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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

terça-feira, 30 de agosto de 2011

Posicionamento de entidades médicas e científicas sobre a participação de crianças e adolescentes no boxe

Pediatrics. 2011 Aug 28. [Epub ahead of print]

Policy Statement--Boxing Participation by Children and Adolescents.

AMERICAN ACADEMY OF PEDIATRICS; COUNCIL ON SPORTS MEDICINE AND FITNESS; CANADIAN PAEDIATRIC SOCIETY; HEALTHY ACTIVE LIVING AND SPORTS MEDICINE COMMITTEE.

Abstract

Thousands of boys and girls younger than 19 years participate in boxing in North America. Although boxing provides benefits for participants, including exercise, self-discipline, and self-confidence, the sport of boxing encourages and rewards deliberate blows to the head and face. Participants in boxing are at risk of head, face, and neck injuries, including chronic and even fatal neurologic injuries. Concussions are one of the most common injuries that occur with boxing. Because of the risk of head and facial injuries, the American Academy of Pediatrics and the Canadian Paediatric Society oppose boxing as a sport for children and adolescents. These organizations recommend that physicians vigorously oppose boxing in youth and encourage patients to participate in alternative sports in which intentional head blows are not central to the sport.

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.

Abstract
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.

Abstract

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

http://esportes.terra.com.br/judo/noticias/0,,OI5317987-EI15566,00-COB+pede+seis+podios+do+judo+em+Londres+e+ve+cabeca+de+campeao.html

segunda-feira, 22 de agosto de 2011

Artigo na Science indica uso de artes marciais para melhoria da função executiva de crianças

Science. 2011 Aug 19;333(6045):959-64.


Interventions shown to aid executive function development in children 4 to 12 years old.

Diamond A, Lee K.

SourceUniversity of British Columbia and Children's Hospital, Vancouver, BC V6T 2A1, Canada. adele.diamond@ubc.ca



Abstract

To be successful takes creativity, flexibility, self-control, and discipline. Central to all those are executive functions, including mentally playing with ideas, giving a considered rather than an impulsive response, and staying focused. Diverse activities have been shown to improve children's executive functions: computerized training, noncomputerized games, aerobics, martial arts, yoga, mindfulness, and school curricula. All successful programs involve repeated practice and progressively increase the challenge to executive functions. Children with worse executive functions benefit most from these activities; thus, early executive-function training may avert widening achievement gaps later. To improve executive functions, focusing narrowly on them may not be as effective as also addressing emotional and social development (as do curricula that improve executive functions) and physical development (shown by positive effects of aerobics, martial arts, and yoga).

Perda de peso e uso de suplementos entre wrestlers iranianos

Patterns of weight loss and supplement consumption of male wrestlers in Tehran

Ramin Kordi1*, Vahid Ziaee1, Mohsen Rostami1, William A Wallace2

Abstract

Background: To evaluate the weight loss behavior of male wrestlers in Tehran
Methods: This study was a population-based cross sectional survey. Subjects were 436 wrestlers randomly selected from the wrestling clubs in Tehran employing cluster sample setting method. Subjects were interviewed based on a designed questionnaire. Body fat levels were measured based on skin fold measurements.
Results: Weight loss methods practiced by 62% of all subjects during the previous year employing rapid (≤7 days before the matches) and gradual (>7 days before the matches) weight reduction methods (73% and 34% of wrestlers who reduced their weight respectively). In addition, opinions on weight reduction, the methods of weight loss used, and the side effects of the weight loss practices as well as consumption of supplements among the subjects were reported in this study. The mean percentage of body fat of subjects was 15.9%. Conclusions: Rapid weight loss for matches and the use of unsafe methods of weight reduction such as fasting, and fluid reduction methods as well as acute side effects of weight loss were prevalent among wrestlers in Tehran. Some preventive measures including education and new rules such as scheduling weigh-ins immediately prior to the competitions and mat-side weigh-in are needed to prevent these unhealthy practices. The weight loss behaviors of these wrestlers should be changed from using dehydration methods to using gradual methods of weight loss.
http://www.springerlink.com/content/c48727205u116275/fulltext.pdf

sexta-feira, 19 de agosto de 2011

EMG em boxeadoras

Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2011 May;27(2):253-6.


Women boxing athletes' EMG of upper limbs and lumbar muscles in the training of air striking of straight punch
[Article in Chinese]

Zhang RH, Kang ZX.

Department of Human Sports Science, Shenyang Sport University, Shenyang 110102, China. rhzhang75@yahoo.com.cn

Abstract
OBJECTIVE: To study training effect of upper limbs and lumbar muscles in the proceed of air striking of straight punch by analyzing boxing athletes' changes of electromyogram (EMG).
METHODS: We measured EMG of ten women boxing athletes' upper arm biceps (contractor muscle), upper arm triceps (antagonistic muscle), forearm flexor muscle (contractor muscle), forearm extensor muscle (antagonistic muscle), and lumbar muscles by ME6000 (Mega Electronics Ltd.). The stipulated exercise was to do air striking of straight punch with loads of 2.5 kg of dumbbell in the hand until exhausted.
RESULTS: In the proceed of exercise-induce exhausted, the descend magnitude and speed of median frequency (MF) in upper limb antagonistic muscle exceeded to contracting muscle, moreover, the work percentage showed that contractor have done a larger percentage of work than antagonistic muscle. Compared with world champion's EMG, the majority of ordinary athletes' lumbar muscles MF revealed non-drop tendency, and the work percentage showed that lumbar muscles had a very little percentage of work.
CONCLUSION: After comparing the EMG test index in upper limb and lumbar muscle of average boxing athletes with that of the world champion, we find the testees lack of the training of upper limb antagonistic muscle and lumbar muscle, and more trainings aimed at these muscles need to be taken.

Mínima massa corporal de atletas de luta olímpica

Ann Nutr Metab. 2011 Aug 12;58(3):245-249. [Epub ahead of print]


Validity of the Current NCAA Minimum Weight Protocol: A Brief Review.

Loenneke JP, Wilson JM, Barnes JT, Pujol TJ.

Department of Health and Exercise Science, The University of Oklahoma, Norman, Okla., USA.

Abstract
Historically, collegiate wrestlers have been associated with utilizing rapid weight loss methods to reach a desired weight class. Following three deaths in 1997, the National Collegiate Athletic Association (NCAA) implemented a program which prevents wrestlers from wrestling below a minimum weight (MW) of 5% body fat. Although numerous studies have investigated adolescent wrestlers, few have investigated collegiate wrestlers using the methods outlined by the NCAA. The purpose of this review paper is to outline potential problems with the current NCAA protocol as well as critique studies investigating the validity of methods to assess MW.

Concussão e MMA

J Neurol Sci. 2011 Aug 15. [Epub ahead of print]

The King-Devick test and sports-related concussion: Study of a rapid visual screening tool in a collegiate cohort.

Galetta KM, Brandes LE, Maki K, Dziemianowicz MS, Laudano E, Allen M, Lawler K, Sennett B, Wiebe D, Devick S, Messner LV, Galetta SL, Balcer LJ.

Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.

Abstract
OBJECTIVE: Concussion, defined as an impulse blow to the head or body resulting in transient neurologic signs or symptoms, has received increasing attention in sports at all levels. The King-Devick (K-D) test is based on the time to perform rapid number naming and captures eye movements and other correlates of suboptimal brain function. In a study of boxers and mixed martial arts (MMA) fighters, the K-D test was shown to have high degrees of test-retest and inter-rater reliability and to be an accurate method for rapidly identifying boxers and mixed martial arts fighters with concussion. We performed a study of the K-D test as a rapid sideline screening tool in collegiate athletes to determine the effect of concussion on K-D scores compared to a pre-season baseline.
METHODS: In this longitudinal study, athletes from the University of Pennsylvania varsity football, sprint football, and women's and men's soccer and basketball teams underwent baseline K-D testing prior to the start of the 2010-11 playing season. Post-season testing was also performed. For athletes who had concussions during the season, K-D testing was administered immediately on the sidelines and changes in score from baseline were determined.
RESULTS: Among 219 athletes tested at baseline, post-season K-D scores were lower (better) than the best pre-season scores (35.1 vs. 37.9s, P=0.03, Wilcoxon signed-rank test), reflecting mild learning effects in the absence of concussion. For the 10 athletes who had concussions, K-D testing on the sidelines showed significant worsening from baseline (46.9 vs. 37.0s, P=0.009), with all except one athlete demonstrating worsening from baseline (median 5.9s).
CONCLUSION: This study of collegiate athletes provides initial evidence in support of the K-D test as a strong candidate rapid sideline visual screening tool for concussion. Data show worsening of scores following concussion, and ongoing follow-up in this study with additional concussion events and different athlete populations will further examine the effectiveness of the K-D test.


Treinamento intervalado de alta intensidade aplicado a lutadores de wrestling

Embora o protocolo adicional não seja específico, o estudo é interessante.

J Strength Cond Res. 2011 Aug 16. [Epub ahead of print]


Physiological and Performance Changes From The Addition of a Sprint Interval Program to Wrestling Training.

Farzad B, Gharakhanlou R, Agha-Alinejad H, Curby DG, Bayati M, Bahraminejad M, Mäestu J.

Department of Physical Education and Sports Sciences, School of Humanity Sciences, Tarbiat Modares University, Tehran, Iran; 2Overtime School of Wrestling, Naperville, Illinois; 3Physical Fitness Assessment and Improvement Center, National Olympic and Paralympic Academy, Tehran, Iran; and 4Institute of Sport Pedagogy and Coaching Sciences, Centre of Behavioural and Health Sciences, University of Tartu, Tartu, Estonia.

Abstract
Farzad, B, Gharakhanlou, R, Agha-Alinejad, H, Curby, DG, Bayati, M, Bahraminejad, M, and Mäestu, J. Physiological and performance changes from the addition of a sprint-interval program to wrestling training. J Strength Cond Res 25(9): 2392-2399, 2011-Increasing the level of physical fitness for competition is the primary goal of any conditioning program for wrestlers. Wrestlers often need to peak for competitions several times over an annual training cycle. Additionally, the scheduling of these competitions does not always match an ideal periodization plan and may require a modified training program to achieve a high level of competitive fitness in a short-time frame. The purpose of this study was to examine the effects of 4 weeks of sprint-interval training (SIT) program, on selected aerobic and anaerobic performance indices, and hormonal and hematological adaptations, when added to the traditional Iranian training of wrestlers in their preseason phase. Fifteen trained wrestlers were assigned to either an experimental (EXP) or a control (CON) group. Both groups followed a traditional preparation phase consisting of learning and drilling technique, live wrestling and weight training for 4 weeks. In addition, the EXP group performed a running-based SIT protocol. The SIT consisted of 6 35-m sprints at maximum effort with a 10-second recovery between each sprint. The SIT protocol was performed in 2 sessions per week, for the 4 weeks of the study. Before and after the 4-week training program, pre and posttesting was performed on each subject on the following: a graded exercise test (GXT) to determine VO2max, the velocity associated with VO2max (νVO2max), maximal ventilation, and peak oxygen pulse; a time to exhaustion test (Tmax) at their νVO2max; and 4 successive Wingate tests with a 4-minute recovery between each trial for the determination of peak and mean power output (PPO, MPO). Resting blood samples were also collected at the beginning of each pre and posttesting period, before and after the 4-week training program. The EXP group showed significant improvements in VO2max (+5.4%), peak oxygen pulse (+7.7%) and Tmax (+32.2%) compared with pretesting. The EXP group produced significant increases in PPO and MPO during the Wingate testing compared with pretesting (p < 0.05). After the 4-week training program, total testosterone and the total testosterone/cortisol ratio increased significantly in the EXP group, whereas cortisol tended to decrease (p = 0.06). The current findings indicate that the addition of an SIT program with short recovery can improve both aerobic and anaerobic performances in trained wrestlers during the preseason phase. The hormonal changes seen suggest training-induced anabolic adaptations.

segunda-feira, 15 de agosto de 2011

MMA: significados

Social and Cultural Geography

Volume 12, Issue 4, June 2011, Pages 378-396
It hurts so it is real: Sensing the seduction of mixed martial arts

Green, K.

Department of Sociology, University of Minnesota-Twin Cities, 909 Social Sciences, 267 19th Ave S, Minneapolis, MN 55455, United States

Abstract



This paper explores the seduction of pain within the increasingly popular practice of mixed martial arts. It is based on a three-year ethnographic study of training schools in Minnesota. Within these sites, often-affluent men train their bodies in combat skills, learning to strike and grapple, while building a community around the shared exchange of pain. The drive is often explained with a variation of the statement: 'I do this because you don't know who you are ... you don't feel aliv ... until you get hit.' This paper contributes to the growing body of geographic literature centered on practice and affect. Within this approach, there has been little appreciation of physical and violent encounters. Appreciation of the role of pain shifts focus to the moment when the body retreats in upon itself, becoming a united mass of flesh and nerves. I suggest that pain attracts participants through serving three purposes within these fightbased schools: (1) it provides confidence that the experience is 'real'; (2) it is itself an avenue to encounter the body as a united 'self' with clear limits and boundaries; (3) it establishes intimacy between participants, which is necessary for the formation of community within each site.

Estrutura temporal de lutas de judô para cegos

J Sports Sci. 2011 Aug 11. [Epub ahead of print]


The temporal structure of judo bouts in visually impaired men and women.

Gutiérrez-Santiago A, Prieto I, Camerino O, Anguera T.

Faculty of Education and Sport , University of Vigo , Pontevedra , Spain.

Abstract
Abstract The aim of this study was to determine the temporal structure of judo bouts in visually impaired men and women (n = 117 judokas in the senior category; 92 men and 25 women). We developed a data recording system based on the temporal parameters of judo and applied it to a broad sample of international bouts (n = 219; 184 between men and 35 between women). The descriptive analysis of frequency of occurrence revealed that most of the bouts ended before the time-up bell sounded (81% men/74% women). Other defining features are shown in the following mean values (for men/women): the total bout time was 266/242 s; the total time paused was 158/172 s; the total time spent in standing combat was 82/54 s (P = 0.008), while that of floor combat was 60/84 s (P = 0.021); each bout had 6.9/5.7 paused sequences with a duration of 19.6/21.1 s, and 12.4/11.7 active sequences with a duration of 22/19.7 s. The sequential analysis by means of T-patterns (THEME) confirmed that the temporal structure of judo is not the same for men and women, thereby highlighting the need for a range of training methods matched to the needs of visually impaired competitors.

terça-feira, 2 de agosto de 2011

Prática de TKD e desenvolvimento do equilíbrio e de funções sensoriais

J Sci Med Sport. 2011 Jul 27. [Epub ahead of print]

Taekwondo training speeds up the development of balance and sensory functions in young adolescents.
Fong SS, Fu SN, Ng GY.
Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong (SAR), China.
Abstract
Objectives: This study aimed (1) to identify the developmental status of balance and sensory functions in young adolescents as compared to adults and, (2) to explore the effect of Taekwondo (TKD) training on the development of balance and sensory systems in young adolescents. Design: Cross-sectional controlled trial. Methods: Sixty-six participants including 42 adolescents (21 TKD practitioners, 21 non-TKD practitioners) and 24 adults were tested. The sway velocity of centre of gravity was recorded during standing on the non-dominant leg on a Smart Equitest(®) system. The somatosensory, vestibular and visual ratios were also measured with the machine. Results: Adult participants swayed slower than both TKD and non-TKD adolescent groups during single leg stance with eyes open (p=0.007 and p<0.001, respectively). The TKD adolescent group, in turn, swayed slower than the non-TKD adolescent group (p<0.001). Adult participants had better visual ratio than both TKD and non-TKD adolescents (p=0.001 and p<0.001, respectively) while there was no difference between the TKD and non-TKD adolescents (p=0.164). For the vestibular ratio, there was no significant difference between adult participants and TKD adolescents (p=0.432). Adolescents who did not practice TKD showed significantly lower vestibular ratio than TKD adolescents and adults (p=0.003 and p<0.001, respectively). In addition, there was no significant difference in the somatosensory ratio among the 3 participant groups (p=0.711). Conclusions: Participation in TKD appears to speed up the development of postural control and vestibular function in adolescents. Clinicians might advocate TKD exercise as a therapeutic intervention for young people with balance or vestibular dysfunctions.