Differences in Impact Force between Side Kicks and Turning Kicks in Male Practitioners of Taekwon-Do—Case Studies

The purpose of this study was to understand the different forces exerted between the side kick and turning kick in taekwon-do, which would add knowledge to the field, as well as help inform future research. Eighty kicks performed by four elite ITF (International Taekwon-do Federation) athletes (age: 28.5 ± 7.2 years; body mass: 77.5 ± 6.7 kg; height: 180.0 ± 1.6 cm) were analysed. Participants performed a series of turning and side kicks with the right and left leg to the target. The impact-force-measuring apparatus was a training shield mounted on a force plate manufactured by AMTI, model MC12-2K. The mean resultant impact force for the turning kick was significantly lower than the mean resultant impact force for the side kick. There were no significant differences in the impact force between turning kicks performed with either the right or left leg. With regard to the correlations for the turning kick performed by both legs, there was almost a full correlation between FZ and the resultant impact force (r = 0.988 for the right leg and r = 0.994 for the left leg). The side kicks’ significantly higher resultant force (4429.77 ± 1361.25 N) than that of a turning kick (2648.98 ± 441.41 N) could be due to more effective mass being used. The turning kick peaked in a shorter time; this indicates that a turning kick has a shorter contact time with the target. The strong correlations between Fz and the resultant impact force in both kicks could be due to the direction of the kicks, suggesting that the force in the Z axis was the most important direction.