensation system was found to be appropriate only for a limited range of jumping distances as the gradient of the landing slope slows down the rate of distance change in long jumps.

  9. Filtering and control of stochastic jump hybrid systems

    CERN Document Server

    Yao, Xiuming; Zheng, Wei Xing

    2016-01-01

    This book presents recent research work on stochastic jump hybrid systems. Specifically, the considered stochastic jump hybrid systems include Markovian jump Ito stochastic systems, Markovian jump linear-parameter-varying (LPV) systems, Markovian jump singular systems, Markovian jump two-dimensional (2-D) systems, and Markovian jump repeated scalar nonlinear systems. Some sufficient conditions are first established respectively for the stability and performances of those kinds of stochastic jump hybrid systems in terms of solution of linear matrix inequalities (LMIs). Based on the derived analysis conditions, the filtering and control problems are addressed. The book presents up-to-date research developments and novel methodologies on stochastic jump hybrid systems. The contents can be divided into two parts: the first part is focused on robust filter design problem, while the second part is put the emphasis on robust control problem. These methodologies provide a framework for stability and performance analy...

  10. Determinants of the abilities to jump higher and shorten the contact time in a running 1-legged vertical jump in basketball.

    Science.gov (United States)

    Miura, Ken; Yamamoto, Masayoshi; Tamaki, Hiroyuki; Zushi, Koji

    2010-01-01

    This study was conducted to obtain useful information for developing training techniques for the running 1-legged vertical jump in basketball (lay-up shot jump). The ability to perform the lay-up shot jump and various basic jumps was measured by testing 19 male basketball players. The basic jumps consisted of the 1-legged repeated rebound jump, the 2-legged repeated rebound jump, and the countermovement jump. Jumping height, contact time, and jumping index (jumping height/contact time) were measured and calculated using a contact mat/computer system that recorded the contact and air times. The jumping index indicates power. No significant correlation existed between the jumping height and contact time of the lay-up shot jump, the 2 components of the lay-up shot jump index. As a result, jumping height and contact time were found to be mutually independent abilities. The relationships in contact time between the lay-up shot jump to the 1-legged repeated rebound jump and the 2-legged repeated rebound jump were correlated on the same significance levels (p jumping height existed between the 1-legged repeated rebound jump and the lay-up shot jump (p jumping height between the lay-up shot jump and both the 2-legged repeated rebound jump and countermovement jump. The lay-up shot index correlated more strongly to the 1-legged repeated rebound jump index (p jump index (p jump is effective in improving both contact time and jumping height in the lay-up shot jump.

  11. Temperature jump boundary conditions in radiation diffusion

    International Nuclear Information System (INIS)

    Alonso, C.T.

    1976-12-01

    The radiation diffusion approximation greatly simplifies radiation transport problems. Yet the application of this method has often been unnecessarily restricted to optically thick regions, or has been extended through the use of such ad hoc devices as flux limiters. The purpose of this paper is to review and draw attention to the use of the more physically appropriate temperature jump boundary conditions for extending the range of validity of the diffusion approximation. Pioneering work has shown that temperature jump boundary conditions remove the singularity in flux that occurs in ordinary diffusion at small optical thicknesses. In this review paper Deissler's equations for frequency-dependent jump boundary conditions are presented and specific geometric examples are calculated analytically for steady state radiation transfer. When jump boundary conditions are applied to radiation diffusion, they yield exact solutions which are naturally flux- limited and geometry-corrected. We believe that the presence of temperature jumps on source boundaries is probably responsible in some cases for the past need for imposing ad hoc flux-limiting constraints on pure diffusion solutions. The solution for transfer between plane slabs, which is exact to all orders of optical thickness, also provides a useful tool for studying the accuracy of computer codes

  12. Scaling the viscous circular hydraulic jump

    Science.gov (United States)

    Argentina, Mederic; Cerda, Enrique; Duchesne, Alexis; Limat, Laurent

    2017-11-01

    The formation mechanism of hydraulic jumps has been proposed by Belanger in 1828 and rationalised by Lord Rayleigh in 1914. As the Froude number becomes higher than one, the flow super criticality induces an instability which yields the emergence of a steep structure at the fluid surface. Strongly deformed liquid-air interface can be observed as a jet of viscous fluid impinges a flat boundary at high enough velocity. In this experimental setup, the location of the jump depends on the viscosity of the liquid, as shown by T. Bohr et al. in 1997. In 2014, A. Duchesne et al. have established the constancy of the Froude number at jump. Hence, it remains a contradiction, in which the radial hydraulic jump location might be explained through inviscid theory, but is also viscosity dependent. We present a model based on the 2011 Rojas et al. PRL, which solves this paradox. The agreement with experimental measurements is excellent not only for the prediction of the position of the hydraulic jump, but also for the determination of the fluid thickness profile. We predict theoretically the critical value of the Froude number, which matches perfectly to that measured by Duchesne et al. We acknowledge the support of the CNRS and the Universit Cte d'Azur, through the IDEX funding.

  13. A locust-inspired miniature jumping robot.

    Science.gov (United States)

    Zaitsev, Valentin; Gvirsman, Omer; Ben Hanan, Uri; Weiss, Avi; Ayali, Amir; Kosa, Gabor

    2015-11-25

    Unmanned ground vehicles are mostly wheeled, tracked, or legged. These locomotion mechanisms have a limited ability to traverse rough terrain and obstacles that are higher than the robot's center of mass. In order to improve the mobility of small robots it is necessary to expand the variety of their motion gaits. Jumping is one of nature's solutions to the challenge of mobility in difficult terrain. The desert locust is the model for the presented bio-inspired design of a jumping mechanism for a small mobile robot. The basic mechanism is similar to that of the semilunar process in the hind legs of the locust, and is based on the cocking of a torsional spring by wrapping a tendon-like wire around the shaft of a miniature motor. In this study we present the jumping mechanism design, and the manufacturing and performance analysis of two demonstrator prototypes. The most advanced jumping robot demonstrator is power autonomous, weighs 23 gr, and is capable of jumping to a height of 3.35 m, covering a distance of 1.37 m.

  14. Biomechanics of stair walking and jumping.

    Science.gov (United States)

    Loy, D J; Voloshin, A S

    1991-01-01

    Physical activities such as stair walking and jumping result in increased dynamic loading on the human musculoskeletal system. Use of light weight, externally attached accelerometers allows for in-vivo monitoring of the shock waves invading the human musculoskeletal system during those activities. Shock waves were measured in four subjects performing stair walking up and down, jumping in place and jumping off a fixed elevation. The results obtained show that walking down a staircase induced shock waves with amplitude of 130% of that observed in walking up stairs and 250% of the shock waves experienced in level gait. The jumping test revealed levels of the shock waves nearly eight times higher than that in level walking. It was also shown that the shock waves invading the human musculoskeletal system may be generated not only by the heel strike, but also by the metatarsal strike. To moderate the risk of degenerative joint disorders four types of viscoelastic insoles were utilized to reduce the impact generated shock waves. The insoles investigated were able to reduce the amplitude of the shock wave by between 9% and 41% depending on the insole type and particular physical activity. The insoles were more effective in the reduction of the heel strike impacts than in the reduction of the metatarsal strike impacts. In all instances, the shock attenuation capacities of the insoles tested were greater in the jumping trials than in the stair walking studies. The insoles were ranked in three groups on the basis of their shock absorbing capacity.

  15. Detection block

    International Nuclear Information System (INIS)

    Bezak, A.

    1987-01-01

    A diagram is given of a detection block used for monitoring burnup of nuclear reactor fuel. A shielding block is an important part of the detection block. It stabilizes the fuel assembly in the fixing hole in front of a collimator where a suitable gamma beam is defined for gamma spectrometry determination of fuel burnup. The detector case and a neutron source case are placed on opposite sides of the fixing hole. For neutron measurement for which the water in the tank is used as a moderator, the neutron detector-fuel assembly configuration is selected such that neutrons from spontaneous fission and neutrons induced with the neutron source can both be measured. The patented design of the detection block permits longitudinal travel and rotation of the fuel assembly to any position, and thus more reliable determination of nuclear fuel burnup. (E.S.). 1 fig

  16. The effect of spiritual intelligence on quality of sleep and attention of skilled volleyball players

    Directory of Open Access Journals (Sweden)

    sodabeh ghadami

    2017-05-01

    Full Text Available Spiritual intelligence is something more than mental ability and connects an individual to beyond. The aim of this study was to assess the effect of spiritual intelligence on sleep quality and attention of skilled volleyball players.  Therefore 116 (76 female, 40 male volleyball players of Mobarakeh county in Isfahan who had participated in regional competitions were selected. Abdollazadeh’s Spiritual Intelligence Questionnaire, Pittsburgh Sleep Quality, and Mari shook Test were used to measure the data.  Results of path analysis showed that spiritual intelligence affects both sleep quality and attention. Moreover, the quality of sleep mediated the effect of spiritual intelligence on attention, and the results showed the appropriateness of structural equation model fit.

  17. Analysis the percentage frequency to estimate Volleyball´s performance

    Directory of Open Access Journals (Sweden)

    Santiago Calero-Morales

    2012-12-01

    Full Text Available The study analyzes the percentage frequency as a mathematical model used to estimate the international volleyball performance. Based on the description of its practical objectives, the paper shows some positive and negative characteristics of the equation, characteristics that affect decision making by the coach. Three studies were conducted involving a population of 42 games in volleyball, men's youth category, 10 game of 13 possible belonging to the Final round of 2006 FIVB World League, and a ranked players in the qualifying phase of the 2006 World League with 48 games as population. The investigation determined that the percentage frequency is a simple computer model that defines a value perfectly isolated from reality, but does not model correctly all variables that significantly influence the final performance, creating false interpretations of reality.

  18. Use of Nutritional Supplements by High School Football and Volleyball Players

    Science.gov (United States)

    Mason, Melanie A; Giza, Matthew; Clayton, Lori; Lonning, Jim; Wilkerson, Rick D

    2001-01-01

    The known use of performance enhancing agents by athletes has occurred throughout history. In the 1960s and 1970s steroids and amphetamines were the supplements most often used. Now athletes are turning to supplements that are either natural or stimulate the release of natural hormones. The purpose of this study is to evaluate the prevalence of use of nutritional supplements among high school football and volleyball players. This study surveyed 495 male football players and 407 female volleyball players from 20 high schools in Northwest Iowa. These athletes completed anonymous surveys and returned them to their coaches. Results showed that 8% of the male athletes and 2% of the female athletes were using supplementation. Supplements used included creatine, androstiendione, HMB, amino acids, DHEA, phosphogen, weight gainer 1850, Tribulus, muscle plus, multivitamins, calcium, GABA, and Shaklee Vita Lea and Physique. PMID:11813950

  19. [Anthropometrical profile of Brazilian junior volleyball players for different sports requirement levels].

    Science.gov (United States)

    Fonseca-Toledo, Cláudio; Roquetti, Paula; Fernandes-Filho, José

    2010-12-01

    This study was aimed at investigating the anthropometrics characteristics of male Brazilian junior volleyball players, organised into 3 sports requirement groups: high qualification (HQ) formed by the national team, middle qualification (MQ) formed by athletes playing in the Brazilian national championships and low qualification (LQ) formed by players at school level. 101 athletes were observed, HQ (n=16), MQ (n=68) and LQ (n=17), aged 16.7 ± 0.5; 16.6 ± 0.5 and 16.2 ± 0.7 years, respectively. There following were evaluated: body mass, height, standing reach height, % body fat and Heath & Carter somatotype. The statistical analysis was descriptive and inferential, the Kruskal Wallis test being used for detecting differences between groups (pcharacteristics and requirement levels, considering psports' selection instrument for young talented volleyball players.

  20. 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.

  1. Recent Advancements in Lightning Jump Algorithm Work

    Science.gov (United States)

    Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.

    2010-01-01

    In the past year, the primary objectives were to show the usefulness of total lightning as compared to traditional cloud-to-ground (CG) networks, test the lightning jump algorithm configurations in other regions of the country, increase the number of thunderstorms within our thunderstorm database, and to pinpoint environments that could prove difficult for any lightning jump configuration. A total of 561 thunderstorms have been examined in the past year (409 non-severe, 152 severe) from four regions of the country (North Alabama, Washington D.C., High Plains of CO/KS, and Oklahoma). Results continue to indicate that the 2 lightning jump algorithm configuration holds the most promise in terms of prospective operational lightning jump algorithms, with a probability of detection (POD) at 81%, a false alarm rate (FAR) of 45%, a critical success index (CSI) of 49% and a Heidke Skill Score (HSS) of 0.66. The second best performing algorithm configuration was the Threshold 4 algorithm, which had a POD of 72%, FAR of 51%, a CSI of 41% and an HSS of 0.58. Because a more complex algorithm configuration shows the most promise in terms of prospective operational lightning jump algorithms, accurate thunderstorm cell tracking work must be undertaken to track lightning trends on an individual thunderstorm basis over time. While these numbers for the 2 configuration are impressive, the algorithm does have its weaknesses. Specifically, low-topped and tropical cyclone thunderstorm environments are present issues for the 2 lightning jump algorithm, because of the suppressed vertical depth impact on overall flash counts (i.e., a relative dearth in lightning). For example, in a sample of 120 thunderstorms from northern Alabama that contained 72 missed events by the 2 algorithm 36% of the misses were associated with these two environments (17 storms).

  2. Validity of a Jump Mat for assessing Countermovement Jump Performance in Elite Rugby Players.

    Science.gov (United States)

    Dobbin, Nick; Hunwicks, Richard; Highton, Jamie; Twist, Craig

    2017-02-01

    This study determined the validity of the Just Jump System ® (JJS) for measuring flight time, jump height and peak power output (PPO) in elite rugby league players. 37 elite rugby league players performed 6 countermovement jumps (CMJ; 3 with and 3 without arms) on a jump mat and force platform. A sub-sample (n=28) was used to cross-validate the equations for flight time, jump height and PPO. The JJS systematically overestimated flight time and jump height compared to the force platform (Pjump height ( with R 2 =0.945; without R 2 =0.987). Our equations revealed no systematic difference between corrected and force platform scores and an improved the agreement for flight time (Ratio limits of agreement: with 1.00 vs. 1.36; without 1.00 vs. 1.16) and jump height ( with 1.01 vs. 1.34; without 1.01 vs. 1.15), meaning that our equations can be used to correct JJS scores for elite rugby players. While our equation improved the estimation of PPO ( with 1.02; without 1.01) compared to existing equations (Harman: 1.20; Sayers: 1.04), this only accounted for 64 and 69% of PPO. © Georg Thieme Verlag KG Stuttgart · New York.

  3. CLIMATIC JUMP IN THE POLAR REGION (I)

    OpenAIRE

    ヤマモト, リョウザブロウ; イワシマ, タツヤ; ホシアイ, マコト; Ryozaburo, YAMAMOTO; Tatsuya, IWASHIMA; Makoto, HOSHIAI

    1987-01-01

    From the analysis of the climatic elements over Japan, we can detect the "climatic jumps" around the years 1920 and 1950,which is a new concept in the climatic diagnosis proposed by the present authors (R. YAMAMOTO et al. : J. Meteorol. Soc. Jpn., 63,1157,1985,64,273,1986). Taking account of several results which show the simultaneous occurrence of the climatic jumps of the surface air temperature, precipitation, etc., in the other regions by the other investigators, we may infer the "climati...

  4. THE EFFECT OF MEDIA LITERACY ON THE SOCIAL IDENTITY OF VOLLEYBALL SPECTATORS THROUGH PERSONAL IDENTITY

    OpenAIRE

    Mahsa Nematzadeh

    2017-01-01

    This research aim was investigating the effect of media literacy on volleyball spectator's social identity through personal identity. The present study, psychologically, is divided in to 8 layers of view paradigm, the main type of applied research: deductive research approaches, quantity research strategies theories, field research tone, cross sectional survey methods, research objectives, description and finally data collection methods, library resource reviews, and questionnaires. The stati...

  5. 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 ...

  6. STRUCTURE OF ISOLATED PRECISION FACTORS OF THE MALE STUDENT ON VOLLEYBALL

    Directory of Open Access Journals (Sweden)

    Bahri Gjinovci

    2015-06-01

    Full Text Available The aim of this study was to verify the current status of accuracy in volleyball for the students of the faculty of physical education and sports of the University of Prishtina, all the students have successfully passed the exam in volleyball. Also, another aim was to observe whether there are significant statistical differences between both generations of students. In the study were included 70 students (35 from the second academic year and 35 from the fourth academic year. To achieve the aim, were applied standard tests of accuracy in volleyball, such as the following: overhand pass, underhand pass, as well as underhand serve on the six positions and float (tactic serve on three positions. From the basic statistical parameters, it has been noticed that grouping of results from the students of forth academic year are more homogenous, and for this group showed that results are better than at students of first year of studying. While, in the variables is noticed that there are changes into the favour of students of fourth academic year, it has also been noticed that standard deviation is smaller with this group, which shows even more homogenous groups, for example, SFIP group 1 mean 21.65 ±6.48 SD, gr.2 mean 23.68 ±5.76 SD. The obtained results from T-test shows significant statistical changes in both applied tests. The best obtained results are a derivate of continuous professional work, as well as result of “selection”, due to continuous testing and completion of both exams of hand sports and volleyball as an elective subject.

  7. INVESTIGATION THE JOB SATISFACTION LEVELS OF HANDBALL, BASKETBALL AND VOLLEYBALL CLASSIFYING REFEREES

    OpenAIRE

    KARATAŞ, Özgür; SAVUCU, Yüksel; BİÇER, Yonca; YILDIRIM, Eyyup; ÇEVRİM, Hakan

    2013-01-01

    This study was performed to determine the level of job satisfaction (gender, age, marital status, class status, branch, other job, duration of referee, duration of playing the branch, and revenue status) on totally 222 Handball, Basketball and Volleyball referees who working in federation leagues. One-way variance analysis (ANOVA) and LSD test was performed to determine the differences between the groups for the statistical data. Measuring tool has two sections in the study. In the first sect...

  8. Assessment of nutrition, supplementation and body composition parameters on the example of professional volleyball players.

    Science.gov (United States)

    Zapolska, Joanna; Witczak, Katarzyna; Mańczuk, Angelika; Ostrowska, Lucyna

    2014-01-01

    Volleyball is a team game belonging to a group of sports disciplines that involve indirect fighting. Adequate energy coverage in athletes is a crucial issue. It depends primarily on the type, intensity and duration of physical activity related to the sports discipline practiced and to the training cycle duration. The average energy requirement in sportsmen is 50% higher than that of adults. The aim of the study was to characterize the mode of nutrition, including dietary supplements and to assess somatic indices in female volleyball players of the AZS Bialystok team. The study involved 17 women. Research tools included a questionnaire consisting of 24-hour recall, a questionnaire survey concerning supplement intake and body composition analysis performed using a bioimpedance analyzer InBody 220. Data analysis indicates that the anthropometric characteristics and body composition of the AZS Bialystok players meet the recommendations associated with the somatic features in volleyball. Daily diet of the volleyball players were of low-energy with regard to the recommendations for physically active people, with very low supply of carbohydrates and dietary fiber, excessive proportion of saturated fatty acids and dietary cholesterol, and too low content of monounsaturated and polyunsaturated fatty acids. Supply of vitamins and minerals was found to be alarmingly low, especially of iron and calcium; diet supplementation was insufficient. No significant abnormalities were noted in body composition of the study athletes. However, they are recommended to increase muscle mass and slightly reduce body fat. Results of diet evaluation show the need for education in the field of nutrition and the necessity of further research into dietary habits among sportsmen.

  9. Heart rate variability during pre-competition and competition periods in volleyball players

    OpenAIRE

    Podstawski Robert; Boraczyński Michał; Nowosielska-Swadźba Danuta; Zwolińska Danuta

    2014-01-01

    Study aim: Regular exercise training is thought to modify cardiac autonomic control. One of the body’s responses to training stimuli is heart rate variability (HRV). The use of HRV in the management of sport training is a common practice. The objective of the present study was to assess the impact of the physical activity level on HRV of 1st league national volleyball players prior to and during the competition period.

  10. Heart rate variability during pre-competition and competition periods in volleyball players

    Directory of Open Access Journals (Sweden)

    Podstawski Robert

    2014-01-01

    Full Text Available Study aim: Regular exercise training is thought to modify cardiac autonomic control. One of the body’s responses to training stimuli is heart rate variability (HRV. The use of HRV in the management of sport training is a common practice. The objective of the present study was to assess the impact of the physical activity level on HRV of 1st league national volleyball players prior to and during the competition period.

  11. The positioning of federate sports in Portugal: handball, basketball, roller hockey and volleyball

    OpenAIRE

    Gonçalves, Celina; Correia, Abel

    2005-01-01

    Sport is constituted by a multiplicity of activities with different purposes, concepts and cultural representations. Before the increase of supply, Sports Federations need to understand the practitioners in relation to the several possibilities of practice and to position their sports according to their competitors. In this context, the purpose of this study is the positioning of team federate sports (handball, basketball, roller hockey and volleyball). According to Lindon et al.,...

  12. Acute injuries in soccer, ice hockey, volleyball, basketball, judo, and karate: analysis of national registry data.

    OpenAIRE

    Kujala, U. M.; Taimela, S.; Antti-Poika, I.; Orava, S.; Tuominen, R.; Myllynen, P.

    1995-01-01

    OBJECTIVE--To determine the acute injury profile in each of six sports and compare the injury rates between the sports. DESIGN--Analysis of national sports injury insurance registry data. SETTING--Finland during 1987-91. SUBJECTS--621,691 person years of exposure among participants in soccer, ice hockey, volleyball, basketball, judo, or karate. MAIN OUTCOME MEASURES--Acute sports injuries requiring medical treatment and reported to the insurance company on structured forms by the patients and...

  13. The differences in acceleration, maximal speed and agility between soccer, basketball, volleyball and handball players

    OpenAIRE

    Šimonek, Jaromír; Horička, Pavol; Hianik, Ján

    2017-01-01

    Complex reaction speed, acceleration, maximum speed, speed of whole-body change of direction and agility represent the basic components of sport performance mainly in sport games and combat sports. However, contradictory findings have been reported as to the extent of the relationship between the different speed and agility components. This study comprised 117 players (soccer – 56, basketball – 17, volleyball – 20, and handball – 24) playing youth leagues U15-U17 who were assessed for 10-m sp...

  14. Does trampoline or hard surface jumping influence lower extremity alignment?

    Science.gov (United States)

    Akasaka, Kiyokazu; Tamura, Akihiro; Katsuta, Aoi; Sagawa, Ayako; Otsudo, Takahiro; Okubo, Yu; Sawada, Yutaka; Hall, Toby

    2017-12-01

    [Purpose] To determine whether repetitive trampoline or hard surface jumping affects lower extremity alignment on jump landing. [Subjects and Methods] Twenty healthy females participated in this study. All subjects performed a drop vertical jump before and after repeated maximum effort trampoline or hard surface jumping. A three-dimensional motion analysis system and two force plates were used to record lower extremity angles, moments, and vertical ground reaction force during drop vertical jumps. [Results] Knee extensor moment after trampoline jumping was greater than that after hard surface jumping. There were no significant differences between trials in vertical ground reaction force and lower extremity joint angles following each form of exercise. Repeated jumping on a trampoline increased peak vertical ground reaction force, hip extensor, knee extensor moments, and hip adduction angle, while decreasing hip flexion angle during drop vertical jumps. In contrast, repeated jumping on a hard surface increased peak vertical ground reaction force, ankle dorsiflexion angle, and hip extensor moment during drop vertical jumps. [Conclusion] Repeated jumping on the trampoline compared to jumping on a hard surface has different effects on lower limb kinetics and kinematics. Knowledge of these effects may be useful in designing exercise programs for different clinical presentations.

  15. Test-retest reliability of jump execution variables using mechanography: a comparison of jump protocols.

    Science.gov (United States)

    Fitzgerald, John S; Johnson, LuAnn; Tomkinson, Grant; Stein, Jesse; Roemmich, James N

    2018-05-01

    Mechanography during the vertical jump may enhance screening and determining mechanistic causes underlying physical performance changes. Utility of jump mechanography for evaluation is limited by scant test-retest reliability data on force-time variables. This study examined the test-retest reliability of eight jump execution variables assessed from mechanography. Thirty-two women (mean±SD: age 20.8 ± 1.3 yr) and 16 men (age 22.1 ± 1.9 yr) attended a familiarization session and two testing sessions, all one week apart. Participants performed two variations of the squat jump with squat depth self-selected and controlled using a goniometer to 80º knee flexion. Test-retest reliability was quantified as the systematic error (using effect size between jumps), random error (using coefficients of variation), and test-retest correlations (using intra-class correlation coefficients). Overall, jump execution variables demonstrated acceptable reliability, evidenced by small systematic errors (mean±95%CI: 0.2 ± 0.07), moderate random errors (mean±95%CI: 17.8 ± 3.7%), and very strong test-retest correlations (range: 0.73-0.97). Differences in random errors between controlled and self-selected protocols were negligible (mean±95%CI: 1.3 ± 2.3%). Jump execution variables demonstrated acceptable reliability, with no meaningful differences between the controlled and self-selected jump protocols. To simplify testing, a self-selected jump protocol can be used to assess force-time variables with negligible impact on measurement error.

  16. DIFFERENCES IN FUNCTIONAL AND MOTOR ABILITIES OFYOUNG FOOTBALL PLAYERS, BASKETBALL AND VOLLEYBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Franja Fratrić

    2009-11-01

    Full Text Available The main goal of this research is to determine whether and what differences exist between the three groups of subjects (high-quality football, volleyball and basketball cadets and youth age, in the motoric and functional abilities, as well as to identify dif- ferences between subgroups within each sport. The sample consists of 61 volleyball, 31 basketball player and football player 31 (total n = 123 male, cadet and youth age are members of local clubs. Subjects were born between 01.01.1991 and 12.12.1994. The sample of variables are the values of 17 tests for the evaluation of functional and mobile status. The Motor-functional status on the basis of the results of secondary value of foot- ball, basketball and volleyball make a clear conclusion that the football players showed the best results in almost all the tests and that they had the smallest disbalance in the power of certain groups of muscles.The football players hve the highest homogeneity.

  17. Nonoperative Management and Novel Imaging for Posterior Circumflex Humeral Artery Injury in Volleyball.

    Science.gov (United States)

    van de Pol, Daan; Planken, R Nils; Terpstra, Aart; Pannekoek-Hekman, Marja; Kuijer, P Paul F M; Maas, Mario

    We report on a 34-yr-old male elite volleyball player with symptomatic emboli in the spiking hand from a partially thrombosed aneurysm of the posterior circumflex humeral artery (PCHA) in his dominant shoulder. At initial diagnosis and follow-up, a combination of time-resolved and high-resolution steady state contrast-enhanced magnetic resonance angiography (CE-MRA) enabled detailed visualization of: (1) emboli that were not detectable by vascular ultrasound; and (2) the PCHA aneurysm, including compression during abduction and external rotation (ABER provocation). At 15-month follow-up, including forced cessation of volleyball activities over the preceding 9 months, the PCHA aneurysm remained unchanged. Central filling defects in the palmar arch and digital arteries resolved over time and affected arterial vessel segments showed postthrombotic changes. Digital blood pressure values improved substantially and almost normalized during follow-up. In conclusion, this case report is the first to show promising results of nonoperative management for a vascular shoulder overuse injury in a professional volleyball player as an alternative to invasive therapeutic options.

  18. Ultrasonographic evaluation of the shoulder in elite Italian beach volleyball players.

    Science.gov (United States)

    Monteleone, G; Tramontana, A; Mc Donald, K; Sorge, R; Tiloca, A; Foti, C

    2015-10-01

    Beach volleyball is an overhead sport that subjects the hitting shoulder to intense functional loads. The purpose of this study is to identify ultrasonographically the prevalence of myotendinous alterations in professional Italian beach volleyball players at the Italian championship and to look for associations between ultrasound findings and the other data collected. Fifty-three beach volleyball players (31 women, 22 men) were recruited during the second stage of the Italian championship held in July 2012 in Rome, Italy. Clinical history was obtained from all subjects, followed by physical exam. Each athlete completed a questionnaire regarding sports activities. Bilateral ultrasonographic evaluation of the shoulders was then performed. Calcific tendinopathy of the rotator cuff of the hitting shoulder was identified ultrasonographically in 30% of the athletes. The mean age of the athletes with calcific tendinopathy was older than subjects with other abnormalities on ultrasonographic examination (33.1 years vs. 25.8 years, t-test; Pvolleyball players has a prevalence of 30% ultrasonographically, greater than that reported in the general population. In these athletes, the presence of calcific tendinopathy correlates positively with age.

  19. Shoulder-Rotator Strength, Range of Motion, and Acromiohumeral Distance in Asymptomatic Adolescent Volleyball Attackers.

    Science.gov (United States)

    Harput, Gulcan; Guney, Hande; Toprak, Ugur; Kaya, Tunca; Colakoglu, Fatma Filiz; Baltaci, Gul

    2016-09-01

    Sport-specific adaptations at the glenohumeral joint could occur in adolescent athletes because they start participating in high-performance sports in early childhood. To investigate shoulder-rotator strength, internal-rotation (IR) and external-rotation (ER) range of motion (ROM), and acromiohumeral distance (AHD) in asymptomatic adolescent volleyball attackers to determine if they have risk factors for injury. Cross-sectional study. University laboratory. Thirty-nine adolescent high school-aged volleyball attackers (22 boys, 17 girls; age = 16.0 ± 1.4 years, height = 179.2 ± 9.0 cm, mass = 67.1 ± 10.9 kg, body mass index = 20.7 ± 2.6 kg/m 2 ). Shoulder IR and ER ROM, total-rotation ROM, glenohumeral IR deficit, AHD, and concentric and eccentric strength of the shoulder internal and external rotators were tested bilaterally. External-rotation ROM was greater (t 38 = 4.92, P 18°). We observed greater concentric internal-rotator (t 38 = 2.89, P = .006) and eccentric external-rotator (t 38 = 2.65, P = .01) strength in the dominant than in the nondominant shoulder. The AHD was less in the dominant shoulder (t 38 = -3.60, P volleyball attackers demonstrated decreased IR ROM, total ROM, and AHD and increased ER ROM in their dominant shoulder. Therefore, routine screening of adolescent athletes and designing training programs for hazardous adaptive changes could be important in preventing shoulder injuries.

  20. SPECIFIC SITES OF BONE EXPANSION DEPEND ON THE LEVEL OF VOLLEYBALL PRACTICE IN PREPUBESCENT BOYS

    Directory of Open Access Journals (Sweden)

    Hamada Chaari

    2013-06-01

    Full Text Available The purpose of this study was to investigate the effect of 18 months of high and low levels of volleyball practice on bone acquisition. 130 prepubescent boys (mean age 11.4 ± 0.7 were divided into a high-level training group (HLG, low-level training group (LLG, and controls. Bone mineral content (BMC and bone area at the whole body, lumbar spine L2-L4, femoral neck of the dominant leg, and right and left radius were measured using dual-photon X-ray absorptiometry. Enhanced BMC resulted from high-training volleyball activity in all measured sites except the third left and right distal radius, which is not modified by low-level training in prepubescent players but it was accompanied by a bone area expansion in radius and weight-bearing sites for the HLG, and in legs, whole right and left radius for the LLG. Significant improvement of skeletal tissues is associated with the intensity and duration of volleyball training.

  1. Foveal and peripheral fields of vision influences perceptual skill in anticipating opponents' attacking position in volleyball.

    Science.gov (United States)

    Schorer, Jörg; Rienhoff, Rebecca; Fischer, Lennart; Baker, Joseph

    2013-09-01

    The importance of perceptual-cognitive expertise in sport has been repeatedly demonstrated. In this study we examined the role of different sources of visual information (i.e., foveal versus peripheral) in anticipating volleyball attack positions. Expert (n = 11), advanced (n = 13) and novice (n = 16) players completed an anticipation task that involved predicting the location of volleyball attacks. Video clips of volleyball attacks (n = 72) were spatially and temporally occluded to provide varying amounts of information to the participant. In addition, participants viewed the attacks under three visual conditions: full vision, foveal vision only, and peripheral vision only. Analysis of variance revealed significant between group differences in prediction accuracy with higher skilled players performing better than lower skilled players. Additionally, we found significant differences between temporal and spatial occlusion conditions. Both of those factors interacted separately, but not combined with expertise. Importantly, for experts the sum of both fields of vision was superior to either source in isolation. Our results suggest different sources of visual information work collectively to facilitate expert anticipation in time-constrained sports and reinforce the complexity of expert perception.

  2. 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.

  3. Characteristics and contributing factors related to sports injuries in young volleyball players

    Science.gov (United States)

    2013-01-01

    Background The participation of young in volleyball is becoming increasingly common, and this increased involvement raises concerns about the risk of installation of sports injuries. Therefore, the objectives the study were identify the characteristics of sports injuries in young volleyball players and associate anthropometric and training variables with contributing factors for injuries. Methods A total of 522 volleyball players participating in the High School Olympic Games of the State of São Paulo (Brazil) were interviewed. A reported condition inquiry was used to gather information on injuries, such as anatomic site affected, mechanism and moment of injury, as well as personal and training data. The level of significance was set at 5%. Results A 19% frequency of injuries was found. Higher age, weight, height, body mass index and training duration values were associated with the occurrence of injuries. The most affected anatomic site was the ankle/foot complex (45 injuries, 36.3%). Direct contact and contactless mechanisms were the main causes of injuries (61 injuries; 49.2% and 48 injuries; 38.7%, respectively). Training was the moment in which most injuries occurred (93 injuries; 75%), independently of personal and training characteristics. Conclusion Injuries affected the ankle/foot complex with a greater frequency. Direct contact and contactless mechanisms were the most frequently reported and injuries occurred mainly during training sessions. Personal and training characteristics were contributing factors for the occurrence of injuries. PMID:24124803

  4. Variables that Predict Serve Efficacy in Elite Men's Volleyball with Different Quality of Opposition Sets.

    Science.gov (United States)

    Valhondo, Álvaro; Fernández-Echeverría, Carmen; González-Silva, Jara; Claver, Fernando; Moreno, M Perla

    2018-03-01

    The objective of this study was to determine the variables that predicted serve efficacy in elite men's volleyball, in sets with different quality of opposition. 3292 serve actions were analysed, of which 2254 were carried out in high quality of opposition sets and 1038 actions were in low quality of opposition sets, corresponding to a total of 24 matches played during the Men's European Volleyball Championships held in 2011. The independent variables considered in this study were the serve zone, serve type, serving player, serve direction, reception zone, receiving player and reception type; the dependent variable was serve efficacy and the situational variable was quality of opposition sets. The variables that acted as predictors in both high and low quality of opposition sets were the serving player, reception zone and reception type. The serve type variable only acted as a predictor in high quality of opposition sets, while the serve zone variable only acted as a predictor in low quality of opposition sets. These results may provide important guidance in men's volleyball training processes.

  5. The Effects of Core Stability Exercise on the Dynamic Balance of Volleyball Players

    Directory of Open Access Journals (Sweden)

    Hassan Sadeghi

    2013-12-01

    Full Text Available Dynamic balance is a key component of injury prevention and rehabilitation in sports. Training the core muscles has been hypothesized as an intervention for improving balance. However, there is a lack of current scientific evidence to support this claim. The purpose of this study was to evaluate the effects of a core stability program on dynamic balance of volleyball players as measured with the Star Excursion Balance Test (SEBT. Thirty healthy participants were divided into 2 groups: control and exercise groups. All participants performed the SEBT before and after 8-week exercise time. During the 8-week time, the exercise group performed a core stability program, whereas the control group abstained from any new exercise. These results also illustrated there was significant differences in the scores for pre-test and post-test of all direction according SEBT in the experimental group. An independent sample t-test was conducted to compare experimental and control group (F=43.573, Sig=0.000. These results were a significant difference in the scores for control and experimental groups. Maximum excursion distances improved for the exercise group, compared with the control group. This result justifies the hypothesis that core strengthening can improve dynamic postural control during landing of volleyball players significantly. Keywords: Core stabilization; volleyball player; dynamic balance; SEBT

  6. Characteristics and contributing factors related to sports injuries in young volleyball players.

    Science.gov (United States)

    Vanderlei, Franciele Marques; Bastos, Fabio Nascimento; Tsutsumi, Gustavo Yuki Cantalejo; Vanderlei, Luiz Carlos Marques; Netto Júnior, Jayme; Pastre, Carlos Marcelo

    2013-10-14

    The participation of young in volleyball is becoming increasingly common, and this increased involvement raises concerns about the risk of installation of sports injuries. Therefore, the objectives the study were identify the characteristics of sports injuries in young volleyball players and associate anthropometric and training variables with contributing factors for injuries. A total of 522 volleyball players participating in the High School Olympic Games of the State of São Paulo (Brazil) were interviewed. A reported condition inquiry was used to gather information on injuries, such as anatomic site affected, mechanism and moment of injury, as well as personal and training data. The level of significance was set at 5%. A 19% frequency of injuries was found. Higher age, weight, height, body mass index and training duration values were associated with the occurrence of injuries. The most affected anatomic site was the ankle/foot complex (45 injuries, 36.3%). Direct contact and contactless mechanisms were the main causes of injuries (61 injuries; 49.2% and 48 injuries; 38.7%, respectively). Training was the moment in which most injuries occurred (93 injuries; 75%), independently of personal and training characteristics. Injuries affected the ankle/foot complex with a greater frequency. Direct contact and contactless mechanisms were the most frequently reported and injuries occurred mainly during training sessions. Personal and training characteristics were contributing factors for the occurrence of injuries.

  7. Influence of Knee-to-Feet Jump Training on Vertical Jump and Hang Clean Performance.

    Science.gov (United States)

    Stark, Laura; Pickett, Karla; Bird, Michael; King, Adam C

    2016-11-01

    Stark, L, Pickett, K, Bird, M, and King, AC. Influence of knee-to-feet jump training on vertical jump and hang clean performance. J Strength Cond Res 30(11): 3084-3089, 2016-From a motor learning perspective, the practice/training environment can result in positive, negative, or neutral transfer to the testing conditions. The purpose of this study was to examine the training effect of a novel movement (knee-to-feet [K2F] jumps) and whether a 6-week training program induced a positive transfer effect to other power-related movements (vertical jump and hang clean [HC]). Twenty-six intercollegiate athletes from power-emphasized sports were paired and counter-balanced into a control (i.e., maintained their respective sport-specific lifting regimen) or an experimental group (i.e., completed a 6-week progressive training program of K2F jumps in addition to respective lifting regimen). A pre- and posttest design was used to investigate the effect of training on K2F jump height and transfer effect to vertical jump height (VJH) and 2-repetition maximum (RM) HC performance. A significant increase in K2F jump height was found for the experimental group. Vertical jump height significantly increased from pre- to posttest but no group or interaction (group × time) effect was found, and there were nonsignificant differences for HC. Posttest data showed significant correlations between all pairs of the selected exercises with the highest correlation between K2F jump height and VJ H (R = 0.40) followed by VJH and 2RM HC (R = 0.38) and 2RM HC and K2F jump height (R = 0.23). The results suggest that K2F jump training induced the desired learning effect but was specific to the movement in that no effect of transfer occurred to the other power-related movements. This finding is value for strength and condition professionals who design training programs to enhance athletic performance.

  8. Filtering of a Markov Jump Process with Counting Observations

    International Nuclear Information System (INIS)

    Ceci, C.; Gerardi, A.

    2000-01-01

    This paper concerns the filtering of an R d -valued Markov pure jump process when only the total number of jumps are observed. Strong and weak uniqueness for the solutions of the filtering equations are discussed

  9. Jumping on the Social Media Bandwagon

    Science.gov (United States)

    Blakeslee, Lori

    2012-01-01

    Should a school district jump on the social media bandwagon? Yes! Social media provide a low-cost way to communicate school district priorities, influence decision makers, and tell its story without filters. Equally important, social media are where constituents are spending a lot of their time. With more than 800 million members, Facebook is an…

  10. User Survey of 3 Ankle Braces in Soccer, Volleyball, and Running: Which Brace Fits Best?

    Science.gov (United States)

    Janssen, Kasper; Van Den Berg, Anjulie; Van Mechelen, Willem; Verhagen, Evert

    2017-08-01

      Recurrence rates for ankle sprains are high. Therefore, preventive measures such as ankle bracing during sports are recommended.   To systematically evaluate the perceived ease of use, quality, comfort, stability, and hindrance of and the overall satisfaction with 3 contemporary brace types in 3 types of sports.   Randomized comparative user survey.   Recreational sports: soccer, volleyball, and running.   Young adult recreational athletes (29 soccer players, 26 volleyball players, and 31 runners).   Compression brace (CB), lace-up brace (LB), and semirigid brace (SB).   Rating of perceived ease of use, quality, comfort, stability, and hindrance of and overall satisfaction with the brace types during sports on a 5-point Likert scale. The secondary outcome measure was participants' willingness to buy the tested brace.   Overall, the 3 brace types received high mean scores for ease of use and quality. Soccer players preferred the CB over both alternatives, considering the higher scores for comfort (CB = 4.0, LB = 3.5, SB = 2.8), hindrance (CB = 3.7, LB = 2.9, SB = 2.8), overall satisfaction (CB = 3.6, LB = 3.0, SB = 2.5), and greatest willingness to buy this brace. Volleyball players preferred the LB over both alternatives, considering the higher scores for stability (LB = 4.2, CB = 3.2, SB = 3.3), overall satisfaction (LB = 3.8, CB = 3.0, SB = 3.0), and greatest willingness to buy this brace. Runners preferred the CB over both alternatives considering the better score for hindrance (CB = 3.6, LB = 2.8, SB = 2.9) and greatest willingness to buy this brace.   All 3 ankle-brace types scored high on perceived ease of use and quality. Regarding the brace types, soccer players, volleyball players, and runners differed in their assessments of subjective evaluation of comfort, stability, hindrance, overall satisfaction, and willingness to buy the brace. Soccer players and runners preferred the CB, whereas volleyball players preferred the LB.

  11. Jump as Far as You Can [Problem Solvers: Problem

    Science.gov (United States)

    Bofferding, Laura; Yigit, Melike

    2013-01-01

    The standing long jump was an Olympic event until 1912. In 1904, Ray Ewry set the world record for the longest standing long jump, which was about 11.5 feet, or 138 inches. Although the standing long jump is no longer an Olympic event, the Norwegians still include it in their National Competition, and Arne Tvervaag set a new world record at about…

  12. Thomson's Jumping Ring over a Long Coil

    Science.gov (United States)

    Jeffery, Rondo N.; Amiri, Farhang

    2018-01-01

    The classic jumping ring apparatus consists of a coil with an iron core that extends out of the coil. A copper or aluminum ring placed over the iron core jumps upward when AC power is applied to the coil. In this paper we will examine a modified design of the jumping ring apparatus, called the "long-coil design." It allows the ring to…

  13. Vorticity determination in a hydraulic jump by application of method ...

    African Journals Online (AJOL)

    The method of characteristics for solving systems of partial differential equations coupled with jump conditions is used in analysing flow downstream of a hydraulic jump instead of the normal analytical approach adopted in Hornung [1]. It is shown that the method of characteristics together with the jump conditions can ...

  14. Scaling and jumping: Gravity loses grip on small jumpers

    NARCIS (Netherlands)

    Scholz, M.N.; Bobbert, M.F.; van Soest, A.J.

    2006-01-01

    There are several ways to quantify jumping performance, a common definition being the height gained by the body's centre of mass (CM) in the airborne phase. Under this definition, jump height is determined by take-off velocity. According to the existing literature on jumping and scaling, take-off

  15. Effect of early training on the jumping technique of horses

    NARCIS (Netherlands)

    Santamaría, Susana; Bobbert, Maarten F.; Back, Willem; Barneveld, Ab; van Weeren, P. Rene

    Objective - To investigate the effects of early training for jumping by comparing the jumping technique of horses that had received early training with that of horses raised conventionally. Animals - 40 Dutch Warmblood horses. Procedure - The horses were analyzed kinematically during free jumping at

  16. Deriving appropriate boundary conditions, and accelerating position-jump simulations, of diffusion using non-local jumping

    International Nuclear Information System (INIS)

    Taylor, P R; Baker, R E; Yates, C A

    2015-01-01

    In this paper we explore lattice-based position-jump models of diffusion, and the implications of introducing non-local jumping; particles can jump to a range of nearby boxes rather than only to their nearest neighbours. We begin by deriving conditions for equivalence with traditional local jumping models in the continuum limit. We then generalize a previously postulated implementation of the Robin boundary condition for a non-local process of arbitrary maximum jump length, and present a novel implementation of flux boundary conditions, again generalized for a non-local process of arbitrary maximum jump length. In both these cases we validate our results using stochastic simulation. We then proceed to consider two variations on the basic diffusion model: a hybrid local/non-local scheme suitable for models involving sharp concentration gradients, and the implementation of biased jumping. In all cases we show that non-local jumping can deliver substantial time savings for stochastic simulations. (paper)

  17. Option Valuation with Observable Volatility and Jump Dynamics

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

    Under very general conditions, the total quadratic variation of a jump-diffusion process can be decomposed into diffusive volatility and squared jump variation. We use this result to develop a new option valuation model in which the underlying asset price exhibits volatility and jump intensity...... dynamics. The volatility and jump intensity dynamics in the model are directly driven by model-free empirical measures of diffusive volatility and jump variation. Because the empirical measures are observed in discrete intervals, our option valuation model is cast in discrete time, allowing...

  18. Option Valuation with Observable Volatility and Jump Dynamics

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

    2015-01-01

    Under very general conditions, the total quadratic variation of a jump-diffusion process can be decomposed into diffusive volatility and squared jump variation. We use this result to develop a new option valuation model in which the underlying asset price exhibits volatility and jump intensity...... dynamics. The volatility and jump intensity dynamics in the model are directly driven by model-free empirical measures of diffusive volatility and jump variation. Because the empirical measures are observed in discrete intervals, our option valuation model is cast in discrete time, allowing...

  19. DESIGN OF A FAST CHROMATICITY JUMP IN RHIC

    International Nuclear Information System (INIS)

    MONTAG, C.; KEWISCH, J.; BRUNO, D.; GANETIS, G.; LOUIE, W.

    2003-01-01

    During transition crossing in the .Relativistic Heavy Ion Collider (RHIC), chromaticities have to change sign. This sign change is partially accomplished by the γ t quadrupole jump; however, the resulting chromaticity jump is only Δξ x = 2.1 in the horizontal and Δξ y = 2.4 in the vertical plane. To increase the jump height, a dedicated chromaticity jump scheme has been designed, consisting of fast power supplies connected to six sextupoles per ring, which is capable of providing a chromaticity jump of Δξ = 6

  20. The methodological basis for determining individual characteristics of volleyball players at the stage of basic training specialist.

    Directory of Open Access Journals (Sweden)

    Kozina Zh.L.

    2012-03-01

    Full Text Available Purpose of work - to form and methodologically ground conception of individualization of training process in the playing types of sport. The algorithm of determination of individual features is presented in the structure of preparedness of skilled volley-ballers. In research 20 volley-ballers took part on the stage of the specialized base preparation. The stages of determination of command and individual factor structure of preparedness of sportswomen are presented. It is exposed that individual descriptions of volley-ballers and their line of business not always are related exceptionally to anthropometric information. Descriptions also depend and from the row of other physiological and психофизиологических indexes. These indexes for certain differentiate for the players of different line of role.

  1. Biomechanical Analysis of the Jump Shot in Basketball

    Directory of Open Access Journals (Sweden)

    Struzik Artur

    2014-10-01

    Full Text Available Basketball players usually score points during the game using the jump shot. For this reason, the jump shot is considered to be the most important element of technique in basketball and requires a high level of performance. The aim of this study was to compare the biomechanical characteristics of the lower limbs during a jump shot without the ball and a countermovement jump without an arm swing. The differences between variables provide information about the potential that an athlete can utilise during a game when performing a jump shot. The study was conducted among 20 second-league basketball players by means of a Kistler force plate and the BTS SMART system for motion analysis. The variables measured included the take-off time, mean power, peak power, relative mean power, jump height, maximum landing force and calculated impact ratio. Surprisingly, more advantageous variables were found for the jump shot. This finding suggests a very high performance level in the jump shot in the studied group and a maximum utilisation of their motor abilities. Both types of jumps were characterised by high mean and peak power values and average heights. The high forces at landing, which result in considerable impact ratios, may have prompted the studied group to land softly. Use of the countermovement jump without an arm swing is recommended to assess and predict the progression of player’s jumping ability

  2. Validity of Hip-worn Inertial Measurement Unit Compared to Jump Mat for Jump Height Measurement in Adolescents.

    Science.gov (United States)

    Rantalainen, T; Hesketh, K D; Rodda, C; Duckham, R L

    2018-06-16

    Jump tests assess lower body power production capacity, and can be used to evaluate athletic ability and development during growth. Wearable inertial measurement units (IMU) seem to offer a feasible alternative to laboratory-based equipment for jump height assessments. Concurrent validity of these devices for jump height assessments has only been established in adults. Therefore, the purpose of this study was to evaluate the concurrent validity of IMU-based jump height estimate compared to contact mat-based jump height estimate in adolescents. Ninety-five adolescents (10-13 years-of-age; girls N=41, height = 154 (SD 9) cm, weight = 44 (11) kg; boys N=54, height=156 (10) cm, weight = 46 (13) kg) completed three counter-movement jumps for maximal jump height on a contact mat. Inertial recordings (accelerations, rotations) were concurrently recorded with a hip-worn IMU (sampling at 256 Hz). Jump height was evaluated based on flight time. The mean IMU-derived jump height was 27.1 (SD 3.8) cm, and the corresponding mean jump-mat-derived value was 21.5 (3.4) cm. While a significant 26% mean difference was observed between the methods (5.5 [95% limits of agreement 2.2 to 8.9] cm, p = 0.006), the correspondence between methods was excellent (ICC = 0.89). The difference between methods was weakly positively associated with jump height (r = 0.28, P = 0.007). Take-off velocity derived jump height was also explored but produced only fair congruence. In conclusion, IMU-derived jump height exhibited excellent congruence to contact mat-based jump height and therefore presents a feasible alternative for jump height assessments in adolescents. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  3. A Jump Diffusion Model for Volatility and Duration

    DEFF Research Database (Denmark)

    Wei, Wei; Pelletier, Denis

    by the market microstructure theory. Traditional measures of volatility do not utilize durations. I adopt a jump diffusion process to model the persistence of intraday volatility and conditional duration, and their interdependence. The jump component is disentangled from the continuous part of the price......, volatility and conditional duration process. I develop a MCMC algorithm for the inference of irregularly spaced multivariate process with jumps. The algorithm provides smoothed estimates of the latent variables such as spot volatility, jump times and jump sizes. I apply this model to IBM data and I find...... meaningful relationship between volatility and conditional duration. Also, jumps play an important role in the total variation, but the jump variation is smaller than traditional measures that use returns sampled at lower frequency....

  4. Propulsion efficiency and imposed flow fields of a copepod jump

    DEFF Research Database (Denmark)

    Jiang, H.; Kiørboe, Thomas

    2011-01-01

    Pelagic copepods jump to relocate, to attack prey and to escape predators. However, there is a price to be paid for these jumps in terms of their energy costs and the hydrodynamic signals they generate to rheotactic predators. Using observed kinematics of various types of jumps, we computed...... the imposed flow fields and associated energetics of jumps by means of computational fluid dynamics simulations by modeling the copepod as a self-propelled body. The computational fluid dynamics simulation was validated by particle image velocimetry data. The flow field generated by a repositioning jump...... the flow structure. The flow field associated with an escape jump sequence also includes two dominant vortex structures: one leading wake vortex generated as a result of the first jump and one around the body, but between these two vortex structures is an elongated, long-lasting flow trail with flow...

  5. A Comparison of Women's Collegiate and Girls' High School Volleyball Injury Data Collected Prospectively Over a 4-Year Period.

    Science.gov (United States)

    Reeser, Jonathan C; Gregory, Andrew; Berg, Richard L; Comstock, R Dawn

    2015-01-01

    There is a relative paucity of research examining the sport-specific injury epidemiology of high school and collegiate volleyball athletes. Moreover, differences in study methodology frequently limit our ability to compare and contrast injury data collected from selected populations. There are differences between the injury patterns characteristic of high school and collegiate female volleyball athletes. Retrospective clinical review. Level 3. We statistically analyzed injury incidence and outcome data collected over a 4-year interval (2005-2006 to 2008-2009) by 2 similar injury surveillance systems, the National Collegiate Athletic Association's Injury Surveillance System (NCAA ISS) and the High School Reporting Injuries Online (HS RIO). We compared diagnoses, anatomic distribution of injuries, mechanisms of injury, and time lost from training or competition between high school and collegiate volleyball athletes. The overall volleyball-related injury rate was significantly greater among collegiate athletes than among high school athletes during both competition (injury rate ratio, 2.9; 95% CI, 2.5-3.4) and practice (injury rate ratio, 3.5; 95% CI, 3.1-3.9). Collegiate athletes had a higher rate of ankle sprain, knee injury, and shoulder injury. Concussions represented a relatively high percentage of injuries in both populations (5.0% of total NCAA ISS injuries vs 4.8% of total HS RIO injuries, respectively). The data suggest that although similar, there were distinct differences between the injury patterns of the 2 populations. Compared with high school volleyball players, collegiate athletes have a higher rate of acute time loss injury as well as overuse time loss injury (particularly patellar tendinosis). Concussions represented a significant and worrisome component of the injury pattern for both study populations. The injury data suggest that important differences exist in the injury patterns of female high school compared with collegiate volleyball athletes

  6. Gamma Transition Jump for PS2

    CERN Document Server

    Bartmann, W; Métral, E; Möhl, D; Peggs, S

    2008-01-01

    The PS2, which is proposed as a replacement for the existing ~50-year old PS accelerator, is presently considered to be a normal conducting synchrotron with an injection kinetic energy of 4 GeV and a maximum energy of 50 GeV. One of the possible lattices (FODO option) foresees crossing of transition energy near 10 GeV. Since the phase-slip-factor $\\eta$ becomes very small near transition energy, many intensity dependent effects can take place in both longitudinal and transverse planes. The aim of the present paper is on the one hand to scale the gamma transition jump, used since 1973 in the PS, to the projected PS2 and on the other hand based on these results the analysis of the implementation and feasibility of a gamma transition jump scheme in a conventional FODO lattice.

  7. Testing jumps via false discovery rate control.

    Science.gov (United States)

    Yen, Yu-Min

    2013-01-01

    Many recently developed nonparametric jump tests can be viewed as multiple hypothesis testing problems. For such multiple hypothesis tests, it is well known that controlling type I error often makes a large proportion of erroneous rejections, and such situation becomes even worse when the jump occurrence is a rare event. To obtain more reliable results, we aim to control the false discovery rate (FDR), an efficient compound error measure for erroneous rejections in multiple testing problems. We perform the test via the Barndorff-Nielsen and Shephard (BNS) test statistic, and control the FDR with the Benjamini and Hochberg (BH) procedure. We provide asymptotic results for the FDR control. From simulations, we examine relevant theoretical results and demonstrate the advantages of controlling the FDR. The hybrid approach is then applied to empirical analysis on two benchmark stock indices with high frequency data.

  8. Testing jumps via false discovery rate control.

    Directory of Open Access Journals (Sweden)

    Yu-Min Yen

    Full Text Available Many recently developed nonparametric jump tests can be viewed as multiple hypothesis testing problems. For such multiple hypothesis tests, it is well known that controlling type I error often makes a large proportion of erroneous rejections, and such situation becomes even worse when the jump occurrence is a rare event. To obtain more reliable results, we aim to control the false discovery rate (FDR, an efficient compound error measure for erroneous rejections in multiple testing problems. We perform the test via the Barndorff-Nielsen and Shephard (BNS test statistic, and control the FDR with the Benjamini and Hochberg (BH procedure. We provide asymptotic results for the FDR control. From simulations, we examine relevant theoretical results and demonstrate the advantages of controlling the FDR. The hybrid approach is then applied to empirical analysis on two benchmark stock indices with high frequency data.

  9. Entropy jump across an inviscid shock wave

    Science.gov (United States)

    Salas, Manuel D.; Iollo, Angelo

    1995-01-01

    The shock jump conditions for the Euler equations in their primitive form are derived by using generalized functions. The shock profiles for specific volume, speed, and pressure are shown to be the same, however density has a different shock profile. Careful study of the equations that govern the entropy shows that the inviscid entropy profile has a local maximum within the shock layer. We demonstrate that because of this phenomenon, the entropy, propagation equation cannot be used as a conservation law.

  10. Price jumps on European stock markets

    Czech Academy of Sciences Publication Activity Database

    Hanousek, Jan; Kočenda, Evžen; Novotný, Jan

    2014-01-01

    Roč. 14, č. 1 (2014), s. 10-22 ISSN 2214-8450 R&D Projects: GA ČR(CZ) GAP403/11/0020; GA ČR(CZ) GBP402/12/G097 Grant - others:UK(CZ) UNCE 204005/2012 Institutional support: PRVOUK-P23 Keywords : stock markets * price jump indicators * non-parametric testing Subject RIV: AH - Economics

  11. Take-off aerodynamics in ski jumping.

    Science.gov (United States)

    Virmavirta, M; Kivekäs, J; Komi, P V

    2001-04-01

    The effect of aerodynamic forces on the force-time characteristics of the simulated ski jumping take-off was examined in a wind tunnel. Vertical and horizontal ground reaction forces were recorded with a force plate installed under the wind tunnel floor. The jumpers performed take-offs in non-wind conditions and in various wind conditions (21-33 m s(-1)). EMGs of the important take-off muscles were recorded from one jumper. The dramatic decrease in take-off time found in all jumpers can be considered as the result of the influence of aerodynamic lift. The loss in impulse due to the shorter force production time with the same take-off force is compensated with the increase in lift force, resulting in a higher vertical velocity (V(v)) than is expected from the conventional calculation of V(v) from the force impulse. The wind conditions emphasized the explosiveness of the ski jumping take-off. The aerodynamic lift and drag forces which characterize the aerodynamic quality of the initial take-off position (static in-run position) varied widely even between the examined elite ski jumpers. According to the computer simulation these differences can decisively affect jumping distance. The proper utilization of the prevailing aerodynamic forces before and during take-off is a very important prerequisite for achieving a good flight position.

  12. Hydraulic jumps in ''viscous'' accretion disks

    International Nuclear Information System (INIS)

    Michel, F.C.

    1984-01-01

    We propose that the dissipative process necessary for rapid accretion disk evolution is driven by hydraulic jump waves on the surface of the disk. These waves are excited by the asymmetric nature of the central rotator (e.g., neutron star magnetosphere) and spiral out into the disk to form a pattern corotating with the central object. Disk matter in turn is slowed slightly at each encounter with the jump and spirals inward. In this process, the disk is heated by true turbulence produced in the jumps. Additional effects, such as a systematic misalignment of the magnetic moment of the neutron star until it is nearly orthogonal, and systematic distortion of the magnetosphere in such a way as to form an even more asymmetric central ''paddle wheel'' may enhance the interaction with inflowing matter. The application to X-ray sources corresponds to the ''slow'' solutions of Ghosh and Lamb, and therefore to rms magnetic fields of about 4 x 10 10 gauss. Analogous phenomena have been proposed to act in the formation of galactic spiral structure

  13. Sex Differences in Countermovement Jump Phase Characteristics

    Directory of Open Access Journals (Sweden)

    John J. McMahon

    2017-01-01

    Full Text Available The countermovement jump (CMJ is commonly used to explore sex differences in neuromuscular function, but previous studies have only reported gross CMJ measures or have partly examined CMJ phase characteristics. The purpose of this study was to explore differences in CMJ phase characteristics between male and female athletes by comparing the force-, power-, velocity-, and displacement-time curves throughout the entire CMJ, in addition to gross measures. Fourteen men and fourteen women performed three CMJs on a force platform from which a range of kinetic and kinematic variables were calculated via forward dynamics. Jump height (JH, reactive strength index modified, relative peak concentric power, and eccentric and concentric displacement, velocity, and relative impulse were all greater for men (g = 0.58–1.79. Relative force-time curves were similar between sexes, but relative power-, velocity-, and displacement-time curves were greater for men at 90%–95% (immediately before and after peak power, 47%–54% (start of eccentric phase and 85%–100% (latter half of concentric phase, and 65%–87% (bottom of countermovement and initial concentric phase of normalized jump time, respectively. The CMJ distinguished between sexes, with men demonstrating greater JH through applying a larger concentric impulse and, thus, achieving greater velocity throughout most of the concentric phase, including take-off.

  14. Jump Squat is More Related to Sprinting and Jumping Abilities than Olympic Push Press.

    Science.gov (United States)

    Loturco, I; Kobal, R; Maldonado, T; Piazzi, A F; Bottino, A; Kitamura, K; Abad, C C C; Pereira, L A; Nakamura, F Y

    2017-07-01

    The aim of this study was to test the relationships between jump squat (JS) and Olympic push press (OPP) power outputs and performance in sprint, squat jump (SJ), countermovement jump (CMJ) and change of direction (COD) speed tests in elite soccer players. 27 athletes performed a maximum power load test to determine their bar mean propulsive power (MPP) and bar mean propulsive velocity (MPV) in the JS and OPP exercises. Magnitude-based inference was used to compare the exercises. The MPV was almost certainly higher in the OPP than in the JS. The MPP relative to body mass (MPP REL) was possibly higher in the OPP. Only the JS MPP REL presented very large correlations with linear speed ( r> 0.7, for speed in 5, 10, 20 and 30 m) and vertical jumping abilities ( r> 0.8, for SJ and CMJ), and moderate correlation with COD speed ( r= 0.45). Although significant (except for COD), the associations between OPP outcomes and field-based measurements (speed, SJ and CMJ) were all moderate, ranging from 0.40 to 0.48. In a group composed of elite soccer players, the JS exercise is more associated with jumping and sprinting abilities than the OPP. Longitudinal studies are needed to confirm if these strong relationships imply superior training effects in favor of the JS exercise. © Georg Thieme Verlag KG Stuttgart · New York.

  15. An efficient interpolation technique for jump proposals in reversible-jump Markov chain Monte Carlo calculations

    Science.gov (United States)

    Farr, W. M.; Mandel, I.; Stevens, D.

    2015-01-01

    Selection among alternative theoretical models given an observed dataset is an important challenge in many areas of physics and astronomy. Reversible-jump Markov chain Monte Carlo (RJMCMC) is an extremely powerful technique for performing Bayesian model selection, but it suffers from a fundamental difficulty and it requires jumps between model parameter spaces, but cannot efficiently explore both parameter spaces at once. Thus, a naive jump between parameter spaces is unlikely to be accepted in the Markov chain Monte Carlo (MCMC) algorithm and convergence is correspondingly slow. Here, we demonstrate an interpolation technique that uses samples from single-model MCMCs to propose intermodel jumps from an approximation to the single-model posterior of the target parameter space. The interpolation technique, based on a kD-tree data structure, is adaptive and efficient in modest dimensionality. We show that our technique leads to improved convergence over naive jumps in an RJMCMC, and compare it to other proposals in the literature to improve the convergence of RJMCMCs. We also demonstrate the use of the same interpolation technique as a way to construct efficient ‘global’ proposal distributions for single-model MCMCs without prior knowledge of the structure of the posterior distribution, and discuss improvements that permit the method to be used in higher dimensional spaces efficiently. PMID:26543580

  16. Force generation and temperature-jump and length-jump tension transients in muscle fibers.

    Science.gov (United States)

    Davis, J S; Rodgers, M E

    1995-01-01

    Muscle tension rises with increasing temperature. The kinetics that govern the tension rise of maximally Ca(2+)-activated, skinned rabbit psoas fibers over a temperature range of 0-30 degrees C was characterized in laser temperature-jump experiments. The kinetic response is simple and can be readily interpreted in terms of a basic three-step mechanism of contraction, which includes a temperature-sensitive rapid preequilibrium(a) linked to a temperature-insensitive rate-limiting step and followed by a temperature-sensitive tension-generating step. These data and mechanism are compared and contrasted with the more complex length-jump Huxley-Simmons phases in which all states that generate tension or bear tension are perturbed. The rate of the Huxley-Simmons phase 4 is temperature sensitive at low temperatures but plateaus at high temperatures, indicating a change in rate-limiting step from a temperature-sensitive (phase 4a) to a temperature-insensitive reaction (phase 4b); the latter appears to correlate with the slow, temperature-insensitive temperature-jump relaxation. Phase 3 is absent in the temperature-jump, which excludes it from tension generation. We confirm that de novo tension generation occurs as an order-disorder transition during phase 2slow and the equivalent, temperature-sensitive temperature-jump relaxation. PMID:7612845

  17. Do Bilateral Vertical Jumps With Reactive Jump Landings Achieve Osteogenic Thresholds With and Without Instruction in Premenopausal Women?

    Science.gov (United States)

    Clissold, Tracey L; Winwood, Paul W; Cronin, John B; De Souza, Mary Jane

    2018-04-01

    Jumps have been investigated as a stimulus for bone development; however, effects of instruction, jump type, and jump-landing techniques need investigation. This study sought to identify whether ground reaction forces (GRFs) for bilateral vertical jumps (countermovement jumps and drop jumps) with reactive jump-landings (ie, jumping immediately after initial jump-landing), with instruction and with instruction withdrawn, achieve magnitudes and rates of strain previously shown to improve bone mass among premenopausal women. Twenty-one women (Mean ± SD: 43.3 ± 5.9 y; 69.4 ± 9.6 kg; 167 ± 5.5 cm; 27.5 ± 8.7% body fat) performed a testing session 'with instruction' followed by a testing session performed 1 week later with 'instruction withdrawn.' The magnitudes (4.59 to 5.49 body weight [BW]) and rates of strain (263 to 359 BW·s -1 ) for the jump-landings, performed on an AMTI force plate, exceeded previously determined thresholds (>3 BWs and >43 BW·s -1 ). Interestingly, significantly larger peak resultant forces, (↑10%; P = .002) and peak rates of force development (↑20%; P jump-landing (postreactive jump). Small increases (ES = 0.22-0.42) in all landing forces were observed in the second jump-landing with 'instruction withdrawn.' These jumps represent a unique training stimulus for premenopausal women and achieve osteogenic thresholds thought prerequisite for bone growth.

  18. Utility of Genetic Testing in Elite Volleyball Players with Aortic Root Dilation.

    Science.gov (United States)

    Herrick, Nicole; Davis, Christopher; Vargas, Lisa; Dietz, Hal; Grossfeld, Paul

    2017-07-01

    Basketball and volleyball attract individuals with a characteristic biophysical profile, mimicking features of Marfan syndrome. Consequently, identification of these abnormalities can be lifesaving. To determine how physical examination, echocardiography, and genetic screening can identify elite volleyball players with a previously undiagnosed aortopathy. We have performed cardiac screening on 90 US Volleyball National Team members and identified four individuals with dilated sinuses of Valsalva. This case series reports on three individuals who underwent a comprehensive genetics evaluation, including gene sequencing. Cardiac screening combined with genetic testing can identify previously undiagnosed tall athletes with an aortopathy, in the absence of noncardiac findings of a connective tissue disorder. Subject 1 had a revised Ghent systems (RGS) score of 2 and a normal aortopathy gene panel. Subject 2 had a RGS score of 1 and genetic testing revealed a de novo disease causing mutation in the gene encoding fibrillin-1 (FBN1). Subject 3 had an RGS score of 4.0 and had a normal aortopathy gene panel. Despite variable clinical features of Marfan syndrome, dilated sinuses of Valsalva were found in 4.9% of the athletes. A disease-causing mutation in the FBN1 gene was identified in subject 2, who had the lowest RGS but the largest aortic root measurement. Subjects 1 and 3, with the highest RGS, had a normal aortopathy gene panel. Our findings provide further evidence suggesting that a cardiac evaluation, including a screening echocardiogram, should be performed on all elite tall adult athletes independent of other physical findings. Genetic testing should be considered for athletes with dilated sinuses of Valsalva (male, >4.2 cm; female, >3.4 cm), regardless of other extracardiac findings.

  19. Injuries in Collegiate Women’s Volleyball: A Four-Year Retrospective Analysis

    Science.gov (United States)

    Sole, Christopher J.; Kavanaugh, Ashley A.; Stone, Michael H.

    2017-01-01

    A four-year retrospective analysis of injury data was conducted on a collegiate (NCAA Division I) women’s volleyball team. Twenty athletes (Year 1: age = 19.4 ± 0.9 y, height = 175.2 ± 5.1 cm, body mass = 70.5 ± 10.2 kg; Year 2: age = 20.1 ± 1.0 y, height = 175.7 ± 4.7 cm, body mass = 69.5 ± 10.1 kg; Year 3: age = 20.1 ± 1.4 y, height = 173.8 ± 6.3 cm, body mass = 69.9 ± 10.8 kg; Year 4: age = 19.5 ± 1.4 y, height = 174.4 ± 8.6 cm, body mass = 72.7 ± 10.8 kg) participated in this study, accounting for 1483 total training exposures. Injury was defined as any damage to a body part, incurred during volleyball or strength and conditioning-related activities, which interfered with training and/or competition. Injury rate was normalized to the number of athletes and exposure and expressed as injuries per 1000 exposures. A total of 133 injuries were recorded. The most common injury was to the knee (left = 7.5%, right = 12.0%). Injuries occurred most often in volleyball practice (75.2%), followed by competition (20.3%), and strength and conditioning-related activities (4.5%). Non-contact injuries (upper body = 26.3%, lower body = 53.4%) were more common than contact injuries (upper-body = 13.5%, lower-body = 6.8%). An examination of injury rates relative to the training year revealed patterns in injury occurrence. Specifically, spikes in injury rate were consistently observed during periods of increased training volume that were preceded by breaks in organized training, such as the early pre-season and off-season training periods.

  20. BMP4 and FGF3 haplotypes increase the risk of tendinopathy in volleyball athletes.

    Science.gov (United States)

    Salles, José Inácio; Amaral, Marcus Vinícius; Aguiar, Diego Pinheiro; Lira, Daisy Anne; Quinelato, Valquiria; Bonato, Letícia Ladeira; Duarte, Maria Eugenia Leite; Vieira, Alexandre Rezende; Casado, Priscila Ladeira

    2015-03-01

    To investigate whether genetic variants can be correlated with tendinopathy in elite male volleyball athletes. Case-control study. Fifteen single nucleotide polymorphisms within BMP4, FGF3, FGF10, FGFR1 genes were investigated in 138 elite volleyball athletes, aged between 18 and 35 years, who undergo 4-5h of training per day: 52 with tendinopathy and 86 with no history of pain suggestive of tendinopathy in patellar, Achilles, shoulder, and hip abductors tendons. The clinical diagnostic criterion was progressive pain during training, confirmed by magnetic resonance image. Genomic DNA was obtained from saliva samples. Genetic markers were genotyped using TaqMan real-time PCR. Chi-square test compared genotypes and haplotype differences between groups. Multivariate logistic regression analyzed the significance of covariates and incidence of tendinopathy. Statistical analysis revealed participant age (p=0.005) and years of practice (p=0.004) were risk factors for tendinopathy. A significant association between BMP4 rs2761884 (p=0.03) and tendinopathy was observed. Athletes with a polymorphic genotype have 2.4 times more susceptibility to tendinopathy (OR=2.39; 95%CI=1.10-5.19). Also, association between disease and haplotype TTGGA in BMP4 (p=0.01) was observed. The FGF3 TGGTA haplotype showed a tendency of association with tendinopathy (p=0.05), and so did FGF10 rs900379. FGFR1 showed no association with disease. These findings indicate that haplotypes in BMP4 and FGF3 genes may contribute to the tendon disease process in elite volleyball athletes. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  1. Epidemiology of Basketball, Soccer, and Volleyball Injuries in Middle-School Female Athletes

    Science.gov (United States)

    Barber Foss, Kim D.; Myer, Greg D.; Hewett, Timothy E.

    2014-01-01

    Background An estimated 30 to 40 million school children participate in sports in the United States; 34% of middle-school participants become injured and seek medical treatment at an annual cost close to $2 billion. The purpose of the current study was to evaluate the injury incidence and rates in female athletes in the middle-school setting during the course of 3 seasons. Methods Female basketball, soccer, and volleyball players were recruited from a single county public school district in Kentucky consisting of 5 middle schools. A total of 268 female athletes (162 basketball, 26 soccer, and 80 volleyball) participated. Athletes were monitored for sports-related injury and number of athlete exposures (AEs) by an athletic trainer. Injury rates were calculated for specific types of injuries within each sport. Injury rates for games and practices were also calculated and compared for each sport. Results A total of 134 injuries were recorded during the 3 sport seasons. The knee was the most commonly injured body part (99 injuries [73.9%]), of which patellofemoral dysfunction (31.3%), Osgood-Schlatter disease (10.4%), and Sinding-Larsen-Johansson/patella tendinosis (9%) had the greatest incidence. The ankle was the second most commonly injured body part, accounting for 16.4% of all injuries. The overall rates of injury by sport were as follows: soccer, 6.66 per 1000 AEs; volleyball, 3.68 per 1000 AEs; and basketball, 2.86 per 1000 AEs. Conclusions Female middle-school athletes displayed comparable injury patterns to those seen in their high-school counterparts. Future work is warranted to determine the potential for improved outcomes in female middle-school athletes with access to athletic training services. Clinical Relevance As the participation levels and number of injuries continue to rise, middle-school athletes demonstrate an increasing need for medical services provided by a certified athletic trainer. PMID:24875981

  2. Sensorimotor Control of the Shoulder in Professional Volleyball Players with Isolated Infraspinatus Muscle Atrophy.

    Science.gov (United States)

    Contemori, Samuele; Biscarini, Andrea; Botti, Fabio Massimo; Busti, Daniele; Panichi, Roberto; Pettorossi, Vito Enrico

    2017-06-12

    Isolated infraspinatus muscle atrophy (IIMA) only affects the hitting shoulder of overhead-activity athletes, and is caused by suprascapular nerve neuropathy. No study has assessed the static and dynamic stability of the shoulder in overhead professional athletes with IIMA to reveal possible shoulder sensorimotor alterations. To assess the shoulder static stability, dynamic stability, and strength in professional volleyball players with IIMA and in healthy control players. Cross-sectional study. Research laboratory. Twenty-four male professional volleyball players (12 players with diagnosed IIMA and 12 healthy players) recruited from local volleyball teams. Static stability was evaluated with two independent force platforms and dynamic stability was assessed with the "Upper Quarter Y Balance Test". The static stability assessment was conducted in different support (single hand and both hand) and vision (open and closed eyes) conditions. Data from each test were analyzed with ANOVA and paired t-test models, to highlight statistical differences within and between groups. In addition to reduced abduction and external rotation strength, athletes with IIMA consistently demonstrated significant less static (P < 0.001) and dynamic stability (P < 0,001), compared with the contralateral shoulder and with healthy athletes. Closed eyes condition significantly enhanced the static stability deficit of the shoulder with IIMA (P = 0.039 and P = 0.034 for both hand and single hand support, respectively), but had no effect in healthy contralateral and healthy players' shoulders. This study highlights an impairment of the sensorimotor control system of the shoulder with IIMA, which likely results from both proprioceptive and strength deficits. This condition could yield subtle alteration in the functional use of the shoulder and predispose it to acute or overuse injuries. The results of this study may help athletic trainers and physical/physiotherapists to prevent shoulder injuries

  3. Bootstrapping integrated covariance matrix estimators in noisy jump-diffusion models with non-synchronous trading

    DEFF Research Database (Denmark)

    Hounyo, Ulrich

    to a gneral class of estimators of integrated covolatility. We then show the first-order asymptotic validity of this method in the multivariate context with a potential presence of jumps, dependent microsturcture noise, irregularly spaced and non-synchronous data. Due to our focus on non...... covariance estimator. As an application of our results, we also consider the bootstrap for regression coefficients. We show that the wild blocks of bootstrap, appropriately centered, is able to mimic both the dependence and heterogeneity of the scores, thus justifying the construction of bootstrap percentile...... intervals as well as variance estimates in this context. This contrasts with the traditional pairs bootstrap which is not able to mimic the score heterogeneity even in the simple case where no microsturcture noise is present. Our Monte Carlo simulations show that the wild blocks of blocks bootstrap improves...

  4. Spring-block Model for Barkhausen Noise

    International Nuclear Information System (INIS)

    Kovacs, K.; Brechet, Y.; Neda, Z.

    2005-01-01

    A simple mechanical spring-block model is used for studying Barkhausen noise (BN). The model incorporates the generally accepted physics of domain wall movement and pinning. Computer simulations on this model reproduces the main features of the hysteresis loop and Barkhausen jumps. The statistics of the obtained Barkhausen jumps follows several scaling laws, in qualitative agreement with experimental results. The model consists of a one-dimensional frictional spring-block system. The blocks model the Bloch-walls that separate inversely oriented magnetic domains, and springs correspond to the magnetized regions. Three types of realistic forces are modelled with this system: 1. the force resulting from the magnetic energy of the neighboring domains in external magnetic field (modelled by forces having alternating orientations and acting directly on the blocks); 2. the force resulting from the magnetic self-energy of each domain (modelled by the elastic forces of the springs); 3. the pinning forces acting on the domain walls (modelled by position dependent static friction acting on blocks). The dynamics of the system is governed by searching for equilibrium: one particular domain wall can jump to the next pinning center if the resultant of forces 1. and 2. is greater then the pinning force. The external magnetic field is successively increased (or decreased) and the system is relaxed to mechanical equilibrium. During the simulations we are monitoring the variation of the magnetization focusing on the shape of the hysteresis loop, power spectrum, jump size (avalanche size) distribution, signal duration distribution, signal area distribution. The simulated shape of the hysteresis loops fulfills all the requirements for real magnetization phenomena. The power spectrum indicates different behavior in the low (1/f noise) and high (white noise) frequency region. All the relevant distribution functions show scaling behavior over several decades of magnitude with a naturally

  5. Thoracic Outlet Syndrome in a Volleyball Player Due to Nonunion of the First Rib Fracture.

    Science.gov (United States)

    Puttmann, Kathleen T; Satiani, Bhagwan; Vaccaro, Patrick

    2016-11-01

    Fracture of the first rib with ensuing callus formation is a rare cause of thoracic outlet syndrome. We report a case of a 17-year-old female volleyball player who presented with months of chronic arm pain. Radiographic imaging demonstrated nonunion fracture of the first rib. Physical therapy had been unsuccessful in relieving the pain, and surgical management was performed with resection of the first rib through a transaxillary approach with complete resolution of symptoms. Inflammation surrounding such fractures may destroy tissue planes, making dissection more technically difficult.

  6. 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

  7. ANTHROPOMETRIC AND MOTORIC COMPARISONS BETWEEN THE TWO VOLLEYBALL TEAMS IN PRISHTINA

    Directory of Open Access Journals (Sweden)

    Malsor Gjonbalaj

    2014-06-01

    Full Text Available Introduction: The increase in sports results today not only identifies the quantity (volume and intensity of the work put in, but also the quality (changing the stereotypical notion of effort, eliminating redundant movements, rationalizing the sport in all elements etc. All of these circumstances and factors referred in this paper are stimulated through practical methods for processing positive results and aiming to present a realistic and factual reflection of the current condition, particularly emphasizing the evaluation of several anthropometric and motor characteristics of the players in both volleyball clubs from Prishtina. Methods: These methods are elaborated among arithmetic methods, variance, standard deviation and standard error of the arithmetic mean, the coefficient of variance, the maximum and minimum score test, the score in accordance to the Pearson correlation coefficient-whereas the instruments measured 14 variables such as anthropometric 8, 4 motors and 2 situational. The main purpose to which is addressed in this paper is verifying the situation and the differences between the players in two of the clubs by analyzing the results from the variables I have chosen. Results: The results show that there is a significant differentiation between one volleyball group to the other in terms of motor, anthropometric and situational. This is proven by the results of the data based on the parameters abovementioned. Discussion: Results acquired on in the research, verifies the hypotheses which sets forth previously, it helps to us to understand that the main goal in this research has largely been achieved. Statistical methods that have been processed results may explain the state of anthropometric and motor characteristics. Moreover, with the help of T-test we came to understand the valuable statistical differences between two clubs which have been subject to research. These results are best justified considering the fact that the first

  8. The organization of the sport process: The perspective of elite volleyball Brazilian coaches.

    OpenAIRE

    Vieira, Ana Luiza; Dias, Cláudia Salomé Lima; Corte-Real, Nuno José; Fonseca, António Manuel

    2014-01-01

    Abstract The purpose of this study was to analyze the coaching knowledge of 24 expert high-performance Brazilian volleyball coaches in the organization of training and competition. A semi-structured interview was used, and the resulting data analyzed following the procedures outlined by Côté and colleagues (Côté & Salmela, 1994, 1996; Côté, Salmela, & Russell, 1995a, 1995b). Overall, the data highlighted that the coaches of male and female teams organized competition and train...

  9. Jump Shrug Height and Landing Forces Across Various Loads.

    Science.gov (United States)

    Suchomel, Timothy J; Taber, Christopher B; Wright, Glenn A

    2016-01-01

    The purpose of this study was to examine the effect that load has on the mechanics of the jump shrug. Fifteen track and field and club/intramural athletes (age 21.7 ± 1.3 y, height 180.9 ± 6.6 cm, body mass 84.7 ± 13.2 kg, 1-repetition-maximum (1RM) hang power clean 109.1 ± 17.2 kg) performed repetitions of the jump shrug at 30%, 45%, 65%, and 80% of their 1RM hang power clean. Jump height, peak landing force, and potential energy of the system at jump-shrug apex were compared between loads using a series of 1-way repeated-measures ANOVAs. Statistical differences in jump height (P .05). The greatest magnitudes of jump height, peak landing force, and potential energy of the system at the apex of the jump shrug occurred at 30% 1RM hang power clean and decreased as the external load increased from 45% to 80% 1RM hang power clean. Relationships between peak landing force and potential energy of the system at jump-shrug apex indicate that the landing forces produced during the jump shrug may be due to the landing strategy used by the athletes, especially at lighter loads. Practitioners may prescribe heavier loads during the jump-shrug exercise without viewing landing force as a potential limitation.

  10. Jumping robots: a biomimetic solution to locomotion across rough terrain.

    Science.gov (United States)

    Armour, Rhodri; Paskins, Keith; Bowyer, Adrian; Vincent, Julian; Megill, William; Bomphrey, Richard

    2007-09-01

    This paper introduces jumping robots as a means to traverse rough terrain; such terrain can pose problems for traditional wheeled, tracked and legged designs. The diversity of jumping mechanisms found in nature is explored to support the theory that jumping is a desirable ability for a robot locomotion system to incorporate, and then the size-related constraints are determined from first principles. A series of existing jumping robots are presented and their performance summarized. The authors present two new biologically inspired jumping robots, Jollbot and Glumper, both of which incorporate additional locomotion techniques of rolling and gliding respectively. Jollbot consists of metal hoop springs forming a 300 mm diameter sphere, and when jumping it raises its centre of gravity by 0.22 m and clears a height of 0.18 m. Glumper is of octahedral shape, with four 'legs' that each comprise two 500 mm lengths of CFRP tube articulating around torsion spring 'knees'. It is able to raise its centre of gravity by 1.60 m and clears a height of 1.17 m. The jumping performance of the jumping robot designs presented is discussed and compared against some specialized jumping animals. Specific power output is thought to be the performance-limiting factor for a jumping robot, which requires the maximization of the amount of energy that can be stored together with a minimization of mass. It is demonstrated that this can be achieved through optimization and careful materials selection.

  11. Neuromuscular function during drop jumps in young and elderly males.

    Science.gov (United States)

    Piirainen, Jarmo M; Linnamo, Vesa; Sippola, Niina; Avela, Janne

    2012-12-01

    The Hoffman reflex (H-reflex), indicating alpha-motoneuron pool activity, has been shown to be task - and in resting conditions - age dependent. How aging affects H-reflex activity during explosive movements is not clear at present. The purpose of this study was to examine the effects of aging on H-reflexes during drop jumps, and its possible role in drop jump performance. Ten young (26.8 ± 2.7 years) and twenty elderly (64.2 ± 2.7 years) subjects participated in the study. Maximal drop jump performance and soleus H-reflex response (H/M jump) 20 ms after ground contact were measured in a sledge ergometer. Maximal H-reflex, maximal M-wave, Hmax/Mmax-ratio and H-reflex excitability curves were measured during standing rest. Although in young the H-reflex response (Hmax/Mmax) was 6.5% higher during relaxed standing and 19.7% higher during drop jumps (H jump/M jump) than in the elderly group, these differences were not statistically significant. In drop jumps, the elderly subjects had lower jumping height (30.4%, p push-off force (18.0%, p push-off time (31.0% p push-off force (r = 0.833, p push-off time (r = -0.857, p < 0.01) in young but not in the elderly. Correlations between H-reflex response and jumping parameters in young may indicate different jumping and activation strategies in drop jumps. However, it does not fully explain age related differences in jumping performance, since age related differences in H-reflex activity were non-significant. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Ski jumping boots limit effective take-off in ski jumping.

    Science.gov (United States)

    Virmavirta, M; Komi, P V

    2001-12-01

    In this study, we measured the vertical and horizontal take-off forces, plantar pressures and activation patterns of four muscles (vastus lateralis, gluteus maximus, tibialis anterior, gastrocnemius) in 10 ski jumpers in simulated laboratory conditions when wearing either training shoes or ski jumping boots. We found significant differences in vertical (P boots condition resulted in a smaller displacement in the final position of the following joint angles: ankle angle (P knee angle (P boots condition, significantly more pressure was recorded under the heel (P knee and hip extensors when wearing jumping boots. We conclude that the stiffness of the structure of the jumping boots may result in a forward shift of pressure, thus limiting the effective vertical force. To avoid this pressure shift, the pattern of movement of simulated take-offs should be carefully controlled, particularly when wearing training shoes.

  13. Estudio y análisis de la recepción en el Voleibol Masculino de Alto Rendimiento. (Research and analysis of the reception in the current high performance Men’s Volleyball.

    Directory of Open Access Journals (Sweden)

    Diego Callej��n Lirola

    2009-07-01

    to consider paragraph of the reception with the intention of find trends which teams develop and thus determining the key aspects to achieve maximum performance. The study includes the analysis of 2820 serves of which 2212 were received, corresponding to 15 games of high level competitions such as the 2003 World League and the Final phase of the European Championship that same year. Once the different categories and their corresponding variables were established, they were analyzed from both a quantitative and qualitative point of view, following the criteria established in the observational methodology and using the new technologies for the observation, study and analysis of volleyball. The categories and their variables were groups in the following manner: Reception techniques: Overhead passing, forearm pass, barrel roll and dive. Serving techniques: Jump power, jump float and float. Reception zone: Zone 4, zone 3, zone 2, zone 1 back, zone 1 front, zone 6 back, zone 6 front, zone 5 back, zone 5 front. Player who receives: Receiver or libero. Evaluation of the reception efficacy: 5 values. With this data and its study with the statistical program SPSS (v. 12.0, we try to identify trends, in the reception, which the men in Current High Performance Volleyball.

  14. Jump Tails, Extreme Dependencies, and the Distribution of Stock Returns

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Todorov, Viktor

    We provide a new framework for estimating the systematic and idiosyncratic jump tail risks in financial asset prices. The theory underlying our estimates are based on in-fill asymptotic arguments for directly identifying the systematic and idiosyncratic jumps, together with conventional long...... market portfolio, we find that the distributions of the systematic and idiosyncratic jumps are both generally heavy-tailed and not necessarily symmetric. Our estimates also point to the existence of strong dependencies between the market-wide jumps and the corresponding systematic jump tails for all...... of the stocks in the sample. We also show how the jump tail dependencies deduced from the high-frequency data together with the day-to-day temporal variation in the volatility are able to explain the “extreme” dependencies vis-a-vis the market portfolio....

  15. Plyometric type neuromuscular exercise is a treatment to postural control deficits of volleyball players: A case study

    Directory of Open Access Journals (Sweden)

    A. Asadi

    2016-06-01

    Conclusions: It can be recommend that strength and conditioning professionals in the field of volleyball do not perform other type of landing exercise in plyometric training sessions because of postural control impaired and consequently the probability of lower extremity injuries will increase.

  16. Vascular Endothelial Growth Factor Receptor-2 Polymorphisms Have Protective Effect against the Development of Tendinopathy in Volleyball Athletes.

    Science.gov (United States)

    Salles, José Inácio; Duarte, Maria Eugenia Leite; Guimarães, João Matheus; Lopes, Lucas Rafael; Vilarinho Cardoso, Jessica; Aguiar, Diego Pinheiro; Machado Neto, João Olyntho; Machado, Daniel Escorsim; Perini, Jamila Alessandra

    2016-01-01

    The aim of the study was to investigate whether genetic variants in VEGF and KDR genes can be correlated with susceptibility of tendinopathy in volleyball athletes. This study was conducted at the Brazilian Volleyball Federation, and comprised 179 volleyball athletes: 88 had a confirmed diagnosis of tendinopathy (cases), whereas 91 had no evidence of the disease (controls). The VEGF (-2578C>A, -460T>C and +936C>T) and KDR (-604C>T, 1192G>A and 1719T>A) polymorphisms were determined by TaqMan real-time polymerase chain reaction. The odds ratio (OR) with their 95% confidence intervals (CI) were calculated using an unconditional logistic regression model. The evaluation of demographic and clinical characteristics revealed the athlete age (P volleyball (P T, 1192G>A and 1719T>A) haplotypes CGA and CAT were associated with decreased tendinopathy risk (OR: 0.46, 95% CI: 0.21-0.99 and OR: 0.23, 95% CI: 0.07-0.76, respectively). With regards to pain, traumatic lesion and away from training due to injury, VEGF and KDR polymorphisms were not associated with clinical symptoms complaints. The present results provide evidence that the KDR polymorphisms were associated with development of tendinopathy, and can contribute to identify new therapeutic targets or personalized training programs to avoid tendinopathy development in athletes.

  17. Proficiency Assessment of Male Volleyball Teams of the 13-15-Year Age Group at Estonian Championships

    Science.gov (United States)

    Stamm, Meelis; Stamm, Raini; Koskel, Sade

    2008-01-01

    Study aim: Assessment of feasibility of using own computer software "Game" at competitions. Material and methods: The data were collected during Estonian championships in 2006 for male volleyball teams of the 13-15-years age group (n = 8). In all games, the performance of both teams was recorded in parallel with two computers. A total of…

  18. Anatomical glenohumeral internal rotation deficit and symmetric rotational strength in male and female young beach volleyball players.

    Science.gov (United States)

    Saccol, Michele Forgiarini; Almeida, Gabriel Peixoto Leão; de Souza, Vivian Lima

    2016-08-01

    Beach volleyball is a sport with a high demand of shoulder structures that may lead to adaptations in range of motion (ROM) and strength like in other overhead sports. Despite of these possible alterations, no study evaluated the shoulder adaptations in young beach volleyball athletes. The aim of this study was to compare the bilateral ROM and rotation strength in the shoulders of young beach volleyball players. Goniometric passive shoulder ROM of motion and isometric rotational strength were evaluated in 19 male and 14 female asymptomatic athletes. External and internal ROM, total rotation motion, glenohumeral internal rotation deficit (GIRD), external rotation and internal rotation strength, bilateral deficits and external rotation to internal rotation ratio were measured. The statistical analysis included paired Student's t-test and analysis of variance with repeated measures. Significantly lower dominant GIRD was found in both groups (pvolleyball athletes present symmetric rotational strength and shoulder ROM rotational adaptations that can be considered as anatomical. These results indicate that young practitioners of beach volleyball are subject to moderate adaptations compared to those reported for other overhead sports. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Nutritional analysis of dietary intake of professional female volleyball players during the competitive phase of the regular season

    Directory of Open Access Journals (Sweden)

    Juan Mielgo-Ayuso

    2013-03-01

    Full Text Available Introduction: nutritional aspects women’s volleyball has been little studied and more in a specific period of training as the competitive period. The aim is to assess and know the caloric and macronutrients intake by professional volleyball players of the Spanish Superliga for 16 weeks of training for the competition phase and compare with the references marked for athlete population.Material and methods: the study included 10 female volleyball players (JVF (26.6±5.9 years and height 178.05±8.7cm, for a total of 16 weeks of training and competition. They all gave written informed consent. They completed a food intake frequency questionary of the 16 week study, data corroborated by a dietary record (CFCA of 7 consecutive days in week 9 and 16. We were calculated daily nutritional intake from CFCA with the food composition table of CESNID by Easy Diet software, the Spanish Association of Dietitians-Nutritionists (AEDN.Results: the energy and nutritional analysis of the female professional volleyball players shows that the amount of energy and macronutrients does not meet to the recommendations for sports collective.Conclusions: it is observed low energy and carbohydrates intake and high intake of protein and lipids. Recommended practical aspects for improving nutrition education in this professional sports group.

  20. 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

  1. Influence of magnetic history on flux jump fields

    International Nuclear Information System (INIS)

    Sosnowski, J.

    1986-01-01

    A formalism describing the fields at which flux jumps occur in hard superconductors has been confirmed by the description of an experimentally observed shift of flux jump fields in the second hysteresis loop of a Nb 3 Al superconducting sample. By fitting the theoretical model to experimental data, values of the proportionality parameter between the stability limit and the flux jump field, the first stability limit, and the first penetration field have been estimated

  2. Dynamics and stability of directional jumps in the desert locust.

    Science.gov (United States)

    Gvirsman, Omer; Kosa, Gabor; Ayali, Amir

    2016-01-01

    Locusts are known for their ability to jump large distances to avoid predation. The jump also serves to launch the adult locust into the air in order to initiate flight. Various aspects of this important behavior have been studied extensively, from muscle physiology and biomechanics, to the energy storage systems involved in powering the jump, and more. Less well understood are the mechanisms participating in control of the jump trajectory. Here we utilise video monitoring and careful analysis of experimental directional jumps by adult desert locusts, together with dynamic computer simulation, in order to understand how the locusts control the direction and elevation of the jump, the residual angular velocities resulting from the jump and the timing of flapping-flight initiation. Our study confirms and expands early findings regarding the instrumental role of the initial body position and orientation. Both real-jump video analysis and simulations based on our expanded dynamical model demonstrate that the initial body coordinates of position (relative to the hind-legs ground-contact points) are dominant in predicting the jumps' azimuth and elevation angles. We also report a strong linear correlation between the jumps' pitch-angular-velocity and flight initiation timing, such that head downwards rotations lead to earlier wing opening. In addition to offering important insights into the bio-mechanical principles of locust jumping and flight initiation, the findings from this study will be used in designing future prototypes of a bio-inspired miniature jumping robot that will be employed in animal behaviour studies and environmental monitoring applications.

  3. The influence of the external ankle support on the dynamic balance in volleyball athletes

    Directory of Open Access Journals (Sweden)

    Manuela Azevedo Correia de Lima

    2015-09-01

    Full Text Available AbstractThe purpose of this study was to assess the effect of ankle external supports on proprioception and dynamic balance in volleyball players. Seventeen female volleyball players (18.94±2.49 years; 65.45±9.49 kg; 1.71±0.05 m; BMI=22.0±2.67 kg/m² took part in this study. The dynamic balance was assessed through the Star Excursion Balance Test (SEBT. Comparisons between stabilization (no stabilizer/NS, orthosis/ORT and functional bandaging/FB modes and the SEBT grid lines and inter-limb were carried out. The SEBT assessment showed a significant difference between the groups NS x ORT and NS x FB (p < .01, and between the lines (p< .01. Significant line/limb interaction in DL and NDL (p< .01 was detected. The external supports tested herein showed similar effects on balance, restricting lower limb's reach in the SEBT execution in some of tested directions.

  4. Sleep Quality, Mood and Performance: A Study of Elite Brazilian Volleyball Athletes

    Directory of Open Access Journals (Sweden)

    Alexandro Andrade, Guilherme G. Bevilacqua, Danilo R. Coimbra, Fabiano S. Pereira, Ricardo Brandt

    2016-12-01

    Full Text Available This investigation analyzed the relationships between sleep quality, mood, and game results in the elite athletes participating in Brazilian volleyball competitions. Participants (n = 277 elite Brazilian volleyball athletes, 214 (77.3% men and 63 (22.7% women completed the Brunel Mood Scale (BRUMS and reported their subjective sleep perception. Athletes with poor sleep quality reported higher scores for confusion compared to athletes with good sleep quality (p < 0.01, d = 0.43. In addition, athletes who lost their game at the time of evaluation showed higher tension (p < 0.01, d = 0.49 and confusion (p < 0.01, d = 0.32 levels compared to athletes who won their game. A regression analysis demonstrated that for each point increase in the confusion level, there was a 19.7% reduction in sleep quality. Multivariate analysis of variance indicated that athletes who slept well, and won their games, had lower tension levels. Further, our results indicated that the athletes’ mood associated with their success in the competitions. Therefore, in a competition, it is important that the athletes show good sleep quality, and use techniques and strategies to ease their mood variations.

  5. The Cognitive and Motivation Intervention Program in Youth Female Volleyball Players

    Directory of Open Access Journals (Sweden)

    Claver Fernando

    2017-10-01

    Full Text Available This study, grounded in Self-Determination Theory (Deci and Ryan, 1985, 2002 was aimed to determine the influence of a cognitive-motivational intervention program, to improve the basic psychological need satisfaction of autonomy and competence, autonomous motivation, procedural knowledge, perceived performance and sport commitment, in youth volleyball players. Participants included 34 Under-19 female volleyball players. A quasi-experimental design was carried out with an experimental group (n = 16; M = 17.45; SD = .45 and a control group (n = 18; M = 16.64; SD = .70. The experimental group followed a multidimensional intervention program comprised of 24 sessions held over three months (two training sessions per week. It was based on two strategies: giving athletes the possibility of choice in specific training tasks (proposing training situations with several action alternatives and questioning (cognitively involving players through tactical questions. A repeated-measures MANOVA 2 (group: experimental and control x 2 (time: pre-test and post-test was used to analyse the effect of Group x Time interaction. The results of the inter-group analysis showed significant differences in the post-test measurement between the experimental group and the control group (in favour of the experimental group in the variables: basic psychological need satisfaction of autonomy and competence, autonomous motivation, procedural knowledge, perceived performance and sport commitment. Given the relevance of the cognitive-motivational processes, not only for performance but also for sport commitment, this intervention has important implications for sport coaching.

  6. The Cognitive and Motivation Intervention Program in Youth Female Volleyball Players.

    Science.gov (United States)

    Claver, Fernando; Jiménez, Ruth; Gil-Arias, Alexander; Moreno, Alberto; Moreno, M Perla

    2017-10-01

    This study, grounded in Self-Determination Theory (Deci and Ryan, 1985, 2002) was aimed to determine the influence of a cognitive-motivational intervention program, to improve the basic psychological need satisfaction of autonomy and competence, autonomous motivation, procedural knowledge, perceived performance and sport commitment, in youth volleyball players. Participants included 34 Under-19 female volleyball players. A quasi-experimental design was carried out with an experimental group (n = 16; M = 17.45; SD = .45) and a control group (n = 18; M = 16.64; SD = .70). The experimental group followed a multidimensional intervention program comprised of 24 sessions held over three months (two training sessions per week). It was based on two strategies: giving athletes the possibility of choice in specific training tasks (proposing training situations with several action alternatives) and questioning (cognitively involving players through tactical questions). A repeated-measures MANOVA 2 (group: experimental and control) x 2 (time: pre-test and post-test) was used to analyse the effect of Group x Time interaction. The results of the inter-group analysis showed significant differences in the post-test measurement between the experimental group and the control group (in favour of the experimental group) in the variables: basic psychological need satisfaction of autonomy and competence, autonomous motivation, procedural knowledge, perceived performance and sport commitment. Given the relevance of the cognitive-motivational processes, not only for performance but also for sport commitment, this intervention has important implications for sport coaching.

  7. Effectiveness of PETTLEP imager on performance of passing skill in volleyball.

    Science.gov (United States)

    Afrouzeh, M; Sohrabi, E; Haghkhan, A; Rowshani, F; Goharrokhi, S

    2015-01-01

    This study was conducted to compare the effectiveness of PETTLEP-based imagery, and traditional imagery interventions, on performance of passing skill in volleyball. 36 beginners male volleyball players (Mage =13.5 years, SD=0.55 years) with 5-6 months practice experience were randomly assigned to one of three groups: physical practice + PETTLEP imagery (PP+PI) (N.=15), physical practice + traditional imagery (N.=15), and physical practice only (PP; N.=15). Subjects in the PP+PI group applied the seven components of PETTLEP imagery training; whereas subjects in the PP+TI engaged in a relaxation session before imagery and used response laden motor imagery scripts. The two groups completed 15 minutes of imagery training followed immediately by 13 minutes of "passing" practice three times per week. The PP group completed only 13 minutes of "passing" practice three times per week. Each group performed its respective tasks for 7 weeks. A pre-test took place during the first practice session in which "passing" was assessed. After the 7-week practice program, a post-test took place followed by a retention test, one "no-practice" week later. All groups improved significantly (Pvolleyball when combined with physical practice.

  8. Decreased Circulating mtDNA Levels in Professional Male Volleyball Players.

    Science.gov (United States)

    Nasi, Milena; Cristani, Alessandro; Pinti, Marcello; Lamberti, Igor; Gibellini, Lara; De Biasi, Sara; Guazzaloca, Alessandro; Trenti, Tommaso; Cossarizza, Andrea

    2016-01-01

    Exercise exerts various effects on the immune system, and evidence is emerging on its anti-inflammatory effects; the mechanisms on the basis of these modifications are poorly understood. Mitochondrial DNA (mtDNA) released from damaged cells acts as a molecule containing the so-called damage-associated molecular patterns and can trigger sterile inflammation. Indeed, high plasma levels of mtDNA are associated to several inflammatory conditions and physiological aging and longevity. The authors evaluated plasma mtDNA in professional male volleyball players during seasonal training and the possible correlation between mtDNA levels and clinical parameters, body composition, and physical performance. Plasma mtDNA was quantified by real-time PCR every 2 mo in 12 professional volleyball players (PVPs) during 2 consecutive seasons. As comparison, 20 healthy nonathlete male volunteers (NAs) were analyzed. The authors found lower levels of mtDNA in plasma of PVPs than in NAs. However, PVPs showed a decrease of circulating mtDNA only in the first season, while no appreciable variations were observed during the second season. No correlation was observed among mtDNA, hematochemical, and anthropometric parameters. Regular physical activity appeared associated with lower levels of circulating mtDNA, further confirming the protective, anti-inflammatory effect of exercise.

  9. Somatotype, Level of Competition, and Performance in Attack in Elite Male Volleyball

    Science.gov (United States)

    Giannopoulos, Nikiforos; Vagenas, George; Noutsos, Konstantinos; Barzouka, Karolina; Bergeles, Nikolaos

    2017-01-01

    Abstract This study investigated the relationship between somatotype, level of competition, and performance in attack in elite level male volleyball players. The objective was to test for the potential covariation of competition level (Division A1 vs. A2) and playing position (hitters vs. centers vs. opposites) considering performance in attack. Anthropometric, body composition and somatotype variables were measured according to the Heath-Carter method. The attack actions of 144 players from 48 volleyball matches were analyzed and their performance was rated using a 5-point numerical scale. Results showed that players of Division A1 were taller, heavier, more muscular, and less endomorphic compared to those of Division A2. MANOVA and follow-up discriminant function analysis revealed somatotype differences among playing positions with centers and opposites being endomorph-ectomorph and hitters being central. Centers performed constantly better than hitters and opposites regardless of the division and somatotype. Multiple linear regression analysis showed that variables defining ectomorph and endomorph players, centers, and players of Division A1 significantly determined the relative performance superiority and were able to explain the variation in performance by almost 25%. These results could be taken into account by coaches when assigning players to particular playing positions or when designing individualized position-specific training programs. PMID:28828084

  10. Seasonal player wellness and its longitudinal association with internal training load: study in elite volleyball.

    Science.gov (United States)

    Clemente, Filipe M; Mendes, Bruno; Palao, José M; Silvério, André; Carriço, Sandro; Calvete, Francisco; Nakamura, Fábio Y

    2018-04-04

    Monitoring training load is critical to minimize the risk of overreaching, injury or illness. The purpose of this study was to assess the relationships and variance between perceived internal load and wellness status of elite male volleyball. Thirteen elite volleyball players were studied during a full competitive season (nine months, 237 training sessions and 37 official matches). Perceived exertion, muscle soreness, stress, fatigue and sleep quality levels were daily measured using session RPE and the Hopper Questionnaire. Moderate-to-large correlations were found between weekly training load and perceived status of muscle soreness, fatigue and stress. Stronger correlations were found between weekly training loads than daily training load. Significant greater stress levels in match days than in training were found. No correlations between load and wellness were not found in the last month when players perceived higher levels of stress due to the competition. The analysis of the weekly training load had a higher relationship with players' wellness status in pre-season and middle of the season. In the last part of the season (final matches for the title), despite of a decrease in perceived load of last month of the season, there was an increase stress and fatigue levels. These results suggest the importance of including the impact on the competition when elite athletes are monitored. The results show the monitoring tools used may help in to characterize the training process of teams and the player's acute and chronic responses.

  11. Acute injuries in soccer, ice hockey, volleyball, basketball, judo, and karate: analysis of national registry data.

    Science.gov (United States)

    Kujala, U. M.; Taimela, S.; Antti-Poika, I.; Orava, S.; Tuominen, R.; Myllynen, P.

    1995-01-01

    OBJECTIVE--To determine the acute injury profile in each of six sports and compare the injury rates between the sports. DESIGN--Analysis of national sports injury insurance registry data. SETTING--Finland during 1987-91. SUBJECTS--621,691 person years of exposure among participants in soccer, ice hockey, volleyball, basketball, judo, or karate. MAIN OUTCOME MEASURES--Acute sports injuries requiring medical treatment and reported to the insurance company on structured forms by the patients and their doctors. RESULTS--54,186 sports injuries were recorded. Injury rates were low in athletes aged under 15, while 20-24 year olds had the highest rates. Differences in injury rates between the sports were minor in this adult age group. Overall injury rates were higher in sports entailing more frequent and powerful body contact. Each sport had a specific injury profile. Fractures and dental injuries were most common in ice hockey and karate and least frequent in volleyball. Knee injuries were the most common cause of permanent disability. CONCLUSIONS--Based on the defined injury profiles in the different sports it is recommended that sports specific preventive measures should be employed to decrease the number of violent contacts between athletes, including improved game rules supported by careful refereeing. To prevent dental injuries the wearing of mouth guards should be encouraged, especially in ice hockey, karate, and basketball. PMID:8520333

  12. Acute injuries in soccer, ice hockey, volleyball, basketball, judo, and karate: analysis of national registry data.

    Science.gov (United States)

    Kujala, U M; Taimela, S; Antti-Poika, I; Orava, S; Tuominen, R; Myllynen, P

    1995-12-02

    To determine the acute injury profile in each of six sports and compare the injury rates between the sports. Analysis of national sports injury insurance registry data. Finland during 1987-91. 621,691 person years of exposure among participants in soccer, ice hockey, volleyball, basketball, judo, or karate. Acute sports injuries requiring medical treatment and reported to the insurance company on structured forms by the patients and their doctors. 54,186 sports injuries were recorded. Injury rates were low in athletes aged under 15, while 20-24 year olds had the highest rates. Differences in injury rates between the sports were minor in this adult age group. Overall injury rates were higher in sports entailing more frequent and powerful body contact. Each sport had a specific injury profile. Fractures and dental injuries were most common in ice hockey and karate and least frequent in volleyball. Knee injuries were the most common cause of permanent disability. Based on the defined injury profiles in the different sports it is recommended that sports specific preventive measures should be employed to decrease the number of violent contacts between athletes, including improved game rules supported by careful refereeing. To prevent dental injuries the wearing of mouth guards should be encouraged, especially in ice hockey, karate, and basketball.

  13. Sports training in volleyball youth sport centers in the Czech republic

    Directory of Open Access Journals (Sweden)

    Michal Lehnert

    2012-03-01

    Full Text Available BACKGROUND: Together with the increase of importance of sport as a social phenomenon importance of optimizing the system of sports training of talented athletes is growing. OBJECTIVES: The aim of this study was to obtain information on the activities of coaches, training process, and conditions under which they are realized in volleyball youth sports centers in the Czech Republic (SpS. METHODS: We have created a survey focused on six topical areas of sports training in volleyball. This paper deals with the analysis of areas "Coaches and their activities" and "training process". The questionnaire was sent to 18 coaches of male teams incorporated to SpS, 18 coaches responded (response rate 100%. RESULTS: We found a statistically significant relationship (rpb = 0.41; p < 0.05 between long-term performance and competences of coaches. The research shows that activity in particular SpS in most areas is consistent with current knowledge and trends in youth training. Reserves exist primarily in the number of coaches working with individual teams (in 13 cases only 1 coach and in regeneration. In some SpS a unified training strategy is missing and training process is not properly structured. CONCLUSIONS: The study allowed partial evaluation of conditions, quality and content of the training process in the SPS. The acquired knowledge can contribute to the improvement of SpS functioning.

  14. Somatotype, Level of Competition, and Performance in Attack in Elite Male Volleyball

    Directory of Open Access Journals (Sweden)

    Giannopoulos Nikiforos

    2017-08-01

    Full Text Available This study investigated the relationship between somatotype, level of competition, and performance in attack in elite level male volleyball players. The objective was to test for the potential covariation of competition level (Division A1 vs. A2 and playing position (hitters vs. centers vs. opposites considering performance in attack. Anthropometric, body composition and somatotype variables were measured according to the Heath-Carter method. The attack actions of 144 players from 48 volleyball matches were analyzed and their performance was rated using a 5-point numerical scale. Results showed that players of Division A1 were taller, heavier, more muscular, and less endomorphic compared to those of Division A2. MANOVA and follow-up discriminant function analysis revealed somatotype differences among playing positions with centers and opposites being endomorph-ectomorph and hitters being central. Centers performed constantly better than hitters and opposites regardless of the division and somatotype. Multiple linear regression analysis showed that variables defining ectomorph and endomorph players, centers, and players of Division A1 significantly determined the relative performance superiority and were able to explain the variation in performance by almost 25%. These results could be taken into account by coaches when assigning players to particular playing positions or when designing individualized position-specific training programs.

  15. Impact of an Interdisciplinary Food, Nutrition and Health Education Program for adolescent Brazilian volleyball players

    Directory of Open Access Journals (Sweden)

    Natália Vilela Silva DANIEL

    Full Text Available ABSTRACT Objective: To evaluate the impact of an Interdisciplinary Food, Nutrition and Health Education Program on nutrition knowledge, intention to change eating behavior, and body dissatisfaction of adolescent volleyball players. Methods: The sample consisted of 10 female volleyball players from the juvenile category of the city of Santos, São Paulo, Brazil, who participated in a program with eight monthly meetings (one discussion group followed by six educational activities and one final discussion group for evaluation. Results: Nutrition knowledge, body perception, intention to change eating behavior, eating attitudes and practices were investigated using questionnaires and discussion groups before and after the athletes' participation in ludic activities designed to address nutrition strategies for athletic performance and healthy eating, and how to deal with pressure for results and self-image. Nutrition knowledge improved from 57.0%±9.9 to 63.0%±11.8 (p=0.03 of correct answers. The mean body distortion score did not change (70.0±14.9 versus 76.5±22.4, p=0.235. Six athletes advanced in their intention to change eating behavior. Positive food practices were reported during the program and the identified discourses indicated the intention of changing the daily eating habits in the future. Conclusion: The program had a positive impact on nutrition knowledge and intention of changing eating behavior; however, for other issues, especially involving emotional aspects, further interventions should be planned.

  16. Response Time, Visual Search Strategy, and Anticipatory Skills in Volleyball Players

    Directory of Open Access Journals (Sweden)

    Alessandro Piras

    2014-01-01

    Full Text Available This paper aimed at comparing expert and novice volleyball players in a visuomotor task using realistic stimuli. Videos of a volleyball setter performing offensive action were presented to participants, while their eye movements were recorded by a head-mounted video based eye tracker. Participants were asked to foresee the direction (forward or backward of the setter’s toss by pressing one of two keys. Key-press response time, response accuracy, and gaze behaviour were measured from the first frame showing the setter’s hand-ball contact to the button pressed by the participants. Experts were faster and more accurate in predicting the direction of the setting than novices, showing accurate predictions when they used a search strategy involving fewer fixations of longer duration, as well as spending less time in fixating all display areas from which they extract critical information for the judgment. These results are consistent with the view that superior performance in experts is due to their ability to efficiently encode domain-specific information that is relevant to the task.

  17. Estudo epidemiológico da entorse de tornozelo em atletas de voleibol de alto rendimento Ankle sprains in volleyball high-performance athletes: an epidemiological study

    Directory of Open Access Journals (Sweden)

    Carlos Rodrigo do Nascimento Fortes

    2008-01-01

    Full Text Available O objetivo desta pesquisa foi caracterizar o último episódio de entorse de tornozelo em atletas de voleibol de alto rendimento. Participaram inicialmente deste estudo, entre os meses janeiro de 2003 e março de 2004, 114 atletas, do sexo masculino, atuantes na categoria adulta de 9 equipes, todas participantes da Divisão Especial ou Primeira Divisão do Campeonato Paulista de Voleibol. Dos 114 atletas inicialmente analisados, 21 relataram não ter sofrido nenhuma lesão nos tornozelos, portanto, seguindo os critérios de exclusão, foram analisados 93 episódios de última entorse de tornozelo de 93 atletas. Os mesmos foram entrevistados de maneira oral e individual pelo pesquisador executante, seguindo a seqüência do questionário pré-estabelecido. Foi encontrada diferença significante na correlação entre a fase da competição e a causa da entorse bem como na relação entre a posição de atuação do atleta e o fundamento realizado no momento da lesão. A posição oposto foi a mais acometida e o fundamento bloqueio foi o que mais ocasionou entorses.The purpose of this research is to characterize the most recent ankle sprain episode occurred with volleyball high performance athletes. From January 2003 to March 2004, 114 male athletes from 9 adult category teams of the Special and First Division of São Paulo State Volleyball Championship were included on this study. From the 114 athletes assessed, 21 have reported no ankle sprains, therefore, by following the exclusion criteria, the last 93 episodes of ankle sprain from 93 athletes were assessed. They have been individually interviewed by the researcher, following a pre-established sequence of the questionnaire. A significant difference was found in the correlation between the competition phase and the ankle sprain cause, as well as for the correlation between the athlete's acting position and the movement made at the injury moment. The opposite position was the most affected and

  18. Biomechanics research in ski jumping, 1991-2006.

    Science.gov (United States)

    Schwameder, Hermann

    2008-01-01

    In this paper, I review biomechanics research in ski jumping with a specific focus on publications presented between 1991 and 2006 on performance enhancement, limiting factors of the take-off, specific training and conditioning, aerodynamics, and safety. The first section presents a brief description of ski jumping phases (in-run, take-off, early flight, stable flight, and landing) regarding the biomechanical and functional fundamentals. The most important and frequently used biomechanical methods in ski jumping (kinematics, ground reaction force analyses, muscle activation patterns, aerodynamics) are summarized in the second section. The third section focuses on ski jumping articles and research findings published after the establishment of the V-technique in 1991, as the introduction of this technique has had a major influence on performance enhancement, ski jumping regulations, and the construction of hill profiles. The final section proposes topics for future research in the biomechanics of ski jumping, including: take-off and early flight and the relative roles of vertical velocity and forward somersaulting angular momentum; optimal jumping patterns utilizing the capabilities of individual athletes; development of kinematic and kinetic feedback systems for hill jumps; comparisons of simulated and hill jumps; effect of equipment modifications on performance and safety enhancement.

  19. Jump phenomena. [large amplitude responses of nonlinear systems

    Science.gov (United States)

    Reiss, E. L.

    1980-01-01

    The paper considers jump phenomena composed of large amplitude responses of nonlinear systems caused by small amplitude disturbances. Physical problems where large jumps in the solution amplitude are important features of the response are described, including snap buckling of elastic shells, chemical reactions leading to combustion and explosion, and long-term climatic changes of the earth's atmosphere. A new method of rational functions was then developed which consists of representing the solutions of the jump problems as rational functions of the small disturbance parameter; this method can solve jump problems explicitly.

  20. Effect of drop jump technique on the reactive strength index.

    Science.gov (United States)

    Struzik, Artur; Juras, Grzegorz; Pietraszewski, Bogdan; Rokita, Andrzej

    2016-09-01

    The basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI) for countermovement drop jumps (CDJs) and bounce drop jumps (BDJs). The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p jump technique that is commonly performed by basketball players.