Effect of eicosapentaenoic acids-rich fish oil supplementation on motor nerve function after eccentric contractions

Background: this study investigated the effect of supplementation with fish oil rich in eicosapentaenoic acid (epa) and docosahexaenoic acid (dha) on the m-wave latency of biceps brachii and muscle damage after a single session of maximal elbow flexor eccentric contractions (ecc). methods: twenty-one men were completed the randomized,double-blind,placebo-controlled,and parallel-design study. the subjects were randomly assigned to the fish oil group (n = 10) or control group (n = 11). the fish oil group consumed eight 300-mg epa-rich fish oil softgel capsules (containing,in total,600 mg epa and 260 mg dha) per day for 8 weeks before the exercise,and continued this for a further 5 days. the control group consumed an equivalent number of placebo capsules. the subjects performed six sets of ten eccentric contractions of the elbow flexors using a dumbbell set at 40% of their one repetition maximum. m-wave latency was assessed as the time taken from electrical stimulation applied to erb's point to the onset of m-wave of the biceps brachii. this was measured before and immediately after exercise,and then after 1,2,3,and 5 days. changes in maximal voluntary isometric contraction (mvc) torque,range of motion (rom),upper arm circumference,and delayed onset muscle soreness (doms) were assessed at the same time points. results: compared with the control group,m-wave latency was significantly shorter in the fish oil group immediately after exercise (p = 0.040),mvc torque was significantly higher at 1 day after exercise (p = 0.049),rom was significantly greater at post and 2 days after exercise (post; p = 0.006,day 2; p = 0.014),and there was significantly less delayed onset muscle soreness at 1 and 2 days after exercise (day 1; p = 0.049,day 2; p = 0.023). conclusion: eight weeks of epa and dha supplementation may play a protective role against motor nerve function and may attenuate muscle damage after eccentric contractions. trial registration: this trial was registered on july 14th 2015 ( https://upload.umin.ac.jp/cgi-open-bin/ctr/index.cgi ). © 2017 the author(s).