The movability of ankle joints is a motor function essential to doing lunges, a basic movement in all kinds of sports. In this study, we examined the effect of ankle dorsiflexion angle on the biomechanics of motion during forward lunges.The limbs of 40 healthy participants,80 limbs in total, were examined, and the forward lunge movements were analyzed using a three-dimensional motion analysis unit and floor reaction force gauge. The analysis focused on when the ankle dorsiflexion reached the maximal degree in performing a lunge. In order to clarify the relation between ankle dorsiflexion angle and each of the analytical items, an optimal model was examined using covariance structure analysis.The ankle dorsiflexion angle was significantly related to the forward movement distance of center of foot pressure and the angle of the sagittal floor reaction force.In a forward lunge, the anterior inclination of the lower leg increases when the ankle dorsiflexion angle is wide. Subsequently, it makes it easier for the weight to be vertically loaded on the front leg and thereby the angle of the sagittal floor reaction force becomes more vertical.
