Since the initial study on contextual interference (CI) in 1966, research has explored how practice schedules impact retention and transfer. Apart from support from scientists and practitioners, the CI effect has also faced skepticism. Therefore, we aimed to review the existing literature on the CI effect and determine how it affects transfer in laboratory and applied settings and in different age groups. We found 1,287 articles in the following databases: Scopus, EBSCO, Web of Science, ScienceDirect, supplemented by the Google Scholar search engine and manual search. Of 300 fully screened articles, 42 studies were included in the systematic review and 34 in the quantitative analysis (meta-analysis). The overall CI effect on transfer in motor learning was medium (SMD = 0.55), favoring random practice. Random practice was favored in the laboratory and applied settings. However, in laboratory studies, the medium effect size was statistically significant (SMD = 0.75), whereas, in applied studies, the effect size was small and statistically non-significant (SMD = 0.34). Age group analysis turned out to be significant only in adults and older adults. In both, the random practice was favored. In adults, the effect was medium (SMD = 0.54), whereas in older adults was large (SMD = 1.28). In young participants, the effect size was negligible (SMD = 0.12). Systematic review registration: https://clinicaltrials.gov/, identifier CRD42021228267.

• Keywords
• blocked practice, contextual interference, motor learning, practice schedule, random practice, transfer,
• Publication type
• Journal Article MeSH
• Systematic Review MeSH

The effect of practice schedule on retention and transfer has been studied since the first publication on contextual interference (CI) in 1966. However, strongly advocated by scientists and practitioners, the CI effect also aroused some doubts. Therefore, our objective was to review the existing literature on CI and to determine how it affects retention in motor learning. We found 1255 articles in the following databases: Scopus, EBSCO, Web of Science, PsycINFO, ScienceDirect, supplemented by the Google Scholar search engine. We screened full texts of 294 studies, of which 54 were included in the meta-analysis. In the meta-analyses, two different models were applied, i.e., a three-level mixed model and random-effects model with averaged effect sizes from single studies. According to both analyses, high CI has a medium beneficial effect on the whole population. These effects were statistically significant. We found that the random practice schedule in laboratory settings effectively improved motor skills retention. On the contrary, in the applied setting, the beneficial effect of random practice on the retention was almost negligible. The random schedule was more beneficial for retention in older adults (large effect size) and in adults (medium effect size). In young participants, the pooled effect size was negligible and statically insignificant.

• MeSH
• Humans MeSH
• Motor Skills * physiology   MeSH
• Retention, Psychology physiology   MeSH
• Learning * physiology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Meta-Analysis MeSH
• Systematic Review MeSH

Decision-making is a complex action requiring efficient information processing. Specifically, in movement in which performance efficiency depends on reaction time, e.g., open-loop controlled movements, these processes may play a crucial role. Information processing includes three distinct stages, stimulus identification, response selection, and response programming. Mainly, response selection may play a substantial contribution to the reaction time and appropriate decision making. The duration of this stage depends on the number of possible choices an individual has to "screen" to make a proper decision. Given that reaction time is crucial in many sports, the possibilities of reducing it through practice are very tempting. The information processing and its relationship to the manner an individual is practicing are discussed. Especially the variability of practice issues will be explored. In variable practice conditions, an individual has to react to one or more stimuli and has to produce one of the many variations of the same movement or different movements they learned. One has to identify a stimulus appropriately and has to select a response optimally, i.e., choosing from as few choices as possible to reduce the reaction time. On the other hand, in constant practice conditions, an individual can be exposed to one or many stimuli. Still, there is only one variation of the movement that can be executed in the presence of a learned stimulus. Based on the information processing theory and the results of the research focusing on variability of practice, I discuss how the practice conditions may affect reaction time and, as a result, the decision-making process. I conceptually frame the possible implications of practice conditions on decision making related to information processing. In this review, a possible mechanism and relationship between practice conditions and decision-making are presented. Future research directions are presented.

• Keywords
• decision making, information processing, motor learning, practice conditions, specificity of practice, variability of practice,
• Publication type
• Journal Article MeSH
• Review MeSH