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Artigo sobre adaptações ao treinamento físico em crianças e adolescentes atletas de judô

J Strength Cond Res. 2012 Apr 3. [Epub ahead of print]


The effects of tournament preparation on anthropometric and sport-specific performance measures in youth judo athletes.

Fukuda DH, Stout JR, Kendall KL, Smith AE, Wray ME, Hetrick RP.

1Metabolic and Body Composition Laboratory; Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019; 2 Sport and Exercise Science Program, University of Central Florida, Orlando, FL 32816; 3 Department of Exercise and Sport Science, University of North Carolina Chapel Hill, Chapel Hill, NC 27599-8700.

Abstract
The purpose of this study was to characterize the adaptations imposed by four weeks of pre-competition judo training in youth athletes. It was hypothesized that anthropometric and sport-specific performance would improve during the preparation for a junior national championship event. Twenty youth athletes (mean±SD; chronological age: 13.1±3.2 years; training age: 5.3±3.5 years; judo experience: 7.8±2.5 hours/week) completed pre- and post-testing procedures. Child (≤ 12 years old; n=8) and Adolescent (≥13 years old; n=12) groups were evaluated to determine the anthropometric and sport-specific performance changes caused by four weeks of judo training conducted in preparation for the junior national championships. The Child group showed an increase in flexibility (+11.5%) and the Adolescent group showed a decrease in skinfold thickness (-12.2%), increased jumping power (+26.7%), force (+7.7%), and velocity (+19.0%), and improved judo-specific ability (-5.9%), as measured by the Special Judo Fitness Test Index. Additionally, the Special Judo Fitness Test Index for all of the study participants was shown to be inversely correlated to handgrip strength (r=-0.681), rope pull performance (r=-0.545), and jump height (r=-0.503). These results support the use of preparatory judo training in the improvement of anthropometric and sport-specific measures in adolescent athletes. Furthermore, the outcomes from this study provide direction for coaches and trainers in their efforts to impact physical performance and judo skills in children and adolescents through pre-competition training.

Bianca no blog do Leandro Guilheiro

http://esportes.terra.com.br/jogos-olimpicos/londres-2012/leandroguilheiro/blog/2012/04/05/selecao-sem-cara-de-concentracao/

MMA e violência juvenil

Violence Vict. 2012;27(1):43-69.


Epidemiology of mixed martial arts and youth violence in an ethnically diverse sample.

Hishinuma ES, Umemoto KN, Nguyen TG, Chang JY, Bautista RP.

Department of Psychiatry, University of Hawai'i at Mānoa, Honolulu, Hawai'i 96813, USA. hishinumae@dop.hawaii.edu


Abstract
Mixed martial arts' (MMAs) growing international popularity has rekindled the discussion on the advantages (e.g., exercise) and disadvantages (e.g., possible injury) of contact sports. This study was the first of its kind to examine the psychosocial aspects of MMA and youth violence using an epidemiologic approach with an Asian American and Pacific Islander (AAPI) adolescent sample (N = 881). The results were consistent with the increased popularity of MMA with 52% (adolescent males = 73%, adolescent females = 39%) enjoying watching MMA and 24% (adolescent males = 39%, adolescent females = 13%) practicing professional fight moves with friends. Although statistically significant ethnic differences were found for the two MMA items on a bivariate level, these findings were not statistically significant when considering other variables in the model. The bivariate results revealed a cluster of risk-protective factors. Regarding the multiple regression findings, although enjoying watching MMA remained associated with positive attitudes toward violence and practicing fight moves remained associated with negative out-group orientation, the MMA items were not associated with unique variances of youth violence perpetration and victimization. Implications included the need for further research that includes other diverse samples, more comprehensive and objective MMA and violence measures, and observational and intervention longitudinal studies.

Marcadores de lesão renal após treino de karate

Asian J Sports Med. 2012 Mar;3(1):41-6.


The effect of exercise on urinary gamma-glutamyltransferase and protein levels in elite female karate athletes.

Shavandi N, Samiei A, Afshar R, Saremi A, Sheikhhoseini R.

Department of Sports Physiology, Arak University, Arak, Iran.

Abstract
PURPOSE: Post exercise proteinuria and increased urinary Gamma-Glutamyl transferase (GGT) levels can be indicative of exercise-induced renal damage. The aim of this investigation is to study the effect of one session of intensive training on renal damage markers and compare their values to those 6 hours after training.
METHODS: In this cross-sectional study with pre- and post-test design, 10 elite volunteer female athletes were selected and participated in one training session (2 hours). Urine samples were collected before training, one hour after training, and 6 hours after training. Urinary protein (Pr), creatinine (Cr), and GGT values were measured through laboratory methods and then Pr/Cr and GGT/Cr ratios were computed.
RESULTS: There were significant differences between values of protein, GGT and Creatinine in the three sampling phases (P<0.05). However, no significant differences were observed between values for GGT/Cr and Pr/Cr ratio. There were significant differences between the mean values of Creatinine, protein and GGT within pre-exercise and 1 hour post-exercise and within 1 hour post-exercise and 6 hours post-exercise (P<0.05).
CONCLUSION: It seems that a session of karate training does not result in renal damage and athletes can continue training after 6 hours.

Associação cria cursos especializados sobre MMA

http://news.yahoo.com/mixed-martial-arts-conditioning-association-website-offers-latest-070445182.html

Contribuição energética no kata

Eur J Appl Physiol. 2012 Mar 23. [Epub ahead of print]

Energetics of basic Karate Kata.

Bussweiler J, Hartmann U.

Institut für Angewandte Trainingswissenschaft, Marschnerstrasse 29, 04109, Leipzig, Germany, bussweiler@iat.uni-leipzig.de.

Abstract

Knowledge about energy requirements during exercises seems necessary to develop training concepts in combat sport Karate. It is a commonly held view that the anaerobic lactic energy metabolism plays a key role, but this assumption could not be confirmed so far. The metabolic cost and fractional energy supply of basic Karate Kata (Heian Nidan, Shotokan style) with duration of about 30 s were analyzed. Six male Karateka [mean ± SD (age 29 ± 8 years; height 177 ± 5 cm, body mass 75 ± 9 kg)] with different training experience (advanced athletes, experts, elite athletes) were examined while performing one time and two time continuously the sport-specific movements. During Kata performance oxygen uptake was measured with a portable spirometric device, blood lactate concentrations were examined before and after testing and fractional energy supply was calculated. The results have shown that on average 52 % of the energy supply for one Heian Nidan came from anaerobic alactic metabolism, 25 % from anaerobic lactic and 23 % from aerobic metabolism. For two sequentially executed Heian Nidan and thus nearly doubling the duration, the calculated percentages were 33, 25 and 42 %. Total energy demand for one Kata and two Kata was approximately 61 and 99 kJ, respectively. Despite measured blood lactate concentrations up to 8.1 mmol l(-1), which might suggest a dominance of lactic energy supply, a lactic fraction of only 17-31 % during these relatively short and intense sequences could be found. A heavy use of lactic energy metabolism had to be rejected.