INFLUENCE OF FOOTWEAR ON THE ANKL SPRAIN PRODUCTION MECHANISM IN BASKETBALL
AbstractINTRODUCTION: Vertical jump is a usual movement pattern in basketball, and it is related to ankle injuries, mainly during rebound actions when falling on another player's foot. The aim of the present study IS to determine the influence of the introduction of certain elements in the footwear on ankle protection when falling on an irregular surface. The study consisted in simulating a rebound action in which the player jumps and falls on an irregular surface, simulated by a 20" inclined plane. 12 footwear prototypes were studied, making a factorial design with the following elements: high or low top, upper vamp stabilizer, hollow midsole at midfoot level and lace anchors. 3 test subjects, students of Physical Education, took part. They performed 36 jumps each, in series of 3, with a recovering time of 3 s between jumps and 3 m between series. Each series was done wearing one of the 12 prototypes at random. Each jump was filmed at 150 Hz and then digitized. The angles of knee and ankle were calculated as a function of time. For the statistical analysis an analysis of variance (ANOVA) was made, considering as factors the elements introduced in the footwear and a level of significance of 0,05 was chosen. RESULTS: The results indicate the high top footwear limited the range of movement during ankle flexion-extension and they produce higher values of inversion than low top. With an upper vamp stabilizer, higher values of inversion were obtained than without it. On the other hand, with a hollow midsole, inversion values were lower. Introducing a movement control system in the rearfoot, by means of lace anchors, did not show influence on the studied movements. CONCLUSIONS: In this way, after landing on an irregular surface, the high top as well as an upper vamp stabilizer increase the degree of inversion, probably because these elements rigidify vertically the footwear and increase the adherence to the floor or to the irregular surface on which the subject IS. However, it must be considered that epidemiological studies state that high top footwear diminish the risk of acute ankle injuries in basketball players. The upper vamp stabilizer, on the contrary, only rigidifies vertically the footwear and it dos not offer any extra reinforcement of the joint, increasing the risk of suffering ankle injuries. REFERENCES: Stacoff, A.; Kalin, X.; Stiitsi, E. (1 989) Torsional movements of the foot during landing. Abstracs of the XI1 Congress of the International Society of Biomechanics. Los Angeles, 1085. Sussman, D. H.; Hamill, J.; Miller, M. (1988) Effect of shoe height and prophylactic taping on ankle joint motion during s~mulated basketball rebounding. In De Groot, G., Hollander, A.P.; Huijing, P.A.; Van lngen Schenau, G.J. (Eds.) Biomechanics XI-6.
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