Introduction
goal-directed arm-movements, Disease-
DISEASES
There is ample research evidence that aging or specific diseases affect motor performance and can lead to functional impairments. Standardized clinical tests help to assess one’s mobility and to monitor its changes, e.g., for estimating the risk of falls. These tests often measure gait and balance capacity, since these are essential for autonomy in daily living activities and thus closely associated with our overall health and mortality [Most studies applying kinematic measures for assessing upper-body performance focus on simple, single-joint movements, e.g., finger tapping or single reaching tasks [For upper-limb performance analysis, we implemented a repetitive movement task challenging the sensorimotor system in terms of fast and goal-directed execution, i.e., an arm-movement test in sitting position. Disease- and age-related changes in upper-limb movements are generally quantifiable e.g., by slower movement speeds, reduced precision and smoothness, and greater variability [As a frequently applied mobility test acknowledged as clinically relevant, we chose the Timed Up and Go (TUG) test [The present study evaluates interrelations between upper- and lower-body performance. This may enable a deeper understanding of movement organization. We hypothesized that the upper-limb performance as measured via rapidly-executed, repetitive, goal-directed arm-movements (arm-movement test) would predict the (gait) performance in a functional highly-relevant mobility test such as TUG. We assumed that arm movements and TUG execution during varying conditions (preferred, dual-task, fast) would both enable us to quantify declining motor function even beyond a sole age effect.