In judokas, reaction time (RT) and rate of force development (RFD) are important muscular functions that contribute to performance. However, the characteristics of trunk muscle RT and RFD in judokas have not been thoroughly investigated. This study aimed to examine differences in trunk muscle reaction time (RT) and rate of force development (RFD) in male collegiate judokas across weight classes.
RT and RFD during isometric trunk flexion and extension were assessed in male collegiate judokas, comprising of 21 lightweight, 18 middleweight, and 21 heavyweight judokas. Participants generated maximum force as quickly as possible upon a signal lighting of a lamp. RT was the time to reach 5 Nm after the signal. RFD was the strength values at 50, 100, and 150 msec after the RT divided by the participant’s body weight and the elapsed time. We compared each value between weight categories using a one-way analysis of variance and the Bonferroni method as a post hoc test.
The results indicated that there was no significant difference in RT. Conversely, in RFD of extension, the lightweight judokas demonstrated significantly higher values at 100 and 150 msec than the heavyweight athletes (p < 0.05). In RFD of flexion, the lightweight group exhibited a significantly higher value at 50 msec than the middleweight group (p < 0.05). Additionally, when compared to the heavyweight group, the lightweight group showed significantly higher values at both 50 (p < 0.01) and 100 (p < 0.05) msec.
These findings indicate that while weight categories may not significantly influence RT, relative RFD tends to be higher in lightweight male collegiate judokas.
