Effects Of Position And Force Control Motor Practice On Accuracy And Corticomuscular Coherence In Children

PURPOSE: To investigate effects of motor practice with an emphasis on either position or force control on motor performance i.e. motor accuracy and variability in preadolescent children. Furthermore, to investigate potential changes in corticomuscular coherence following motor practice. METHODS: A setup allowing discrete wrist flexions of non-dominant hand was designed and motor accuracy and variability were tested when the task was to generate specific movement endpoints (15-75 deg) or force levels (5-25% MVC). Participants were 44 children aged 9-11 years. Motor performance was measured at baseline and post motor practice without augmented feedback on performance. Following baseline assessment, the participants) were randomly assigned to one of three groups; position control (PC) or force control (FC) motor practice groups, or a resting control (CON). PC and FC performed motor practice with emphasis on either position control or force control, respectively, and practiced the tasks with augmented visual feedback on performance during four blocks of practice with 40 trials in each. RESULTS: Following practice there was a significant decrease in error for PC in the position task (-110.48 ± 12.38, CI: [-134.73; -86.22], p < 0.001), a small but significant decrease for CON (-26.91 ± 12.25, CI: [-50.92; -2.9], p = 0.028) and no change in FC in the position task (-6.73 ± 12.24, CI: [-30.72; 17.26], p = 0.58). Following practice, improvements in movement accuracy were significantly greater in PC than in FC and CON (PC vs. FC (-103.75 ± 17.41, CI: [-144.53; -62.96], p < 0.001), and PC vs. CON (-83.57 ± 17.42, CI: [-124.37; -42.77], p < 0.001)). None of the groups had a statistically significant change in error from baseline to post practice in the force task (p = 0.08-0.45). Pooled coherence for each group at baseline and post-practice was consistently low in both the position-control task and the force-control task (coherence ranging from 0-0.0016). CONCLUSIONS: These findings demonstrate that children aged 9-11 years improve position control following dynamic accuracy motor practice. Opposed to previous findings in adults, preadolescent children displayed small or no improvements in force control following isometric motor practice, low transfer between tasks and no changes in corticomuscular coherence.