We have previous discussed the limitations of orthotics to control lower extremity alignment. Another common reason for orthotic use is to control the degree of pronation or flattening of the foot during foot strike in walking and running. The theory believes orthotics are able to impact force absorption by controlling this motion at the foot and ankle joints. Much of this theory is based off an “ideal” neutral position of the foot and ankle called subtalar neutral. The research into subtalar neutral is conflicting and this position may not be optimal for either static or dynamic foot function.
A recent article in the Medicine and Science in Sport and Exercise journal examined asymptomatic participants with flat feet. These participants were given custom orthotics based on the sub talar neutral theory. Each participant then walked at a preferred and fast speed under 3 conditions: barefoot, athletic shoe, and athletic shoe plus orthotic. Authors measured force and EMG data during each condition. Results demonstrated the effects of reduced pronation and energy absorption were similar between shoe and shoe and orthotic conditions indicating no further benefit of orthotic use. Authors reported the benefits of reduced pronation (flattening) and force transmission were due to primarily to shoe wear.