Exercise-induced muscle damage (EIMD) occurs following strenuous and/or unaccustomed exercise including resistance training. EIMD is associated with elevated blood creatine kinase (CK) concentrations, limitations in range of motion (ROM), a reduction in muscular power, and delayed onset muscle soreness (DOMS). EIMD may negatively affect training quality and performance, thus methods to mitigate EIMD may be useful for resistance training populations including both athletes and recreationally active individuals. Omega-3 (n-3) fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are known for their anti-inflammatory and anti-nociceptive properties. The current literature on supplementation with n-3 fatty acids and EIMD is not conclusive, however, there are data showing supplementation can ameliorate EIMD and facilitate recovery in both untrained and resistance-trained individuals following resistance exercise, particularly at higher doses. Presently, a characterization of efficacious doses of n-3 supplementation is currently lacking. Therefore, the purpose of this study was to investigate the effect of 33 days of six and eight grams of n-3 supplementation on markers of muscle damage and recovery after an acute bout of eccentric resistance exercise in resistance trained males. It was hypothesized that both six and eight grams of n-3 supplementation would attenuate EIMD and promote recovery following eccentric resistance exercise. In this double-blind randomized control study, 26 resistance trained males (23 ± 4 years; 173.6 ± 20.5 cm.; 81.9 ± 9.7 kg; 14.2 ± 3.7% BF) supplemented with six grams of n-3 fatty acids (n=10), eight grams n-3 fatty acids (n=7), or placebo (n=9) for 33 days total. On day 30, participants completed an acute bout of eccentric resistance exercise (10 sets of 8 repetitions barbell back squat at 70% 1RM with a four second eccentric, followed by 5 sets of 10 repetitions per side body weight split squat jumps). Participants were instructed to refrain from additional recovery methods post-exercise. Outcome measures included vertical jump height (VJH), perceived muscle soreness (PMS), hip and knee range of motion (ROM), repetitions to fatigue (RTF) at 70% 1RM barbell back squat, and serum creatine kinase (CK). Vertical jump height, PMS, hip and knee ROM, and capillary blood samples were taken immediately pre-exercise bout (day 30), 1 day (1d), 2 days (2d) and 3 days (3d) post-exercise, while number of RTF were completed at the familiarization session (day 21, 22, or 23) and 3d post-exercise. There was a significant difference in VJH from pre to 1d post-exercise (p=0.009, 1d to 2d (p=0.02), and 2d to 3d post-exercise (p=0.002) in all groups. Perceived muscle soreness significantly increased from pre to 1d, 2d, and 3d hour post-exercise (p <0.05), and significantly decreased at 3d post-exercise compared with 1d and 2d (p <0.05) in all groups. No significant changes occurred in hip and knee range of motion from pre to post-exercise in all groups (

0.05), or number of (RTF) from pre-exercise (day 21, 22, or 23) to 3d post-exercise (

p

0.05). There was a significant increase in serum CK from pre-exercise to 1, 2, and 3d-post exercise (p < 0.001) for all groups. In conclusion, supplementation with six and eight grams of n-3 fatty acids did not attenuate markers of muscle damage (i.e. VJH, PMS, hip ROM, knee ROM, RTF, and serum CK) following an acute bout of eccentric resistance exercise. These findings are in contrast to previous work, however, literature has shown n-3 supplementation to be ineffective for mitigating EIMD.Further research focusing on n-3 supplementation duration, dose, and source, as well as EPA and DHA concentrations of supplementation is warranted.