World Medical Association Declaration of Helsinki: ethical principles for medical research involving human subjects.
World Medical Association
https://pubmed.ncbi.nlm.nih.gov/24141714Actively Recruiting
Led by Faculdade de Motricidade Humana · Updated on 2026-05-18
40
Participants Needed
1
Research Sites
26 weeks
Total Duration
Researchers are investigating how natural menstrual cycles and oral contraceptive use affect strength, hydration, energy balance, and body composition in female athletes. This observational study focuses on hormonal changes during specific menstrual phases and oral contraceptive cycles to better understand their impact on athletic performance and health. The study addresses gaps in knowledge about how estrogen and progesterone influence muscle strength, hydration status, and energy availability in female athletes. The study involves 40 female athletes divided into two groups: 24 naturally menstruating athletes and 16 oral contraceptive users. Naturally menstruating participants will be assessed during early follicular, late follicular, and mid-luteal menstrual phases, while oral contraceptive users will be evaluated during active pill and withdrawal phases. Testing includes strength measurements using handgrip dynamometry, bench press, and leg press, along with hormonal blood tests, body water and hydration assessments, energy expenditure and balance measurements, and body composition analysis. Participants will attend sessions during each menstrual or contraceptive phase for detailed assessments of strength and hydration. Researchers will monitor hormone levels, body water compartments, hydration markers, energy intake and expenditure, and resting metabolism. The study aims to validate measurement methods and explore relationships between hormone fluctuations and energy availability. Total participation spans multiple menstrual or contraceptive phases, with data collected longitudinally to capture variations over time.
CONDITIONS
Effects of the Menstrual Cycle and Oral Contraceptive Use on Health and Performance in Athletes
You may qualify if you...
You will not qualify if you...
Complete this quick 3-step screening to check your eligibility
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - Approximately 4 weeks
Participants are observed and assessed across three menstrual or contraceptive cycle phases without receiving any intervention. Assessments include strength testing, hormone measurements, hydration status, energy balance, and body composition.
3 visits for naturally menstruating athletes during early follicular, late follicular, and mid-luteal phases; 3 visits for oral contraceptive users during week 1, weeks 2-3, and withdrawal week
Total: 1 location
1
Faculdade de Motricidade Humana
Cruz Quebrada, Oeiras, Portugal, 1495-751
Actively Recruiting
F
Flávio Jerónimo
Study Type
OBSERVATIONAL
Masking
N/A
Allocation
N/A
Model
N/A
Primary Purpose
N/A
Number of Arms
2
Have more questions? Get in touch with our team for quick support
Explore thousands of other clinical trials that might be a better match.
Sign up to get personalized trial recommendations delivered to your inbox.
Already have an account? Log in here
World Medical Association
https://pubmed.ncbi.nlm.nih.gov/24141714Tine Vrist Dam, Line Barner Dalgaard, Vassilis Sevdalis...
https://pubmed.ncbi.nlm.nih.gov/36106832G H Guyatt, M Townsend, L B Berman...
https://pubmed.ncbi.nlm.nih.gov/3680471Christine M Florez, Christian Rodriguez, Madelin R Siedler...
https://pubmed.ncbi.nlm.nih.gov/39411840S B Heymsfield, J Wang, S Lichtman...
https://pubmed.ncbi.nlm.nih.gov/2683725ZiMian Wang, F Xavier Pi-Sunyer, Donald P Kotler...
https://pubmed.ncbi.nlm.nih.gov/12399267Hiroyuki Sagayama, Yosuke Yamada, Natalie M Racine...
https://pubmed.ncbi.nlm.nih.gov/26989221Catarina N Matias, Diana A Santos, Pedro B Júdice...
https://pubmed.ncbi.nlm.nih.gov/25886709M Rosenbaum, E Ravussin, D E Matthews...
https://pubmed.ncbi.nlm.nih.gov/8780213J B DE B WEIR
https://pubmed.ncbi.nlm.nih.gov/15394301