Abstract
High intensity interval training (HIIT) is effective in modulating brain excitability. This effect on neuroplasticity is thought to promote learning and retention of motor skills. However, it is unclear whether the timing of HIIT with respect to skill training can aid in acquisition and retention. Here we examined the effect of HIIT on motor learning when performed before vs after multiple sessions of task practice, and to examine the effect of HIIT on corticospinal excitability (CSE) and intracortical networks. 28 participants (16 F) performed 4 sessions of HIIT (3x3 min at 90% maximal power output (POmax) separated by 2 min at 50% POmax). HIIT-mediated changes in CSE and intracortical networks were assessed by transcranial magnetic stimulation during session 2. During sessions 3-5, either before or after HIIT, participants trained on a complex motor skill requiring them to reproduce trajectories on a touchscreen. Using Bayesian linear mixed effects modeling a credible difference in performance was observed between the HIIT groups, where the group performing HIIT after task practice showed improved learning when compared to the group performing HIIT before (probability distribution (pd) = 95.4%, d = 0.22). Further, HIIT was shown to drive an increase in CSE immediately after (pd = 98.44%, d = 0.30) and 30 minutes after the exercise session (pd = 99.25%, d = 0.30). This supports the use of HIIT for motor learning through consolidation of a motor skill, and that HIIT-mediated changes in CSE and intracortical networks are a likely mechanism underlying the effect.
