Purpose: This study aimed to investigate the effects of 12 wk of omega-3 fatty acid supplementation during endurance training on omega-3 index (O3I) and indicators of running performance in amateur long-distance runners. Methods: Twenty-six amateur male long-distance runners ≥29 yr old supplemented omega-3 fatty acid capsules (OMEGA group, n = 14; 2234 mg of eicosapentaenoic acid and 916 mg of docosahexaenoic acid daily) or medium-chain triglycerides capsules as placebo (medium-chain triglyceride [MCT] group, n = 12; 4000 mg of MCT daily) during 12 wk of endurance training. Before and after intervention, blood samples were collected for O3I assessment, and an incremental test to exhaustion and a 1500-m run trial were performed. Results: O3I was significantly increased in the OMEGA group (from 5.8% to 11.6%, P < 0.0001). A significant increase in V̇O_2peak was observed in the OMEGA group (from 53.6 ± 4.4 to 56.0 ± 3.7 mL·kg⁻¹⋅min⁻¹, P = 0.0219) without such change in MCT group (from 54.7 ± 6.8 to 56.4 ± 5.9 mL·kg⁻¹⋅min⁻¹, P = 0.1308). A positive correlation between the change in O3I and the change in running economy was observed when data of participants from both groups were combined (−0.1808 ± 1.917, P = 0.0020), without such an effect in OMEGA group alone (P = 0.1741). No effect of omega-3 supplementation on 1500-m run results was observed. Conclusions: Twelve weeks of omega-3 fatty acid supplementation at a dose of 2234 mg of eicosapentaenoic acid and 916 mg of docosahexaenoic acid daily during endurance training resulted in the improvement of O3I and running economy and increased V̇O_2peak without improvement in the 1500-m run trial time in amateur runners.

Physical training and antioxidant supplementation may influence iron metabolism through reduced oxidative stress and subsequent lowering of mRNA levels of genes that are easily induced by this stress, including those responsible for iron homeostasis. Fifteen elderly women participated in our 12-week experiment, involving six weeks of training without supplementation and six weeks of training supported by oral supplementation of 1000 mg of vitamin C daily. The participants were divided into two groups (n = 7 in group 1 and n = 8 in group 2). In group 1, we applied vitamin C supplementation in the first six weeks of training, while in group 2 during the remaining six weeks of training. In both phases, the health-related training occurred three times per week. Training accompanied by vitamin C supplementation did not affect prooxidative/antioxidative balance but significantly decreased ferritin heavy chain (FTH) and ferritin light chain (FTL) mRNA in leukocytes (for FTH mRNA from 2^64.24 to 2^11.06, p = 0.03 in group 1 and from 2^60.54 to 2^16.03, p = 0.01 in group 2, for FTL mRNA from 2^20.22 to 2^4.53, p = 0.01 in group 2). We concluded that vitamin C supplementation might have caused a decrease in gene expression of two important antioxidative genes (FTH, FTL) and had no effect on plasma prooxidative/antioxidative balance.

The ergogenic effects of simultaneous lower- and upper-body ischemic preconditioning (IPC) are a factor that has not been investigated exhaustively. Therefore, this study aimed to investigate the effects of IPC on 500 m rowing performance (time, relative peak [RPP] and mean [MPP] power output, time to peak power [TPP], and blood lactate concentration [BLa]), as well as heart rate (HR) among forty-three physically active male (n = 24) and female (n = 19) subjects. In this cross-over randomized trial, either the IPC (220 mmHg) or SHAM (20 mmHg) protocol was applied to the upper and lower limbs simultaneously for 5 min. Then, after 5 min of reperfusion, the participants performed an all-out 500 m rowing trial. During rowing, HR was recorded, and after the completion of the rowing, the BLa concentration was determined. Wilcoxon’s signed-rank test showed a significantly shorter TPP in the SHAM condition compared to under the IPC condition for females (Z = 2.415, p = 0.017), but not for males (Z = 1.914, p = 0.056). Moreover, a significant main effect of the group was reported for rowing time, BLa, RPP, and RMP (p < 0.001 for all dependent variables). No significant interactions nor a main effect of the condition were observed for rowing time, BLa, RPP, RMP, HR_WP, HR_MEAN, and HR_MAX (p > 0.05 for all dependent variables). Simultaneous lower- and upper-body IPC led to a significant decrease in the time to peak power during the 500 m ergometer rowing trial in females but not in males. Additionally, no significant effects on the time or other power output variables, HR, or BLa concentration were registered.