Wetenschap en waterpolo

2004

AIM: The aim of this study was to compare differences between skinfold thicknesses (SK), bioelectrical impedance analysis (BIA), a 2-compartment model (2C), and 2, 3-compartment models (3C) of percent body fat (%BF) assessment with a 4-compartment model (4C) in professional water polo athletes.
METHODS: Ten male subjects, 18 to 29 years of age, participated in this study. Under water weighing, deuterium dilution, and dual-energy X-ray absorptiometry (DXA) were used to provide the required values for the models. The two, 3C models used were established by Withers et al. (3C-W) and by the DXA manufacturers (3C-DXA). 4C was also established by Withers et al.
RESULTS: There were no significant differences between 2C, 3C-W, and 3C-DXA when compared with 4C (criterion model). There were no significant differences between 2C and 3C-W. %BF was significantly greater using 2C compared with 3C-DXA. %BF derived from SK and BIA were significantly greater than all other METHODS: 4C was best correlated with 3C-W (R2=0.998), followed by 2C (R2=0.806), 3C-DXA (R2=0.5071), SK (R2=0.2945), and BIA (R2=0.2377).
CONCLUSION: We conclude that 2C and 3C-W assess %BF equally as well as 4C; however, SK and BIA significantly over-estimated %BF in water polo athletes.

Fractures in the collegiate athlete
Am J Sports Med. 2004 Mar;32(2):446-51.
Hame SL, LaFemina JM, McAllister DR, Schaadt GW, Dorey FJ.
Sports Medicine Section, Department of Orthopaedic Surgery, University of California, Los Angeles School of Medicine, USA.

PURPOSE: To determine the demographics and incidence of fractures in collegiate athletes.
STUDY DESIGN: Retrospective review of prospectively collected data.
METHODS: Division I collegiate athletes who sustained a fracture while enrolled at the university from 1986 to 2000 were identified through training room records. Type and location of fracture, sport, gender, age, position, height, and weight were recorded and analyzed. Team information was obtained from athletic department records and was used to calculate incidence.
RESULTS: Between 1986 and 2000, 5900 Division I athletes at our institution sustained 349 primary fractures (5.9%). By gender, the incidence did not differ significantly between males and females (P =.236), except in water polo where the men sustained significantly more fractures. By type, females sustained significantly more stress fractures (P =.001) than males. Overall, by location, the hand contributed the greatest number of total fractures. By sport, the incidence rate was highest in basketball (0.081) for male athletes and in gymnastics (0.069) for female athletes. The incidence of a second fracture during the study period was twice the rate of the first fracture.
CONCLUSIONS: As expected, athletes participating in contact sports contributed the greatest number of fractures. Participation in basketball for men and in gymnastics for women posed the greatest risk. Female athletes sustained significantly more stress fractures.

Talent identification and early development of elite water-polo players: a 2-year follow-up study.
J Sports Sci. 2004 Apr;22(4):347-55
Falk B, Lidor R, Lander Y, Lang B.
Ribstein Center for Sport Medicine Sciences and Research, Wingate Institute, Netanya, Israel.

The processes of talent detection and early development are critical in any sport programme. However, not much is known about the appropriate strategies to be implemented during these processes, and little scientific inquiry has been conducted in this area. The aim of this study was to identify variables of swimming, ball handling and physical ability, as well as game intelligence, which could assist in the selection process of young water-polo players. Twenty-four players aged 14-15 years underwent a battery of tests three times during a 2-year period, before selection to the junior national team. The tests included: freestyle swim for 50, 100, 200 and 400 m, 100-m breast-stroke, 100-m 'butterfly' (with breast-stroke leg motion), 50-m dribbling, throwing at the goal, throw for distance in the water, vertical 'jump' from the water, and evaluation of game intelligence by two coaches. A comparison of those players eventually selected to the team and those not selected demonstrated that, 2 years before selection, selected players were already superior on most of the swim tasks (with the exception of breast-stroke and 50-m freestyle), as well as dribbling and game intelligence. This superiority was maintained throughout the 2 years. Two-way tabulation revealed that, based on baseline scores, the prediction for 67% of the players was in agreement with the final selection to the junior national team. We recommend that fewer swim events be used in the process of selecting young water-polo players, and that greater emphasis should be placed on evaluation of game intelligence.

Anthropometric changes in elite male water polo players: survey in 1980 and 1995.
Croat Med J. 2004 Apr;45(2):202-5.
Lozovina V, Pavicic L.
Split University of Maritime Studies, Split, Croatia.

AIM: To assess the differences in anthropometric parameters, body fat, body mass index (BMI), and body density induced by sport-specific morphological optimization (adaptation) between two generations (1980 and 1995) of male elite water polo players.
METHODS: The survey included a total of 160 elite male water polo players, all members of the top clubs in Croatia. The 1980's generation consisted of 95 players (71.9% of target population) aged between 18 and 32 years, and the 1995's generation included 65 players (50% of target population) aged between 19 and 29 years. Trained and qualified anthropometrists performed the measurements under standardized experimental conditions and in accordance with the procedures described by the International Biological Program. They measured 23 anthropometric variables reflecting basic human body characteristics described by skeletal bone lengths (total leg length, total arm length, hand length, foot length, and height), breadths (hand at proximal phalanges, foot in metatarsal area, biacromial, biiliocristal, biepycondylar femur, biepycondyar humerus, and radio-ulnar wrist breadth), girths (chest, arm, forearm, thigh, and calf girth), skinfold thickness as a measure of subcutaneous adiposity (triceps, subscapular, axillary, calf, and abdominal skinfold thickness), and mass. Additionally, estimates of body mass index (BMI), body density, and percentage of body fat were calculated from the primary measures.
RESULTS: Comparison between anthropometric measures of the two generations of water polo players revealed a positive trend in body skeletal measures and negative trend in body adiposity measures. Most noteworthy differences (d) were an increase in height (d=37.3 mm, p<or=0.001), decrease in estimated body fat (d=-1.65%, p<or=0.001) accompanied by higher body density (d=0.01, p<or=0.001), with no significant difference in body mass (d=-0.74 kg, p=0.518).
CONCLUSION: Anthropometric characteristics of elite water polo players have changed over the analyzed 15 years. Body shape changed in terms of greater height and more elongated limbs, with thinner waist and broader shoulders. Body mass remained unchanged. Muscle-to-fat mass ratio increased. The observed changes may be a consequence of population secular trend and sport morphological adaptation (optimization).

Effect of different training programs on the velocity of overarm throwing: a brief review
J Strength Cond Res. 2004 May;18(2):388-96
van den Tillaar R.
Section for Human Movement Science, Faculty of Social and Technology Management, Norwegian University of Science and Technology, Trondheim, Norway.

Throwing velocity in overarm throwing is of major importance in sports like baseball, team handball, javelin, and water polo. The purpose of this literature review was to give an overview of the effect of different training programs on the throwing velocity in overarm throwing, provide a theoretical framework that explains findings, and give some practical applications based on these findings. The training studies were divided into 4 categories: (a) specific resistance training with an overload of velocity, (b) specific resistance training with an overload of force, (c) specific resistance training with a combination of overload of force and velocity, and (d) general resistance training according to the overload of force. Each category is presented and discussed.

Penalty shot importance, success and game context in international water polo.
J Sci Med Sport. 2004 Jun;7(2):221-5.
Smith HK.
Department of Sport and Exercise Science, University of Auckland, New Zealand.