Rationale
The aim of the study is to increase knowledge that can help improve understanding of risk factors for knee injuries and support the development of more effective prevention strategies. Effective injury prevention encourages lifelong participation in physical activity and reduces the long-term consequences of injuries.
Background
Serious knee injuries, such as anterior cruciate ligament (ACL) rupture, are common particularly among female football players. Menstrual cycle-related fluctuations in hormone levels have been proposed as one potential factor predisposing athletes to knee injuries, but the existing evidence is inconsistent and methodologically limited.
Aim
This study investigates whether menstrual cycle phase affects football players’ performance and risk factors for ACL injuries.
Setting
The study is an experimental study using a repeated-measures design. Data will be collected through questionnaires, physical performance tests, and blood sample analyses. Players with a natural menstrual cycle will be tested three times during different phases of the menstrual cycle. The study will also include users of hormonal contraception, who will be tested twice.
Principal Investigator
Dr. Mari Leppänen
Research Group
Mari Leppänen (Title of Docent, PhD), Tampere Research Center of Sports Medicine, UKK Institute; Anu Valtonen (PhD), Metropolia University of Applied Sciences; Heidi Jarske (MSci), Tampere Research Center of Sports Medicine, UKK Institute; Tom Thiel (MSci), Metropolia University of Applied Sciences; Johanna Ihalainen (PhD), University of Jyväskylä; Iida Mustakoski (MSci, Doctoral Researcher), Tampere Research Center of Sports Medicine, University of Jyväskylä; Kati Pasanen (PhD), University of Calgary; Tron Krosshaug (PhD), Oslo Sports Trauma Research Center.
Project Partners
Metropolia University of Applied Sciences, University of Jyväskylä
Funding
The project is funded by the Football Association of Finland and Libresse. The ovulation tests used in the study have been donated by RFSU.
Starting Year
2026
Ethical Approval
Regional Medical Research Ethics Committee of HUS, 16.9.2026 (ETL code HUS/7134/2026)
28.9.2026