Is implicit adaptation improved by physical activity?


Recent studies have found that aerobic exercise improves sensorimotor adaptation (Mackay et al., 2021; Neva et al., 2019). It is well known that sensorimotor adaptation is driven both by an explicit process, through the use of cognitive strategies (Taylor et al., 2014), and an implicit process driven by sensory prediction errors (Mazzoni & Krakauer, 2006). Enhanced adaptation following exercise may be attributable to the explicit component (Mackay et al., 2021), but whether exercise also affects implicit processes remains unclear. This study aimed to test this hypothesis. In a within-subject design, participants (n=13) performed a reaching movement, while being pseudo-randomly exposed to CW or CCW 30° visuomotor rotations for 180 trials, a paradigm known to isolate implicit processes. Implicit adaptation was assessed by the involuntary bias of the hand trajectory in the direction opposite to the error following a rotated trial, termed post-rotation bias (PRB). Participants executed the task before (PRE) and after (POST) a 20 minutes cycling bout at moderate intensity. Results revealed robust PRBs in both the PRE and POST conditions. Critically, however, their magnitude was not significantly modulated by exercise (mean difference = 0.036°, p = 0.873, effect size = 0.045). Further analyses revealed that movement vigour (RT+MT) was significantly reduced in a stepwise function following exercise (mean difference = -22.178 ms, p < 0.001, effect size = 1.604), indirectly confirming that exercise affected motor functions. These results suggest that an acute bout of moderate exercise does not improve implicit adaptation, as measured by the PRB method.