title: Green tea extract supplementation does not hamper endurance-training adaptation but improves antioxidant capacity in sedentary men.
abstract: The purpose of this study was to investigate the effect of green tea extract (GTE) supplementation combined with endurance training on endurance capacity and performance in sedentary men. Forty untrained men (age: 20 ± 1 years) participated in this study. Subjects were assigned to 1 of 4 treatments: (i) placebo-control (CTRL), (ii) GTE, (iii) endurance training (Ex), and (iv) endurance training with GTE (ExGTE). During the 4-week intervention, exercise training was prescribed as 75% oxygen uptake reserve for three 20-min sessions per week, and either GTE (250 mg/day) or placebo was provided. Endurance capacity, malondialdehyde (MDA), total antioxidant status (TAS), and creatine kinase (CK) were examined. Ex and ExGTE but not GTE improved exhaustive-run time (Ex: +8.2%, p = 0.031; ExGTE: +14.3%, p < 0.001); in addition, Ex and ExGTE significantly increased maximal oxygen uptake by ∼14% (p = 0.041) and ∼17% (p = 0.017) above the values of the CTRL group, respectively. Both Ex and ExGTE significantly decreased the increase of CK by ∼11%-32% below that of CTRL following an exhaustive run (Ex: p = 0.007; ExGTE: p = 0.001). Moreover, TAS levels increased by ∼11% in ExGTE after training (p = 0.040), and GTE, Ex, and ExGTE markedly attenuated exercise-induced MDA production (p = 0.01, p = 0.005, p = 0.011, respectively). In conclusion, this investigation demonstrated that daily ingestion of GTE during endurance training does not impair improvements in endurance capacity. Moreover, endurance training combined with GTE not only increases antioxidant capacity without attenuating endurance training adaptations, but also further attenuates acute exercise-induced CK release.
authors: a Department of Exercise and Health Science, National Taipei University of Nursing and Health Sciences, No. 365, Ming-Te Road, Peitou Distric, Taipei City 11219, Taiwan.
authors: Yu-Chi
authors: YC
authors: Kuo
authors: b Graduate Institute of Coaching Science, Chinese Culture University, Taipei, Taiwan.
authors: Jung-Charng
authors: JC
authors: Lin
authors: c Department of Kinesiology, California State University, Stanislaus, Turlock, CA 95382, USA.
authors: Jeffrey R
authors: JR
authors: Bernard
authors: a Department of Exercise and Health Science, National Taipei University of Nursing and Health Sciences, No. 365, Ming-Te Road, Peitou Distric, Taipei City 11219, Taiwan.
authors: Yi-Hung
authors: YH
authors: Liao
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D000975:Antioxidants / Q000378:metabolism*; D019587:Dietary Supplements; D015444:Exercise / Q000502:physiology; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D010936:Plant Extracts; D057185:Sedentary Behavior; D013662:Tea; D055815:Young Adult
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D013662:Tea
keywords: V̇O2max; catechins; catéchines; creatine kinase (CK); créatine kinase (CK); malonaldéhyde (MDA); malondialdehyde (MDA); oxidative stress; stress oxydatif