Author(s): HIRAYAMA, K., SANO, Y., KAWABATA, M., WATANABE, Y., MURASE, M., WATANABE, H., TAKAHIRA, N., Institution: KITASATO UNIVERSITY, Country: JAPAN, Abstract-ID: 1081

INTRODUCTION:
The drop vertical jump (DVJ) has been widely used to evaluate knee abduction moment, a key risk factor for anterior cruciate ligament (ACL) injury. However, the ability of the DVJ to assess ACL injury risk is limited, as it does not adequately incorporate the directional change and deceleration, which are key components of non-contact ACL injury mechanisms. Therefore, this study aimed to determine the effects of a DVJ-based jump task incorporating directional change and deceleration on knee abduction moment.
METHODS:
This cross-sectional observational study included 28 recreational male athletes (age: 20.9 ± 1.4 years; height: 170.1 ± 5.0 cm; body mass: 65.9 ± 7.4 kg). Three single-leg jump tasks were performed from a 15-cm platform in a randomized order. The DVJ consisted of a drop followed by an immediate vertical jump. The drop-medial jump (DMJ) involved a drop followed by an immediate 90° jump toward the direction opposite to the stance limb. The forward-medial jump (FMJ) required a forward jump equivalent to 40% of body height, followed by an immediate 90° jump toward the direction opposite to the stance limb. Using a Plug-in Gait model, kinematic data were collected with a Vicon motion capture system at 500 Hz, synchronized with ground reaction force data at 1000 Hz. Peak knee abduction and tibial internal rotation moments during 0–50 ms and 50–100 ms were analyzed using the Friedman test with Nemenyi post hoc tests. The level of statistical significance was set at p < 0.05.
RESULTS:
During the 0–50 ms, median [interquartile range] peak knee abduction moment was 0.07 [0.03–0.10] Nm/kg in DVJ, 0.08 [0.05–0.12] Nm/kg in DMJ, and 0.12 [0.08–0.16] Nm/kg in FMJ, with FMJ significantly greater than DVJ and DMJ (p < 0.01), while no significant difference was observed between DVJ and DMJ (p = 0.78). During the 50–100 ms, peak knee abduction moment was −0.39 [−0.62 to −0.13] Nm/kg for DVJ, −0.50 [−0.70 to −0.23] Nm/kg for DMJ, and −0.50 [−0.80 to −0.26] Nm/kg for FMJ, with FMJ significantly lower than DVJ (p < 0.01). Peak tibial internal rotation moment did not differ significantly among tasks in either phase (p > 0.05).
CONCLUSION:
FMJ, which incorporated both directional change and deceleration into the DVJ, resulted in a 71% increase in knee abduction moment compared with DVJ, whereas DMJ, which incorporated directional change alone, did not increase knee abduction moment. These findings suggest that the deceleration component during directional change plays an important role in increasing knee abduction moment.