A Meta-Analysis of Resistance Training in Female Youth: Its Effect on Muscular Strength, and Shortcomings in the Literature

Abstract

Background: Resistance training is an effective way to enhance strength in female youth but, to date, no researcher has meta-analysed its effect on muscular strength in that population. Objectives: This meta-analysis characterised female youths’ adaptability to resistance training (RT). A second objective was to highlight the limitations of the body of literature with a view to informing future research. Data Sources: Google Scholar, PubMed, Web of Science. Study Eligibility Criteria: Resistance training interventions in healthy females with a mean age between 8 and 18 years. Programmes of between 4 and 16 weeks’ duration that included a control group. Study Appraisal and Synthesis Methods: The inverse-variance random effects model for meta-analyses was used because it allocates a proportionate weight to trials based on the size of their individual standard errors and facilitates analysis whilst accounting for heterogeneity across studies. Effect sizes, calculated from a measure of muscular strength, are represented by the standardised mean difference and are presented alongside 95% confidence intervals. Results: The magnitude of the main effect was ‘small’ (0.54, 95% confidence interval: 0.23–0.85). Effect sizes were larger in older (> 15 years; ES = 0.72 [0.23–1.21] vs. 0.38 [− 0.02–0.79]), taller (> 163 cm; ES = 0.67 [0.20–1.13] vs. 0.55 [0.08–1.02]) and heavier (< 54 kg; ES = 0.67 [0.30–1.03] vs. 0.53 [− 0.00–1.06]) participants. Conclusions and Implications of Key Findings: Resistance training is effective in female youth. These findings can be used to inform the prescription of RT in female youth.