Forced Marching With Load Decreases Tibiofemoral Joint Space Compared To Running

Knee osteoarthritis (OA) is prevalent among military servicemembers and has been linked to occupational load carriage. Lower extremity injury risk two times higher in female recruits. Effects of ambulation strategy (walk vs. run) on knee kinematics are known, however effects arthrokinematics during high-velocity walking (force march) unknown. Analyzing biomechanics a loaded march essential understand potentially injurious motion OA progression. PURPOSE: To identify carriage magnitude recruit-aged women. METHODS: 12 women (age: 24.5 ± 2.4 years) ran force marched treadmill while carrying no (bodyweight [BW]) with +25%BW + 45%BW (average: 14.3 2.0 kg, 25.6 3.5 kg). Synchronized biplane radiographs the right were collected (150 images/s, 1 s). Computed tomography scans segmented construct subject-specific femur tibia models. Joint coordinate systems created validated model-based tracking system determined vivo bone (accuracy: 0.9°, 0.7 mm). Six degree-of-freedom calculated. Two-way repeated measures analysis variance examined (BW, +25%BW, +45%BW) each movement (run [RN], [FM]) kinematics, joint space, contact center location (CCL) at four time points (foot strike (0%), 10%, 20%, 30% stance, α = 0.05). RESULTS: Treadmill velocity was 0.2 m/s. Knees 7.5° more extended 0.6° abducted FM RN 10-30% (all p ≤ 0.004) 2.4° internally rotated (IR) +45%BW 20-30% < 0.033). IR decreased 1.8° 0.048). Anterior translation increased 0.6 mm (p 0.045) 0%. Medial 20% 0.039). space 0% (Med/Lat: 0.001). CCL medial 0.030). anterior (Med: all 0.001; Lat: 0.002). CONCLUSIONS: Loaded forced marching affects Prolonged could increase degenerative this population. Supported by Freddie H. Fu graduate student research award.