There is increasing evidence that movement variability during motor skill acquisition
plays a functional role. Specifically, initial variability might represent exploration
of the possible motor space for solutions and error identification. Following practice,
individuals might exploit a reduced amount of motor solutions to execute the task.
While this variability pattern has been supported during discrete upper limb and multi-finger
force tasks, there is a paucity of evidence for continuous whole-body motor tasks.
Therefore, the purpose of this study was to characterize the role of variability during
the acquisition of a whole-body continuous motor task across practice sessions in
young adults. Twelve young adults aged 18-35-years participated in this study. Subjects
practiced a novel, sagittal plane task, the kettlebell swing, using an online training
video. We conducted an uncontrolled manifold analysis to partition local variability
of the configuration of the kettlebell and body segments based on their impact on
the position of the center-of-mass (COM) in the sagittal plane. Our results demonstrated
that following initial practice, variability that did not affect the COM position
remained elevated, suggesting sustained exploration of motor solutions. Following
multiple practice sessions, variability related to motor solutions decreased, potentially
indicating exploitation. The results from this study support the proposal that young
adults initially utilize a range of motor solutions when acquiring a whole-body motor
skill, followed by exploitation of stereotypic movement.