Gait patterns observed during obstacle walking in adults with mild intellectual disability.

OBJECTIVE: To compare three-dimensional gait kinematics, pressure-platform-derived variables, and intellectual disability during level walking and obstacle negotiation. METHODS: Twenty participants were enrolled (mild intellectual disability, n = 10; control, n = 10). Participants walked barefoot at a self-selected speed during level walking and obstacle crossing over three heights (2.5, 5.2, and 15.2 cm). Three-dimensional kinematics were captured using inertial measurement units. During level walking, pressure-platform-derived variables, including body-weight-normalized force-related values and peak plantar pressure, were obtained using a pressure platform. Surface EMG activity of the rectus femoris, biceps femoris, tibialis anterior, and medial gastrocnemius was recorded during obstacle walking. RESULTS: During level walking, adults with mild intellectual disability showed greater hip and knee flexion during early stance phase than controls (p < 0.05). During obstacle negotiation, leading-limb responses primarily reflected obstacle-height effects. In the trailing limb, significant obstacle-height effects were observed for hip flexion, knee flexion, ankle dorsiflexion, ankle inversion, rectus femoris, biceps femoris, and tibialis anterior activity. Significant group-related effects were observed for trailing-limb ankle dorsiflexion and tibialis anterior activity, indicating different ankle-control strategies across obstacle heights between groups. CONCLUSION: Adults with mild intellectual disability demonstrate altered gait kinematics and reduced adaptability during obstacle negotiation, particularly in trailing-limb ankle control. These findings support rehabilitation approaches that progressively challenge gait control under commonly encountered environmental constraints to enhance movement regulation during walking.