(48) RELATIONSHIP BETWEEN ESTROGEN AND PROGESTERONE RATIO AND ANAEROBIC PERFORMANCE IN WOMEN: A PILOT ANALYSIS

Background: To date, there is conflicting evidence as to the effects of estrogen and progesterone on anaerobic performance. This may be partly due to the hormonal environment often being characterized at a single timepoint, which does not account for fluctuations in female sex hormones. Estrogen/progesterone ratio (E:P) over the days leading up to performance may provide greater insight into the potential influence of female sex hormones on exercise performance.

Purpose: To explore the relationship between E:P and anaerobic performance (fatigue index (FI), peak power (PP), average power (AP), and power drop (PD)) in eumenorrheic (EUM) and oral contraceptive (OC) using women.

Methods: Healthy, recreationally active, EUM (n=2) and OC users (n=4) (Mean±SD; Age: 23.3±2.3yrs; %BF 26.1±4.1%) completed a repeated sprint ability test (10 × [6s sprint: 30s rest]) on a friction-loaded cycle ergometer. Testing was completed seven days after start of menstruation and five to nine days after ovulation for EUM and during the active and placebo pill phase for OC. Measures of FI (%) were recorded and PP (watts (W)), AP (W), and PD (W) were averaged across the 10 sprints. Estrogen and progesterone were measured using an at-home urine hormone test completed each morning. Hormone ratios were calculated for the day of testing (E:P₁) and over three days leading up to testing using three different methods: first, by averaging estrogen and progesterone levels individually across the three-day period to derive the ratio (E:P₂); second, by calculating the ratio for each of the three days and subsequently averaging them (E:P₃); and third, by calculating the area under the curve of E:P₃ (E:P₄). Separate Pearson correlations were run for each method to evaluate the relationship between E:P and anaerobic performance.

Results: E:P₁ (Mean±SD: 57.92±30.61) was not significantly associated with FI (r=0.23; p=0.61), PP (r=0.25; p=0.58), AP (r=0.36; p=0.43), and PD (r=-0.20; p=0.67). E:P₂ (55.19±41.26) was not significantly associated with FI (r=0.21; p=0.65), PP (r=0.02; p=0.97), AP (r=0.06; p=0.90), and PD (r=-0.34; p=0.46). E:P₃ (64.38±49.64) was not significantly associated with FI (r=0.06; p=0.91), PP (r=0.12; p=0.80), AP (r=0.13; p=0.78), and PD (r=-0.12; p=0.80). E:P₄ (194.95±130.99) was not significantly associated with FI (r=0.04; p=0.93), PP (r=0.21; p=0.65), AP (r=0.22; p=0.63), and PD (r=-0.07; p=0.88).

Conclusions: Results of this pilot analysis suggest that E:P ratio is not significantly associated with anaerobic performance in EUM women and OC users, regardless of if E:P was measured on the day of or the days leading up to performance. However, the current study implemented novel methods and approaches that allow for female hormone fluctuation to be accounted for. In order to refine these methods, future research should explore these methods in a larger population; potentially exploring relationships with estrogen and progesterone separately and/or other statistical modeling approaches to quantify fluctuations in the female hormonal environment. PRACTICAL APPLICATIONS: To date, the relationship between the female hormonal environment and sport and exercise performance remains unclear. However, hormone tracking could be a useful tool to individualize management strategies for EUM and OC using female athletes and active women who experience performance detriments associated with their menstrual cycle or hormonal contraception.

Acknowledgements: This study was supported in part by a Young Investigator Grant from the National Strength and Conditioning Association Foundation and an Early-Career Grant from the Advanced Support for Innovative Research Excellence program at the University of South Carolina.