The aim of this study was to provide a complete profile of elite young soccer players. Fifty-five players of the Under-14 category of Athletic Club Bilbao participated in this study. Players were classified into 4 playing positions: forwards (n=30), midfielders (n=15), defenders (n=37) and goalkeepers (n=15). Complete anthropometry, chronological age (CA), age at peak height velocity, 15-m sprint test, agility test, Yo-Yo IT level 1 (Yo-Yo IR1), counter-movement jump and hand dynamometry were measured. Results were transformed into z-scores and summed up to make two performance composites (SCORE and SCORE^HG). One-way analysis of variance and a Bonferroni post-hoc test were used to examine the differences between playing positions. Multiple linear regression analysis was performed to estimate the contribution of independent variables to performance indicators. The level of significance was set at P<0.05. Significant differences were observed between playing positions in body mass and height (P<0.05); CA, maturity offset and muscle % (P<0.01); sum of skinfolds, fat %, endomorphy, sprint and agility tests (P<0.001). Stepwise regression analysis revealed that CA and sum of skinfolds were the most important predictors of performance. Collectively, playing positions were characterised by specific anthropometrical characteristics whereas no significant positional differences were observed in performance. This study provides further insight concerning coaches’ practice of selecting young soccer players because of anthropometrical characteristics rather than for performance advantages.

Resumen

El objetivo de este estudio fue analizar el perfil antropométrico y fisiológico de los futbolistas jóvenes del Athletic Club Bilbao. Cincuenta y cinco jugadores de la categoría Sub-14 participaron en el estudio. Los jugadores se clasificaron en 4 posiciones de juego: delanteros (n=30), centrocampistas (n=15), defensas (n=37) y porteros (n=15). Se realizaron las siguientes mediciones: antropometría completa, edad cronológica (EC), pico de velocidad de crecimiento, sprint de 15-m, agilidad, Yo-Yo IT nivel 1 (Yo-Yo IR1), salto y dinamometría manual. Los resultados se transformaron en puntuaciones z y se sumaron para hacer dos compuestos de desempeño (SCORE y SCORE^HG). Se realizaron un análisis de varianza y una prueba post-hoc de Bonferroni para examinar las diferencias entre posiciones. Se realizó un análisis de regresión lineal múltiple para estimar la contribución de las variables independientes a los indicadores de rendimiento. El nivel de significación se fijó en P<0.05. Se observaron diferencias significativas entre las posiciones de juego en la masa corporal y la altura (P<0.05); EC, maduración y % muscular (P<0.01); suma de pliegues cutáneos, % de grasa, endomorfismo, sprint y agilidad (P<0.001). El análisis de regresión reveló que la EC y la suma de pliegues cutáneos fueron los predictores más importantes. Se observaron características antropométricas específicas para cada posición pero no se observaron diferencias de rendimiento significativas. Los resultados encontrados respaldan la hipótesis de que los entrenadores seleccionan a los jugadores jóvenes por sus características antropométricas antes que por las de rendimiento.

http://dx.doi.org/10.5232/ricyde2015.03906

-------------------------------------------------------------------------

References/referencias

Bangsbo, J.; Iaia, F.M., & Krustrup, P. (2008). The Yo-Yo intermittent recovery test: a useful tool for evaluation of physical performance in intermittent sports. Sports Medicine, 38(1), 37-51.
http://dx.doi.org/10.2165/00007256-200838010-00004

Bangsbo, J., & Michalsik, L. (2002). Assessment and physiological capacity of elite soccer players. In W. Spinks, T. Reilly, & Murphy, A. (Eds.), Science and Football IV (pp. 53-62). London: Routledge.

Barrow, H. M. (1954). Test of Motor Ability for College Men. Research Quaterly, 25(3), 253-260.

Beunen, G., & Malina, R. M. (1988). Growth and Biologic Maturation: Relevance to Athletic Performance. In H. Hebestreit & O. Bar-Or (Eds.), The Young Athlete (pp. 3-17). Oxford: Blackwell Publishing Ltd.

Beunen, G.; Ostyn, M.; Simons, J.; Renson, R., & Van Gerven, D. (1981). Chronological and biological age as related to physical fitness in boys 12 to 19 years. Annals of Human Biology, 8(4), 321-331.
http://dx.doi.org/10.1080/03014468100005121

Bloomfield, J.; Polman, R.; Butterly, R., & O’Donoghue, P. (2005). Analysis of age, stature, body mass, BMI and quality of elite soccer players from 4 European leagues. The Journal of Sports Medicine and Physical Fitness, 45(1), 58-67.

Carvalho, H.M.; Silva, M.J.; Figueiredo, A.J.; Gonçalves, C.E.; Philippaerts, R.M.; Castagna, C., & Malina, R.M. (2011). Predictors of maximal short-term power outputs in basketball players 14-16 years. European Journal of Applied Physiology, 111(5), 789-796.
http://dx.doi.org/ 10.1007/s00421-010-1703-4

Di Salvo, V.; Baron, R.; Tschan, H.; Calderon Montero, F.J.; Bachl, N., & Pigozzi, F. (2007). Performance characteristics according to playing position in elite soccer. International Journal of Sports Medicine, 28, 222–227.
http://dx.doi.org/10.1055/s-2006-924294

Erkmen, N. (2009). Evaluating the heading in profesional soccer players by playing position. Journal of Strength and Conditioning Research, 23(6), 1723-1728.
http://dx.doi.org/ 10.1519/JSC.0b013e3181b42633

Feliú Rovira, A.; Albanell Pemán, M.; Bestit Cartasona, C.; Baños Martínez, F.; Fernández-Ballart, J., & Marti-Henneberg, C. (1991). Prediction of physical endurance in athletes during puberty: analysis of high performance soccer players. Anales de Pediatría. Asociación española de pediatría, 35(5), 323-326.

Figueiredo, A.J.; Coelho e Silva, M.J., & Malina, R.M. (2011). Predictors of functional capacity and skill in youth soccer players. Scandinavian Journal of Medicine & Science in Sports, 21(3), 446-454.
http://dx.doi.org/ 10.1111/j.1600-0838.2009.01056

Gil, S.M.; Badiola, A.; Bidaurrazaga-Letona, I.; Zabala-Lili; J., Gravina, L.; Santos-Concejero, J.; Lekue, J.A., & Granados, C. (2013). Relationship between the relative age effect and anthropometry, maturity and performance in young soccer players. Journal of Sports Sciences, 32(5), 479-486.
http://dx.doi.org/ 10.1080/02640414.2013.832355

Gil, S.M.; Gil, J.; Ruiz, F.; Irazusta, A., & Irazusta, J. (2007). Physiological and anthropometric characteristics of young soccer players according to their playing position: relevance for the selection process. Journal of Strength Conditioning Research, 21(2), 438-445.

Gil, S.M.; Gil, J.; Ruiz, F.; Irazusta, A., & Irazusta, J. (2010). Anthropometrical characteristics and somatotype of young soccer players and their comparison with the general population. Biology of Sport, 27(1), 17-24.
http://dx.doi.org/10.5604/20831862.906762

Helsen, W.F.; Hodges, N.J.; Van Winckel, J.A., & Starkes, J.L. (2000). The roles of talent, physical precocity and practice in the development of soccer expertise. Journal of Sports Science, 18(9), 727-736.
http://dx.doi.org/10.1080/02640410050120104

Hernández, M., Castellet, J., Narvaíza, J. L., Rincón, J. M., Ruiz, I., & Sánchez, E. (Eds.). (1988). Curvas y tablas de crecimiento. Madrid: Garsi.

Hopkins, W.G.; Marshall, S.W.; Batterham, A.M., & Hanin J. (2009). Progressive statistics for studies in sports medicine and exercise science. Medicine & Science in Sports & Exercise, 41, 3-13.
http://dx.doi.org/10.1249/MSS.0b013e31818cb278

Jiménez, I.P., & Pain, M.T. (2008). Relative age effect in Spanish association football: Its extent and implications for wasted potential. Journal of Sport Science, 26(10), 995-1003.
http://dx.doi.org/10.1080/02640410801910285

Krustrup, P.; Mohr, M.; Amstrup, T.; Rysgaard, T.; Johansen, J.; Steensberg, A., Pedersen, P.K., & Bangsbo, J. (2003). The Yo-Yo Intermittent Recovery Test: Physiological response, reliability, and validity. Medicine and Science in Sports and Exercise, 35(4), 697-705.
http://dx.doi.org/10.1249/01.MSS.0000058441.94520.32

Lago-Peñas, C.; Rey, E.; Casáis, L., & Gómez-López, M. (2014). Relationship between performance characteristics and the selection process in youth soccer players. Journal of Human Kinetics, 40, 189-199.
http://dx.doi.org/ 10.2478/hukin-2014-0021

Malina, R.M. (1994). Physical activity and training: effects on stature and the adolescent growth spurt. Medicine and Science in Sports and Exercise, 26(6), 759-766.
http://dx.doi.org/10.1249/00005768-199406000-00016

Malina, R.M.; Bouchard, C., & Bar-Or, O. (Eds.) (2004). Growth, maturation and physical activity. Leeds: Human Kinetics.

Malina, R.M.; Cumming, S.P.; Morano, P.J.; Barron, M., & Miller, S.J. (2005). Maturity status of youth football players: a noninvasive estimate. Medicine and Science in Sports and Exercise, 37(6), 1044-1052.

Malina, R.M.; Eisennman, J.C.; Cumming, S.P.; Ribeiro, B., & Aroso, J. (2004). Maturity-associated variation in the growth and functional capacities of youth football (soccer) players 13-15 years. European Journal of Applied Physiology, 91(5-6), 555-562.
http://dx.doi.org/10.1097/00005768-200204000-00020

Malina, R.M., & Kozieł, S.M. (2014). Validation of maturity offset in a longitudinal sample of Polish boys. Journal of Sports Sciences, 32(5), 424-437.
http://dx.doi.org/ 10.1080/02640414.2013.828850

Malina, R.M.; Peña Reyes, M.E.; Eisenmann, J.C.; Horta, L.; Rodrigues, J., & Miller, R. (2000). Height, mass and skeletal maturity of elite Portuguese soccer players aged 11-16 years. Journal of Sports Science, 18(9), 685-693.
http://dx.doi.org/10.1080/02640414.2013.828850

Meylan, C.; Cronin, J.; Oliver, J., & Hughes, M. (2010). Talent Identification in Soccer: The role of maturity status on physical, physiological and technical characteristics. International Journal of Sports Science & Coaching, 5(4), 571-591.

Mirwald, R. L., Baxter-Jones, A.D.; Bailey, D.A., & Beunen, G.P. (2002). An assessment of maturity from anthropometric measurements. Medicine & Science in Sports & Exercise, 34(4), 689-694.
http://dx.doi.org/10.1097/00005768-200204000-00020

Mujika, I.; Vaeyens, R.; Matthys, S.P.J.; Santiesteban, J.; Goiriena, J., & Philippaerts, R. (2009).The relative age effect in a professional football club setting. Journal of Sports Science, 27(11), 1153-1158.
http://dx.doi.org/ 10.1080/02640410903220328

Musch, J., & Grondin, S. (2001). Unequal competition as an impediment to personal development: A review of the relative age effect in sport. Developmental Review, 21, 147-167.
http://dx.doi.org/10.1006/drev.2000.0516

Nikolaidis, P.T. (2012a). Elevated Body Mass Index and Body Fat Percentage Are Associated with Decreased Physical Fitness in Soccer Players Aged 14–16 Years. Asian Journal of Sports Medicine, 3(3), 168–174.

Philippaerts, R.M.; Vaeyens, R.; Janssens, M.; Van Renterghem, B.; Matthys, D.; Craen, R.; Bourgois, J.; Vrijens, J.; Beunen, G., & Malina, R.M. (2006). The relationship between peak height velocity and physical performance in youth soccer players. Journal of Sports Science, 24(3), 221-230.
http://dx.doi.org/10.1080/02640410500189371

Reilly, T.; Bangsbo, J., & Franks, A. (2000). Anthropometric and physiological predispositions for elite soccer. Journal of Sports Sciences, 18(9), 669-683.
http://dx.doi.org/10.1080/02640410050120050

Sherar, L.B.; Baxter-Jones, A.D.G.; Faulkner, R.A., & Russell, K.W. (2007). Do physical maturity and birth date predict talent in male youth ice hockey players? Journal of Sports Science, 25(8), 879-886.
http://dx.doi.org/10.1080/02640410600908001

Stroyer, J.; Hansen, L., & Klausen, K. (2004). Physiological profile and activity pattern of young soccer players during match play. Medicine & Science in Sports & Exercise, 36(1), 168-174.
http://dx.doi.org/10.1249/01.MSS.0000106187.05259.96

Valente-dos-Santos, J.; Coelho-e-Silva, M.J.; Simões, F.; Figueiredo, A.J.; Leite, N.; Elferink-Gemser, M.T.; Malina, R.M., & Sherar, L. (2012). Modeling developmental changes in functional capacities and soccer-specific skills in male players aged 11-17 years. Pediatric Exercise Science, 24(4), 603-621.

Vandendriessche, J.B.; Vaeyens, R.; Vandorpe, B.; Lenoir, M.; Lefevre, J., & Philippaerts, R.M. (2012). Biological maturation, morphology, fitness, and motor coordination as part of a selection strategy in the search for international youth soccer players (age 15-16 years). Journal of Sports Sciences, 13(15), 1695-1703.
http://dx.doi.org/ 10.1080/02640414.2011.652654

Wong, P.L.; Chamari, K.; Dellal, A., & Wisløff, U. (2009). Relationship between anthropometric and physiological characteristics in youth soccer players. Journal of Strength and Conditioning Research, 23(4), 1204-1210.
http://dx.doi.org/ 10.1519/JSC.0b013e31819f1e52

Wisløff,U.; Helgerud, J., & Hoff, J. (1998). Strength and endurance of elite soccer players. Medicine & Science in Sports & Exercise, 30(3), 462-467.
http://dx.doi.org/10.1097/00005768-199803000-00019

Ziv, G., & Lidor, R. (2011). Physical characteristics, physiological attributes, and on-field performances of soccer goalkeepers. International Journal of Sports Physiology and Performance, 6, 509-524.