Abstract
Objectives: Two core components of movement execution are offline (i.e. planning) and online (i.e. detection and correction of errors) motor control. There is some ambivalence in the literature as to whether observed reductions in online motor control, under heightened pressure, are caused by a shift to offline-based motor control strategies, or because of impaired online motor control. The present study aimed to provide clarification by directly testing online motor control via cursor perturbations under heightened pressure. Methods: Participants (n=14) performed a target-directed aiming task. Following familiarisation and acquisition phases, participants were transferred to heightened pressure. Pressure was manipulated using a combination of monitoring and outcome pressure. To directly test online motor control, 20% of trials in all phases contained cursor perturbations, which necessitated online corrections to maintain outcome performance. Acquisition (low pressure) and transfer (heightened pressure) phase data were compared. In non-perturbation trials, offline and online motor control performance was inferred from variability profiles. In perturbation trials, correction magnitudes were used to test online motor control. Results and Discussion: In non-perturbation trials, offline motor control performance remained stable from acquisition to pressure transfer, whilst online motor control reduced. However, necessitated online motor control was not impaired by heightened pressure. Conclusion: The above suggests that, when online motor control is not necessitated, heightened pressure may lead individuals to shift to an offline-based motor control strategy. This may be to compensate for potentially impaired online motor control. Conversely, necessitated online motor control may not be impacted by the same impairments under pressure.
