The study investigates the effectiveness of physical strategies in addressing Delayed Onset Muscle Soreness (DOMS) in physically active individuals. DOMS, a common phenomenon following intense or novel physical activity, is characterized by pain, inflammation, and functional impairments such as reduced range of motion, muscle strength, and endurance. These symptoms peak between 24-72 hours post-exercise and are attributed to micro-damage in muscle and connective tissue, followed by inflammatory responses. Despite extensive research, the efficacy of various therapeutic interventions remains inconclusive due to heterogeneity in study designs, outcome measures, and quality of evidence.

The primary objective of this study is to systematically assess and compare the effectiveness of cold water immersion (CWI) or hot water immersion (HWI), in mitigating DOMS symptoms. This study will utilize a multi-arm, parallel, randomized controlled trial (RCT) design to evaluate therapeutic outcomes against a control group receiving simulated therapy.

By employing a standardized exercise protocol to induce DOMS and unified assessment methodologies (e.g., biomechanical, biochemical, and functional tests), the study aims to provide robust evidence for the efficacy of these interventions. The findings will contribute to optimizing post-exercise recovery strategies, offering reliable therapeutic protocols for both clinical and athletic settings.

The study is a multi-arm, parallel, randomized controlled trial (RCT) designed to evaluate the effectiveness of cold water immersion (CWI), warm water immersion (WWI), and simulated laser therapy (control group) in mitigating Delayed Onset Muscle Soreness (DOMS). This trial aims to compare the physiological, biochemical, and functional outcomes of these interventions following exercise-induced muscle damage in healthy male participants. DOMS, which arises from eccentric physical activities, presents with symptoms such as muscle pain, stiffness, inflammation, and functional limitations, reaching a peak 24-72 hours post-exercise.

Setting and Duration The study will be conducted at the laboratories of the Faculty of Physical Education and Health at AWF Biała Podlaska between March and May 2024. The laboratory sessions will take place on weekdays from 8:00 AM to 4:00 PM.

Methodology Participants will be randomly assigned to one of three study groups

Cold Water Immersion (CWI):

Participants will submerge their lower limbs in water maintained at 10-12°C for 15 minutes. The water temperature will be regulated with ice additions to ensure consistency. Participants will perform light movements, such as ankle flexion and extension, to stimulate blood flow.

Sessions will occur 1 hour post-exercise, and at 24 and 48 hours.

Hot Water Immersion (HWI):

Participants will immerse their lower limbs in water at 40°C for 15 minutes, maintaining consistent temperature conditions.

Sessions will follow the same schedule as the CWI group (1, 24, and 48 hours post-exercise).

Simulated Laser Therapy (Control Group):

Participants in this group will receive simulated low-level laser therapy (LLLT). A deactivated laser device will be positioned over the muscles to mimic therapy without delivering actual treatment. Simulated sessions will align with the intervention schedule of the other groups.

Study Procedure

The study comprises three phases:

Baseline Measurements (Phase 1):

Conducted in the morning, fasting, followed by standardized functional and biomechanical tests two hours after a light meal.

Measurements include body composition, joint range of motion, muscle stiffness (elastography), pain assessments (VAS scale), and venous blood sampling to measure baseline biochemical markers.

Exercise-Induced Muscle Damage (Phase 2):

Participants will perform eccentric exercises designed to induce DOMS, targeting the quadriceps muscles. The exercise protocol includes five sets of 20 drop jumps from a 60 cm height with a 5-minute rest between sets.

Experienced physiotherapists will ensure the correct execution of exercise.

Post-Exercise Monitoring and Intervention (Phase 3):

Interventions (CWI, WWI, or simulated LLLT) will be administered within an hour post-exercise and repeated at 24 and 48 hours.

Functional tests and blood sampling will be conducted pre-intervention and at 24, 48, 72, and 96 hours post-exercise to assess recovery dynamics.

Inclusion Criteria:

• Healthy males aged 18-25 years
• BMI between 18.5 and 30 kg/m²
• Experiencing muscle pain (VAS scale) > 5 for muscle soreness within 12 to 30 hours post-exercise
• Engage in moderate physical activity 2-5 hours/week, according to the International Physical Activity Questionnaire-Short Form (IPAQ-SF).
• They must voluntarily sign a written informed consent approved by an ethics/bioethics committee after sufficient explanation prior to participating in the study.

Exclusion Criteria:

• Inflammatory diseases within the past 6 months
• Neurological disorders that affect muscle strength
• Ongoing use of steroids, analgesics, muscle relaxants, or other medications deemed inappropriate by the researchers, including antispasmodics, antidepressants, antidiarrheals, antibiotics, or thrombolytics
• Unstable medical condition such as cardiovascular disease, respiratory disease, gastrointestinal disease, hepatobiliary disease, metabolic disease, endocrine disease, kidney disease, urinary tract disease, genetic disorders, or issues related to the nervous system or mental health.
• Participants who have abused alcohol or drugs in the past year, do not wish to follow the study guidelines, or are deemed inappropriate for the study by the researcher will also be excluded.

Because the study sample is small and participants were locally recruited, there is a heightened risk that individual identities could be inferred. Therefore, we do not plan to share de-identified participant data in order to protect privacy and confidentiality.