A comparison of kinanthropometric, physical and motor- and game-specific skills of talented and less talented 12-year old school netball players

Transcription

1 A comparison of kinanthropometric, physical and motor- and game-specific skills of talented and less talented 12-year old school netball players A Karstens MEd; Supervisor: EJ Spamer Faculty of Educational Sciences, North-West University, Potchefstroom Campus pokkk@puknet.puk.ac.za pokejs@puknet.puk.ac.za Introduction In the present-day sporting world there is a distinction between achievement sport, which is characterised by achievements attained by children at an early age, and participation in sport as exercised by commonality (St Aubin & Sidney, 1996:9). The identification of talent in children at an early age has become necessary in order to identify and develop talented children. The school, and more specifically the teacher, can play a significant role in the identification and development of the talented child. The identification of young talented athletes can be used as a means to guide talented participants to the kind of sport(s) where they have the best chance to achieve success and at the same time reveal weaknesses in the athlete's participation, which in turn can influence his/her chances to be successful in another kind of sport (Woodman, 1985). Yet a further advantage of the identification of talent in young participants is that they, at an early age, have access to specialised coaching as well as medical and sport-psychological services (Bloomfield et al., 1994:268). Effective methods of talent identification and talent development have been established in the last few years. Generally, the application of these methods is regarded as an important factor for young participants to achieve success in a specific kind of sport (Campbell, 1993:15). In South Africa the identification of talented young netball players is extremely limited. This kind of sport, which has many participants, can benefit from a scientific process of talent identification. The identification of talent at an early age, with the accompanying development of those identified as talented, may be one method which can enable South Africa to maintain and improve its competitive position in world netball and in future produce world-class players (De Goede & Du Plessis, 1999:1) It thus follows that netball, seen from a sports development and achievement point of view, will definitely benefit from the scientific process of talent identification. The research question that this study attempted to answer was which kinanthropometric, physical, motor, and game specific variables best discriminate between talented and less talented 12-year old school netball players. Method of research Respondents 41 twelve-year old netball players were used as respondents in this study. 20 represented the three top teams in the 1999 North West Province under 12 schools league. A further 21 girls who did not play netball were selected at random as a control group. The group was thus representative of successful 12-year old players at school level and 12-year old girls who do not play netball.

2 Test Battery Before a battery of tests for netball could be compiled, the requirements of the game of netball first had to be analysed in order to determine which factors play a role in achievement in netball. From a game analysis of netball, possible tests which can be used for talent identification were selected. (Karstens, 2002) These tests consisted of 12 physical and motor tests, 6 game-specific skills tests and 10 kinanthropometric variables. (Thomas & Nelson, 1998; Karstens, 2002) A more detailed description of the tests is subsequently given. Kinanthropometric tests The measurement protocol as suggested by the International Work Group on Kinanthropometric Analyses (IGWK) was used in this study. The following kinanthropometric measurements were used: body mass; body length; tricep and subscapular skinfolds; flexed upper arm, forearm and thigh circumferences; and humerus, femur and biachromical cross sections (De Ridder, 1993:106). Physical and Motor Tests The following physical and motor tests were carried out: hand-eye coordination (response time left and right); foot-eye coordination (response time left and right); balance; onelegged jump on consecutive spots; and 10m speed (Karstens, 2002); zig-zag runs for agility (AAHPER, 1966); vertical jump for explosive strength; (Thomas & Nelson, 1995); an adapted sit and reach test for hip suppleness; (Thomas & Nelson, 1995); shoulder suppleness (Thomas & Nelson, 1985); speed endurance (Hazeldine & McNab, 1991) and shoulder strength (Karstens, 2002). Game Specific Skills Tests New tests to measure the game specific components of youth netball players had to be devised. No standardised tests could be found in related literature. The tests were evaluated for dependability by making use of the retest method (Cohen, 1977). A correlation varying from 0.52 to 0.94 was found in the various tests. The tests included the following: a double-handed throw to an eye-level circle of netball size which had been mounted on a wall; a one-handed throw to an eye-level circle of netball size which had been mounted on a wall; dribbling and shooting at a goal with one hand (left and right); and catching and throwing a ball at a wall (Karstens, 2002). Processing of Statistics The B.M.D.P. ID-programme (Dixon, 1990) was used for the calculation of the descriptive statistics of the test battery. The arithmetical average ( ), standard deviation(s), maximum and minimum values were calculated for each of the variables and transformations. A level of ninety-five percent (95%) meaningfulness was accepted as a significant difference (p < 0.05) between the two groups.

3 Results and discussion Kinanthropometric tests On examining the descriptive statistics of the kinanthropometric variables (Table 1) few differences between the two groups are evident. Length is the only variable which distinguishes meaningfully between the talented and less talented groups (158.3 cm and cm, p = ). The talented group was heavier (50.2 kg to 46.6 kg, p = 0.217) than the less talented group. It is thus apparent that length plays an important role in the identification of talented players (Bale, 1986:18). With regard to the measurement of skinfolds, the talented group showed larger measurements in both measurements (triceps and sub-scapular) than the less talented group, which implies that the talented group had more sub-cutaneous fat than the less talented group. Jordaan (2001:39) maintains that there is a direct relationship between body mass and relocation speed and that the heavier as person is, the slower the relocation speed will be. The cross section measurements of the two groups showed that the talented group had, on average, a larger cross section for all the cross section measurements (femur, humerus and shoulder cross section) than the less talented group. It can be concluded that the talented group was more robust and muscled (Carter Heath, 1990). Circumference measurements revealed that the talented group had larger measurements than the less talented group. This implies that the talented group had thicker arms and legs. Thicker arms and legs, in this instance, do not imply that the talented group was more muscled than the less talented group because fat could also have been a factor. At this age it is very difficult to establish that children are talented or not talented according to kinanthropometric variables. The reason for this is that it is difficult to make accurate measurements of the body composition of children because of changes in water, minerals and protein components which take place during growth and maturation (Jordaan, 2001:43). In conclusion it may be argued that the talented and less talented group had much the same body composition, with the exception of height. Physical and motor abilities When the descriptive statistics of the two groups with regard to the 12 physical and motor abilities are analysed (Tabel 2) it is evident that the talented netball players did better in all the components than their less talented counterparts. In the speed endurance test the talented group showed a smaller (0=5.91%), but not a meaningful decrease than the less talented group (0=6.00%). This manifestation can be attributed to the nature of the activity at a specific age, when children are very active and their natural play and playing activities are stimulated by this component. The differences between the two groups were meaningful in six of the twelve variables, where the talented players were better than the less talented players, namely speed, zig-zag runs, shoulder strength, jumps, hand-eye coordination right, and foot-eye coordination, left. Abilities such as acceleration, nimbleness and speed are important attributes in netball. Faster and nimbler netball players will do better in netball than those who do not have these qualities because the talented player beats her opponent every time she receives the ball and thereby ensures that possession of the ball is retained. Hare (1997)

4 and Badenhorst (1998) found the same tendency in their research on rugby and soccer players respectively. The talented group (0=5.91 sec) also performed significantly better in the nimbleness test than the less talented group (0=6.28 sec., p=0.0406). This is an important indication that the talented netball player must be nimble to carry out fast and sideways movements as quickly as possible. Jordaan (200:148) recommends that it is meaningful to subject netball players to a development programme which exercises horizontal and vertical jumps and in this manner improve their explosive strength. The vertical jump values of the talented players tested significantly better than those of the less talented players (29.60 cm to cm, p=0.0015). Catching and throwing a netball are two primary skills in the game of netball and are regarded as the basis on which the game is founded (Ellis, 2001:45-75). It thus appears that the talented players have a better developed pectoral girdle and that this ensures that the passing and the catching of the ball are more accurate. This is substantiated by the fact that catch-throw meaningfully discriminates as a game-specific skill (p=0.0006). From the results for physical and motor abilities it is clear that the talented netball player is faster and more nimble than the less talented player. Furthermore, talented players have better explosive strength and their shoulder strength is well developed. Speed is an important component in the identification of talented players. Game Specific Skills When the descriptive statistics of the game specific skills are analysed (Table 3) it is evident that the talented players performed better in all six skills than the less talented players. The difference in two of the skills was meaningful, namely catch-throw and passing with one hand, right. In the game of netball it is important that a player must be able to accurately catch and throw and effectively shoot at goal (Crouch, 1992:14). The players must have good control over the ball and the ball must move over the court as quickly as possible; in other words, ball speed is essential (Ellis, 2001:74). The above-mentioned skills will keep the ball in play longer during a match and more goals will consequently be scored. In those skills where catching and passing determined good performance, the talented players performed meaningfully better than the less talented players. (Catchthrow and passing with one hand, right). It is apparent that the talented players especially performed meaningfully better in passing with the dominant hand than with the nondominant hand. The majority of the players in the group were right handed. In passing for accuracy with the dominant hand the talented group achieved an average of 6.80, compared to the 5.33 of the less talented group. The talented group attained an average of 3.85 for passing with the non-dominant hand the less talented group's average was 2.18 (p=0.0624). In conclusion, it is evident from the above-mentioned results that the talented netball player possesses much better netball skills than the less talented. Conclusion The study on the 12-year old netball players showed that coaches can identify talented 12-year old netball players by means of kinanthropometric components, physical and

5 motor abilities and game-specific skill components. The differences with regard to the above-mentioned components are of such a nature that the identification of these variables can be successfully employed to classify 12-year old netball players as talented or less talented. However, a 12-year old child undergoes enormous growth and development and therefore it must be kept in mind that the prediction function will only have application value on 12-year old netball players. It is important that similar models be developed for younger and older netball players, for justice to be done with regard to the development of netball potential in young players. The results of this study showed that coaches can use the profiles (norms) of the talented 12-year old group as criteria to classify talent 12-year old netball players. Kinanthropometric, physical and motor and game-specific variables discriminate well between talented and less talented players. Further research should concentrate on similar variables, but for other age groups.

6 Table 1 Descriptive statistics and significant differences for talented and less talented 12-year-old netball players with reference to physical and motor abilities Talented (N = 20) Non-Talented (N = 21) Significant Variables x s Min Max x s Min Max p Running Speed (s) * Nimbleness (s) * Sit and Reach (cm) Shoulder Suppleness (cm) Shoulder Strength (cm) *.1539 Balance Jumps (s) Vertical Jump (cm) *.4403 Hand-eye Condition right (m.s) * Hand-eye Condition left (m.s) Foot-eye Condition right (m.s.) Foot-eye Condition left (m.s.) * Speed Endurance (%) p<0.05 (*significant differences) x = mean, s = standard deviation, min = minimum value, max = maximum value, t = t-value

7 TABLE 2: Descriptive statistics and significant differences for talented and less talented netball players with reference to kinanthropometric variables Talented (N = 20) Non-Talented (N = 21) Significant Variables x s Min Max x s Min Max p Body mass (kg) Body length (cm) * Skin Fold Triceps (mm) Sub-scapular Circumferences Flexed Upper Arm (cm) Forearm (cm) Upper leg (cm) Cross section measurements Humerus Femur (mm) Shoulder (cm) p<0.05 (*significant differences) x = mean, s = standard deviation, min = minimum value, max = maximum value, t = t-value

8 Table 3: Descriptive statistics and significant differences for talented and less talented 12-year-old netball players with references to game specific skills (N = 41) Talented (N = 20) Non-Talented (N = 21) Significant Variables x s Min Max x Min Max t p Double handed throw One Handed right * One Handed left Dribbling and shooting right Dribbling and shooting left Catching and throwing * p<0.05 (*significant differences) x = mean, s = standard deviation, min = minimum value, max = maximum value, t = t-value References AMERICAN ALLIANCE FOR HEALTH, PHYSICAL EDUCATION AND RECREATION (AAHPER) AAHPER skills test manual for football. Washington, DC: AAHPER. BADENHORST, E 'n Keuringsmodel vir talentidentifisering by 16-jarige sokkerspelers. Potchefstroom : PU vir CHO. (Verhandeling M.Sc.) BALE, P The relationship of somatotype and body composition to strength in a group of men and women sport students. In: Day, JAP (ed. Perspectives in kinanthropometry. Proceedings of the 1984 Olympic Scientific Congress held in Champaign, Illinois. Champaign pp. BARHAM, P. & Maylor, C Reading a game: observation and analysis in team play in netball. Wendover : Network Coaching International Publishers. BLOOMFIELD, J, ACKLAND, TR & ELLIOT, BC Applied anatomy and biomechanics in sport. Melbourne : Blackwell Scientific. CAMPBELL, S Talent identification and development. In: Whittall, R (ed. Pathways to excellence. Annual Conference of the British Institute of Sport Coaches held at East Midlands Airport in the Hilton National Hotel on 4-6 December Leeds. pp CARTER, JEL & HEATH, BH Somatotyping : development and applications. Cambridge University Press. COHEN, J 1977) Statistical Power Analysis for the Behavioural Sciences. Revised edition. Orlando: Academic Press. CROUCH, H Netball Coaching. London : A & C Black Publishers. DE GOEDE, M & DU PLESSIS, M Netbalafrigters : Handleiding gevorderde kursus. Potchefstroom : Herald drukkers. DE RIDDER, JH 'n Morfologiese profiel van junior en senior Cravenweek rugbyspelers. Potchefstroom : PU vir CHO (Proefskrif PhD). DIXON, WJ BMDP statistical software. Barkeley, Calif. : University of California Press. ELLIS, L Playing the game. Sidney : Harper Collings Publishers. HARE, E Die identifisering van rugbytalent by seuns in die senior sekondêre skoolfase. Potchefstroom : PU vir CHO. (Verhandeling M-Ed.) HAZELDINE, R & MCNAB, T Fit for Rugby. London : Kingswood.

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