Gender differences in the knee musculature function in profesional volleyball players Diez-Vega, I.1, Molina, J.J.1, Fernández-del-Valle, M.2, Rodríguez-Matoso, D.3, Rodríguez-Ruiz, D.3 1 European University of Madrid, Spain. ( IGNACIO.DIEZ@uem.es) 2 Texas Tech University, USA. 3 Laboratory of Analysis and Planification of Sport Training (LAPED – ULPGC), Spain. INTRODUCTION Muscular morphology and function differences in professional female and male volleyball players may play a key role in performance and predisposition to injury (1). The knee joint is an anatomical area of great importance in volleyball performance, and a precise assessment of the muscular structures involved in this area might help to understand and prevent injuries associated with this sport (2). The aim of this study was to analyze the gender differences of the knee musculature on high performance volleyball players using Tensiomyography (TMG)(3). METHODS A total of 166 professional players were assessed: 83 women (23.99 +/- 5.07 years, 178.13 +/- 7.29 cm and 71.99 +/- 8.87 Kg) and 83 men (25.87 +/- 4.81 years, 191.26 +/- 7.36 cm and 87.71 +/- 9.27 Kg) from 16 teams in the Spanish women's and men's Superleague (8 each). TMG was used to assess the knee flexor-extensor muscles Vastus Medialis (VM), Rectus Femoris (RF), Vastus Lateralis (VL) y Biceps Femoris (BF). Maximal radial deformation (Dm), delay time (Td), and contraction time (Tc) were analyzed. RESULTS AND DISCUSSION Data obtained in both lower limbs show a greater rigidity (Dm) on BF (p≤0.001) in males, and lower rigidity in the extensor muscles [RF, VM y VL (p≤0.05)] in males compared to females. Delay time (Td) was lower in males on BF (p≤0.001), RF (p≤0.001) and VL (p≤0.05), and only for VM (right leg p≤0.05) in females. Contraction time (Tc) on BF (p≤0.001) were lower for males, while it was similar for both genders on RF, and lower for females on VM (right leg p≤0.05) and VL. Our findings are consistent with previous results reported by Diez et al (2) and with the differences found on BF reported by Rodríguez-Ruiz et al (3). Moreover, the results obtained on VM in females reinforce the stabilization role of the knee joint musculature compared to males (4). However, further research is needed in order to determine other biomechanical aspects of the knee musculature in professional male and female volleyball players. Figure 1. Result in Dm for Vastus Medialis (VM), Rectus Femoris (RF), Vastus Lateralis (VL) y Biceps Femoris (BF) in both lower limbs and genders (men-blue, females-red) Figure 2. Result in Td for Vastus Medialis (VM), Rectus Femoris (RF), Vastus Lateralis (VL) y Biceps Femoris (BF) in both lower limbs and genders (men-blue, females-red) Figure 3. Result in Tc for Vastus Medialis (VM), Rectus Femoris (RF), Vastus Lateralis (VL) y Biceps Femoris (BF) in both lower limbs and genders (men-blue, females-red) REFERENCES Hughes, G., Watkins, J. & Owen, N. (2008) Gender differences in lower limb frontal plane kinematics during landing. Sports Biomechanics. 7(3): 333- 341. Díez, I., Rodríguez-Matoso, D., Fernández-del Valle, M., Sagastume, R., Estevez, R., Molina, J.J., Rodríguez-Ruiz, D. (2011) Diferencias funcionales en la musculatura de la rodilla en jugadoras profesionales de voleibol. Kronos. La revista científica de actividad física y deporte. 10(2): 55-62. Rodríguez-Ruiz D, Rodríguez-Matoso D, Quiroga ME, Sarmiento S, Da Silva-Grigoletto ME, García-Manso JM (2012) Study of mechanical characteristics of the knee extensor and flexor musculature in the knees of volleyball players. European Journal of Sport Science 12(5): 399-407. Travnik L, Djordjevič S, Rozman S, Hribernik M, Dahmane R. (2013) Muscles within muscles: a tensiomyographic and histochemical analysis of the normal human vastus medialis longus and vastus medialis obliquus muscles. J Anat. 222(6):580-587.