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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

quinta-feira, 31 de março de 2011

Perda de peso e humor em atletas de luta olímpica

J Strength Cond Res. 2011 Apr;25(4):1010-5.

Effects of self-selected mass loss on performance and mood in collegiate wrestlers.
Marttinen RH, Judelson DA, Wiersma LD, Coburn JW.
Department of Kinesiology, California State University, Fullerton, California.

Marttinen, RHJ, Judelson, DA, Wiersma, LD, and Coburn, JW. Effects of self-selected mass loss on performance and mood in collegiate wrestlers. J Strength Cond Res 25(4): 1010-1015, 2011-Wrestlers abruptly lose body mass before competition; however, the effects of "weight cutting" are poorly understood because of conflicting evidence. This study aimed to determine the effects of self-selected mass loss on precompetition mood, grip strength, and lower body power in collegiate wrestlers. Sixteen male collegiate wrestlers (age = 20 ± 2 years, height = 177.5 ± 7.2 cm) were weighed 10 days before (D-10) a competitive meet. Euhydrated subjects were administered the Brunel Mood Scale (BRUMS), tested on grip strength, and given a 30-second Wingate Anaerobic Power test to determine lower body power. Additional weigh-ins were conducted 6 (D-6) and 2 (D-2) days before competition. Subjects repeated the testing battery the day of competition (D-0). During the study, wrestlers self-selected the method and timing of mass loss. Wrestlers lost 0.0-8.1% of their body mass using exercise, caloric restriction, or fluid deprivation. Most mass loss occurred between D-2 and D-0 (mean ± SD, D-10 = 81.7 ± 18.2 kg, D-6 = 81.2 ± 17.8 kg, D-2 = 81.1 ± 18.5 kg, D-0 = 79.0 ± 19.2 kg). Wrestlers losing ≥4% body mass became significantly more confused (D-10 = 0 ± 0, D-0 = 3 ± 3); subjects losing less mass showed no difference in confusion. No significant differences existed across time for remaining BRUMS variables, grip strength, and Wingate variables. These results suggest that wrestlers self-select large, rapid mass loss that impairs aspects of psychological functioning without affecting grip strength or lower-body power.

quarta-feira, 30 de março de 2011

Impactos na cabeça em decorrência de diferentes chutes de TKD

Br J Sports Med. 2011 Apr;45(4):318-9.

Effects of olympic style taekwondo kicks on an instrumented head-form and resultant head injury measures.
Fife G, Pieter W, O'sullivan D, Cook D, Kaminski T.

Background In taekwondo (TKD), concussion incidence is four times greater than in American football. Biomechanical investigations on concussion in TKD is sparse. Objective To examine differences in TKD kicks on resultant head linear acceleration (RLA), head injury criterion (HIC15) and peak head velocity (HVEL). Design Between-groups. Setting Biomechanics laboratory. Participants 12 elite male TKD athletes (22.5+3.5 years, 176.9+7.3 cm, 70.9+8.6 kg). Interventions Five head kicks (round kick (RK), front leg axe kick, clench-axe kick (CA), jump spin back kick, jump spin hook kick (JH)) were randomly performed five times each. A Hybrid II Crash Dummy head (H2D) was instrumented with a tri-axial accelerometer (PCB Piezotronics-356A66) mounted inside the H2D head. The H2D was fixed to a height adjustable frame and fitted with a protective TKD helmet. Acceleration data were captured using Qualisys Track Manager (Gothenburg, Sweden) and processed in accordance with SAE J211-1. Main outcome measurements RLA, HIC and HVEL. Results The RK (130.11±51.67 g) produced a higher RLA than the CA (54.95±20.08 g, p<0.001, d=1.84) and a higher HIC15 than the JH (672.74±540.89 vs 300.19±144.35, p<0.001, ES=0.97). The range of the RLA by the RK was 60.50-217.33 g, while the CA was 26.34-99.02 g. The HIC15 range for the RK was 128.40-1608.70 and the JH, 63.90-573.00. There was no difference in HVEL of the RK (4.73±1.67 m/s, range: 3.36-9.52 m/s) and that of the JH (4.43±0.78 m/s, range: 3.00-5.54 m/s) (p=0.977, ES<0.01). Conclusion Our investigations are the first to identify the high-magnitude head impacts in TKD. A previous report suggests an HIC15 concussion threshold of >200. The RK is of concern because it is the most common technique and most common cause of concussion in TKD and has a high RLA and HIC15. Prevention of concussion in TKD should focus on employing qualified medical personnel, injury monitoring, and safer equipment.

quinta-feira, 24 de março de 2011

quarta-feira, 23 de março de 2011

terça-feira, 22 de março de 2011

Artigo sobre o impacto dos chutes no TKD

Energy absorbed by electronic body protectors from kicks in a taekwondo competition

F.B. Del Vecchio, E Franchini, A.H.M. Del Vecchio, W Pieter
Biol Sport 2011; 28 (1):
Objective: Although some scientific information on electronic body protectors in taekwondo is available, no research has been done to assess the impact of kicks in a competitive situation. The purpose of this study, then, was to assess the energy absorbed by these protectors from kicks performed in an actual taekwondo competition. Methods: Subjects consisted of junior (14-17 years) and senior (≥18 years) male taekwondo-in, who participated in an open tournament. Data on the energy imparted by valid kicks in Joules (J) were collected from a public visual electronic monitor. Results: Energy was higher for the seniors: 264.31 ± 56.63 J versus 224.38 ± 48.23 J for the juniors (eta2 = 0.121). The seniors scored lower in percent impact but the effect was trivial: 123.46 ± 24.77% versus 136.70 ± 26.33% (eta2 = 0.087). Conclusions: The difference between senior and junior taekwondo-in in absolute energy generated was small, while the difference in relative energy impact was trivial in favour of the junior taekwondo athletes.


Discurso de formatura, como paraninfo da XVI Turma de Bacharéis em Educação Física da EEFE-USP

Sem dúvida, a atividade acadêmica que tive mais motivação e prazer em realizar neste primeiro trimestre...

Material referente à apresentação da Cássia Regina Palermo Moreira


Conheça a International Network of Wrestling Research, seus pesquisadores e seu periódico


quinta-feira, 17 de março de 2011

Fotos do Estudo do Juliano Schwartz


Novo livro sobre judô


Lesões em boxeadores

Am J Prev Med. 2011 Apr;40(4):462-7.

Boxing injuries presenting to u.s. Emergency departments, 1990-2008.
Potter MR, Snyder AJ, Smith GA.
Center for Injury Research and Policy, the Ohio State University College of Medicine, Columbus, Ohio; The Research Institute at Nationwide Children's Hospital, the Ohio State University College of Medicine, Columbus, Ohio.

BACKGROUND: Boxing injuries can have serious consequences.
PURPOSE: To examine the epidemiology of boxing injuries in the U.S. with attention to head injuries and children.
METHODS: National estimates of boxing injuries were calculated using data from the National Electronic Injury Surveillance System. Injury rates per 1000 participants for the year 2003 were calculated using boxing participation data. Data analysis was conducted in 2009-2010.
RESULTS: An estimated 165,602 individuals (95% CI=134891, 196313) sustained boxing injuries that resulted in a visit to a U.S. hospital emergency department from 1990 through 2008. An average of 8716 (95% CI=7078, 10354) injuries occurred annually, and there was a statistically significant increase in the annual number of injuries during the 19-year study period (slope=610, p<0.001). The rate of injury was 12.7 per 1000 participants. Those injured were predominately male (90.9%). The most common diagnosis was fracture (27.5%), and the most common body regions injured were the hand (33.0%) and head and neck (22.5%). Punching bag-related injuries accounted for 36.8% of boxing injuries. The percentage of injuries that were concussions/closed head injuries in the group aged 12-17 years (8.9%) was similar to that in the group aged 18-24 years (8.1%) and the group aged 25-34 years (8.5%).
CONCLUSIONS: These findings, based on a nationally representative sample, indicate that injuries related to boxing are increasing in number. Increased efforts are needed to prevent boxing injuries.

quinta-feira, 10 de março de 2011

Gasto energético durante diversos jogos de vídeo-game

Arch Pediatr Adolesc Med. 2011 Mar 7. [Epub ahead of print]

Energy Cost of Exergaming: A Comparison of the Energy Cost of 6 Forms of Exergaming.
Bailey BW, McInnis K.
Brigham Young University, Provo, Utah (Dr Bailey), and Department of Exercise and Health Sciences, University of Massachusetts, Boston (Dr McInnis).

OBJECTIVE: To determine the relative effect of interactive digital exercise that features player movement (ie, exergames) on energy expenditure among children of various body mass indexes (BMIs; calculated as weight in kilograms divided by height in meters squared).
DESIGN: Comparison study.
SETTING: GoKids Boston, a youth fitness research and training center located at University of Massachusetts, Boston.
PARTICIPANTS: Thirty-nine boys and girls (mean [SD] age, 11.5 [2.0] years) recruited from local schools and after-school programs. Main Exposure Six forms of exergaming as well as treadmill walking.
MAIN OUTCOME MEASURES: In addition to treadmill walking at 3 miles per hour (to convert miles to kilometers, multiply by 1.6), energy expenditure of the following exergames were examined: Dance Dance Revolution, LightSpace (Bug Invasion), Nintendo Wii (Boxing), Cybex Trazer (Goalie Wars), Sportwall, and Xavix (J-Mat). Energy expenditure was measured using the CosMed K4B2 portable metabolic cart.
RESULTS: All forms of interactive gaming evaluated in our study increased energy expenditure above rest, with no between-group differences among normal (BMI < 85th percentile) and "at-risk" or overweight (BMI ≥ 85th percentile) children (P ≥ .05). Walking at 3 miles per hour resulted in a mean (SD) metabolic equivalent task value of 4.9 (0.7), whereas the intensity of exergaming resulted in mean (SD) metabolic equivalent task values of 4.2 (1.6) for Wii, 5.4 (1.8) for Dance Dance Revolution, 6.4 (1.6) for LightSpace, 7.0 (1.8) for Xavix, 5.9 (1.5) for Cybex Trazer, and 7.1 (1.7) for Sportwall. Enjoyment of the games was generally high but was highest for children with BMIs in the highest percentiles.
CONCLUSION: All games used in our study elevated energy expenditure to moderate or vigorous intensity. Exergaming has the potential to increase physical activity and have a favorable influence on energy balance, and may be a viable alternative to traditional fitness activities for children of various BMI levels.

Sistemas complexos e criatividade no esporte

Nonlinear Dynamics Psychol Life Sci. 2011 Apr;15(2):175-206.

Constraints-induced Emergence of Functional Novelty in Complex Neurobiological Systems: A Basis for Creativity in Sport.
Hristovski R, Davids K, Araujo D, Passos P.
In this paper we present a model of creativity captured as exploration and production of novel and functionally efficient behaviors, based on the statistical mechanics of disordered systems. In support of the modelling, we highlight examples of creative behaviors from our research in sports like boxing and rugby union. Our experimental results show how manipulation of practice task constraints changes the exploratory breadth of the hierarchically soft-assembled action landscape. Because of action metastability and differing task constraints, the specificity of each assembled movement configuration is unique. Empirically, a movement pattern's degree of novelty may be assessed by the value of the order parameter describing action. We show that creative and adaptive movement behavior may be induced by at least two types of interven-tions, based on relaxing task constraints which we term direct and indirect. Direct relaxing is typically a function of changing task constraints so that the number of affordances that can satisfy goal constraints increases. Indirect relaxing of constraints occurs when a habitual action is suppressed by, for example, stringent instructional constraints during sports training. That suppression simultaneously relaxes other correlated constraints that enable larger exploratory capacity and new affordances to emerge for the athlete or team.

quinta-feira, 3 de março de 2011

Suplementação de zinco em wrestlers

Biol Trace Elem Res. 2011 Mar 1. [Epub ahead of print]

Effects of Exercise and Zinc Supplementation on Cytokine Release in Young Wrestlers.
Kara E, Ozal M, Gunay M, Kilic M, Baltaci AK, Mogulkoc R.
Hasan Dogan High School of Physical Education and Sports, Karabuk University, Karabuk, Turkey, kara.ersan@yahoo.com.

The present study aims to examine the effect of zinc supplementation on the release of some cytokines in young wrestlers actively involved in wrestling. A total of 40 male subjects of the same age group were included in the study: half were wrestlers and the other half were not involved in sports. The subjects were equally divided into four groups and treated during an 8-week period as follows: group 1, zinc-supplemented athletes; group 2, non-supplemented athletes; group 3, zinc-supplemented sedentary subjects, and group 4, non-supplemented sedentary group. Blood samples were taken from each subject at the beginning and at the end of the study period. The serum tumor necrosis factor-α (TNF-α), interleukin-2 (IL-2), and interpheron-γ levels (IFN-γ) were determined using the enzyme-linked immunosorbent assay method. At the beginning of the study, there were no significant differences of the measured parameters between the four study groups. At the end of the study, the levels of TNF-α, IL-2, and IFN-γ were significantly higher in the two zinc-supplemented groups compared to those that did not receive supplementation, regardless of the activity status (p < 0.01).