The constraint-led approach to enhancing team synergies in sport - What do we currently know and how can we move forward? A systematic review and meta-analyses

© 2020 Elsevier Ltd Background: During the past decade, an extensive body of work has documented the Constraints-Led Approach (CLA) as a prominent methodology for developing collective synergetic tendencies in sports teams. Objectives: This study aimed to quantify and compare findings, in existing research, related to key synergetic properties of dimensional compression and reciprocal compensation in team sports performance. Method: A literature search was conducted for articles published until December 2019, on electronic databases PubMed, Scopus, EBSCO, SPORTDiscus, Web of Science, and Google Scholar. Inclusion criteria were defined before the selection process. From selected articles information was extracted on authors, year of publication, study design, study context, sample, sport, variables assessed, type of constraints manipulated, statistical methods, and main findings. The manuscripts' methodological quality was assessed through the Downs and Black checklist. A meta-analysis was performed using a random-effects model and subgroup analyses were conducted for two potential moderators: dimensional compression and reciprocal compensation. Results: A total of 62 and 26 studies met the inclusion criteria for systematic and meta-analysis, respectively. Results revealed that investigations tended to mostly evaluate how task constraints manipulations shaped emergent tactical behaviors of male football players within training contexts. A high level of heterogeneity (I2 = 99.56%, p < .001) was found across studies and publication biases were observed in the literature. Conclusions: The high level of heterogeneity is possibly justified by the diversity of metrics applied to assess players' performance behaviors. The level of research heterogeneity observed also supports the assumption that variable behaviors enhance adaptive tendencies in teams. Observed publication and inflation biases highlighted the need to adopt methodological procedures that avoid systematic flaws in future investigations.