Balance control during obstacle-crossing in older adults after a fatiguing protocol

Area of Science:

• Gerontology
• Biomechanics
• Cognitive Neuroscience

Background:

• Obstacle-crossing (OC) demands dynamic balance and cognitive attention, crucial functions that may decline with age and fatigue.
• While age-related gait changes are documented, the combined impact of fatigue and cognitive load on OC performance is not well understood.

Purpose of the Study:

• To investigate how performance fatigability affects balance and crossing performance during single- and dual-task OC in older versus younger adults.

Main Methods:

• Participants (older and younger adults) underwent fatiguing protocols, performing OC tasks under single- and dual-task conditions before and after fatigue.
• Motion capture and force plates quantified gait parameters (toe-obstacle clearance, foot placement, velocity) and balance (inclination angle, IA).
• Fatigue was assessed via perceived exertion and strength, while cognitive performance was measured by accuracy and reaction time.

Main Results:

• Both age groups exhibited similar exertion and strength loss post-fatigue, with increased mediolateral IA indicating poorer balance control.
• Despite stable gait velocity and foot placement, post-fatigue dual-tasking showed reduced toe-obstacle clearance, suggesting compromised safety.
• Cognitive performance unexpectedly improved post-fatigue, with higher accuracy and faster reaction times.

Conclusions:

• Fatigue significantly impairs gait balance control during obstacle-crossing in both age groups.
• Reduced toe-clearance in dual-tasking post-fatigue indicates a decreased prioritization of safe navigation.
• The observed improvement in cognitive function suggests a compensatory shift in attentional resources away from motor control.