Age-related changes in locomotor avoidance strategies and dynamic stability in obstructed dual-task paradigms
The objective of the current work was to provide new observations regarding age-related differences in obstacle avoidance strategies and dynamic stability under unobstructed and obstructed travel path conditions while performing another task (dual task paradigm). We observed seven healthy young adults arid seven healthy older adults participants as they stepped over an obstacle in the travel path while performing an upper body object stability task (motor) or an articulated cognitive task and measured both kinematic and kinetic parameters (e.g. lead heel clearance, trail-toe clearance, landing distance, instantaneous COP-COM separation). Older adults and young adults had more difficulty performing the object stability task under the dual-task condition compared to the single task condition, but only older adults had more difficulty performing the cognitive task under dual-task. Older adults used more cautious obstacle avoidance strategies compared to YA by altering lead foot obstacle clearance and placement during the obstacle crossing step. Gait stability (COP-COM separation) was challenged in older adults just before obstacle crossing in the sagittal plane, but OA appeared to adopt a more stable gait before obstacle crossing in the frontal plane as a cautious anticipatory locomotor strategy and, immediately after obstacle crossing possibly to avoid a trip or fall in the forward direction.