Thoracic Injury Effects Of Linear And Angular Karate Impacts

Abstract

Skilled karate practitioners are reputed to be able to completely disable an opponent with one blow -- when necessary. Immediate questions arise as to whether karate participants: (a) can, in fact, deliver disabling injurious blows to the thorax, (b) can have a greater ability to damage the body with some technique types over others, and (c) can wear readily available safety equipment to temper blows to below the level of medically severe injury. The viscous response criteria (VCmax), based on chest compression and compression velocity, has been devised to estimate level of injury to the thorax or chest. Accordingly, a VCmax =1.0 m/s is the level for a 25% probability of severe injury, such as liver or lung laceration. Twelve international class karate competitors of 3rd, 4th, and 5th degree or higher (master class) black belt ranks, were evaluated impacting the thorax of an instrumented anthropometric test dummy (ATD) to determine the probable injury effects of linear (thrusting) and angular (striking or snapping) types of karate blows, with and without a chest protector. Techniques evaluated were the roundhouse kick, backfist strike, side-thrust kick, and the reverse punch. Data were analyzed using a 2*3*4 ANOVA design with Tukey's Studentized Range follow-up tests to discriminate within condition differences. The adjusted viscous response (VCmax) was the variable used for evaluation. Of the three skill classes evaluated, 3rd (M =1.2096, SD =.5309) and 4th (M =1.1127, SD =.4304) degree ranks generated statistically higher VCmax levels than master class competitors (M =.8036, SD =.2797) across all conaitions, F (2, 60) =7.57, F = .0012. The chest protector was found to be effective, F 0,60) =4.28, F =.0430, in attenuating the impact effects below the serious injury level (M =1.1382, SD = .4423 and M =.9535, SD = .4575, without and with the chest protector, respectively). The roundhouse kick (M =1.3778, SD =.4674) generated higher .VCmax than all other techniques, F (3, 60) =7.17, F = .0003,: the reverse punch (M =1.0122, SD =.3923); the side-thrust kick (M =.9538, SD =.4976); or the backfist strike (M =.8189, SD =.2986). No statistical difference was detected among the technique conditions. It was concluded that the highly skilled karate competitor could deliver severe or greater levels of damage to the thorax with karate techniques, especially the roundhouse kick. The level of damage to the thorax can be reduced below the "serious" level with the use of a chest protector.