The goal of this clinical trial is to find out whether exercise, motor imagery training, and pain neuroscience education can help reduce menstrual pain and improve well-being in young women with primary dysmenorrhea. The study will also look at how these approaches affect menstrual symptoms, movement control, and cognitive flexibility.

The main questions it aims to answer are:

• Does adding motor imagery or pain neuroscience education to an exercise program reduce pain and menstrual symptoms more than exercise alone?
• Do these approaches improve movement control, thinking flexibility, and knowledge about pain?

Researchers will compare three groups:

• Exercise only
• Exercise plus motor imagery training
• Exercise plus pain neuroscience education

Participants will:

• Attend supervised exercise sessions twice a week for 8 weeks
• Practice either motor imagery or receive short pain neuroscience education, depending on their group
• Complete questionnaires and tests before and after the program, during the first three days of menstruation

Primary dysmenorrhea is a common gynecological condition characterized by menstrual pain without underlying pathology. It negatively impacts quality of life and may affect cognitive functions such as attention and flexibility. Non-pharmacological interventions such as exercise, motor imagery, and pain neuroscience education are promising approaches for pain management without side effects. However, evidence on their effectiveness in primary dysmenorrhea is limited.

This randomized controlled trial is designed to compare the effects of three different interventions in young women with primary dysmenorrhea:

• Exercise only (control group)
• Exercise plus Motor Imagery Training
• Exercise plus Pain Neuroscience Education (PNE)

Eligible participants will be women aged 18-25 years who meet the diagnostic criteria for primary dysmenorrhea based on gynecological examination and ultrasound findings. Participants will be randomly assigned into one of the three groups. All groups will undergo an 8-week supervised exercise program (two sessions per week) focusing on lumbopelvic stabilization, flexibility, and endurance training. In addition:

• The Motor Imagery group will practice kinesthetic visualization of the exercises prior to performing them.
• The PNE group will receive weekly face-to-face education sessions on pain mechanisms, supported with home assignments.

Primary outcome measures are:

• Pain intensity (Numeric Pain Rating Scale)
• Pressure pain threshold (Baseline dolorimeter)
• Menstrual symptoms (Menstrual Symptom Questionnaire).

Secondary outcome measures are:

• Lumbopelvic motor control (Physiosupplies Core Stabilizer Unit)
• Movement Imagery Questionnaire
• Central Sensitization Inventory
• Cognitive flexibility (Stroop Test)
• Pain Catastrophizing Scale
• Pain Resilience Scale
• Modified Pain Neurophysiology Questionnaire.

Assessments will be conducted at baseline and after the 8-week intervention, within the first three days of menstruation. Additional follow-up data will be collected through online forms one month after the intervention to evaluate persistence of effects.

The estimated sample size of 51 was calculated considering a 10% attrition rate. Statistical analyses will be performed using SPSS software. Depending on data distribution, repeated measures ANOVA or non-parametric equivalents will be used to compare changes over time and between groups.

This study is expected to provide new evidence regarding the effectiveness of combining exercise with motor imagery or pain neuroscience education for the management of pain, menstrual symptoms, and cognitive flexibility in women with primary dysmenorrhea. The findings may contribute to the development of safe and effective non-pharmacological strategies in women's health and pain management.

Inclusion Criteria:

• Female, aged 18-25 years
• Gynecological examination and ultrasound confirming absence of pelvic pathology
• History of primary dysmenorrhea for at least 6 months, with pain intensity ≥4 on the Numeric Rating Scale (0-10) during the first 3 days of menstruation
• Regular menstrual cycles (21-35 days)
• Nulliparous (no history of pregnancy or childbirth)
• No systemic, metabolic, rheumatologic, or lumbar pathology
• Willingness to participate in the 8-week intervention program and attend follow-up assessments

Exclusion Criteria:

• Diagnosis of secondary dysmenorrhea (e.g., endometriosis, pelvic inflammatory disease, uterine fibroids, ovarian cysts)
• Current pregnancy or planning to become pregnant during the study period
• History of pelvic or abdominal surgery
• History of sexually transmitted diseases
• Current use of antidepressants, anxiolytics, or hormonal therapy (e.g., oral contraceptives, intrauterine device)
• Known neurological, psychiatric, or systemic musculoskeletal disorders
• Cognitive impairment or attention deficit that may interfere with participation
• Participation in regular exercise in the last 6 months
• Use of alternative therapies for dysmenorrhea (e.g., acupuncture, massage)

Only individuals who self-identify as female and have biological capacity for menstruation (i.e., women of reproductive age with regular menstrual cycles) are eligible to participate.

De-identified individual participant data (pain intensity scores, pressure pain threshold values, questionnaire results, and demographic data) will be shared

Data will be available beginning 6 months after study completion and will remain available for 5 years.

Researchers who provide a methodologically sound proposal will be able to access the data for academic purposes. Data will be shared via email request to the principal investigator, subject to approval by the study team.