Ground reaction forces analyses during the gait of healthy individuals with and without the use of a calcaneus insole

Abstract

The foot forms the base of propulsion and balance during the gait. It is well known that excessive or prolonged pronation and supination changes the gait’s mechanical movement. Hence, the use of corrective insoles is recommended when calcaneus alterations (valgus and varun) are present. Objetive: The main purpose of this article was to analyze the effects of a calcaneus insole on normal individuals on the Ground Reaction Force variables. Method: The experiment used ten adults (31.9 ± 6,7 years, 65.9 ± 15.4 kg and 1.7 ± 0.1 m) and registered no apparent changes in gait or pathologies that have an effect on the locomotor system. The following gait conditions were analyzed and compared: barefoot, using a sport shoe, and using the sport shoe with insole. The variables analyzed were vertical, medial lateral, and anterior-posterior dynamic ground reaction forces. An ANOVA one-way was used in order to compare the three different conditions. Statistically significant differences were revealed between the conditions of barefoot and sport shoe with insole for the vertical GRF during initial contact Fz1 (F2,59 = 3.4; p < 0.0406) and for the GRF anterior-posterior in the terminal stance phase Fy2 (F2,59 = 3.63; p < 0.0332). Results: These results indicated that the use of an insole increased the vertical impact on the locomotor system during the response to load phase, probably because of its greater stiffness compared to the barefoot or sport shoe trials. The insole also changed the GRF anterior-posterior during the terminal stance that corresponded with the acceleration/propulsion gait phase. Conclusion: Just based on the analysis of the dynamic variables, it was concluded that the use of insoles did not induce any significant increase in lateral forces that would indicate the reduction of excessive pronation or supination during the response load phase. The use of an insole produced a significant dynamic effect on the pronation/supination only in the propulsive gait phase.