Changes in foot gait patterns after prolonged walking in older adults: An IMU and plantar force analysis

This study aimed to investigate the effects of prolonged walking on foot gait patterns throughout the stance phase in older adults. Eighteen older adults completed a 60-minute treadmill walking trial. Data was collected at baseline and after 60 minutes, including Borg rate of perceived exertion (RPE) scale, electromyography (EMG) signals from eight lower-limb muscles, forces from seven plantar regions, and foot kinematics. The Wilcoxon signed-rank test compared RPE scale, median muscle activation frequency, and tripping risk between two time points. Statistical non-parametric mapping analyzed plantar regional forces and rearfoot kinematics throughout the stance phase, identifying the timing of significant changes across the entire movement cycle. After 60 minutes of walking, RPE scale increased ( p < 0.001, r = 0.87), median frequency of EMG signals decreased in the quadriceps femoris ( p = 0.005, r = 0.66), hamstrings ( p < 0.05, r = 0.48–0.63), and fibularis longus ( p = 0.026, r = 0.53). Foot-ground clearance was reduced ( p = 0.003, r = 0.49) and tripping risk increased ( p = 0.007, r = 0.47). Plantar loading increased at the heel and arch ( p = 0.005, Cohen’s d z = 0.67–1.90), while propulsion power decreased, as indicated by reduced acceleration during push-off ( p ≤ 0.01, Cohen’s d z = 0.86–1.14). Sagittal plane rotation velocity and angle increased during early weight acceptance ( p = 0.005, Cohen’s d z = 0.78–1.16), and rearfoot external rotation slightly increased during mid-stance ( p ≤ 0.01, Cohen’s d z = 0.82–1.24). The observed alterations in plantar force distribution and foot kinematics may represent compensatory strategies to maintain walking speed under muscle fatigue. Our work highlights the value of integrating plantar pressure and inertial measurement unit data in assessing fatigue-related gait impairments.