Young Adults Recruit Similar Motor Modules Across Walking, Turning, and Chair Transfers

Moving about in the world during daily life requires executing and successfully shifting between a variety of functional tasks, such as arising from a chair or bed, walking, turning, and navigating stairs, etc. Moreover, moving about during daily life requires not only navigating between different functional tasks but also performing these tasks in the presence of mental distractions. However, little is known about underlying neuromuscular control for executing and shifting between these different tasks. In this study, we investigated muscle coordination across walking, turning, and chair transfers by applying motor module (aka muscle synergy) analysis to the Timed-Up-and-Go (TUG) test with and without a secondary cognitive dual task. We found that healthy young adults recruit a small set of common motor modules across the subtasks of the TUG test and that their composition is robust to cognitive distraction. Instead, cognitive distraction impacted motor module activation timings such that they became more consistent. This work is the first to demonstrate motor module generalization across multiple tasks that are both functionally different and crucial for healthy mobility. Overall, our results suggest that the central nervous system may draw from a “library” of modular control strategies to navigate the variety of movements and cognitive demands required of daily life. New & Noteworthy We demonstrated that healthy young adults recruit a small set of motor modules across subtasks of the Timed-Up-and-Go test (i.e., walking, turning, and chair transfers). Moreover, we showed that motor module composition, but not activation timing, is robust to cognitive distractions. These results support the hypothesis that healthy young adults recruit from a “library” of motor modules and modulate their activation timing to meet the different mechanical and cognitive demands required to navigate daily life.