Development of a Walking Technique to Reduce Barefoot Walking Impact

Abstract

The impact of barefoot walking is pointed out as a major cause of inter-floor noise in apartment complexes in Korea. This study proposed a 'Quiet Walking (QW)' strategy to reduce the impact of barefoot walking and verified it biomechanically by comparing it with insole interventions. Forty-five healthy adults (23 males/22 females, 25.5±4.6 years old, 167.8±9.1 cm, 68.8±17.6 kg) were tested on a pressure mat (FDM-2, Zebris, Germany) built into a 10-m walkway. They walked at self-selected speeds under five conditions: normal walking (NW), QW, and wearing 1, 2, and 3 layers of insoles (3mm, 6mm, 9mm thickness). The QW instructions were to slightly lean the upper body backward, maintain low foot clearance, and maintain speed at indoor walking level. Vertical loading rate (VLR), impact peak (IP), and impact time were calculated from vertical ground reaction forces. Electromyography (sEMG) was measured in the tibialis anterior (TA), peroneus longus (PL), soleus (SOL), and gastrocnemius lateralis (GL) muscles using Noraxon Ultium EMG systems (2,000 Hz). EMG signals were full-wave rectified, band-pass filtered (20–450 Hz), and low-pass filtered (6 Hz), then normalized to the 95th percentile of NW condition. Spatiotemporal parameters including walking velocity, step length, and step time were also analyzed. Analysis results showed that QW reduced VLR by approximately 29.2% compared to NW (p<.001, 𝜂_𝑝^2=0.53), while 6mm and 9mm insoles showed modest reductions of 7-8%. However, insoles paradoxically increased impact peak by 9-23% (p<.001, 𝜂_𝑝^2=0.41). QW significantly increased TA and PL muscle activity (p<.001), confirming active ankle stabilization mechanisms for impact attenuation, while SOL and GL showed no significant differences. Spatiotemporal analysis revealed that QW decreased walking velocity by 9.1%, step length by 4.2%, and increased step time by 5.2%, indicating comprehensive gait pattern modification. This study demonstrated that behavioral strategies involving active neuromuscular control are substantially more effective than passive assistive devices in reducing indoor walking impacts. The findings provide biomechanical evidence supporting quiet walking as a practical intervention for inter- floor noise reduction in multi-story residential buildings.