Mobility in everyday life requires executing and shifting between a broad assortment of functional tasks and resisting disturbances that could cause falls. Though the importance of successfully performing a variety of functional tasks is recognized and incorporated in clinical assessments (e.g., the Timed-Up-and-Go Test, Berg Balance Scale), little is understood about the underlying neuromuscular control required, or how it changes with age. The neuromuscular control for functional tasks such as walking is typically studied in isolation, or with variations on the same task. Characterizing the coordination required to produce and shift between a wider variety of tasks and resist external disturbances is crucial to understanding mobility in daily life, not just within a controlled lab environment.

In this work, we identify patterns of multi-muscle coordination (motor modules) across functional tasks in healthy young, middle-aged, and older adults. We demonstrate that healthy young adults recruit common motor modules across voluntary functional tasks (walking, turning, and chair transfers), and characterize changes associated with age. Additionally, we investigate whether motor modules are shared between reactive balance and these voluntary tasks, and whether there are age-related changes here. Identifying age-related changes in multi-muscle coordination can lead to a better understanding of the neuromuscular control underlying mobility changes due to normal aging. Further, fully characterizing changes in neuromuscular control that are due to normal aging can provide a basis for identifying the changes associated with impairments that commonly occur in older adults (e.g., stroke).