Dynamic stability on nonmotorized curved treadmill: Self-paced speed versus fixed speed

Understanding dynamic stability during locomotion is very important for preventing falling and injury. Although many previous studies have investigated dynamic stability characteristics under self-paced speed (SP) and fixed-speed (FS) conditions, very few have directly compared the two conditions. In this study, the margin of stability (MOS) was evaluated under the SP and FS conditions using a nonmotorized curved treadmill (NMCT). Interaction effects were found between the curvature radius and speed, the differences between each curvature radius and speed were confirmed, and significant differences were found between the SP and FS conditions. According to experimental results, under both the SP and FS conditions, the dynamic stability increased with the curvature radius during slow and fast walking. However, under the SP condition, as the curvature radius increased, the MOS in the anteroposterior direction decreased during running; however, under the FS condition, no distinctive trend was observed. At most curvature radii and speeds, significant differences were found between the SP and FS conditions. The study results indicated that while exercising on the NMCT, the SP and FS conditions at different curvature radii and speeds could influence the dynamic stability. The results could be utilized for verifying exercise capacity enhancement and rehabilitation exercise effects.