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

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.