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

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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.