Lower extremity biomechanics during kendo strike-thrust motion in healthy kendo athletes

The aim of this study was to demonstrate the kinematics and kinetics of the lower extremity during the kendo strike-thrust motion in experienced kendo athletes.

Fifteen experienced kendo athletes (age 20.4±1.2 years; height 171.5±4 cm; weight 73.9±9.1 kg; the kendo experience 11.1±3.1 years) volunteered to participate in the study. The three-dimensional kinematic and kinetic data was collected by the motion analysis system with eight cameras and with a force platform. We instructed the participants to perform three sets of kendo motion at the distances of 1.8 m, 2 m, and 2.2 m to the target. We then obtained the joint kinematic and kinetic data of the ankle dorsiflexion-planterflexion, foot pronation-supination, knee flexion-extension, and hip flexion-extension during the single support phase. The peak foot pronation angle and the range of motion (ROM) of foot pronation were also calculated.

The result demonstrated the high intra-subject repeatability of the joint angle and the torque curve of the left lower extremity during the single support phase in the kendo motion. Our result also showed that as for the peak foot pronation angle and the pronation ROM there was no significant difference between different distances to the target.

We provided the basic biomechanical information during the kendo strike-thrust motion, and the result will help us to understand the Achilles tendon injury occurrence in kendo athletes.