Analysis of ankle deflection during a forward fall in snowboarding

Toward the general goal of preventing ankle injuries in snowboarding accide nts, the objective of this project to develop a dynamic system model of a s nowboarder and assess which model parameters, particularly those attributed to the boot, most strongly influenced ankle deflections during a forward f all. To satisfy this objective, a system model was created that included th e rider, die boots, the snowboard and the snow as components. Through dynam ic simulations, peak ankle deflections were computed over realistic ranges of input parameter values for each of the model components. Defining sensit ivity as the total change in peak ankle deflection over the range of a part icular parameter studied, results indicated that the peak ankle deflection was most sensitive to the boot stiffness. Although lower the sensitivity of the peak ankle deflection to the snow model parameters was still significa nt, being roughly half of the boot sensitivity. Increases in both snow stif fness and snow damping caused higher ankle deflections. Variations in both snowboard stiffness and anthropometric parameters had little effect. Due to the strong dependence of ankle deflection on boot stiffness, the potential exists for mitigating the ankle injury problem through judicious design of the boot.