Effects of age and mild cognitive impairment on postural control during lifting a load.

Lifting everyday objects destabilizes the body and requires generation of anticipatory (APAs) and compensatory (CPAs) postural adjustments to maintain balance. Aging is associated with reduced efficiency of APA generation and greater reliance on CPAs. The role of Mild Cognitive Impairment (MCI) in postural control during lifting remains unclear. We investigated how age and MCI influence postural adjustments during a standing bimanual lifting task. 13 healthy older adults (OAH), 15 older adults with MCI (OAMCI), and 12 young adults (YAH) performed 35 trials of bimanual lifting of light and heavy loads in standing. Surface electromyography was collected bilaterally from trunk and lower limb muscles, and EMG integrals were calculated during the APA and CPA phases. Center of pressure (COP) displacements were derived from force platform data. YAH generated significantly greater APAs in muscle activity and exhibited larger anticipatory COP responses than both older groups during the heavy-to-light transition (p < .05). They also produced larger compensatory COP responses across transitions. OAMCI showed reduced TA activation during the light-to-heavy transition but demonstrated exaggerated APAs in posterior and lateral muscles during the heavy-to-light transition compared with OAH (p < .05). Change-point analysis indicated faster adaptation to load changes in YAH than in both older groups. Aging and MCI differentially affect the ability to regulate APAs and CPAs during lifting. Young adults demonstrated efficient scaling and rapid adaptation of postural control, whereas older adults showed reduced anticipatory efficiency and slower adjustment. Individuals with MCI exhibited exaggerated yet less targeted APA patterns, suggesting impaired strategy selection.