Effectiveness of Post Isometric Relaxation Technique Versus Simple Stretching Exercises for Pain and Physical Activity in Young Females With Primary Dysmenorrhea in Peshawar

Inclusion Criteria: * Female participants aged 18-30 years. * Self-identification as female. * Unmarried students with regular menstrual cycles (24-35 days). * Diagnosed primary dysmenorrhea with a WaLIDD score ≥ 5. * Able and willing to participate in thrice-weekly physiotherapy sessions for eight weeks. * Provide written informed consent. Exclusion Criteria: * Secondary dysmenorrhea (e.g., endometriosis, pelvic inflammatory disease). * Current use of hormonal contraceptives or any medication for menstrual pain. * History of hip or pelvic surgery in the past year. * Acute musculoskeletal injury or chronic pain conditions unrelated to dysmenorrhea. * Neurological disorders affecting lower-limb muscle function. * Contraindications to TENS or heat therapy (e.g., skin lesions, implanted electronic devices). * Pregnancy or breastfeeding. * Participation in another interventional trial within the past three months.