european college of sport science

Saturday, June 27th, 2009
between visual acuity and game performance in water polo is undocumented. Thus the present study focuses on the effect of corrected
visual acuity in game performance during water polo play.
Methods: Five male water polo players (age: 18.0±3.4 yrs) participated in the study. The participants played games in two conditions; in
the first game the players were using contact lenses and in the second game they were not. Their corrected visual acuity with contact
lenses was between 0.8 and 1.0. The uncorrected visual acuity of players was 0.01 and 0.1. The indicators of game performance were (1)
the rate of errors; (2) the rate of contributed play; and (3) the rate of ball contacts. The indicators of errors and contributed plays followed
the results reported by Enomoto et al. (2001). The participants completed self-evaluations regarding their play.
Results: The results showed the significant difference in the rate of errors committed by players with corrected visual acuity using contact
lenses and those with uncorrected visual acuity. According to their responses of questionnaire, there was a significant difference in
aspects of the game related to vision between players with corrected visual acuity and those with uncorrected visual acuity. For example,
players felt that they could more clearly see their opponents, the goal, and the ball movements in corrected visual acuity conditions as
compared with those playing in uncorrected visual acuity condition.
Conclusion: These findings showed that corrected visual acuity using contact lenses led to a decrease in errors committed; clear vision
during games led to significant improvements in game performance. In conclusion, the study suggested the corrected visual acuity is an
important factor in scoring and winning.
References
Komori Y., Kono I., Tsukuda F., Saito M., Sakata I., and Kono K. (1998) Wearing contact lens might prevent corneal damages and keep
visual functions during water polo play. Med Sci sports exerc, 30, s157.
Enomoto I., Minami T., Takahashi M., Takahashi J., Suga M., and Komori Y. (2001) Game analysis of team contribution for water polo
player. Jpn J Sport Method, 14, 23-30.
DEVELOPMENT OF BIA EQUATIONS FOR ESTIMATING BODY COMPOSITION OF ELITE MALE WRESTLERS
KARLI, U., ACIKADA, C., ALPAR, R., HAZIR, T., DOGU, G.
1. ABANT IZZET BAYSAL UNIVERSITY, SCHOOL OF PHYSICAL EDUCATION AND SPORT, BOLU, TURKEY, 2. HACETTEPE UNIVERSITY, SCHOOL OF
SPORT SCIENCES AND TECHNOLOGY, AND FACULTY OF MEDICINE, ANKARA, TURKEY.
Introduction: Body composition is associated with successful participating in elite wrestling. Although, BIA is relatively simple, quick,
portable and noninvasive method for estimating body composition (Wagner and Heyward, 1999), use of inappropriate equations in BIA
measurements can lead systematic prediction errors (Heyward and Stolarczyk, 1996). Therefore, the purpose of this study was to develop
bioelectrical impedance equations for estimating body composition (fat free mass) of elite male wrestlers.
Methods: Hundred and eleven highly active elite male senior wrestlers (mean ± SD, age: 21.054±2.993yr, height (H): 171.852±7.518cm,
body weight (BW): 78.362±15.931kg) were participated in this study as volunteers. H, BW, bioelectrical impedance analysis (BIA) and
hydrostatic weighing (HW) measurements with residual volume were performed at least four hours after breakfast between 11:00 and
13:00 o’clock. Each subjects resistance (R), reactance (Xc) and impedance (Z) values were recorded by BIA and fat free mass (FFM) was
calculated by using the hydrostatic weighing (HW) measurements as the reference variable. Pearson Correlation Coefficient was used to
measure the interrelationship between reference variable (FFM) and independent variables. Then, Multiple Linear Regression Analysis
was performed using the FFM as the reference variable and other measured items as the explanatory variables in order to form prediction
regression equations (EQ) for BIA. Finally, validity of the equations was examined with Cross Validation Method.
Results: Five equations were derived for FFM to use in BIA measurements. The explanatory variables of the equations were BW, R, height
squared (Hsqr), Xc, Z, resistance index (Hsqr/R) and impedance index (Hsqr/Z). The multiple coefficient of determination (R square= Rsqr)
and standard error of estimate (SEE) of the equations are given as followed: Rsqr =0.98384, SEE =1.45821kg (EQ1); Rsqr =0.98375, SEE
=1.46214kg (EQ2); Rsqr =0.98543, SEE =1.37370kg (EQ3); Rsqr =0.98533, SEE =1.37825kg (EQ4) and Rsqr =0.98613, SEE =1.36336kg (EQ5).
By the use of Stepwise Linear Regression Analysis, the results of this study indicated that BW, R, Hsqr, and Xc as ideal explanatory variables
to estimate FFM of elite male wrestlers in BIA measurements. Final prediction equation and its Rsqr and SEE are given as followed:
FFM= 19.69292 + 0.5233 (BW) – 0.05256(R) + 0.00085(Hsqr) + 0.11211(Xc); Rsqr = 0.98613, SEE= 1.36336.
Conclusion: Finally, cross validated prediction equations with high Rsqr and low SEE were derived for FFM of elite male wrestlers to use in
BIA measurements. Population specific equations should be developed for accurate estimation of body composition in specific homogeneous
groups.
References
Heyward VH, Stolarczyk LM (1996). Applied Body Composition Assessment, 54. Champaign, IL; Human Kinetics, USA
Wagner DR, Heyward VH (1999). Res Q Exerc Sport, 70, 135-49.
GAME PERFORMANCE AND ACTIVITY PROFILE OF WHEELCHAIR BASKETBALL PLAYERS
YODA, T., YASUMATSU, M., KAWANISHI, M., ISHIWATA, T., TANAKA, H.
1. DOKKYO UNIVERSITY (JAPAN), 2. RIKKYO UNIVERSITY (JAPAN), 3. YOKOHAMA NATIONAL UNIVERSITY (JAPAN)
Introduction: The specific rule in wheelchair basketball is the Player Classification System in which players are classified into classes (Class
I, II, III, and IV) based upon the players’ functional capacity to play (Class I is the most disabled). The players are required to have good
skills for controlling wheelchair as well as for playing basketball. However, there is little study that analyzed both game performances
and activities. The aim of this study was to compare these two abilities between a Japanese top team and a team in the medium level.
Methods: We recorded video images of players of the team C (the men’s top team in Japan) and the team K (medium level) in the preliminary
game of the Japan wheelchair basketball championship in 2007. From the video images we measured the wheelchair basketball
performances and compared each data of team C and team K. The wheelchair basketball performances were classified the game
performance and the activity profile which was divided into high, middle, low intensities of pushing the wheel (high being fast rotation of
the wheel and low being slow rotation).
Results: The number of screen plays per one offence period was also higher in the team C than in the team K. In the team C, field players
almost equally played for passing, dribbling and screening, however the number of attempted shots and rebounds were higher in Class
III and IV players. In the team K, players of Class III and IV held possession for the majority of the offence. As for the control of wheelchair,
the rate of high intensity in total playing time was higher in the team C than in the team K. The average time of high intensity in team C
was longer than in team K.
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