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Quem sou eu

São Paulo, São Paulo, Brazil
Professor da EEFE-USP; Praticante e Pesquisador de Judô; Preparador físico de atletas de modalidades esportivas de combate.

Arquivo do blog

domingo, 28 de agosto de 2011

Mudanças nos fluídos corporais e na força isométrica máxima em atletas de judô

J Strength Cond Res. 2011 Sep;25(9):2488-2495.

Relationship Between Changes in Total-Body Water and Fluid Distribution With Maximal Forearm Strength in Elite Judo Athletes.

Silva AM, Fields DA, Heymsfield SB, Sardinha LB.

1Exercise and Health Laboratory, Faculty of Human Kinetics-Technical University of Lisbon, Lisbon, Portugal; 2Department of Pediatrics, Children's Medical Research Institute's Metabolic Research Program, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma; and 3Pennington Biomedical Research Foundation, Baton Rouge, Louisiana.

Silva, AM, Fields, DA, Heymsfield, SB, and Sardinha, LB. Relationship between changes in total-body water and fluid distribution with maximal forearm strength in elite judo athletes. J Strength Cond Res 25(9): 2488-2495, 2011-Among judo athletes, strong grip strength is crucial for performing offensive and defensive maneuvers that rely predominantly on forearm maximal strength (FMS). The study aims were to evaluate changes in total-body water (TBW) and its compartments (extracellular water [ECW] and intracellular water [ICW]) and their relationship with loss of FMS in elite judo athletes. At baseline (weight stability), 27 male elite athletes were evaluated (age: 23.2 ± 2.8 years) and again evaluated 1-3 days before competition. Athletes were free to gain or lose weight based upon their specific competition needs. Using dilution techniques (deuterium and bromide), TBW and ECW were estimated, and ICW was calculated (ICW = TBW - ECW). Fat, fat-free mass, and appendicular lean soft tissue (LST) were assessed by dual-energy x-ray absorptiometry. Handgrip was used to assess FMS. Using a reduction of 2% as a representative outcome for decreased FMS, 10 athletes were identified as having lost FMS, whereas 17 changed <2% or gained. Comparison of means and logistic regression analysis were performed. Results from baseline to before competition indicated that those who lost ≥2% of FMS significantly decreased TBW and ICW by -2.7 ± 3.0 and -4.4 ± 4.2%, respectively. The groups differed in ICW changes (-4.4 ± 4.2 vs. 1.9 ± 6.1%), respectively, for those who lost FMS by ≥2%. The ICW changes, but not in TBW or ECW, significantly predicted the risk of losing FMS (β = 0.206; p = 0.027), even adjusting for weight and arm LST changes. These findings indicated that reductions in ICW increased the risk of losing grip strength in elite judo athletes.

Estresse oxidativo em judocas e indivíduos sedentários

J Strength Cond Res. 2011 Sep;25(9):2400-2409.

Antioxidant Status and Oxidative Stress at Rest and in Response to Acute Exercise in Judokas and Sedentary Men.

Abed KE, Rebai H, Bloomer RJ, Trabelsi K, Masmoudi L, Zbidi A, Sahnoun Z, Hakim A, Tabka Z.

1Laboratory of Cardio-Circulatory, Respiratory, Metabolic, and Hormonal Adaptations to the Muscular Exercise, Faculty of Medicine Ibn El Jazzar, Sousse, Tunisia; 2Laboratory of Pharmacology, Faculty of Medicine, Sfax, Tunisia; and 3Cardiorespiratory/Metabolic Laboratory, University of Memphis, Memphis, Tennessee.


El Abed, K, Rebai, H, Bloomer, RJ, Trabelsi, K, Masmoudi, L, Zbidi, A, Sahnoun, Z, Hakim, and A Tabka, Z. Antioxidant status and oxidative stress at rest and in response to acute exercise in judokas and sedentary men. J Strength Cond Res 25(9): 2400-2409, 2011. It is well recognized that acute strenuous exercise is accompanied by an increase in free-radical production and subsequent oxidative stress, in addition to changes in blood antioxidant status. Chronic exercise provides protection against exercise-induced oxidative stress by upregulating endogenous antioxidant defense systems. Little is known regarding the protective effect afforded by judo exercise. Therefore, we determined antioxidant and oxidative stress biomarkers at rest and in response to acute exercise in 10 competitive judokas and 10 sedentary subjects after mixed exercise (anaerobic followed by aerobic). The subjects performed a Wingate test, followed by 30 minutes of aerobic exercise performed at 60% of maximal aerobic power. Blood samples were taken, by an intravenous catheter, at rest (R), immediately after the physical exercise (P0), and at 5 (P5), 10 (P10), and 20 (P20) minutes postexercise. The measured parameters included the activity of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and glutathione reductase, in addition to α-tocopherol, and total antioxidant status. Malondialdehyde was measured as a representation of lipid peroxidation. At rest, the judokas had higher values for all antioxidant and oxidative stress markers as compared to the sedentary subjects (p < 0.05). Plasma concentrations of all parameters except for α-tocopherol increased significantly above resting values for both the judokas and sedentary subjects (p < 0.05) and remained elevated at 20 minutes postexercise. A significant postexercise decrease was observed for α-tocopherol (p < 0.05) at P20 for judokas and at P5 for sedentary subjects. These data indicate that competitive judo athletes have higher endogenous antioxidant protection compared to sedentary subjects. However, both groups of subjects experience an increase in exercise-induced oxidative stress that is not different.

Londres 2012