Acute Effects of Visual Information Blocking during the Pre-Set on Drop Jump Performance, Lower Limb Kinematics and Kinetics
(Takuya Yoshida, Amane Zushi, Hirohiko Maemura, Seiji Ono, Satoru Tanigawa)

This study investigated how visual information blocking influenced drop jump (DJ) performance and lower limb mechanics, with a specific focus on its impact on stretch-shortening cycle (SSC) efficiency and neuromuscular adaptation in plyometric training. Fourteen male students (age: 22.0 ± 2.2 years; body height: 174.8 ± 2.4 cm; body mass: 70.3 ± 4.8 kg) performed DJs from a 0.3 m platform under normal and blind conditions. The DJ-index (jump height/contact time), joint kinematic and kinetic variables were measured. The blind condition resulted in a significantly lower DJ-index (p < 0.001) and longer contact time (p < 0.001), while jump height remained unchanged. Knee flexion (p = 0.028), hip flexion (p = 0.014), and knee extension (p = 0.046) increased significantly. Peak (p = 0.011) and mean (p = 0.006) ground reaction forces, as well as ankle joint kinetics were lower under blind condition. These results suggest that visual feedback enhances SSC efficiency by regulating lower limb joint movement and force production. Without visual input, increased joint flexion compensates for reduced ankle force exertion, leading to longer contact times. These findings suggest that while visual information blocking decreases SSC efficiency, explosive power can be maintained through biomechanical adjustments.