The ability to produce a timely explosive force may affect loading rate at landing

Abstract

Abstract Background Sports injuries are strongly associated with the impact loading at landing. The abilities to produce force and adjust timing are simultaneously required to absorb impact loading. Aims Hence, we aimed to examine the hypothesis that the ability to produce an explosive force at the right timing is related to the ability to absorb the impact loading at landing. Methods Twenty-nine healthy young men volunteered to participate in the study. We proposed a new test to measure the rate of force development (RFD) in accordance with the countdown signal. To evaluate the ability to produce explosive force at the right time, we measured the rate of change between the RFD at the standard start signal and the RFD at the countdown signal. Furthermore, to evaluate the ability to land from a jump, we measured the loading rate at single-leg drop landing (20 cm). Results We divided the participants into two groups based on the timing effect: the positive group (participants with increased RFD at the countdown signal, n = 11) and the negative group (participants with decreased RFD at the countdown signal, n = 18). The loading rate was significantly greater (P < .01) in the negative group (47.4 ± 11.2 body weight (BW)/s) than in the positive group (34.7 ± 7.1 BW/s). Conclusions Participants with increased RFD at the countdown signal had a lower loading rate at landing. Our results suggest that the ability to produce a timely explosive force may be a determinant of safe landing ability.