Antioxidant Supplementation and Muscle Recovery From DOMS in Trained Women

Delayed onset muscle soreness (DOMS) is a common physiological response to eccentric exercise, characterized by muscle pain, reduced force production, and impaired neuromuscular function. Antioxidant and anti-inflammatory compounds such as creatine, omega-3 fatty acids, N-acetylcysteine (NAC), and coenzyme Q10 (CoQ10) have been proposed as potential modulators of exercise-induced muscle damage. This study used a 4-arm parallel RCT design with participant and assessor blinding. Participants underwent a standardized eccentric exercise protocol to induce DOMS, followed by 72 hours of monitoring. Measurements were taken at baseline (T1), post-exercise (T2), 24h (T3), 48h (T4), and 72h (T5) post-exercise. Analysis of covariance (ANCOVA) was performed with baseline values and age as covariates.

• Creatine Monohydrate (Dietary supplement): Creatine monohydrate administered at 5 g/day for 4 weeks. Used in G1, G2, and G3 arms
• Omega 3 FA (Fish Oil) (Dietary supplement): Administered as 2 capsules/day (456 mg EPA + 225 mg DHA per capsule; EPA:DHA ratio 2:1) for 4 weeks. Included in G1, G2, and G3 arms.
• N-Acetyl Cysteine (NAC) (Dietary supplement): Administered at 600 mg/day for 4 weeks. Included in G2 and G3 arms.
• Coenzyme Q10 100 MG Oral Capsule (Dietary supplement): Administered at 100 mg/day for 4 weeks. Included in G3 arm only.
• Placebo (Dietary supplement): Maltodextrin (5 g/day) and olive oil capsules (2 capsules/day), visually identical to active arms. Administered for 4 weeks in G4 arm.

Primary outcomes

• Countermovement Jump Height (CMJ) [Baseline (Day 0), immediately post-exercise (Day 2), 24 hours after exercise (Day 3), 48 hours after exercise (Day 4), and 72 hours post-eccentric exercise (Day 5)]: Assessed using My Jump Lab app (240 fps). Jump height in centimeters as indicator of lower limb neuromuscular performance recovery
• Muscle Pain Pressure Threshold [Baseline (Day 0), immediately post-exercise (Day 2), 24 hours after exercise (Day 3), 48 hours after exercise (Day 4), and 72 hours post-eccentric exercise (Day 5)]: Assessed using a pressure algometer (BASELINE). Measures the minimum pressure at which the participant perceives pain, expressed in kg/cm²
• 30- Meter Sprint Time [Baseline (Day 0), immediately post-exercise (Day 2), 24 hours after exercise (Day 3), 48 hours after exercise (Day 4), and 72 hours post-eccentric exercise (Day 5)]: Assessed using Witty photocell system (Microgate). Time in seconds to complete a 30-meter sprint.
• Creatine Kinase (CK) [Baseline (Day 0), immediately post-exercise (Day 2), 24 hours after exercise (Day 3), 48 hours after exercise (Day 4), and 72 hours post-eccentric exercise (Day 5)]: ssessed using SimplexTAS 101 analyzer. Serum CK activity in U/L as a biochemical marker of muscle damage.

Secondary outcomes

• RIGHT LEG DYNAMOMENTRY [Baseline (Day 0), immediately post-exercise (Day 2), 24 hours after exercise (Day 3), 48 hours after exercise (Day 4), and 72 hours post-eccentric exercise (Day 5)]: Assessed using Activforce 2 dynamometer. Maximum isometric knee extension force in kg.
• LEFT LEG DYNAMOMETRY [Baseline (Day 0), immediately post-exercise (Day 2), 24 hours after exercise (Day 3), 48 hours after exercise (Day 4), and 72 hours post-eccentric exercise (Day 5)]: Assessed using Activforce 2 dynamometer. Maximum isometric knee extension force in kg.
• Thermography [Baseline (Day 0), immediately post-exercise (Day 2), 24 hours after exercise (Day 3), 48 hours after exercise (Day 4), and 72 hours post-eccentric exercise (Day 5)]: Assessed using FLIR T2 A315 thermographic camera. Skin temperature of the quadriceps region in degrees Celsius as marker of local inflammation.
• Heart Rate Variability [Baseline (Day 0), immediately post-exercise (Day 2), 24 hours after exercise (Day 3), 48 hours after exercise (Day 4), and 72 hours post-eccentric exercise (Day 5)]: Assessed using Polar Team Pro chest straps. 5-minute supine recording with eyes closed and deep breathing. Root mean square of successive differences in ms as autonomic recovery indicator.

Sex: Female, ages: 18 Years to 35 Years, accepts healthy volunteers

Inclusion Criteria:

* Female sex
* Age 18-35 years
* Trained status (regular resistance or sport training)
* Enrolled at Universidad Europea de Madrid
* Absence of musculoskeletal injury at time of recruitment
* No use of anti-inflammatory drugs or nutritional supplements in the 4 weeks prior to the study

Exclusion Criteria:

* History of chronic musculoskeletal or cardiovascular disease
* Use of anti-inflammatory medication or antioxidant supplementation in the prior 4 weeks
* Pregnancy or breastfeeding
* Inability to complete the eccentric exercise protocol
* Non-compliance with supplementation or dietary control requirements