Wetenschap en waterpolo


Comparison of two anaerobic water polo-specific tests with the Wingate test.
J Strength Cond Res. 2009 Jan;23(1):336-40.
Bampouras TM, Marrin K.
School of Sport, University of Cumbria, Lancaster, United Kingdom.

The purpose of the current study was to compare 2 water polo-specific tests-the 14 x 25-m swims (SWIM) and the 30-second crossbar jumps (30CJ)-with a laboratory-based test of anaerobic power, the Wingate Anaerobic Test (WAnT). Thirteen elite women's water polo players (mean +/- SD: age 22.0 +/- 4.4 years, height 168.7 +/- 7.9 cm, body mass 65.9 +/- 6.1 kg, body fat 23.6 +/- 3.5 %, maximum oxygen uptake 51.4 +/- 4.5 mlxkgxmin) participated in the study. The SWIM involved 14 repeated "all-out" sprints every 30 seconds. Swimming time was recorded, and sprint velocity, mean velocity (Vmean), and the gradient of the linear regression equation (GRADIENT) were calculated. The 30CJ involved repeated in-water water polo jumps and touching the goal crossbar with both hands. The number of touches in 30 seconds was recorded. Additionally, the subjects completed a 30-second WAnT, and mean power (Mp) and fatigue index (FI) were calculated. Kendall tau (tau) rank correlation was used to examine for correlation between ranks. Significance level was set at p <or= 0.05. No significant correlation was found between any of the measures of the WAnT and the 2 sport-specific tests. It was suggested that the WAnT may not be an appropriate evaluation tool for anaerobic power assessment of water polo players, stressing the importance of sport-specific tests.

Shoulder pain in water polo: a systematic review of the literature.
J Sci Med Sport. 2009 Jan;12(1):3-11.
Webster MJ, Morris ME, Galna B.
School Physiotherapy, The University of Melbourne, Parkville, Australia.

The main aim of this systematic review is to synthesize and critically evaluate literature on the incidence and clinical presentation of shoulder pain in water polo. A secondary aim is to examine the contributing factors to shoulder pain in water polo. Medline, Cinahl, Embase, Ausport, Ovid, Sports Discus, Pubmed and Google Scholar data bases were electronically searched. Data were extracted regarding research design, injuries, pain, incidence, interventions and therapy outcomes. Of an initial yield of 23 papers, 11 fulfilled the inclusion criteria and were categorized into studies on incidence, shoulder pain, shoulder mobility, strength and throwing injuries. Methodological limitations included sampling and measurement biases, inadequate internal validity of measurement tools, poor specification of testing protocols and limitations in statistical analysis. The review found a high incidence of shoulder pain in water polo. Although there was limited evidence regarding causation, the repeated action of throwing was identified as a contributing factor to shoulder pain. Future studies need to explore the relative contributions of hyper-mobility and muscle strength imbalance to shoulder pain in water polo.

Physiological demands of water polo goalkeeping.
J Sci Med Sport. 2009 Jan;12(1):244-50.
Platanou T.
Department of Aquatic Sports, Faculty of Physical Education and Sport Science, University of Athens, Greece.

The purpose of this study was to investigate the physiological demands of water polo goalkeepers during competition and to examine whether the playing intensity of the goalkeeper decreases as the game time progresses. During eight official games the following measurements were performed on eight elite water polo goalkeepers: (1) video analysis of activities, (2) monitoring of blood lactate (BLa) and (3) continuous recording of heart rate (HR) responses. Mean HR of total mixed playing time, excluding breaks among quarters, was 134.3+/-20.3bpm for 36 (4x9) min of game duration. The large portion of the game (85.6%) was performed with a HR lower than 151.4+/-2.7bpm (82.1+/-1.4% of HRpeak) an intensity corresponding to the players' anaerobic threshold (3.49+/-0.60mmolL(-1)). However, an important part of the game (14.4%) contained activities with sudden HR increases above the anaerobic threshold. Mean BLa accumulation at the end of each game period was 3.93+/-1.64mmolL(-1). Individual lactate values varied from 2.0 to 8.3mmolL(-1). Goalkeeper exercise intensity reached its peak value (152.5+/-10.1bpm) whenever his team competed with one player less due to player exclusion. No significant differences were found in HR, BLa and the percentage of time spent in each of the activity categories between game periods. In conclusion, goalkeeper's game can be described as of intermittent nature with great variability in the intensity performed. The greater part of the game is associated with a low aerobic demand while an important part of the game contains activities with sudden HR increases above the anaerobic threshold implying also a considerable demand on anaerobic metabolism. The intensity of exercise of the goalkeeper does not differ from period to period.

Gastroesophageal reflux disease: work-related disease?
Dig Dis. 2009;27(1):38-44.
Pregun I, Bakucz T, Banai J, Molnár L, Pavlik G, Altorjay I, Orosz P, Csernay L, Tulassay Z, Herszényi L.
2nd Department of Medicine, Semmelweis University, and Clinical Gastroenterology Research Unit, Hungarian Academy of Science, Budapest, Hungary.

BACKGROUND: An occupation-related susceptibility of professional singers to experience gastroesophageal reflux has been suggested.
AIMS: To investigate the prevalence of gastroesophageal reflux symptoms in a series of professional opera choristers, wind players, glassblowers and water polo players in comparison with a sample of general population.
SUBJECTS AND METHODS: A total of 202 professional opera choristers from well-known choirs in different Hungarian regions, 71 professional wind players, 43 glassblowers, 54 water polo players were identified and 115 control subjects were compared prospectively. Reflux symptoms together with selected individual characteristics and lifestyle habits were investigated in study groups through a reflux questionnaire.
RESULTS: Professional opera choristers reported a statistically significantly higher prevalence of heartburn, regurgitation and hoarseness than control subjects (p < 0.001). Among professional wind players, heartburn and regurgitation were significantly more frequent compared with controls (p < 0.05 and p < 0.01, respectively). Glassblowers reported a significantly higher prevalence of acid regurgitation in comparison with controls (p < 0.01). The prevalence of reflux symptoms in water polo players was similar to that of controls. In opera choristers, wind players and glassblowers, reflux symptoms appeared to be significantly correlated with the cumulative lifetime duration of professional singing, playing and working activity, respectively (p < 0.05).
CONCLUSIONS: Our results demonstrate that professional opera choristers, professional wind players and glassblowers have a higher prevalence of reflux symptoms compared with control subjects. Gastroesophageal reflux in these professions should be considered as a work-related disorder that may have an impact on quality of life and may negatively interfere with professional performance.

Lipid peroxidation and total antioxidant status in unprofessional athletes before and after a cardiopulmonary test.
Clin Hemorheol Microcirc. 2009;43(3):235-41.
Caimi G, Canino B, Amodeo G, Montana M, Lo Presti R.
Dipartimento di Medicina Interna, Malattie Cardiovascolari e Nefrourologiche Universitŕ di Palermo, Palermo, Italy.

We examined lipid peroxidation, expressed as thiobarbituric acid-reactive substances (TBARS) and total antioxidant status (TAS) before and after a cardiopulmonary test, in 20 sedentary controls and in 62 unprofessional male athletes subdivided into 3 subgroups. The first included subjects who practised endurance sports (14 cyclists and 9 endurance swimmers), the second subjects who practised mixed sports (6 basket players, 6 judoists, 8 water polo players) and the third group subjects who practised power sports (3 sprint runners, 4 weightlifters, 12 sprint swimmers). In the whole group of athletes an increase in TBARS and a decrease in TAS were present at baseline. Subdividing the whole group into three subgroups we observed an increase in TBARS in all and a decrease in TAS only in the endurance and mixed athletes. After the test, TBARS showed a more significant increase in controls compared to the whole group and each subgroup of athletes, while TAS increased only in the whole group and in those who practised mixed sports. In conclusion, at baseline in athletes the oxidative status shows a different behaviour compared to controls, while after the test the antioxidant protection is more marked and it may be related to an increase of antioxidant systems.

Comparative study of stabilometric parameters in sportsmen of various disciplines.
Bull Exp Biol Med. 2009 Feb;147(2):233-5.
Arkov VV, Abramova TF, Nikitina TM, Ivanov VV, Suprun DV, Shkurnikov MU, Tonevitskii AG.
All-Russian Institute of Physical Training and Sport, Moscow, Russia.

Stabilometric parameters were compared in sportsmen of various disciplines (biathlon, boat racing, judo, and water polo). A decrease in the role of gravitational factor in sport activity was accompanied by the impairment of balance characteristics, which remained within normal limits of the mean population level.

A physiological, time-motion, and technical comparison of youth water polo and Acquagoal.
J Sports Sci. 2009 Jun;27(8):823-31.
Lupo C, Tessitore A, Cortis C, Ammendolia A, Figura F, Capranica L.
Department of Human Movement and Sport Sciences, University of Rome "Foro Italico", Rome.

The aims of this study were to provide a profile of young water polo players and to compare technical and tactical aspects, movement patterns, and cardiac loads of youth water polo and Acquagoal codes. Ten young (age 12.3 years, s = 0.6) male water polo players underwent anthropometric (stature, body mass, body mass index, chest circumference, hand breadth, and length), strength, and [Vdot]O(2max) evaluations. Friendly youth water polo and Acquagoal matches were arranged to evaluate heart rates and swimming patterns (horizontal and vertical, with and without the ball) of players, and technical and tactical aspects of matches (number of actions, passes, player involved in an action, lost possessions, shots, goals, and the origin and types of shot). Independent of code, matches imposed a high cardiac load on players. Vertical swimming occurred more frequently (P < 0.05) in Acquagoal (71%) than youth water polo (45%). Technical and tactical measures also differed (P < 0.05), with players performing more passes and shots inside the penalty area and showing a higher goal-to-shot ratio during youth water polo than during Acquagoal. These results indicate that youth water polo better resembles the swimming patterns of adult water polo and facilitates the technical and tactical aspects of play better than Acquagoal.

Comparison of progressive maximal swimming tests in elite female water polo players.
Int J Sports Physiol Perform. 2009 Jun;4(2):206-17.
Tan FH, Polglaze T, Dawson B.
School of Sport Science, Exercise, and Health, University of Western Australia, Crawley, WA, Australia.

PURPOSE: To compare the Multistage Shuttle Swim Test (MSST), Water Polo Intermittent Shuttle Test (WIST) and 5 200 m Incremental Swimming Test (IST) responses in elite female water polo players.
METHODS: Fourteen Australian Women's National Water Polo Squad members performed the MSST and WIST, and 13 players from a National Water Polo League club performed the IST, MSST and WIST on separate occasions (no goalkeepers were involved). Peak heart rate, blood lactate and ratings of perceived exertion were obtained for all tests. Expired air was collected following all tests for the National League players.
RESULTS: The National Squad players scored significantly better (ie, distance covered) in the MSST and WIST than the National League players (effect sizes=1.60 to 1.79, P<.001). The MSST and WIST scores were significantly correlated (r=.80 to 0.88, P<.001). The MSST scores were significantly correlated with peak oxygen uptake (VO2peak; mL.kg(-1).min(-1)) obtained for all tests (r=.58 to 0.59, P<.05). In contrast, there were no significant correlations between the WIST scores and VO2peakobtained for any of the tests (r=.43 to 0.52, P>.05). Differences in VO2peakfor the IST, MSST and WIST were nonsignificant (P>.05).
CONCLUSIONS: The MSST and WIST can discriminate players of different competition standards. The MSST can be used to estimate a player's aerobic fitness and peak heart rate. The WIST appears to better mimic the intermittent activity pattern of the game, but its application to female players, to assess maximal intermittent endurance swimming performance, requires further evaluation.

Morphogenetic variability during selection of elite water polo players.
J Sports Sci. 2009 Jul;27(9):941-7.
Cvjeticanin S, Marinkovic D.
Institute of Human Genetics, School of Medicine, University of Belgrade, Belgrade, Serbia.

In this population-genetic study, we compared morphological and genetic variability of a control group of individuals with that of developing and elite water polo players from Serbia, using a test of determination of homozygously recessive characteristics in humans (HRC-test). Comparisons of the frequencies of ABO and Rh blood types were also made for the groups examined. The degree of genetic homozygosity showed not only statistically significant differences in the mean values obtained for the studied samples (control group 5.1 +/- 0.2; emerging water polo players 3.5 +/- 0.1; elite water polo players 1.9 +/- 0.3 HRCs, out of 20 analysed characteristics), but also differences in the type of distribution, as well as the presence of specific combinations of such traits. During identification of swimming talents, the degree of genetic homozygosity showed a significant decrease, from 4.8 +/- 0.3 in the group of pre-competitive young boys, to 2.7 +/- 0.3 in selected adult team members, to only 1.9 +/- 0.3 in elite water polo players. In the group of pre-competitive young individuals, all characteristics tested also had homo-recessive combinations, while in the group of elite water polo players only 8 of 20 traits were expressed as homozygously recessive. In the group of elite water polo players, who were World and European champions as well as Olympic champions, the frequencies of the A and B blood types were low, AB was absent, and the frequency of the O blood type was high at 72.2% (i.e., almost twice the expected percentage).

Anthropometric and fitness characteristics of elite Australian female water polo players.
J Strength Cond Res. 2009 Aug;23(5):1530-6.
Tan FH, Polglaze T, Dawson B, Cox G.
School of Sport Science, Exercise and Health, The University of Western Australia, Crawley, Western Australia, Australia.

The purpose of this study was to investigate the anthropometric and fitness characteristics of elite female water polo players and examine the differences between players of different competition levels (national and international) and playing positions (center and perimeter). Twenty-six female water polo players (National League, n = 12, and National Squad, n = 14) underwent measurements of standard anthropometry (height, body mass, and sum of 7 skinfolds), lower-body muscular power (in-water vertical jump), speed (10-m maximal sprint swim), and aerobic fitness (multistage shuttle swim test). No goalkeepers were involved. The National Squad players were taller (173.7 +/- 5.5 vs. 169.6 +/- 4.4 cm; p < 0.05) and heavier (74.6 +/- 8.0 vs. 65.8 +/- 8.4 kg; p < 0.05) and had better jumping (139.0 +/- 7.0 vs. 129.7 +/- 4.6 cm; p < 0.001), sprinting (5.96 +/- 0.21 vs. 6.26 +/- 0.34 seconds; p < 0.05), and endurance swimming abilities (652 +/- 84 vs. 449 +/- 124 m; p < 0.001) compared with the National League players. Perimeter players had lower-body mass (70.2 +/- 3.8 vs. 82.5 +/- 7.4 kg; p < 0.001) and skinfold levels (88.7 +/- 14.1 vs. 118.6 +/- 22.2 mm; p < 0.01) and better sprinting (5.88 +/- 0.19 vs. 6.10 +/- 0.19 seconds; effect size [ES] = 1.16, p > 0.05) and endurance swimming abilities (678 +/- 65 vs. 606 +/- 102 m; ES = 0.84, p > 0.05) compared with center players. These findings demonstrate that anthropometric and fitness characteristics can discriminate between players of different competition levels and playing positions. These water polo-specific field tests may assist coaches in profiling players and evaluating adaptations to training.

Activity profiles and physical demands of elite women's water polo match play.
J Sports Sci. 2009 Aug;27(10):1095-104.
Tan F, Polglaze T, Dawson B.
School of Sport Science, Exercise and Health, University of Western Australia, Perth, Australia.

The aim of this study was to quantify the movement patterns of contemporary elite women's water polo match play. Thirty-three player matches (centre, n = 15 and perimeter, n = 18) were analysed using video-based time-motion analysis. Frequency and duration of individual movements and distance swum were assessed. Mean match time and playing time were 69:48 +/- 04.30 min:s and 33:14 +/- 14:40 min:s, respectively. Players performed 330 +/- 158 discrete movements per match, representing a change in movement every 6.2 s. There were 54 +/- 25 high-intensity activities per match, or one every 38.4 s. These findings characterise women's water polo as a high-intensity intermittent sport. Total distance swum per match was 699.3 +/- 296.8 m. Positional differences showed a predominance of wrestling in centre players (4:13 vs. 1:53 min:s; P < 0.001) and sprint swimming in perimeter players (2:09 vs. 0:52 min:s; P < 0.001). Players performed 6.7 +/- 3.5 repeated high-intensity activity bouts per match, suggesting that this facet of play is important in water polo. Overall, exercise intensity decreased as a match progressed, suggesting the likelihood of fatigue during the latter stages. These findings provide important information for the planning and monitoring of training in women's water polo.

Shuttle swim test for water polo players: validity and reliability.
J Sports Med Phys Fitness. 2009 Sep;49(3):327-30.
Melchiorri G, Manzi V, Padua E, Sardella F, Bonifazi M.
Motor Science Department, Tor Vergata University, Rome, Italy.

AIM: The purpose of this study, carried out on elite water polo players, was to examine: 1) the relationship between the shuttle swim test (SST) and the performance during official water polo games, and 2) the SST reliability.
METHODS: Sixteen male players of the Italian National Water Polo Team (age: 27.9 + or - 2.1 years, body mass: 88.5 + or - 10.3 kg, height: 186.6 + or - 6.9 cm) performed the SST, consisting of two sets of seven repetitions from 40 to 10 m (total of 120 m for each set) at a maximal intensity with 90 s of rest between sets. During the SST, average swimming speed, blood lactate concentration and heart rate were recorded. Direct validity of the SST was evaluated by comparing the average swimming speed with the total distance covered (TD) and the distance covered at high intensity swimming (above 1.8 m x s(-1), HIS) during three official water polo games. SST reliability was assessed by testing the same athletes one week apart.
RESULTS: Average swimming speed during the SST was significantly correlated with TD (r=0.67, P<0.01) and HIS (r=0.74, P<0.004). The mean average speed during SST showed high reliability (TE=0.4%; CI 95%: 0.2% to 1.0% ). The T1 vs. T2 difference in mean average speed was not significant.
CONCLUSIONS: Present findings demonstrate the validity and reliability of the SST for evaluation of the swimming fitness of water polo players.

Position specific morphological characteristics of elite water polo players.
Coll Antropol. 2009 Sep;33(3):781-9.
Lozovina M, Durovic N, Katic R.
Faculty of Kinesiology, University of Split, Split, Croatia.

The aim of the study was to determine morphological characteristics of elite water polo players. In a sample of 121 water polo players, the structure of a set of 23 morphological space variables was determined by use of factor analysis, followed by determination of differences between all pairs of playing positions in the manifest morphological space by use of Post Hoc analysis. Factor structure indicated the presence of four basic superior latent dimensions responsible for directly measurable manifestations of morphological parameters: first component acting as a general mechanism of growth and development; second component being bipolar, at one pole almost exclusively determined by adipose tissue, and on the other pole by longitudinal skeletal growth; third component differentiating longitudinal skeletal growth accompanied by subcutaneous adipose tissue from muscle mass development and transverse skeletal growth; and fourth component mostly differentiating transverse skeletal development relative to longitudinal skeletal development. Oblimin transformation of the main components was employed to define the factor of circular dimensionality, factor of subcutaneous adipose tissue, factor of longitudinal skeleton dimensionality, and factor of transverse skeleton dimensionality. Results of obtained by the analysis of variance (ANOVA) and homogenization of playing positions in water polo for each individual variable upon Post Hoc analysis yielded significant differences both within and between groups in all anthropometric variables except for the variable of triceps skinfold. Statistically significant differences were recorded between two groups of playing positions, i.e. centers and backs versus goalkeepers, wingers and outside forwards. Significant differences were found between water polo players playing at center and back positions, characterized by higher values of all measures of longitudinal and transverse skeleton dimensionality in comparison with water polo players playing at other positions (goalkeepers, wingers and outside forwards). Significant differences were observed according to body mass and volume between water polo players playing at center position, characterized by considerably higher values of all measures in comparison with water polo players at other positions, and between centers and backs versus other positions according to body weight, chest circumference and forearm circumference. Considering subcutaneous adipose tissue, skinfold variable was significantly more pronounced in water polo players playing at center position than in those playing at other positions.

Echocardiographic and spiroergometric data of elite Hungarian female water polo players.
Acta Physiol Hung. 2009 Dec;96(4):449-57.
Horváth P, Petrekanits M, Györe I, Kneffel Z, Varga-Pintér B, Pavlik G.
Department of Health Sciences and Sports Medicine, Faculty of Physical Education and Sports Sciences, Semmelweis University, Budapest, Hungary.

In the authors' earlier study the relative aerobic power of Hungarian top-level male water polo players was found to be smaller than that of other top-level athletes, while their echocardiographic parameters proved to be the most characteristic of the athlete's heart. In the present investigation echocardiographic and spiroergometric data of female top-level water polo players were compared to those of other female elite athletes and of healthy, non-athletic subjects. Relative aerobic power in the water polo players was lower than in endurance athletes. Mean resting heart rates were the slowest in the water polo players and endurance athletes. Morphologic indicators of the heart (body size related left ventricular wall thickness and muscle mass) were the highest in the water polo players, endurance and power athletes. In respect of diastolic functions (diastolic early and late peak transmitral flow velocities) no difference was seen between the respective groups.These results indicate that, similarly to the males, top-level water polo training is associated with the dimensional parameters of the heart rather than with relative aerobic power. For checking the physical condition of female water polo players spiroergometric tests seem to be less appropriate than swim-tests with heart rate recovery studies such as the ones used in the males.