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The use of preclinical models to investigate antitumor effects of exercise on breast tumor (BT) development and progression are critical. However, published results have not been quantitatively summarized or examined for potential exercise-moderating variables. We conducted this review to summarize and quantify the effect-size of exercise on BT outcomes in preclinical studies. A literature search was performed in MEDLINE, PubMed, Web of Science and System for Information on Grey Literature in Europe (SIGLE) databases. Risk of bias was assessed using SYRCLE's RoB tool. A total of 116 correlations were performed to analyze 28 preclinical studies published through December 2016, which included 2,085 animals and 51 exercise programs. Positive effects of small, medium and large magnitude were observed in tumor incidence, growth and multiplicity, respectively. In the tumor microenvironment, positive effects of large magnitude were also observed in proliferation and apoptosis but not in angiogenesis. Moderator variables correlated with higher intervention effects were identified along with a considerable heterogeneity in exercise protocols that precluded us from clearly perceiving the benefits of exercise exposure. In conclusion, exercise performed under specific conditions benefits BT outcomes. Preclinical studies with exercise designs mimicking exercise exposure that can be used in clinical contexts are needed. [ABSTRACT FROM AUTHOR]

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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. 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. 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. 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. 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. • Cross-sectional studies have explored task constraints in sports practice. • Studies analyzed mainly the performance of male football players in training. • Several statistical procedures have been used to record key synergetic properties. • A high level of heterogeneity was found across studies selected for meta-analysis. • Publication and inflation biases were observed in the literature selected. [ABSTRACT FROM AUTHOR]