Effect of Shoe Heel Height and Total-Contact Insert on Muscle Loading and Foot Stability While Walking

Background: Women wearing high-heeled shoes often complain of foot instability and low-back pain. Previous studies have demonstrated that using total-contact inserts (TCIs) in running shoes reduces impact on leg muscles and alters rearfoot motion. This study investigated how shoe heel height and use of TCIs in high-heeled shoes affect the wearer's rearfoot complex, muscle loading, and subjective comfort. Methods: Fifteen inexperienced high heel wearers walked under 6 test conditions formed by the cross-matching of shoe insert (with and without TCI) and heel height (1.0, 5.1, and 7.6 cm) at a speed of 1.3 m/s. The measures of interest were rearfoot kinematics; muscle activities by electromyography (EMG) of the tibialis anterior (TA), medial gastrocnemius (MG), quadriceps (QUA), hamstrings (HAM), and erector spinae (ES); and subjective comfort rating by visual analogue scale for each test condition. Results: The statistical results showed that elevated heel height significantly increased plantar flexion (P < .001) and inversion (P < .01) at heel strike, prolonged TA-MG co-contraction (P < .001) and QUA activation period (P < .001), and increased root mean square (RMS) EMG in all measured muscles (TA, MG, QUA, ES: P < .001; HAM: P < .01). The use of TCIs reduced the rearfoot inversion angle (P < .01) and RMS EMG in both QUA and ES muscles (P < .01) and increased comfort rating (P < .001). Conclusions: These findings suggest that wearing high-heeled shoes adversely affects muscle control and reduces loads in QUA and ES muscles.