Currently accepted at: JMIR Research Protocols
Date Submitted: Apr 6, 2026
Open Peer Review Period: Apr 6, 2026 - Jun 1, 2026
Date Accepted: Oct 27, 2026
(closed for review but you can still tweet)
This paper has been accepted and is currently in production.
It will appear shortly on 10.2196/97370
The final accepted version (not copyedited yet) is in this tab.
Menstrual Cycle Phase, Hamstrings-to-Quadriceps Ratio, and Injury Risk Markers: Protocol for a Repeated-Measures Study in Physically Active Women
ABSTRACT
Background:
The relationship between female physical performance and menstrual cycle (MC) phases is widely discussed in applied sports science and clinical kinesiology. However, current evidence remains inconsistent, particularly regarding muscle strength and biomechanical risk factors for injury.
Objective:
This study aims to examine the relationship between MC phases and lower limb injury risk factors, with a particular focus on the hamstrings-to-quadriceps strength ratio (H/Q ratio).
Methods:
Following an initial session, participants will monitor their MC over 3 months using a mobile application, urinary ovulation tests, and self-reported symptoms, while also recording perceived readiness for physical activity. Each participant will then complete two laboratory assessments: the early follicular phase (days 1–3 of menstrual bleeding) and the peri-ovulatory phase. Testing will include isokinetic strength assessment, evaluation of muscle–tendon mechanical properties, and body composition analysis.
Results:
Recruitment will begin in June 2026. A total of 32 participants will be enrolled in two waves (June–July 2026 and June–July 2027). Preliminary results are expected by 06/2028.
Conclusions:
This study may improve understanding of MC–related changes in neuromuscular function and support individualized, non-invasive approaches to training and injury prevention in women. Associating objectively estimated MC phases with a mobile application, urinary ovulation tests and subjective perceptions of performance will provide insights into the agreement between perceived and physiological indicators of performance readiness. Clinical Trial: NCT07462286
Citation
Request queued. Please wait while the file is being generated. It may take some time.
Copyright
© The authors. All rights reserved. This is a privileged document currently under peer-review/community review (or an accepted/rejected manuscript). Authors have provided JMIR Publications with an exclusive license to publish this preprint on it's website for review and ahead-of-print citation purposes only. While the final peer-reviewed paper may be licensed under a cc-by license on publication, at this stage authors and publisher expressively prohibit redistribution of this draft paper other than for review purposes.