Table 4.

Changes in blood parameters of oxidative stress and muscle damage induced by the repeated sprint test (4 × 15 s) in sprinters (n = 16) after 4-week supplementation with placebo (PL) or green tea extract (GTE)

	PL	GTE	Time	Treatment	Time × treatment
Total antioxidant capacity (TAC) (mmol/L)
Rest	1.33 ± 0.04	1.52 ± 0.03‡	Yes	Yes	Yes
5 min	1.58 ± 0.04***	1.54 ± 0.04
24 h	1.51 ± 0.05**	1.59 ± 0.06
Uric acid (UA) (mg/dL)
Rest	5.15 ± 0.26	4.31 ± 0.20	Yes	No	No
5 min	5.16 ± 0.26	4.30 ± 0.15
24 h	6.61 ± 0.29***, †††	6.81 ± 0.28***, †††
Albumin (AL) (g/dL)
Rest	4.09 ± 0.14	4.06 ± 0.10	Yes	No	No
5 min	4.68 ± 0.18**	4.89 ± 0.20***
24 h	4.20 ± 0.08†	4.44 ± 0.14†
Superoxide dismutase (SOD) (U/g Hb)
Rest	1,596.8 ± 55.7	1,524.0 ± 28.4	Yes	Yes	Yes
5 min	1,797.4 ± 33.9***	1,497.2 ± 32.5‡‡‡
24 h	1,794.3 ± 34.3***	1,468.8 ± 25.8‡‡‡
Glutathione peroxidase (GPx) (U/g Hb)
Rest	46.8 ± 2.2	39.0 ± 2.1	No	No	No
5 min	38.8 ± 1.7	37.1 ± 1.1
24 h	38.3 ± 3.2	37.8 ± 1.9
Malondialdehyde (MDA) (µmol/L)
Rest	1.15 ± 0.09	0.66 ± 0.04‡	Yes	Yes	No
5 min	1.48 ± 0.08**	0.85 ± 0.06‡‡
24 h	0.86 ± 0.09†††	0.53 ± 0.02††
Creatine kinase (CK) (U/L)
Rest	192.0 ± 18.2	178.1 ± 15.0	Yes	No	No
5 min	219.5 ± 18.9	199.0 ± 17.2
24 h	230.6 ± 21.5*	231.5 ± 19.8**

Values are presented as mean ± SEM. Blood samples were collected before the test (at rest), 5 min after the test (5 min), and after 24 h of recovery (24 h). The data were analyzed using two-way ANOVA: two treatment (placebo and GTE) × three time points (at rest, 5 min, and 24 h after completion of the test)

*, **, *** Significantly different (p < 0.05; p < 0.01; p < 0.001, respectively) from the resting value (within the same treatment; Bonferroni test)

^{††, †††}Significantly different (p < 0.01; p < 0.001, respectively) from the value determined at 5 min (within the same treatment; Bonferroni test)

^{‡, ‡‡, ‡‡‡}Significantly different (p < 0.05; p < 0.01; p < 0.001, respectively) from the respective value determined after placebo treatment (Bonferroni test)