The influence of design variations in footwear medial-lateral support on the running biomechanics of older female runners

Reports of greater incidence of knee pain and injury in older female runners compared with their younger counterparts may be associated with differences in lower limb biomechanics that influence knee joint loading. The aim of this study was to investigate footwear interventions aimed at influencing lower limb biomechanics in older female runners (>45 years). Strategies for reducing peak rearfoot eversion and the external knee adductor moment were investigated, since both measures have been associated with knee joint injury. Twenty female runners (mean age 50.7 +/- 5.6 years) performed 10 running trials in four footwear conditions: neutral running shoe (Control); neutral shoe with 4 degrees medial heel wedge insole (Medial Wedge); neutral shoe with 4 degrees lateral heel wedge insole (Lateral Wedge); and neutral shoe with combined insole with 5 degrees lateral wedge and medial arch support (Combined Insole). Peak rearfoot eversion and knee external adductor moment were compared for the four conditions using RMANOVA and post-hoc Tukey tests (p < 0.05). Compared with the Control, peak rearfoot eversion was lower for the Combined Insole condition, with this value being lower than for all other insole conditions (p < 0.05). Compared with the Control, the peak knee external adductor moment was lower for the Lateral Wedge and the Combined Insole conditions (p < 0.05). These results support the use of a combined insole with lateral wedge and medial arch support for the reduction of peak rearfoot eversion and peak knee external adductor moment, variables that have been associated with increased risk of knee injury. If aiming to reduce knee external adductor moment alone, then the lateral wedge technology employed in this study provides an effective method for older female runners.