Dr. Tyler N. Brown
Increasing toe out (i.e., foot progression angle) reportedly increases knee adduction and risk of premature knee osteoarthritis (OA) that is prevalent in military personnel. Yet, it is currently unknown if the body borne load military personnel routinely carry during operational exercises, such as running, increases either foot progression or knee adduction. This study examined the effect of body borne load on foot progression angle and knee adduction biomechanics, and whether it differs between sexes. Twenty male and 16 female participants had lower limb biomechanics quantified while running (4.0 m/s) with four body borne loads (20, 25, 30 and 35 kg). Foot progression at initial contact (FPA), and peak stance knee adduction angle (KAA) and moment (KAM) were submitted to a linear model with load (20, 25, 30 and 35 kg) and sex (male, female) as fixed effects. FPA was considered a covariate for KAA and KAM. Males exhibited greater FPA (p=0.046) and KAM (p=0.013), but not KAA (p=0.681) than females. Load increased KAM (p=0.037), but not FPA (p=0.261) or KAA (p=0.111). FPA was a significant covariate for both PS KAM (p=0.003) and KAA (p < 0.001), and each 1 degree increase in FPA predicted 0.01 Nm/kgm greater KAM and 0.2 degree greater KAA, knee biomechanics thought to increase OA risk. Males may be at greater risk of knee OA, as they exhibited 3.5 degrees greater FPA and 0.16 Nm/kgm greater KAM than females. But, the military may decrease risk of knee OA, particularly for males, by modifying foot progression during training programs.
McDonald, Matthew W.; Parikh, Alay; and Brown, Tyler N., "Foot Progression Angle Predicts Knee Adduction During Load Running" (2020). 2020 Undergraduate Research Showcase. 116.