The Effects of Menstrual Cycle Phase on Exercise Performance in Eumenorrheic Women: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and Bayesian network meta-analysis of experimental studies
PubMed 32661839 · doi:10.1007/s40279-020-01319-3
What was done
Authors conducted a systematic review and Bayesian multilevel network meta-analysis of experimental studies across four databases following PRISMA guidelines. Eligible studies evaluated exercise performance across two or more defined menstrual cycle phases in eumenorrheic women. An initial pairwise meta-analysis compared the early follicular phase against all other phases combined. A Bayesian network meta-analysis then evaluated direct and indirect comparisons among all phases (early follicular, late follicular, ovulation, early luteal, mid-luteal, late luteal), quantified using Surface Under the Cumulative Ranking curve (SUCRA). Methodological quality was evaluated using a modified Downs and Black checklist and GRADE criteria.
What was found
Across 78 included studies, 51 contributed to the pairwise analysis and 73 to the network meta-analysis. Pooled analysis showed a trivial reduction in endurance- and strength-based performance during the early follicular phase compared to all other phases combined (median effect size [ES] = -0.06, 95% CrI: -0.16 to 0.04). The largest difference was between the early follicular and late follicular phases (median ES = -0.14, 95% CrI: -0.26 to -0.03). SUCRA ranking was lowest for the early follicular phase (30%) compared to other phases (53% to 55%). Quality of evidence was classified as low (42%).
Why it matters
Performance fluctuations across the menstrual cycle are trivial at the population level, indicating that universal phase-based training recommendations are unsupported and individualized tracking should be used instead.
Limits
The total number of human participants is not reported in the abstract. Methodological quality across the primary studies was predominantly low, between-study variation was high, and details regarding hormonal verification versus calendar-based phase determination are omitted in the abstract.