How cat lands: insights into contribution of the forelimbs and hindlimbs to attenuating impact force

To safely land after different drops, cats can perfectly use their limbs as dampers to dissipate impact forces. Yet, we know little about the contribution of the forelimbs and hindlimbs of cats to attenuating the impact forces during landing. In order to investigate this, we analyzed the landing impulses and energy absorption based on the ground reaction forces and high-speed video recordings of cats performing self-initiated jump downs at different heights. Our results show that the distribution of impact forces between forelimbs and hindlimbs exhibits a landing height-dependent manner. Furthermore, combining the experimental measurements and the inverted pendulum-spring model, we find that variation in landing angle is correlated with the distribution manner. This posture-dependent actuation allows the animal to tune the distribution of energy absorption between forelimbs and hindlimbs. These findings highlight how cats perfectly jump down using their limbs, providing fundamental insights into the importance of control mechanisms that attenuate landing impulses safely and efficiently.