EFFECT OF FOOTWEAR ON LATERAL BRAKING AND TURNING MOVEMENTS IN TENNIS
Keywords: pronation, lateral movement, footwear, tennis
AbstractINTRODUCTION: Lateral displacements can be considered the most characteristic type of displacements in tennis, and therefore they have been the most studied movement in tennis footwear research (Luethi et al., 1986, Nigg et al., 1989). The present study was conducted to analyze the cinematic and kinetic variables affected by tennis footwear in lateral braking and turning movements. METHODS: The sample of footwear used comprised the ten best-selling tennis shoes available in Valencia, and the subjects were 5 players who met a set of previously set requirements. Each player performed a lateral braking and turning movement five times on an extensometric force plate with a sampling frequency of 1000 Hz. The movements were filmed with a photogrammetry-video system at 50 Hz with the kinetic model of Vaughan and cols. (1992) Each parameter in the study was considered a statistical variable with which an ANOVA was made, taking the subjects and the shoes as factors, with a significance level of 0.05 and making a post hoc with LSD methodology. With the kinematic and kinetic variables dependent on footwear a Pearson type correlation analysis was made. RESULTS: The kinematic variables most affected by footwear were ankle flexoextension and subastragalar prono-supination. The footwear-dependent kinetic variables were the second maximum of the vertical and mediolateral (p=0.032) components of reaction forces, as well as the time lapse between the two maximums. Prono-supination values correlated both to the maximums of vertical (r=-0.1224, p=0.028) and medio-lateral forces and to the time lapse between the two maximums. The footwear that controls (limits) the prono-supination movements related to higher force levels in the second maximum of the vertical and medio-lateral components, as well as with lower time lapse between maximums. Consequently, the control of prono-supination movement becomes a performance criterion in lateral displacements, since it permits subjects to perform these displacements faster. REFERENCES: Nigg, B.M., Luethi, S.M., Bahlsen, H.A. (1989). The tennis shoes. Biomechanical design criteria. The shoe in sport, B. Segesser, W. Pförringer (Eds.). Wolfe Publishing, Ltd. Luethi, S.M., Frederick, E.C., Hawes, M.R., Nigg, B.M. (1986). Influence of shoe construction on lower extremity kinematics and load during lateral movements in tennis. Int. J. Sport Biomech. 2, 3, 166-174.
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