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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, 30 de agosto de 2012

Impacto nos chutes de TKD


 2012 Aug 28. [Epub ahead of print]

Effects of Olympic-style taekwondo kicks on an instrumented head-form and resultant injury measures.

Source

Department of Physical Education, Yonsei University, Seoul, Republic of Korea.

Abstract

OBJECTIVE:

The objective of this study was to assess the effect of taekwondo kicks and peak foot velocity (FVEL) on resultant head linear acceleration (RLA), head injury criterion (HIC15) and head velocity (HVEL).

METHODS:

Each subject (n=12) randomly performed five repetitions of the turning kick (TK), clench axe kick (CA), front leg axe kick, jump back kick (JB) and jump spinning hook kick (JH) at the average standing head height for competitors in their weight division. A Hybrid II Crash Test Dummy head was fitted with a protective taekwondo helmet and instrumented with a triaxial accelerometer and fixed to a height-adjustable frame. Resultant head linear acceleration, HVEL, FVEL data were captured and processed using Qualysis Track Manager.

RESULTS:

The TK (130.11±51.67 g) produced a higher RLA than the CA (54.95±20.08 g, p<0 .001=".001" 300.19="300.19" a="a" and="and" d="1.84)" difference="difference" es="es" hic15="hic15" higher="higher" hvel="hvel" in="in" jb="jb" jh="jh" m="m" no="no" of="of" p="p" s="s" than="than" that="that" the="the" there="there" tk="tk" vs="vs" was="was">

CONCLUSIONS:

The TK is of concern because it is the most common technique and cause of concussion in taekwondo. Future studies should aim to understand rotational accelerations of the head.

quarta-feira, 29 de agosto de 2012

Os animais também brincam de lutar


 2012 Aug 29. [Epub ahead of print]

Paternal deprivation alters play-fighting, serum corticosterone and the expression of hypothalamic vasopressin and oxytocin in juvenile male mandarin voles.

Source

Key Laboratory of Ecology Model and Applications of State Ethnic Affairs Commission, College of Biology Sciences and Engineering, Beifang University of Nationalities, Yinchuan, 750021, Ningxia, China, wang_jianli@163.com.

Abstract

Although early paternal deprivation significantly affects offspring behavioral and neuroendocrine development, the link between paternal deprivation and social play behavior remains unclear. Mandarin voles (Microtus mandarinus) are socially monogamous and display bi-paternal care. The present study examined the development of social play in juvenile male mandarin voles and the paternal influence on play-fighting, vasopressin- and oxytocin-immunoreactive neurons and serum corticosterone and testosterone levels. The results show that social play was more pronounced during postnatal days 28-35, differing from the ontogenetic pattern of other forms of social behavior. On postnatal day 35, the peak in play-fighting activity, paternal deprivation reduced boxing/wrestling levels and vasopressin-immunoreactive neurons in the anterior hypothalamus and oxytocin-immunoreactive neurons in the paraventricular nucleus, but increased vasopressin-immunoreactive neurons in the paraventricular nucleus and corticosterone levels. These results suggest that mandarin voles engage in social play according to an inverted U-shaped curve in ontogeny, and paternal deprivation influences the development of offspring play-fighting; hypothalamic vasopressin, oxytocin and serum corticosterone may play a modulatory role in the alteration of play-fighting elicited by paternal deprivation; decreased play-fighting may correlate with depressed vasopressin levels in the anterior hypothalamus.

terça-feira, 28 de agosto de 2012

Tipo de superfície e impacto em movimento da esgrima


 2012 Aug 22. [Epub ahead of print]

Influence of Surface on Impact Shock Experienced during a Fencing Lunge.

Source

School of Life Sciences, University of Hertfordshire, Hatfield, UK.

Abstract

The purpose of this study was to investigate the effect of sports surface on the magnitude of impact shock experienced during a lunge movement. Thirteen experienced, competitive fencers (age 32.4 ± 4.6 years; Height 178.4 ± 7.2 cm; Mass 74.4 ± 9.1 kg) performed ten lunges on four different surfaces: concrete with an overlaid vinyl layer (COVL); wooden sprung court surface (WSCS); metallic carpet fencing piste overlaid on the WSCS and: aluminium fencing piste overlaid on the WSCS. An accelerometer measured accelerations along the longitudinal axis of the tibia at 1000Hz. The results identified a significantly (P < 0.05) larger impact shock magnitude was experienced during a lunge on the COVL (14.88 ± 8.45g) compared to the WSCS (11.61 ± 7.30g), WSCS with metallic carpet piste (11.14 ± 6.38g) and WSCS with aluminium piste (11.95 ± 7.21g). Furthermore, the two types of piste used had no significant effect the impact shock magnitude measured when overlaid on the WSCS compared to the WSCS on its own. The results of this investigation suggest that occurrences of injuries related to increased levels of impact shock, may be reduced through the utilization of a WSCS as opposed to a COVL surface, during fencing participation.

Procurando artigos sobre estrangulamento, veja com o que me deparo : )


 2012 Aug 23. [Epub ahead of print]

Three Nonlethal Ligature Strangulations Filmed by an Autoerotic Practitioner: Comparison of Early Agonal Responses in Strangulation by Ligature, Hanging, and Manual Strangulation.

Source

From the *Office of the Chief Medical Examiner, Edmonton, Alberta, Canada; and †Office of the Chief Medical Examiner, Jamaica, NY.

Abstract

ABSTRACT: Despite great advances in forensic sciences in the last decades, our knowledge of the pathophysiology of ligature strangulation is still largely based on old writings from the 19th and beginning of the 20th century. The study of filmed hangings by the Working Group on Human Asphyxia has contributed to a better understanding of the agonal responses to strangulation by hanging, and judo-related studies have given some insight into the pathophysiology of manual strangulation, but the pathophysiology of ligature strangulation has remained largely unexplored so far. Three nonlethal strangulations filmed by an autoerotic practitioner are here presented. In these 3 ligature strangulations, the 35-year-old man is sitting on a chair. A pair of pajama pants is rolled once around his neck, with the extremities of the pants falling down on each side of his chest. The man is pulling the extremities of the pants with both hands to apply compression on his neck. After losing consciousness, he ceases to pull on the ligature, and the pants slowly loosen around the neck. A few seconds later, he regains consciousness and gets up from the chair. In the 3 nonlethal ligature strangulations presented in this study, the loss of consciousness occurred in 11 seconds. The loss of consciousness was closely followed by the onset of convulsions (7-11 seconds). These results are compared with the early agonal responses documented in filmed hangings and judo studies.