Strategies for stability in quadrupedal stance

Summary form only given. Kinematic and kinetic analyses in the cat are used to determine how the central nervous system simplifies the problem of maintaining stance. Cats were trained to stand quietly on four triaxial force plates (each 6*6 cm) mounted on a movable support surface (45*25 cm). The distance between the forepaws and the hindpaws in the sagittal plane (F-H distance) could be adjusted by changing the placement of the force plates. The force responses of cats were recorded during linear ramp-and-hold translation of the support surface in each of 16 different directions in the horizontal plane. Ground reaction forces and positions of the body segments were recorded during quiet stance. It is shown that standing cats exhibit certain preferred body segment orientations related to paw placement. During perturbations of stance, ground reaction forces are controlled for efficient restoration of stability.<>