During walking, posture of the trunk and head provide a stable platform for the head and sensory systems. Age related changes in sensory systems can challenge the ability of older adults to maintain head stability particularly during dynamic tasks such as walking. The broad aim of this project is to determine motor control strategies used by older adults to compensate for changes in sensory systems that occur with age. Of specific interest are the upper body movement patterns used to maintain head stability during functional, dynamic activities such as walking and how these strategies are effected by changes in visual conditions. Twenty healthy, older adults and 20 young adults will be screened for current health status. Balance, vision and flexibility testing will be used in addition to self report of medical and fall history. Subjects will perform 3 walking tasks: a) natural walking at the subject's preferred cadence; b) walking with eyes closed to increase reliance on vestibular input; c) walking while fixing gaze on a distant target to enhance head stability. Sagittal plane head and trunk movements will be recorded using a MacReflex camera system. Frequency analyses will determine gain and phase characteristics of head on trunk movement patterns adopted by subjects to maintain head stability in each condition. These analyses should reveal increasing challenges to head stability in older adults for natural walking and eyes closed walking respectively. Fixation of gaze will improve head stability for both young and older adults at low frequencies showing compensatory head on trunk movements. Older adults will also show improved head stability at higher frequencies while fixing their gaze. Information obtained from this study will characterize head stability in healthy older adults and provide insights regarding changes in visual and vestibular contributions to head stability with age. This study will serve as a basis for examining head stability in older adults with a history of falling.