Analysis of the Correlation Between Individuals’ Shoulder-to-Step Width Ratio and Stability Indicators

Purpose: This study aimed to analyze the correlation between the shoulder-to-step width ratio (SSWR) and changes in stability indicators under different base of support (BoS) conditions.Specifically, it focused on the difference values of stability indicators between a natural step width condition and a narrow stance condition (feet together) to indirectly assess neuromuscular adaptability to changes in the BoS.Methods: Twenty-three adults from K University in Busan and C University in Ulsan participated.Individuals with no musculoskeletal, neurological, visual, or vestibular disorders during the past 3 months were included.Step width was measured by participants walking barefoot over a 10-meter path with inked soles, and shoulder width was measured between the acromions and averaged across the three trials.Dynamic stability was assessed by measuring COP displacement during 8-second weight shifts in four directions.Static stability was evaluated during a 30-second standing task by analyzing COP displacement, 90% confidence ellipse area, velocity variability, and X/Y-axis displacement variability.The main analysis examined the differences in stability indicators between step-width and feet-together conditions and correlated these with SSWR.Statistical analysis was conducted using SPSS 25.0 (=0.05,power=80%).Results: SSWR showed a significant positive correlation with lateral COP displacement differences in dynamic stability and a negative correlation with static stability indicators, such as total COP displacement, 90% ellipse area, velocity,