An Exploratory Meta-Analytic Review on the Empirical Evidence of Differential Learning as an Enhanced Motor Learning Method.

Bruno Tassignon,Ben Serrien,Alli Gokeler,Ron Clijsen,Jean-Pierre Baeyens,Jo Verschueren,Anne Benjaminse

doi:10.3389/fpsyg.2021.533033

Abstract

Background: Differential learning (DL) is a motor learning method characterized by high amounts of variability during practice and is claimed to provide the learner with a higher learning rate than other methods. However, some controversy surrounds DL theory, and to date, no overview exists that compares the effects of DL to other motor learning methods.Objective: To evaluate the effectiveness of DL in comparison to other motor learning methods in the acquisition and retention phase.Design: Systematic review and exploratory meta-analysis.Methods: PubMed (MEDLINE), Web of Science, and Google Scholar were searched until February 3, 2020. To be included, (1) studies had to be experiments where the DL group was compared to a control group engaged in a different motor learning method (lack of practice was not eligible), (2) studies had to describe the effects on one or more measures of performance in a skill or movement task, and (3) the study report had to be published as a full paper in a journal or as a book chapter.Results: Twenty-seven studies encompassing 31 experiments were included. Overall heterogeneity for the acquisition phase (post-pre; I2 = 77%) as well as for the retention phase (retention-pre; I2 = 79%) was large, and risk of bias was high. The meta-analysis showed an overall small effect size of 0.26 [0.10, 0.42] in the acquisition phase for participants in the DL group compared to other motor learning methods. In the retention phase, an overall medium effect size of 0.61 [0.30, 0.91] was observed for participants in the DL group compared to other motor learning methods.Discussion/Conclusion: Given the large amount of heterogeneity, limited number of studies, low sample sizes, low statistical power, possible publication bias, and high risk of bias in general, inferences about the effectiveness of DL would be premature. Even though DL shows potential to result in greater average improvements between pre- and post/retention test compared to non-variability-based motor learning methods, more high-quality research is needed before issuing such a statement. For robust comparisons on the relative effectiveness of DL to different variability-based motor learning methods, scarce and inconclusive evidence was found.

Highlights

Motor learning is a set of processes associated with practice or experience leading to relatively permanent gains in the capability for skilled performance (Schmidt and Lee, 2013)
Differential learning (DL) has been used in a variety of contexts: (1) sport performance outcomes; (2) technical skills in a single sports movement; (3) tactical skills in a sport context; (4) fine motor skills; and (5) rehabilitation (Repšaite et al, 2015; Kurz et al, 2016)
Based on the meta-analyses and in light of the low methodological quality of the included studies, DL shows potential to be considered as an enhanced motor learning method in comparison to TL methods when aiming to improve motor learning during the acquisition and retention phase

Summary

Introduction

Motor learning is a set of processes associated with practice or experience leading to relatively permanent gains in the capability for skilled performance (Schmidt and Lee, 2013). Traditional (= non-variability based) motor learning (TL) methods include, for instance, repetitive practice (REP) (Gentile, 1972) or methodological series of exercises (MSE) (Djatschkow, 1973) wherein practice variability is minimized to natural movement variability and a fixed progression of exercises Methods such as variable practice (VP) (Schmidt, 1975), contextual interference (CtIt) (Shea and Morgan, 1979), DL (Schöllhorn et al, 2010a), structural learning (SL) (Braun et al, 2010; Hossner et al, 2016b), or the constraint-led approach (CLA) (Renshaw et al, 2010) utilize practice variability in an attempt to further enhance motor learning outcomes. Schöllhorn et al (2009a) depicted these various motor learning methods in a continuum of increasing variability and noise, with optimal variability levels being dependent on subject and situational constraints (Schöllhorn and Horst, 2020) These different theoretical concepts are often merged when trainers or clinicians aim to improve the motor performance of athletes or patients. Some controversy surrounds DL theory, and to date, no overview exists that compares the effects of DL to other motor learning methods

Results

Discussion

Conclusion