Effects of Prolonged Walking with Body Borne Load on Knee Adduction Biomechanics

Background: Soldiers that suffer a service-related knee musculoskeletal injury routinely develop joint osteoarthritis. Knee osteoarthritis is a substantial and costly problem among soldiers, yet it is unknown how body borne load and duration of walking impact knee adduction biomechanics linked to progression and severity of osteoarthritis. Research question: This study determined the adaptations in magnitude and variability of knee adduction joint angle (KAA) and moment (KAM) during prolonged walking with body borne load. Methods: Thirteen recreationally active participants had knee biomechanics quantified while walking over-ground for 60-min at 1.3 m/s with three body borne loads (0, 15, and 30 kg). Magnitude and variability of KAA and KAM measures were quantified and submitted to a RM ANOVA to test the main effect and interactions between load (0, 15 and 30 kg) and time (0, 15, 30, 45 and 60 min). Results: Body borne load increased peak KAM (p \u3c 0.001), whereas time increased peak and range of KAA (both: p \u3c 0.001). Specifically, peak KAM increased with each addition of body borne load (all: p \u3c 0.025), and peak and range of KAA increased after 30 min of walking (both: p \u3c 0.040). Neither body borne load, nor time had a significant effect on KAA or KAM variability (both: p \u3e 0.05). Significance: Prolonged walking with heavy body borne load increased knee adduction biomechanics related to osteoarthritis. Adding heavy body borne load increased in peak KAM whereas duration of walking increased KAA, knee biomechanics that may increase loading of the medial knee joint compartment and risk of OA at the joint