Torque prediction at the shoe-surface interface using insole pressure technology

Excessive rotational traction between the foot and the playing surface has been shown to increase the risk of athletic injuries to ligaments in the knee and ankle. It is not currently feasible to accurately determine the free torque generated at the shoe-surface interface utilizing live participants without an embedded force plate. The goal of the current research was to predict the free torques that developed at the shoe-surface interface during voluntary internal and external rotations of the body relative to a planted foot using an insole pressure measurement system. Six participants fitted with a shoe containing an insole pressure measurement device performed trials on an embedded force plate. A pressure sensor mask of specific sensors was determined based on the degree of linear correlation between sensor pressure and the free torque. Linear regression analyses were utilized to develop a General Linear Regression Model and Participant-Specific Linear Regression Models. The results of this study indicated that insole pressure technology, in conjunction with linear regression models, can be utilized to predict free torques generated at the shoe-surface interface during isolated rotational motions of the body with respect to a planted foot. Furthermore, Participant-Specific Linear Regression models may be more accurate in these predictions than a general model, based on a group of participants. When used with computational modeling, this technique might allow the investigation of strains produced in ligaments of the ankle and knee that are generated during internal and external rotations of the body with a planted foot on various turf surfaces outside a laboratory setting.