Skilled adult movers plan for a comfortable end position even when this requires an uncomfortable start position (end-state-comfort effect). This ability declines in late adulthood and has been linked to age-related differences in cognitive functioning. Other factors, which may also drive difference in motor planning in later adulthood have not been systematically examined. These include perceptions of comfort and levels of motor imagery ability (one's ability to mentally simulate action/predict the outcome of action). Therefore, this study investigated the constraints on movement planning across the life span, including executive functions, general motor ability, physical constraints to movement and motor imagery ability. One hundred and twenty-two participants aged 20-81 years completed an end-state-comfort task with increasing levels of complexity. Individuals' executive functions, motor control, motor imagery ability, and perceived rotation span were also examined. Age-related decline was shown in planning for sequential movements but not in simple single-step movements. Motor planning demonstrated an age-related difference that was associated with an increasing number of constraints as age increased, and in older adults chronological age influenced the effect of each constraint on motor planning. Age-related difference in motor planning may reflect effective compensatory strategies in response to differing constraints in motor imagery ability, executive functions, perceived rotation span, and general speed and accuracy of movement as we age. (PsycInfo Database Record (c) 2020 APA, all rights reserved).