The purpose of the current study was to examine the relationship

Transcription

1 Sport Science Review, vol. Sport XXIV, Science No. Review, 1-2, April vol. XXIV, 2015 no. 1-2, 2015, DOI: /ssr The Relationship of Kicking Ball Velocity with Anthropometric and Physiological Factors in Soccer Evangelos BEKRIS 1 Aristotelis GIOLDASIS 1 Vasilis BEKRIS 2 Ioannis GISSIS 3 Stergios KOMSIS 3 Ioannis MITROUSIS 1 The purpose of the current study was to examine the relationship of kicking ball velocity with anthropometric and physiological parameters in soccer. Specifically, the researchers examined how the anthropometric variables such as body weight, body fat, body mass index, and body height, as well as the physiological variables such as running speed, lower body explosive strength, lower limb endurance, balance, and agility are related to ball velocity. Fifty eight U-12 male soccer players, sixty one U-14, forty three U-16, and thirty five adult male soccer players participated in this study. The results showed that ball velocity is related to both anthropometric and physiological factors differently according to the age of the players. It was also confirmed that ball velocity is an indicator of playing level. The key finding from this research was that ball velocity is related to the explosive strength parameters. Thus this relationship is an indicator that coaches and trainers have to take into account so as maximize the kicking potential of their players. Keywords: soccer, velocity, coaching, anthropometric factors, physiological factors, explosive strength 1 Department of Physical Education and Sport Science, National and Kapodistrian University of Athens, Greece 2 Department of Business Administration, University of Piraeus, Greece 3 Department of Physical Education and Sports Science, Aristotle University of Thessaloniki, Greece ISSN: (print) /(online) National Institute for Sport Research Bucharest, Romania 71

2 Kicking Ball Velocity and Anthropometric/Physiological Factors in Soccer 72 Introduction Team performance in soccer is the outcome of interactions among physiological, social, tactical, technical and psychological factors (Bangsbo, 1994; Little & Williams, 2006) as well as chronological age, maturity status and playing experience (Malina et al., 2005; Rosch et al., 2000; Vänttinen, Blomqvist, & Häkkinen, 2010). Specifically, in a soccer game, players have to perform several technical and tactical tasks. Technical skills which determine players individual ability are classified as on-the-ball-performance actions. Ball control, long and short passes, dribbles, crosses, tackles, headers, shots, corners, free-kicks and throw-ins are considered as the basic technical skills (Huijgen 2013; Rampinini, Impellizzeri, Castagna, Coutts, & Wisloff, 2007; Taylor, Mellalieu, James, & Shearer, 2008). On target shooting is a high-value skill as it determines the final result of the soccer game. Success of soccer kick depends on several factors including the distance (short or long shots), the type of kick used (internal or external foot), the environment (air resistance), and the technique of the kick which is best described by biomechanical analysis (Kellis & Katis, 2007). The best biomechanical indicators of kicking success are the ball velocity and contact surface with the ball (Isokawa & Lees, 1988; Kellis, Katis, & Gissis, 2004), the kicking type and accuracy (Kermond & Konz, 1978; Nunome, Asai, Ikegami, & Sakurai, 2002; Wang & Griffin, 1997), as well as the optimum energy transfer between the kicking segments (Plagenhoef & Curtis, 1971). Recently studies on kicking ability have mainly used electromyography (EMG) method (Bollens, De Proft, & Clarys, 1987; De Proft, Clarys, Bollens, Cabri, & Dufour, 1988; Dorge, Bull-Andersen, Sorensen, Simonsen, Aagaard, Dyhre Poulsen, & Klausen, 1999; Kellis et al., 2004; McCrudden & Reilly, 1993; McDonald, 2002; Orchard, Walt, McIntosh, & Garlick, 2002; Kellis & Katis 2007). Although it is undeniable that players kicking ability affects the game result, it is the ball velocity that is executed which is of the highest importance as it determines the outcome. Previous research has shown that the combination of muscle and motion-dependent moments configures kicking ability (Kellis & Katis, 2007). Several muscles activation such as vastus medialis, vastus lateralis, and iliopsoas, configure muscle moments, as well as muscle activity stabilize the involved joints and segments so as to achieve a well-coordinated movement. Furthermore, the higher the speed of foot before the contact with the ball because of muscle coordination the better the ball velocity is. However, an aspect that affects the ball velocity of the kicks is the accuracy of the shoot. Past research revealed that the higher power of the kicks the less accuracy is. Thus the combination of ball velocity and kicking accuracy determine the kicking effectiveness. In addition, successful teams perform higher number and percentage of shoot on target (Bekris, Gioldasis, Gissis, Komsis, & Alipasali,

3 Sport Science Review, vol. XXIV, No. 1-2, April ; Castellano, Casamichana, & Lago, 2012). That finding indicates that the improvement of soccer instep kicks effectiveness is a very important target of training sessions (Weineck, 1997). The main question of the current study was how does kicking ability evolve in several developmental ages, and which performance and anthropometric factors affect it? Therefore the aim of the study was to examine the physiological parameters that affect the ball velocity of succeed kicks (on target shoots) of a non-moving ball. Furthermore the researchers looked out the anthropometric characteristics that affect ball velocity during the developmental as well as the adult age stages. Finally, they examined which indicators greater predict the ability of achieving high ball velocity during kicking. Participants Methods One hundred ninety seven male soccer players from Greek amateur teams took part in the current study, and performed all the tests described below. The researchers divided players according to their age in the following age groups: Under-12 years old, Under-14, Under-16 years old and adult players. The players studied trained at least 3 times per week apart from the weekly league games. Consent forms approved by the university Research Ethics Committee were completed for each participant by a parent or guardian because some of the players were under the legal age of consent. Measurements Anthropometrical parameters. All the anthropometric measurements were obtained using standardized laboratory procedures. A calibrated precision weighing scale (BC1000, Tanita) was used to obtain body weight (in kilograms), body fat (%) and body mass index (in kilograms), as well as a cursor was placed on each participant s head to measure height (in centimeters). Physiological parameters. The running speed of players was evaluated on a synthetic field from a standing start over distances of 10 and 30m, respectively, using two pairs of photocells (Microgate, RACETIME 2), placed on the beginning and in the end of the distance. Two trials for each distance, separated by a five minute rest interval, were undertaken with data from the fastest trial being recorded. Soccer research (Katis & Kellis, 2009; Mirkov, Nedeljkovic, Kukolj, Ugarkovic, & Jaric, 2008; Scott & Docherty, 2004; Wong, Chamari, 73

4 Kicking Ball Velocity and Anthropometric/Physiological Factors in Soccer Dellal, &Wisløff, 2009) has confirmed the reliability and validity of running speed tests in young players (ICC > 0.90). Lower body explosive strength was determined by a vertical jump on an optical device called OptoJump System (Microgate, Bolzano, Italy). OptoJump System is an optical measurement system consisting of two bars, the transmitter and the receiver. These bars contain photocells, in a distance of 2 mm from the ground which are constantly communicating. The device detects any interruptions in communication between the bars and calculates their duration. Thus it is possible to assess the vertical jump by recording the highest jump of three maximal voluntary repetitions. Based on Markovic and colleauges (2004) suggestions, who also confirmed the validity and the reliability of the test, the participants kept the hands on their hips throughout the tests while they were jumping from a semi-squatting position (Markovic, Dizdar, Jukic, & Cardinale, 2004). Lower limb endurance was also estimated by the specialized software of the Optojump System. Specifically, the mean height of 15 continuous jumps was used to estimate the lower limb endurance (Wong et al., 2009) with satisfactory reliability and validity rates for young soccer players (ICC= 0.96). The balance was assessed with the shark skill test (Gatz, 2009). A box that was consisted of 9 squares 30cm each of these was used. The participants had to stand on the center square on one foot, and hop inside each of the boxes in a row. Before each advancing they had to return to the center box. Participants practiced one time before the two trials for each foot. The researchers indicated the starting and finishing time. Furthermore, 0.10 seconds were added for every time the participants touching the lines of each box, not returning to the starting box and touching the ground with the non-hopping foot. Agility was assessed using the Illinois agility run (Hastad & Lacy, 1994; Svensson & Drust, 2005). The test started with a player standing with one foot in front of the other behind the starting line. Then the subjects sprinted 9m straight, and turned back to the starting line of the cones. Then they swerved in and out of four cones, completing two 9m sprints go and return. Finally to finish the test they had to run 9m go and return to the finishing line. Two trials, separated by a five minute rest interval, were undertaken with data from the best trial being recorded. Time was measured by gates using photocells (Microgate, RACETIME 2) positioned at the starting and the finishing line. Past literature (Katis &Kellis, 2009) also confirmed its reliability and validity for young soccer players (ICC= 0.94). 74

5 Sport Science Review, vol. XXIV, No. 1-2, April 2015 Technical parameters. The players performed long distance shoots (16.5 m) without a goalkeeper so as to examine the ball velocity of their kicking ability with a non-moving ball. They performed 4 kicks and the researchers recorded the best performance. Instructions as far as the movement toward the ball and the contact surface with the ball were given to the participants. The participants used their dominant foot to kick the ball. A limitation of the study was that only on target shoots were evaluated by the researchers. The used ball was size 4 and 5 according to the age of the kids with pressure (0.9 atmospheres). A radar speed gun (Speedster III Bushnell) with satisfactory reliability and validity index in athletes (ICC= 0.90) was used to examine the ball velocity (English & Howe, 2007). Procedure Researchers specialized in sport ergophysiology and sport psychology evaluated the characteristics of the players in the beginning of the preparation period. Specifically they measured the adults on August, before the first training session and the younger players on September. They informed both participants and their parents or guardians about the aims, the benefits, the risks and the ethics of the study before completing consent forms for each participant. Indoor (anthropometric, balance, vertical jump, lower limb endurance) and field tests (running speed, agility, kicking ball) were used. The breaks between the tests as well as the trials were around 5 minutes. The measurements were scheduled under similar conditions of time, light, temperature, motivation and a 20 minute standardized warm-up. Statistical analysis All the values of anthropometric, physiological and technical parameters are expressed as means and standard deviations. Principally, Kolmogorov-Smirnov and Levene s tests were used to examine the homogeneity and the normality in distribution of the variables. Analyses of variance (ANOVA) followed by post hoc comparisons (Tukey) were performed to find out the significant differences in selected parameters according to the kicking ability of the players. Results Data controls. The researchers examined differences in ball velocity of the players according to their anthropometric and physiological characteristics. The Kolmogorov-Smirnov statistical tests indicated normality in distribution for all the variables (p>.05). Similarly, Levene s test showed homogeneity as the variances of the variables were not significantly different (p>.05). 75

6 Kicking Ball Velocity and Anthropometric/Physiological Factors in Soccer Descriptive statistics. The following table shows the descriptive statistics for all the anthropometric and physiological characteristics according to the age of the players (Table 1). Table 1 Means and standard deviations of anthropometric and physiological characteristics Age group U-12 U-14 U-16 Adults ANOVA analyses. The following table shows descriptive statistics of the significant differences among U-12 players with different ball velocity regarding their anthropometric and physiological characteristics (Table 2). Table 2 Ball velocity differences according to U-12 players anthropometric and physiological characteristics Note: * p<.10; ** p<.05; *** p<.01; **** p<.001 M (SD) M (SD) M (SD) M (SD) Height (80.05) (8.02) (6.44) (6.98) Weight (9.29) (7.92) (9.14) (10.30) Body Fat (4.70) (3.12) (2.46) (4.39) BMI (2.33) (1.81) (1.59) (2.38) Left leg balance 8.37 (2.55) 7.17 (1.24) 5.92 (.83) 6.36 (1.71) Right leg balance 7.59 (1.56) 7.08 (1.22) 5.85 (.90) 6.19 (1.51) Lower limb endurance (3.21) (3.28) (2.91) (4.55) 10m running speed 2.14 (.15) 2.04 (.11) 1.94 (.09) 1.98 (.13) 30m running speed 3.77 (.23) 4.24 (.71) 4.58 (.15) 4.58 (.29) Lower body explosive strength (4.78) (4.16) (3.25) (4.81) Agility (.85) (.63) (.45) (1.10) Ball velocity (6.69) (7.11) (8.29) (8.98) N U-12 Height Weight Lower limb endurance 10m running speed 30m running speed Agility Ball velocity M (SD) M (SD) M (SD) M (SD) M (SD) M (SD) Very low (7.15) (7.85) (2.54) 2.20 (.16) 3.89 (.25) (.90) Low (8.47) (5.72) (2.21) 2.12 (.12) 3.75 (.22) (.42) High (5.13) (6.00) (3.98) 2.14 (.13) 3.71 (.23) (.75) Very high (8.86) (13.23) (3.31) 2.08 (.14) 3.69 (.20) (.88) F 3.885*** 3.490** 2.802** * 4.881*** Tukey 1<4; 2<4; 3<4 1<4; 2<4 1<4 1<4 1<4 1<4; 2<4; 3<4 76

7 Sport Science Review, vol. XXIV, No. 1-2, April 2015 Table 3 shows descriptive statistics of the significant differences among U-14 players with different ball velocity regarding their anthropometric and physiological characteristics. Table 3 Ball velocity differences according to U-14 players anthropometric and physiological characteristics U-14 Height Weight BMI Agility Ball velocity M (SD) M (SD) M (SD) M (SD) Very low (9.08) (6.31) (1.53) (.52) Low (6.75) (6.03) (1.40) (.72) High (6.47) (6.39) (2.44) (.51) Very high (6.52) (6.63) (1.30) (.45) F 7.203**** **** 6.068**** 4.222*** Tukey 1<3; 1<4; 2<4 1<3; 1<4; 2<4 1<4; 2<4 1<4 Note: * p<.10; ** p<.05; *** p<.01; **** p<.001 Table 4 shows descriptive statistics of the significant differences among U-16 players with different ball velocity regarding their anthropometric and physiological characteristics. Table 4 Ball velocity differences according to U-16 players anthropometric and physiological characteristics U-16 10m running speed 30m running speed Lower body explosive strength Ball velocity M (SD) M (SD) M (SD) Very low (.07) 4.64 (.10) (3.77) Low (.10) 4.66 (.17) (3.23) High (.09) 4.51 (.12) (2.06) Very high (.07) 4.50 (.14) (3.14) F 2.462* 4.023*** 2.150* Tukey 2<3 1<4; 2<3; 2<4 1<4 Note: * p<.10; ** p<.05; *** p<.01; **** p<

8 Kicking Ball Velocity and Anthropometric/Physiological Factors in Soccer Finally, the following tables show descriptive statistics of the significant differences among adult players with different ball velocity regarding their anthropometric (Table 5) and physiological (Table 6) characteristics. Table 5 Ball velocity differences according to adults anthropometric characteristics Adults Height Weight BMI Left leg balance Right leg balance Ball velocity M (SD) M (SD) M (SD) M (SD) M (SD) Very low (7.86) (9.15) (3.06) 8.32 (1.93) 7.72 (1.81) Low (7.55) (10.41) (2.17) 6.08 (1.19) 6.08 (1.32) High (4.83) (6.32) (1.51) 6.15 (1.57) 5.74 (1.29) Very high (5.29) (7.05) (1.51) 5.28 (.27) 5.38 (.53) F 2.221* 6.267*** 3.551** 7.352**** 4.848*** Tukey 1<2; 1<3; 1<4 1<4 1<2; 1<3; 1<4 1<2; 1<3; 1<4 Note: * p<.10; ** p<.05; *** p<.01; **** p<.001 Table 6 Ball velocity differences according to adults physiological characteristics Adults Lower limb endurance 10m running speed 30m running speed Lower body explosive strength Agility Ball velocity M (SD) M (SD) M (SD) M (SD) M (SD) Very low (3.36) 2.07 (.13) 4.83 (.27) (2.73) (1.04) Low (2.34) 1.98 (.12) 4.55 (.24) (3.09) (.84) High (3.85) 1.98 (.13) 4.60 (.32) (4.58) (1.22) Very high (4.56) 1.90 (.09) 4.37 (.17) (4.04) (.39) F 7.185**** 2.978** 4.577*** 6.830**** 6.219*** Tukey 1<4; 2<4; 3<4 1<4 1<4 1<4; 2<4; 3<4 1<2; 1<3; 1<4 Note: * p<.10; ** p<.05; *** p<.01; **** p<.001 Further ANOVA analyses showed that players kicking ability differed significantly regarding their age (F (3, 191) = , p=.000) and their competitive level (F (3, 191) = , p=.000). Specifically older players performed higher levels of kicking ability as well as players of higher league teams. Discussion Age differences. The present study concludes that age and ball velocity are moderately correlated. It has been already reported that age positively affects 78

9 Sport Science Review, vol. XXIV, No. 1-2, April 2015 ball velocity and knee angular velocity (Capranica, Cama, Fanton, Tessitore, & Figura,1992; Luhtanen, 1988; Narici, Sirtori, & Mognoni, 1988). In this context, past research investigating this relationship concluded that players muscle mass and kicking technique are improved as they become older (Poulmedis, Rondoyannis, Mitsou, & Tsarouchas, 1988; Rodano & Tavana, 1993; Taiana, Grehaigne, & Cometti,1993; Tol, Slim, van Soest, & van Dijk, 2002; Trolle, Aagaard, Simonsen, Bangsbo, & Klaysen, 1993). Furthermore, the development of neural coordination through training sessions focused on strength and technique training also improves the ball velocity (Manolopoulos, Papadopoulos, & Kellis, 2006; Manolopoulos, Katis, Manolopoulos, K., Kalapotharakos, & Kellis, 2013). Under-12. Apart from the biomechanical parameters which affect ball velocity, the results of the current study revealed that anthropometric and physiological characteristics are related to ball velocity. In U-12 players, ball velocity is affected by anthropometric characteristics such as height and weight. Players with higher rates of height and weight perform higher ball velocity. This finding is probably explained by the fact that body height involves longer lower body (legs) which positively affects the knee angular velocity. Similarly, a greater rate of weight which is probably connected with early maturation characteristics (Augste & Lames, 2011) improves the total strength as well as the ball velocity (Kellis & Katis, 2007). Thus it is clear that anthropometric factors affect the success of kicking through its velocity. Talent detection systems have to include measurements of kicking ability. Physiological characteristics are also related to ball velocity. Specifically, players with higher rate of ball velocity perform better in the following factors: running speed, agility, and lower limb endurance. Running speed and agility performance are very important indicators of successful kicking and ball velocity. Fast-twitch muscle fibers (running speed indicators) as well as the concentric and eccentric muscle strength (agility indicators) determine kicking performance. Literature review confirms this conclusion because it suggests that kicking force is an explosive strength parameter (Weineck 1997). Furthermore, performance in consecutive squat jumps which is related to lower limb endurance and balance determines the ball velocity of kicking ability. Under-14. Regarding U-14 players the study showed that the ones with higher rate of height, weight and BMI succeed significantly higher ball velocity. This finding confirms the suggestion that maturation is related to ball velocity. Moreover, it was found that agility is a significant moderator of ball velocity. Under-16. The present study revealed that in U-16 age, running speed and vertical jump performance tend to be related with ball velocity. It is suggested that high running speed and explosive strength performance might predict 79

10 Kicking Ball Velocity and Anthropometric/Physiological Factors in Soccer the ball velocity. The study confirms that muscle strength and power of the players are factors that affect the ball velocity of kicking even in developmental ages (Cabri, De Proft, Dufour, & Clarys, 1988; De Proft et al., 1988; Dutta & Subramanium, 2002; Manolopoulos et al., 2006; Trolle et al., 1993). Therefore improvement of anthropometric as well as physiological factors such as running speed and agility benefit the kicking ability even if the training is not focused on kicking skill. Adults. In adults it is obvious that anthropometric factors such as weight and BMI are related to ball velocity. Regarding balance ability, players with high rates of dynamic balance perform higher ball velocity. Balance clearly benefits players technical skills as most of them such as kicking include one-leg stance balance. Literature review in soccer indicates the importance of balance and proprioception training for the improvement of technical skills (Bekris et al., 2012). Moreover several studies have reported that strength training increases balance (Heitkamp, Horstmann, Mayer, Weller, & Dickhuth, 2001; Pintsaar, Brynhildsen, & Tropp, 1996) while other studies have shown that balance training improves strength (Heitkamp et al., 2001). Consequently this relationship probably moderates kicking ability of the players. Therefore improvement of balance leads to higher ball velocity. Finally, the study concludes that greater rates of running speed, agility, vertical jump, and lower limb endurance are positively related with ball velocity. Skill level. Regarding the ball velocity and playing level relationship the results of the study revealed its significance. Specifically it was found that higher level players performed greater rate of ball velocity than lower level players. Thus ball velocity of kicking ability is considered as a significant predictor of performance. Several studies reported differences between amateur and professional players (Asami & Nolte, 1983), whereas others concluded the opposite (Commetti, Maffiuletti, Pousson, Chatard, & Maffulli, 2001). Conclusions Based on the results in this study, ball velocity of on-target shoot is related to anthropometric factors such as weight, height, and BMI. The data also suggest that players age differentiate their kicking ability. Therefore, talent detection experts have to take into account the role of anthropometric factors as well as early maturation characteristics on the evaluation of youngsters. Ball velocity is also related to physiological factors such as running speed, vertical jump, agility and lower limb endurance. It thus seems to be fairly clear that training sessions focused on these physiological factors also improve the kicking ability. A factor that we have to highlight is the significance of balance on kicking ability 80

11 Sport Science Review, vol. XXIV, No. 1-2, April 2015 and specifically on ball velocity. Soccer trainers and coaches have to focus on balance training in order to improve technical skills of the players. Regardless of past research findings concerning kicking ability biomechanics, the current study indicates the physiological factors that affect this technical skill. Finally the study confirms the positive relationship between playing level and ball velocity. Soccer coaches have to develop training programs that include improvements in ball velocity and kicking accuracy ability. To conclude the study shows that the development of a better physiological profile improves also players kicking ability. Further research is needed to determine specific training programs that improve kicking ability of the players. Finally, the key finding from this research is that ball velocity is related to the explosive strength parameters (vertical jump, running speed). When players perform high explosive strength but low ball velocity they probably have to improve their shooting technique (i.e. biomechanics). Thus ball velocity and explosive strength relationship is an indicator that coaches and trainers are able to use so as to maximize the kicking potential of their players. References Augste, C., & Lames, M. (2011). The relative age effect and success in German elite U-17 soccer teams. Journal of Sports Sciences, 29(9), Asami, T., & Nolte, V. (1983). Analysis of powerful ball kicking. Biomechanics VIII-B, 4, Bangsbo, J. (1993). The physiology of soccer--with special reference to intense intermittent exercise. Acta Physiologica Scandinavica. Supplementum, 619, Bekris E., Gioldasis, A., Gissis, I., Komsis, S., & Alipasali, F. (2014). Winners and losers in top level soccer. How do they differ? Journal of Physical Education and Sport, 14(3), Bekris E., Kahrimanis, G., Anagnostakos, K., Gissis, I., Papadopoulos, C., & Sotiropoulos, A. (2012). Proprioception and balance training can improve amateur soccer players technical skills. Journal of Physical Education and Sport, 12(1), Bollens, E. C., De Proft, E., & Clarys, J. P. (1987). The accuracy and muscle monitoring in soccer kicking. Biomechanics XA, Cabri, J., De Proft, E., Dufour, W., & Clarys, J. P. (1988). The relation between muscular strength and kick performance. Science and football, 1,

12 Kicking Ball Velocity and Anthropometric/Physiological Factors in Soccer Capranica L., Cama G., Fanton F., Tessitore A., & Figura F. (1992). Force and power of preferred and non-preferred leg in young soccer players. Journal of Sports Medicine and Physical Fitness, 32(4), Castellano, J., Casamichana, D., & Lago, C. (2012). The use of match statistics that discriminate between successful and unsuccessful soccer teams. Journal of Human Kinetics, 31(1), Commetti G., Maffiuletti N. A., Pousson M., Chatard J. C., & Maffulli N. (2001). Isokinetic strength and anaerobic power of elite, subelite and amateur French soccer players. International Journal of Sports Medicine, 22, De Proft E., Clarys J., Bollens E., Cabri J., & Dufour W. (1988). Muscle activity in the soccer kick. In: Science and Football. Eds: Reilly T., Lees A., Davids K., Murphy, W. J., editors. London: E & FN Spon; Dørge, H. C., Andersen, T., Sørensen, H., Simonsen, E. B., Aagaard, H., Dyhre- Poulsen, P., & Klausen, K. (1999). EMG activity of the iliopsoas muscle and leg kinetics during the soccer place kick. Scandinavian Journal of Medicine & Science in Sports, 9(4), Dutta, P., & Subramanium, S. (2002). Effect of six weeks of isokinetic strength training combined with skill training on soccer kicking performance. Science and soccer IV, English, T., & Howe, K. (2007). The effect of pilates exercise on trunk and postural stability and throwing velocity in college baseball pitchers: single subject design. North American Journal of Sports Physical Therapy, 2(1), 8. Gatz, G. (2009). Complete Conditioning for Soccer. Leeds: Human Kinetics. Hastad, D. N., & Lacy, A. C. (1994). Measurement and evaluation in physical education and exercise science (2nd ed.). Scottsdale, AZ: Gorsuch Scarisbrick, Publishers. Heitkamp, H. C., Horstmann, T., Mayer, F., Weller, J., & Dickhuth, H. H. (2001). Gain in strength and muscular balance after balance training. International Journal of Sports Medicine, 22(4), Huijgen, B. C. (2013). Technical skills the key to success?

13 Sport Science Review, vol. XXIV, No. 1-2, April 2015 Isokawa, M., & Lees, A. (1988). A biomechanical analysis of the instep kick motion in soccer. Science and football, 1, Kellis, E., & Katis, A. (2007). Biomechanical characteristics and determinants of instep soccer kick. Journal of Sports Science & Medicine, 6(2), 154. Katis, A., & Kellis, E. (2009).Effects of small-sided games on physical conditioning and performance in young soccer players. Journal of Sports Science & Medicine, 8(3), 374. Kellis E., Katis A., & Gissis I. (2004). Knee biomechanics of the support leg in soccer kicks from three angles of approach. Medicine and Science in Sports & Exercise, 36(6), Kermond, J., & Konz, S. (1978). Support leg loading in punt kicking. Research Quarterly. American Alliance for Health, Physical Education and Recreation, 49(1), Little, T. & Williams, A. G. (2006). Suitability of soccer training drills for endurance training. The Journal of Strength & Conditioning Research, 20(2), Luhtanen, P. (1988). Kinematics and kinetics of maximal instep kicking in junior soccer players. Science and football, 1, Malina, R. M., Cumming, S. P., Kontos, A. P., Eisenmann, J. C., Ribeiro, B., & Aroso, J. (2005). Maturity-associated variation in sport-specific skills of youth soccer players aged years. Journal of Sports Sciences, 23(5), Manolopoulos, E., Katis, A., Manolopoulos, K., Kalapotharakos, V., & Kellis, E. (2013). Effects of a 10-week resistance exercise program on soccer kick biomechanics and muscle strength. The Journal of Strength & Conditioning Research, 27(12), Manolopoulos, E., Papadopoulos, C., & Kellis, E. (2006). Effects of combined strength and kick coordination training on soccer kick biomechanics in amateur players. Scandinavian Journal of Medicine & Science in Sports, 16(2), Markovic, G., Dizdar, D., Jukic, I., & Cardinale, M. (2004). Reliability and factorial validity of squat and countermovement jump tests. The Journal of Strength & Conditioning Research, 18(3),

14 Kicking Ball Velocity and Anthropometric/Physiological Factors in Soccer McCrudden, M., & Reilly, T. (1993). A comparison of the punt and the drop-kick. Science and football II, McDonald, M. (2002). Relative timing of EMG profiles for novice and elite soccer players. Science and football IV, Mirkov, D., Nedeljkovic, A., Kukolj, M., Ugarkovic, D., & Jaric, S. (2008). Evaluation of the reliability of soccer-specific field tests. The Journal of Strength & Conditioning Research, 22(4), Narici, M. V., Sirtori, M. D., & Mognoni, P. (1988). Maximal ball velocity and peak torques of hip flexor and knee extensor muscles. Science and football, 1, Nunome H., Asai T., Ikegami Y., & Sakurai S. (2002). Three-dimensional kinetic analysis of side-foot and instep soccer kicks. Medicine and Science in Sports & Exercise, 34(12), Orchard, J., Walt, S., McIntosh, A., & Garlick, D. (2002). Muscle activity during the drop punt kick. Science and football IV, Pintsaar, A., Brynhildsen, J., & Tropp, H. (1996). Postural corrections after standardised perturbations of single limb stance: Effect of training and orthotic devices in patients with ankle instability. British Journal of Sports Medicine, 30(2), Plagenhoef, S., & Curtis, D. (1971). Patterns of human motion: A cinematographic analysis (pp ). Englewood Cliffs, NJ: Prentice-Hall. Poulmedis, P., Rondoyannis, G., Mitsou, A., & Tsarouchas, E. (1988). The influence of isokinetic muscle torque exerted in various speeds on soccer ball velocity. Journal of Orthopaedic & Sports Physical Therapy, 10(3), Rampinini, E., Impellizzeri, F. M., Castagna, C., Coutts, A. J., & Wisloff, U. (2009). Technical performance during soccer matches of the Italian Serie A league: Effect of fatigue and competitive level. Journal of Science and Medicine in Sport, 12, Rodano, R., & Tavana, R. (1993). Three dimensional analysis of the instep kick in professional soccer players. Science and football II,

15 Sport Science Review, vol. XXIV, No. 1-2, April 2015 Rösch, D., Hodgson, R., Peterson, L., Graf-Baumann, T., Junge, A., Chomiak, J., & Dvorak, J. (2000). Assessment and evaluation of football performance. The American Journal of Sports Medicine, 28(suppl 5), S-29. Scott, S. L., & Docherty, D. (2004). Acute effects of heavy preloading on vertical and horizontal jump performance. The Journal of Strength & Conditioning Research, 18(2), Svensson, M., & Drust, B. (2005). Testing soccer players. Journal of Sports Sciences, 23(6), Taiana, F., Grehaigne, J. F., & Cometti, G. (1993). The influence of maximal strength training of lower limbs of soccer players on their physical and kick performances. Science and soccer II, Taylor, J. B., Mellalieu, S. D., James, N., & Shearer, D. A. (2008). The influence of match location, quality of opposition, and match status on technical performance in professional association football. Journal of Sports Sciences, 26(9), Tol, J. L., Slim, E., van Soest, A. J., & van Dijk, C. N. (2002). The relationship of the kicking action in soccer and anterior ankle impingement syndrome a biomechanical analysis. The American Journal of Sports Medicine, 30(1), Trolle, M., Aagaard, P., Simonsen, E. B., Bangsbo, J., & Klausen, K. (1993). Effects of strength training on kicking performance in soccer. Science and football II, Vänttinen, T., Blomqvist, M., & Häkkinen, K. (2010). Development of body composition, hormone profile, physical fitness, general perceptual motor skills, soccer skills and on-the-ball performance in soccer-specific laboratory test among adolescent soccer players. Journal of Sports Science & Medicine, 9(4), 547. Wang, J., & Griffin, M. (1997). Kinematic analysis of the soccer curve ball shot. Strength & Conditioning Journal, 19(1), Weineck, J. (1997). Fußballtraining. Teil 1: Konditionstraining des Fussballspielers. Perimed. Wong, P. L., Chamari, K., Dellal, A., & Wisløff, U. (2009). Relationship between anthropometric and physiological characteristics in youth soccer players. The Journal of Strength & Conditioning Research, 23(4),

16 Kicking Ball Velocity and Anthropometric/Physiological Factors in Soccer Evangelos BEKRIS, Dr., Msc. is currently an associate professor of soccer coaching at the Kapodistrian University of Athens. He earned his PhD in Biochemistry at the Kapodistrian University of Athens. He began his research career examining the effect of exercise on health of youth. His research interests include soccer coaching, match analysis, biomechanics, fatigue and talent identification. He publishes regularly books and papers about soccer and medical issues. He can be contacted: Aristotelis GIOLDASIS is currently a PhD student at the Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese in Sparta. He earned his Master of Science degree in Sport Psychology at the Kapodistrian University of Athens. He began his research career examining psychological factors that influence soccer performance. His current research interests include physiological, biochemical and psychological effects on performance. He publishes regularly in international sport sciences journals. Vasilis E BEKRIS is currently a student at University of Piraeus. There, he is at the Department of Business Administration since October of He is also a member of a research team as he takes part in some ergometric measurements of young athletes as a user of the measurement devices. He also concerns himself with football matches statistics mostly because he elaborates them when taking part in a research on football. He can be contacted at: vasilisbekris1996@yahoo.gr Ioannis GISSIS, PhD is currently an assistant professor in soccer coaching/training at Aristotle University of Thessaloniki, Greece. He earned his PhD in Social Sciences (Sports Science) at Eberhard Karls University Tuebingen, Germany. His research interests include analysis and training of soccer technique, evaluation and training of soccer physical fitness, evaluation and training of soccer physical fitness in childhood and adolescence, evaluation and training of physical fitness. He can be contacted at: igkisis@phed-sr.auth.gr Stergios KOMSIS is a Ph.D candidate of Kinesiology (Human Kinetics) at the Department of Physical Education and Sport Sciences of Aristotle University of Thessaloniki, Serres. He earned his Master degree M.Sc. in Kinesiology / Sports Biomechanics at the Department of Physical Education and Sport Sciences of Aristotle University of Thessaloniki, Serres. He began his research career examining the effects of various training programs especially using eccentric isokinetic loads in amateur and professional soccer players. His current research include training programs in different training seasons for soccer players, and specifically the transition period in soccer. He publishes regularly in training and sports journals. 86

17 Sport Science Review, vol. XXIV, No. 1-2, April 2015 Corresponding address: Stergios Komsis Aigaiou Street 08 Evosmos Thessaloniki Greece snkomsis@phed-sr.auth.gr; skomsis@hotmail.com Phone: Mobile: Ioannis MITROUSIS has earned his degree Department of Physical Education and Sport Science in National and Kapodistrian University of Athens.He began his research career by examining the effects of far infrared clothes on dynamic balance and agility. Now he is a teacher of physical education and he works as a fitness coach in soccer teams. He is also responsible for the development of physical condition in soccer academies. 87