Table 1 – changes in indices of EIMD following damaging exercise Effect of an acute dose of omega-3 fish oil following exercise-induced muscle damage John Jakeman1*, Brandon Wooley2, Danielle Lambrick3, John Babraj4, and James Faulkner5 Introduction As exercise-induced muscle damage (EIMD) is a common consequence of strenuous physical activity, a number of conditioning, rehabilitation and nutritional strategies have been used in an effort to ameliorate its deleterious symptoms. As a result of the anti-inflammatory properties associated with the fatty acids EPA and DHA, which are found in fish oil capsules, supplementation of omega-3 fish oil has been considered as a possible recovery intervention, with positive effects on symptoms of EIMD when taken over prolonged periods. However, there is limited research considering its use in an acute dose, which may be considered more ecologically valid as a recovery strategy than prolonged consumption. It is also possible that the amount of EPA and DHA in the supplement may have an effect on recovery because of different anti-inflammatory properties 1Oxford Brookes University, UK ; 2Massey university, NZ; 3Southampton University, UK; 4University of Abertay, Dundee, UK; 5University of Winchester, UK Figure 2 – changes in squat jump performance (A), and quadriceps peak torque at 600.s-1 (B) Method Twenty-seven recreationally active participants were recruited for this double-blind, placebo controlled trial, and were randomly allocated to a high EPA (High), low EPA (Low) or placebo control (Con) group (n = 9). Measures of muscle soreness, quadriceps peak torque (at 600 and 1800.s-1), squat jump and countermovement jump performance were recorded before, and 1, 24, 48, 72, and 96h, following the completion of 100 plyometric drop jumps. Participants took omega-3 fish oil at a dose of 1g.10kg body mass immediately after completing the damaging exercise. Data for jump performance and quadriceps peak torque were converted to a proportion of baseline, and analysed using a repeated measures ANOVA (presented as mean±SEM) Results There was a significant time main effect on all indices of muscle damage. A significant decrement in squat and countermovement jump performance was observed at 1h, and was maintained until 96h following damaging exercise. High dose EPA supplementation attenuated the decrement in squat jump performance (-6.1%) in comparison to both low dose EPA (-15.9%) or placebo (13.9%) supplementation at 1h. A similar, non-significant trend was observed for countermovement jump performance, and quadriceps peak torque at 600.s-1 but not 1800.s-1. No group or group x time interaction effects were observed on perceived muscle soreness (Table 1). A B Table 1 – changes in indices of EIMD following damaging exercise Discussion Previous studies have indicated that chronic supplementation (≥ 7 days) of omega-3 can reduce symptoms of perceived muscle soreness following EIMD1. We did not find this in the current study, which may be due to the short supplementation period. However, the current findings did indicate effects of supplementation on performance measures, with all parameters except quadriceps peak torque at 1800.s-1 being positively influenced. This may have been due to changes in the voluntary activation capability of the muscle, which have been previously observed2. In practical terms, it may be of interest to note that performance in both squat and countermovement jump recovered to within 2% of baseline after 96h, while participants in the Low and Pla groups remained 8.1 and 4.1% respectively below baseline at this time point. As a result of the anti-inflammatory properties of EPA and DHA, and the timing of the supplementation, it may be that in addition to the initial protective effect of omega-3, the incidence of secondary muscle damage was moderated, further facilitating recovery. Further, EPA may have a more potent effect on skeletal muscle protein metabolism than DHA3, which may contribute to the observed differences between the supplementation conditions. References Jouris et al. (2011). The effect of omega-3 fatty acid supplementation on the inflammatory response to eccentric strength exercise. Journal of Sports Science and Medicine, 10, 432-438. Lewis et al. (2015). 21 days of mammalian omega-3 fatty acid supplementation improves aspects of neuromuscular function and performance in male athletes compared to olive oil placebo. Journal of the International Society of Sports Nutrition, 12:28. Kamolrat, T., and Gray S.R. (2013). The effect of eicosapentaenoic and docosahexaenoic acid on protein synthesis and breakdown in murine C2C12 myotubes. Biochemistry and BiophysicalResearch Communications, 432, 593-598. Pre 1h 24h 48h 72h 96h   High 0.8 (0.3) 3.3 (1.1) 4.2 (0.8) 3.5 (0.5) 1.8 (0.3) 0.8 (0.2) Soreness Low 1.2 (0.5) 3.1 (1.0) 4.5 (0.8) 4.2 (1.0) 2.4 (0.9) 1.4 (0.6) Pla 0.6 (0.3) 3.2 (0.8) 5.7 (0.8) 5.4 (0.9) 2.9 (0.6) 1.6 (0.5) 100.0 96 (1.5) 99.5 (1.5) 98.7 (3.9) 97.4 (3.6) 98.4 (3.2) CMJ (%) 85 (2.1) 94.3 (3.3) 90.8 (4.6) 93 (2.5) 96.2 (3.2) 89.9 (2.8) 91.7 (2.3) 90.8 (2.3) 91.4 (1.8) 95.6 (1.8) 93.9 (2.7) 98 (2.0) 98.9 (1.7) 98.4 (2.2) 98.4 (2.7) SJ (%) 84.1 (1.9) 87.7 (2.5) 86.6 (3.9) 90.6 (2.7) 91.9 (2.7) 86.1 (2.0) 87.9 (3.3) 89.6 (2.5) 90.6 (2.6) 95.9 (2.5) 89.1 (2.3) 92.9 (1.9) 93.5 (2.2) 96.6 (2.8) 97.7 (2.5) Q Torque 60 88.5 (2.6) 85.4 (2.7) 84.9 (3.6) 90.9 (2.5) 95.1 (2.7) (%) 87 (2.1) 85.3 (3.4) 85.9 (3.6) 93.8 (3.2) 98 (2.5) 87.7 (3.4) 92.4 (2.3) 95.8 (2.2) 97.1 (2.0) 99 (2.1) Q Torque 180 88 (4.4) 91.3 (3.7) 89.1 (3.0) 94.9 (3.3) 100.2 (5.5) (%)  86 (1.8) 90.9 (2.6) 90.5 (1.9) 95.5 (3.0) 96.3 (2.8)