Identifying optimal scheduling parameters for the application of motor imagery after physical practice to enhance learning


While it is thought that motor imagery (MI), the mental rehearsal of a motor task may enhance consolidation when applied after physical practice (PP), little is known about the optimal scheduling of when MI should be applied after PP to improve motor learning. Here, we explore the effects of time between PP and MI sessions within a single day of practice. Participants (N = 15) were randomized into two groups and engaged in PP of a shape-tracing task involving random and repeated shapes. Participants then performed MI either one hour (1HR group) or six hours (6HR group) after PP. Physical test blocks were administered in a pre/post/retention (~24 hours after practice) design, with error (px) used to measure performance. Effect sizes (Cohen’s d) were calculated to quantify motor learning (pre minus retention) for each shape type (random, repeated). Motor learning related to random shapes did not occur in either group, as evidenced by negligible effect sizes (6HR: MPRE = 214.17±50.58, MRET = 216.82±30.16, d =0.05; 1HR: MPRE = 224.74±25.79, MRET = 223.38±24.94, d =0.05). Motor learning related to repeated shapes occurred for both groups, the 6HR group learned to a greater extent as evidenced by a large vs. moderate effect size (6HR: MPRE = 214.63±38.13, MRET = 179.59±41.21, d =0.92; 1HR: MPRE = 211.77±28.54, MRET = 193.58±19.78, d =0.63). Findings suggest that a larger time period between PP and MI (within a single day) enhanced learning, overall informing scheduling of MI and PP to enhance motor learning.