This randomized controlled trial aims to investigate the effects of abdominal muscle strengthening exercises using a stabilizer pressure biofeedback device on menstrual symptoms and abdominal muscle strength in young women with primary dysmenorrhea. Primary dysmenorrhea, characterized by painful menstrual cramps without underlying pelvic pathology, is common among women of reproductive age and can negatively affect quality of life.

In this study, 58 female participants aged 18-25 with regular menstrual cycles and a Visual Analog Scale (VAS) pain score of ≥4 will be randomly assigned to either an intervention group or a control group. The intervention group will perform abdominal strengthening and stretching exercises guided by a stabilizer pressure biofeedback device, three times per week for 6 weeks (excluding menstruation weeks).

The main outcomes include menstrual symptom severity (assessed by the Menstrual Symptom Scale), pain intensity (VAS), and abdominal muscle strength (measured using the stabilizer pressure biofeedback device). The results will help determine whether targeted abdominal muscle training can reduce menstrual symptoms and improve muscle strength in women with primary dysmenorrhea.

Primary dysmenorrhea (PD) is one of the most common gynecological problems in women of reproductive age, characterized by spasmodic cramps in the lower abdomen before or during menstruation, without pelvic pathology. The underlying pathophysiology involves increased release of prostaglandin F2α during menstruation, leading to stronger uterine contractions, reduced blood flow, hypoxia, and pain. PD often begins soon after menarche and may be accompanied by nausea, vomiting, diarrhea, fatigue, and sleep disturbances.

Conventional treatment approaches include pharmacological methods such as nonsteroidal anti-inflammatory drugs (NSAIDs) and hormonal contraceptives. However, these treatments may have side effects and limited patient compliance. Non-pharmacological interventions, especially exercise programs, have shown potential in reducing menstrual pain by increasing endorphin release, relaxing uterine muscles, and improving regional blood flow. Strengthening abdominal and core muscles can improve pelvic stability and potentially reduce dysmenorrhea symptoms.

The stabilizer pressure biofeedback unit is a simple, non-invasive device that provides visual feedback during muscle activation, helping to target deep stabilizing muscles such as the transversus abdominis. By enhancing activation capacity, it may improve abdominal muscle strength and reduce menstrual symptoms.

Study Design:

This is a randomized, controlled, single-blind trial. Fifty-eight eligible women aged 18-25 with regular menstrual cycles, a VAS score ≥4, and no diagnosis of secondary dysmenorrhea or other gynecological disorders will be enrolled. Participants will be allocated to the intervention or control group using permuted block randomization. Assessments will be conducted three times: at baseline (first day of the menstrual cycle), mid-intervention (week 3-4), and post-intervention (week 8).

Intervention:

The intervention group will perform a structured exercise program targeting the lumbar and abdominal muscles, supervised three times per week for 6 weeks (excluding menstruation weeks). Exercises will include stretching, mobility, and strengthening activities, with abdominal muscle training guided by a stabilizer pressure biofeedback device. The control group will not receive this intervention during the study period.

Outcome Measures:

Primary outcomes: Menstrual symptom severity (Menstrual Symptom Scale), pain intensity (VAS).

Secondary outcome: Abdominal muscle strength (stabilizer pressure biofeedback).

Significance:

This study will provide evidence on whether non-pharmacological abdominal muscle strengthening using stabilizer pressure biofeedback can reduce menstrual symptoms and improve muscle strength in young women with primary dysmenorrhea. The findings may guide future exercise-based interventions for menstrual pain management.

Inclusion Criteria:

• Female participants aged 18-25 years
• Regular menstrual cycles
• Diagnosed with primary dysmenorrhea (no secondary dysmenorrhea or other gynecological disorders)
• Menstrual pain intensity ≥ 4 on the Visual Analog Scale (VAS) during the menstrual cycle
• Willingness to participate and ability to provide informed consent

Exclusion Criteria:

• Diagnosis of secondary dysmenorrhea or other gynecological disorders (e.g., endometriosis, adenomyosis, uterine fibroids)
• Current pregnancy or breastfeeding
• History of abdominal or pelvic surgery in the past 6 months
• Current use of hormonal therapy or analgesic medication that could affect menstrual pain assessment
• Participation in regular abdominal or core strengthening exercise programs within the last 3 months
• Any musculoskeletal, neurological, or systemic condition that could interfere with exercise performance or study participation

Individual participant data (IPD) will not be shared because the study protocol and informed consent do not include provisions for public data sharing, and data protection regulations restrict the release of personally identifiable health information.

This study uses a single-blind design in which the outcomes assessor is unaware of participants' group allocation. Participants and care providers are aware of the assigned interventions, but the assessor responsible for data collection and outcome evaluation remains blinded throughout the trial to reduce measurement bias.