Estimation of Muscle Activations in Black Belt Taekwondo Athletes During the Bandal Chagui Kick Through Inverse Dynamics

The purpose of this study was to analyze the agreement between muscle activations calculated using Static Optimization (SO) and experimental measurements from surface electromyography (EMG), applying different exponentials to the cost function, during the Bandal Chagui kick. Three-dimensional kinematics, of three kicks, from five black belt athletes, were analyzed. The fastest kick for each subject was processed using the freely available software OpenSim. The tools used were inverse kinematics, residual reduction algorithm (RRA) and SO. The waveforms, estimated with the SO, from eight muscles of the dominant lower limb were compared with surface EMG measurements in phase (P), magnitude (M) and global agreement (C) by equations in which a perfect agreement results in zero. A global agreement close to zero was found for the gluteus medius and maximus (C ≤ 0.12) using 4 as the exponential and for the biceps femoris, with 2 as exponential, the global agreement was good (C = 0.19).