Isometric Exercise for Delayed Onset Muscle Soreness

The goal of this clinical trial is to learn whether isometric exercise can improve recovery following experimentally induced delayed onset muscle soreness (DOMS) in healthy young adults. The main questions it aims to answer are: * Does isometric exercise reduce pain associated with delayed onset muscle soreness? * Does isometric exercise improve pressure pain threshold, knee joint range of motion, muscle strength, and recovery following delayed onset muscle soreness? Researchers will compare participants performing an isometric exercise program with a control group receiving no intervention to determine whether isometric exercise improves recovery after experimentally induced DOMS. Participants will: * Undergo a standardized exercise protocol to induce delayed onset muscle soreness. * Be randomly assigned to either an isometric exercise group or a control group. * Complete assessments of pain intensity, pressure pain threshold, knee range of motion, muscle strength, and thigh circumference. * Be evaluated before exercise, immediately after exercise, and on Days 1, 3, and 5 following DOMS induction.

Inclusion Criteria: * Active athletes competing in University sports teams. * Age between 18 and 30 years. * Participation in organized sports training at least three times per week for the previous six months. * No lower-extremity pain at the time of enrollment. * Ability to safely perform the exercise protocol used to induce delayed onset muscle soreness (DOMS). * Willingness to provide written informed consent. Exclusion Criteria: * History of lower-extremity musculoskeletal injury within the previous 6 months. * Previous lower-extremity surgery. * Current musculoskeletal pain or injury affecting sports participation. * Neurological, rheumatological, cardiovascular, or systemic disorders affecting physical performance. * Use of analgesic, anti-inflammatory, or muscle-relaxant medications during the study period. * Participation in strenuous eccentric exercise within 72 hours prior to baseline testing. * Use of recovery interventions (e.g., massage, cryotherapy, compression garments, electrical stimulation) during the study period. * Inability to complete the exercise protocol or follow-up assessments.