Muscle recruitment patterns and consistency, and their correlation with motor time during a karate front kick

摘要

Adequate muscle recruitment patterns and their consistency are essential to achieve effective posture and force exertion during a karate front kick. The purpose of this study was to evaluate the reaction time (RT), motor time (MT) and total response time (TRT), as well as their correlation during a front kick, and to investigate the muscle recruitment patterns and their consistency during motor time. Fourteen professional karate athletes (age: 23.7 ± 2.6 years; height: 174.6 ± 7.1 cm; mass: 72.8 ± 10.7 kg) participated in the current study. Each subject was instructed to pose in combat stance first and then to use their right leg to kick at an instrumented kicking target as soon as they saw the start signal. Surface electromyograms (EMG) were recorded from 16 muscles. Start and stop signals from the instrumented target were also recorded synchronously to obtain the TRT. Significant correlation between MT and TRT indicated that MT was a primary determinant for the TRT of the kick. The muscle recruitment synergies during karate front kicks were identified. When performing a front kick, the athletes initiated the postural adjustments of the supporting leg prior to the onset of the voluntary kick. A successful motion of the karate front kick was dependent not only on the kicking leg, but also on the supporting leg. Tibialis anterior, biceps femoris and gluteus maximus of the supporting leg were the primary muscles providing stabilization, while the ankle and knee flexors, and tensor fasciae latae of the kicking leg were dominant muscles for the kicking movement. These results provide important information on the patterns and the consistencies of the muscle recruitment for coaching a karate front kick, which should be helpful for a better understanding of the motor control strategies of a karate front kick and for developing a suitable training protocol.