ABSTRACT
BACKGROUND: The clinical measure of forefoot-shank alignment (FSA) predicts the amount of foot pronation during weight-bearing tasks. This may be mediated by a relationship between FSA and the mechanical resistance of the midfoot joint complex (MFJC) to forefoot inversion, which is a component of weight-bearing foot pronation. OBJECTIVE: To investigate if the clinical measure of FSA is associated with MFJC mechanical resistance to inversion. DESIGN: Cross-sectional observational study. METHOD: Forty-six healthy individuals (27 males; 19 females) with mean age of 26.4 years (SD 5.3) participated in this study. FSA was measured with photographs. The resistance torque of the MFJC against inversion was measured with a specially designed device. Mean torque, mean torque normalized by body mass, and joint resting position were calculated as variables related to MFJC mechanical resistance. Correlation analyses were carried out to test the association between each MFJC resistance variable and the FSA (αâ¯=â¯0.05). RESULTS: /findings: There were significant moderate correlations of FSA with mean torque (râ¯=â¯-0.44, pâ¯=â¯0.002), mean normalized torque (râ¯=â¯-0.42, pâ¯=â¯0.004) and resting position (râ¯=â¯0.39, pâ¯=â¯0.007). The clinical measure of FSA is associated to the mechanical resistance of the MFJC: (a) the greater the FSA, the smaller the resistance torques; (b) the greater the FSA, the more inverted the forefoot resting position. CONCLUSIONS: These results showed that the clinical measure of FSA is moderately related to mechanical properties of the MFJC.
