# Gait Kinematics Analysis of Flatfoot Adults
###### Abstract  
Background: Foot postural alignment has been associated with altered gait pattern. This study aims to investigate gait kinematic differences in flatfoot subjects' regarding all lower limb segments compared to neutral foot subjects. Methods: A total of 31 participants were recruited (age: 23.26 yo \(\pm\) 4.43; height: 1.70 m \(\pm\).98; weight: 75.14 kg \(\pm\) 14.94). A total of 15 subjects were integrated into the flatfoot group, and the remaining 16 were placed in the neutral foot group. All of the participants were screened using the Navicular Drop Test and Resting Calcaneal Stance Position test to characterize each group, and results were submitted to gait analysis using a MOCAP system. Results: Significant kinematic differences between groups were found for the ankle joint dorsiflexion, abduction, and internal and external rotation (\(p<0.05\)). Additionally, significant differences were found for the knee flexion, extension, abduction, and external rotation peak values (\(p<0.001\)). Significant differences were also found for the hip flexion, extension, external rotation, pelvis rotation values (\(p<0.02\)). Several amplitude differences were found concerning ankle abduction/adduction, knee flexion/extension and abduction/adduction, hip flexion/extension and rotation, and pelvis rotation (\(p<0.01\)). Conclusion: Flatfooted subjects showed kinematic changes in their gait patterns. The impact on this condition on locomotion biomechanical aspects is clinically essential, and 3D gait biomechanical analysis use could be advantageous in the early detection of health impairments related to foot posture. flatfoot; walking; biomechanics; kinematics; gait analysis +
Footnote †: journal: Medical Imaging  
doi: 10.1007/s10020  
along the foot, affecting shock absorption, muscular activity, and gait pattern [15; 16]. Moreover, foot sole afferent input affects postural awareness and FF triggered by neurological or muscular restrictions, ligament or joint laxity, excessive motion, and muscle activity [13]. For every daily living activity, both static and dynamic postural control are required [17]. However, foot posture can induce altered plantar pressure patterns and, therefore alter the motion of adjacent joints. The neuromuscular function as well as the biomechanics of the lower limbs can be affected by an altered afferent sensory input. The Central Nervous system uses the muscle coactivation system through the neuromotor response, a motor control mechanism used to modulate joint stiffness, postural stability, and gait pattern [16]. Muscle joint coactivation varies during the gait cycle, reaching higher heel-strike and unilateral weight-bearing values during the balance transition phase and lower values in mid-stance [18]. [PERSON] et al. (2015) stated that during gait pattern, FF subjects exhibit more motion compared to NF subjects, and cavus foot subjects exhibit less motion when compared to FF subjects. Those alterations can reveal abnormal biomechanical parameters that, as previously stated, influence injury appearance throughout the entire lower limb. These injuries can be due to lesser energy dissipation due to the reduced movement of FF, inducing impact attenuation impairment [5]. In a systematic review, [PERSON] et al. (2013) found that FF subjects showed alterations in plantar pressure characteristics, specifically higher pressure, force, and contact area values relative to the medial arch, central forefoot, and the hallux, while the same parameters were minor in the lateral and medial forefoot [6]. Additionally, the authors investigated the kinematic variables of the foot complex. They stated that FF subjects presented significantly higher rearfoot inversion and adduction motion during the last 20% of the stance phase. They also found a positive correlation regarding condition subjects and the rearfoot peakevers in the first half of the stance phase [6]. Based on gait analysis, other authors identified differences among FF subjects compared to neutral ones.