Contextual Interference Effect on Motor Skills

Abstract

Previous research has reached conflicting conclusions regarding the effects of random (R) versus block (B) practice in motor skill acquisition and retention, an important component of fitness. PURPOSE: Use the aggregate data meta-analytic approach to examine the effects of R versus B practice in motor skill acquisition and retention. METHODS: Randomized trials of B versus R skill acquisition published up to 2014 were included by searching eleven databases, cross-referencing and expert review. Studies were selected and extracted by the first author, with 45% of those extracted checked by the third author. Risk of bias was assessed using a self-developed instrument (maximum points = 5). Random effects models using the standardized mean difference effect size (ES) were used to pooled results. Heterogeneity was examined using the Q statistic and inconsistency using I2. An alpha value < 0.05 was considered statistically significant. RESULTS: Of 481 studies screened, 25 representing 1256 males and females and up to 43 ES were included. Risk of bias was M ± SD = 2.3 ± 0.48. For within-group analysis, the B group significantly improved performance during the acquisition phase (ES = 0.69, CI95%= 0.40 to 0.97; Q= 219, p< 0.001, I2= 82%) and significantly decreased performance during the retention phase (ES = -0.25, CI95%= -0.51 to -0.02; Q= 209.4, p< 0.001, I2= 79%). The R group also significantly improved performance during the acquisition phase (ES = 0.79, CI95%= 0.43 to 1.15; Q= 182.2, p< 0.001, I2= 83%) with no statistically significant changes during the retention phase (ES = 0.12, CI95%= -0.12 to 0.38; Q= 159.1, p< 0.001, I2= 74%). For between-group analysis, the B group outperformed the R group in the acquisition phase (ES = -0.15, CI95%= -0.30 to -0.01; Q= 41.8, p< 0.07, I2= 7%) with no statistically significant between-group differences during the retention phase (ES = 0.02, CI95%= -0.20 to 0.26; Q= 124.1, p< 0.001, I2= 71%). CONCLUSIONS:The overall results suggest that (1) both B and R practice improve motor skills during the acquisition phase, with greater improvements observed for B practice, (2) B practice results in decreases in performance during the retention phase, with no differences for R practice, and (3) no differences exist between B and R practice during the retention phase.