Conception of effective mass and effect of force – measurement of taekwon-do master

Abstract

Background: Engagement of mass during a strike in martial arts and its relation to generated force is one of the factor, deciding on the success of an athlete. The aim of this study was to calculate the quantitative portion of effective mass of a athlete who execute striking techniques, by registering a force of strike and time of its contact with a sensor (target). Material and methods: Black belt taekwon-do (International Taekwon-do Federation) master (age 32 years, body mass of 60 kg, height of 160 cm) performed three types of techniques for three times; roundhouse kick, front kick, side kick and straight punch. His target was a shield mounted on force plate MC 12-2K with amplifier GEN5. Acceleration data was obtained by mounting wireless IMU sensor manufactured by Noraxon attached to a lateral side of a foot. Results: The highest force was registered for side kick (2406.9 ± 299.8 N), and the lowest for front kick (2008.6 ± 284.8 N). The shortest time of contact with a target had roundhouse kick (0.026 ± 0.010 s), while the longest front kick (0.119 ± 0.052 s). The highest effective mass was achieved by front kick (44%). The highest effect of force coefficient was obtained by roundhouse kick. Other techniques with much lower values seems to be push-like movements. Conclusions: During strike, a crucial factor for its effectiveness lies in its destructive power. It does not only depend on generated force and engaged mass, but also on contact duration. Proposed quantitative indicators could be beneficial during preparation of an athlete to sport competition. Correctly calculated effective mass allows to measure force in a training environment.