This study examines how different phases of the menstrual cycle are associated with selected performance and musculoskeletal parameters in physically active women aged 18-35 years. Participants will track their menstrual cycle using a mobile app for approximately 2 months and attend 3 laboratory visits scheduled to specific cycle phases. At each visit, participants will complete non-invasive assessments including lower-limb strength/performance testing, musculoskeletal measurements (muscle and tendon properties), body composition assessment, and symptom-related questionnaires. The goal is to improve understanding of physiological variability across the menstrual cycle and support evidence-based planning of training, testing, and clinical practice in women.
Background and rationale: Female physiology changes across menstrual cycle phases, which may influence neuromuscular performance, perceived symptoms, and selected tissue/mechanical properties. Current evidence is heterogeneous, partly due to methodological differences in cycle-phase identification and measurement protocols. This study aims to provide standardized data from repeated within-subject assessments across the menstrual cycle. Objectives: Primary objective is to evaluate associations between menstrual cycle phase and selected performance-related outcomes in physically active women. Secondary objectives are to explore phase-related differences in musculoskeletal parameters, body composition outputs, and self-reported symptoms. Study design: Prospective, repeated-measures observational study. Each participant is measured repeatedly across predefined menstrual cycle phases. Participants: Women from the general population, 18-35 years, with occasional to recreational physical activity level. Procedures: Screening and eligibility confirmation according to protocol criteria. Menstrual cycle tracking via mobile application for approximately 2 months. Three laboratory visits timed to predefined cycle phases. At each visit, non-invasive assessments are performed, including: lower-limb strength/performance testing, assessment of muscle and tendon mechanical properties, body composition measurement, recording of subjectively perceived menstrual-related symptoms. Outcomes: Main outcomes include phase-specific differences/associations in selected performance and musculoskeletal variables; additional outcomes include symptom profiles and selected body-composition variables. Duration and setting: Individual participation lasts approximately 2 months including cycle tracking and 3 lab visits (approximately 60-90 minutes per visit). Study procedures are conducted at FTVS UK (Prague). Ethics and data protection: Participation is voluntary, and participants may withdraw at any time without giving a reason. Data are processed in compliance with applicable data-protection regulations (including GDPR), pseudonymized for analysis, and reported in aggregate/anonymized form. The study is conducted according to institutional ethics approval and the Declaration of Helsinki.
Study Type
OBSERVATIONAL
Enrollment
32
Menstrual cycle monitoring using a mobile application for approximately 2 months to schedule laboratory visits to predefined cycle phases.
Repeated lower-limb performance/strength assessments during laboratory visits in different menstrual cycle phases.
Non-invasive assessment of selected muscle and tendon mechanical properties across cycle phases.
Body composition measurement and collection of self-reported menstrual-related symptoms at laboratory visits.
Faculty of Physical Education and Sport, Charles University, José Martího 269/31
Prague, Prague, Czechia
Phase-specific change in lower-limb neuromuscular performance across the menstrual cycle
Within-subject differences in lower-limb performance/strength outcomes measured during three laboratory visits scheduled to predefined menstrual cycle phases.
Time frame: Assessed at 3 laboratory visits across approximately 2 months (cycle tracking period)
Phase-specific differences in muscle mechanical properties
Within-subject changes in selected skeletal muscle mechanical properties measured non-invasively across predefined menstrual cycle phases.
Time frame: Assessed at 3 laboratory visits across approximately 2 months
Phase-specific differences in tendon mechanical properties
Within-subject changes in selected tendon mechanical properties measured non-invasively across predefined menstrual cycle phases.
Time frame: Assessed at 3 laboratory visits across approximately 2 months
Phase-specific differences in body composition variables
Within-subject differences in body composition parameters assessed at laboratory visits scheduled to predefined menstrual cycle phases.
Time frame: Assessed at 3 laboratory visits across approximately 2 months
Menstrual-related symptom profile across menstrual cycle phases
Self-reported menstrual-related symptoms recorded via questionnaires/standardized symptom reporting and compared across predefined cycle phases.
Time frame: Collected during cycle tracking and at 3 laboratory visits across approximately 2 months
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