Random practice enhances 24-h motor skill retention across levels of baseline task performance.

BACKGROUND: Random practice (RP) impairs acquisition performance but often enhances retention relative to blocked practice (BP), a pattern known as the contextual interference (CI) effect. Whether this benefit varies with baseline task performance remains unclear. OBJECTIVE: To examine whether baseline performance moderates the retention benefit of RP. METHODS: We conducted a secondary analysis of 70 right-handed participants who practiced a discrete sequence production (DSP) task under RP (n = 35) or BP (n = 35). Participants were classified within each practice group as having higher or lower baseline performance based on baseline response time. After excluding one median-ranked participant per group, subgroup analyses included 68 participants. Acquisition and retention at 5 min, 6 h, and 24 h were analyzed using repeated measures ANOVA and generalized estimating equations. RESULTS: BP produced better performance at the end of practice, whereas RP produced better 24-h retention at both levels of baseline performance. No significant BP-RP differences were detected at the 5-min or 6-h retention tests. The directional hypothesis that the retention advantage of RP would be greater in the subgroup with higher baseline performance was not supported. Secondary exploratory comparisons within the RP group did not detect significant retention differences between the two baseline-performance subgroups, but these comparisons were not equivalence tests. CONCLUSION: The 24-h retention benefit of RP was observed at both levels of baseline performance represented in this DSP sample. Prospective studies using continuous measures of baseline performance are needed to determine the generalizability and practical significance of this finding.