The Effect of Lower Limb Muscle Fatigue on Running Tempo- Spatial Parameters and Joint Excursion in Individuals with Pes Planus

Context: The relation between running kinematics parameters and lower limb muscle fatigue in association with low longitudinal arch (LLA) is not well understood. Objective: The purpose of the present study was to examine the effects of fatigue on running kinematics in Subjects who had a low longitudinal arch. Design: Quasi- Experimental study. Setting: Clinical Biomechanics Laboratory. Participants: forty four subjects were equally divided into two groups, a healthy one and a group with LLA. Main Outcome Measures: The kinematics parameter of running includes tempo-spatial parameters and joint angles, which were calculated by Vicon Nexus 1.8.5 software. A two-way repeated measure ANOVA (group x fatigue) was used to compare the data between the two groups. Results: In the unfatigued conditions, running speed, ankle plantar flexion/ dorsiflexion, and ankle external rotation, knee flexion and hip flexion/extension in the low arch subjects are significantly different than those in the healthy subjects (P<0.05). Induced fatigue increased Step time (p=0.014) and Subtalar inversion (p=0.034); too decreased Step length (p=0.027) in LLA. The observed Induced fatigue decreased running speed and ankle plantar flexion, and increased Knee flexion, Knee abduction, Knee Internal rotation, Knee external rotation, Hip flexion, Hip adduction, hip Internal rotation and hip external rotation in both groups (p≤0.05). A significant interaction between group and time was found for Step time, ankle plantar flexion, hip extension and hip adduction (p≤0.05). Conclusion: Patients suffering from low arches will respond differently to lower extremity fatigue. Individuals with flat feet arches appear to be more prone to the risk of injury to the lower extremities at exhausting activities.