Long-term motor programming improvements occur via concatenation of movement sequences during random but not during blocked practice.

According to S. T. Klapp (1995, 1996), extensive practice serves to induce the concatenation of multiple-element responses. One benefit of the chunking process, argued Klapp, is more efficient execution of motor programming. The authors conducted the present study with 30 participants to investigate that proposition. The chunking process was found to be very transient following some practice regimes. Specifically, compared with exposure to random practice, extensive blocked practice resulted in only temporary movement sequence consolidation. The present results provide support for the claim that random practice not only leads to improvements in the completion of intratrial movement planning processes but also affects the structure of the memory developed during practice. Both components are important contributors to long-term improvements in movement preparation associated with a high contextual-interference practice condition.