Table 3 Body weight, plasma and urinary parameters, and relative values of effort test, before (D0) and after (D30) supplementation of GE or placebo in elite sportsmen. Values are means (± SEM) of 20 determinations performed in duplicate on samples from different subjects; n = 20 elite sportsmen. Placebo n=20 Grape extract n=20 D0 D30 D0 D30 Weight (kg) 84.4 (3.1) 83.7 (2.9) 84.8 (3.1) 84.0 ( 3.1) Biomarkers of antioxidant status and oxidative stress ORAC (µmol·L-1) 14 488 (380) 14 242 (339) 13 885 (360) 14 966 (335) *# FRAP (µmol·L-1 Fe2+) 1 084 (43) 994 (27) * 1 071 (32) 1 054 (32) # LDLox (mU·mL-1) 481 (98) 473 (106) 556 (119) 576 (128) SOD (U·g-1 Hb) 2 368 (85) 2 438 (77) 2 523 (105) 2 541 (92) GPx (µmol·min-1·g -1 Hb) 17.1 (1.0) 15.1 (.9) * 18.9 (1.1) 17.4 (.9) # Catalase (mol·min-1.g -1 Hb) .625 (.039) .560 (.051) .653 (.030) .673 (.057) Vitamin E (µg·mL-1) 12.49 (.36) 12.50 (.46) 12.79 (.49) 13.15 (.41) # Vit E/cholesterol ratio (µg·mg-1) 6.74 (.20) 6.97 (.20) 6.99 (.21) 7.24 (.25) # Vit C (µmol·L-1) 62.8 (4.9) 57.6 (4.6) 55.8 (3.2) 54.5 (4.3) Isoprostanes (ng·mg-1 creatinine) 1.18 (.11) 1.64 (.18) * 1.24 (.12) 1.26 (.13) # Biomarker of skeletal muscle damage Creatine phosphokinase (UI·L-1) 529 (122) 696 (177) 605 (158) 480 (81) General plasmatic biomarkers Triglycerides (g·L-1) .54 (.05) .58 (.06) .59 (.07) .68 (.10) Cholesterol (g·L-1) 1.87 (.05) 1.81 (.05) 1.84 (.06) 1.85 (.05) Ferritin (µg·L-1) 76.9 (9.7) 69.2 (9.3) * 79.0 (10.9) 69.8 (10.8) * Urea (g·L-1) .287 (.012) .279 (.013) .301 (.013) .291 (.019) Hemoglobin (g·dL-1) 14.7 (.1) 14.5 (.2) 14.5 (.2) 14.8 (.2) *# Effort test Performance (EnRJ45, %) -.47 (3.77) 4.59 (5.99) Explosive power (RJ110, %) -1.53 (1.92) .73 (2.65) Fatigue (RJ5, %) 1.64 (3.22) 9.55 (5.34) * Significantly different from the pre-treatment (D0); p < 0.05 (paired t test). # Significantly different from the placebo post-treatment (D30); p < 0.05 (paired t test).