Author(s): NISHIKAWA, K., TSURUTA, O., MURASE, N., SAKURAI, S., FUJIBAYASHI, N., Institution: CHUKYO UNIVERSITY, Country: JAPAN, Abstract-ID: 896

INTRODUCTION:
Shortening men strike time is a critical determinant of competitive success in kendo, as it enables athletes to initiate an attack before the opponent’s defensive response is established. Although rapid force generation during the stepping phase is considered essential for effective men strikes, the relationship between men strike time and rate of force development (RFD) has not been fully clarified. Therefore, the purpose of this study was to examine how RFD and kinematic and kinetic variables during the men strike motion relate to men strike time in kendo athletes.
METHODS:
Twenty-one male and fifteen female collegiate kendo athletes participated in this study. Men strike motions were recorded using a synchronized motion capture system with fourteen high-speed cameras (200 Hz) and a force plate (1000 Hz). Participants performed men strikes toward a target positioned 2.3 m from the left foot, and five successful trials were recorded.
Men strike time was defined as the duration from the moment the resultant center of mass velocity reached 0.2 m/s to the instant of impact. Calculated variables included time, center of mass displacement and mean velocity, peak ground reaction force (PGRF), stepping time to peak ground reaction force (TP_PGRF), peak RFD (PRFD), and average RFD (ARFD). Relationships between men strike time and calculated variables were examined using Pearson’s product–moment correlation coefficients.
RESULTS:
In both male and female athletes, men strike time was positively correlated with stepping time, indicating that athletes who executed the stepping motion more rapidly exhibited shorter men strike times. Men strike time was also positively correlated with center of mass displacement and negatively correlated with mean center of mass velocity, suggesting that efficient forward propulsion with shorter displacement and higher velocity contributed to a shorter men strike time.
In male athletes, men strike time showed significant correlations with TP_PGRF and ARFD, but not with PGRF, indicating that the rapid development of ground reaction force rather than force magnitude was a key factor influencing the shortening of men strike time. In female athletes, men strike time showed significant correlations with TP_PGRF, ARFD, PGRF, and PRFD, suggesting that both rapid force development and a sufficient level of force magnitude contributed to the shortening of men strike time.
CONCLUSION:
These findings indicate that shortening men strike time in kendo depends strongly on the ability to rapidly and efficiently execute the stepping motion. In particular, the strong correlations between men strike time, stepping time, and RFD-related variables suggest that the ability to rapidly develop ground reaction force plays a crucial role in shortening men strike time.