4-week eicosapentaenoic acid-rich fish oil supplementation partially protects muscular damage following eccentric contractions

Abstract

Background We previously showed that the 8-week supplementation of fish oil attenuates muscle damage. However, the effect of a shorter period of fish oil supplementation is unclear. The present study investigates the effect of supplementation of fish oil in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) for 4 weeks on muscular damage caused by eccentric contractions (ECCs) of the elbow flexors. Methods Twenty-two untrained men were recruited in this double-blind, placebo-controlled, parallel design study and the subjects were randomly assigned to the EPA and DHA group (EPA, n = 11) and placebo group (PL, n = 11). They consumed either EPA 600 mg and DHA 260 mg per day or placebo supplement for 4 weeks prior to exercise. Subjects performed 60 ECCs at 100% maximal voluntary contraction (MVC) using a dumbbell. Changes in MVC torque, range of motion (ROM), upper arm circumference, muscle soreness, echo intensity, muscle thickness, serum creatine kinase (CK), and interleukin-6 (IL-6) were assessed before exercise; immediately after exercise; and 1, 2, 3, and 5 days after exercise. Results ROM was significantly higher in the EPA group than in the PL group immediately after performing ECCs (p < 0.05). No differences between groups were observed in terms of MVC torque, upper arm circumference, muscle soreness, echo intensity, and thickness. A significant difference was observed in serum CK 3 days after ECCs (p < 0.05). Conclusion We concluded that shorter period EPA and DHA supplementation benefits joint flexibility and protection of muscle fiber following ECCs.