Unrestrained walking in intact cats.

In five freely moving cats walking with speeds of 0.4-1.0 m/s several parameters of locomotion were investigated. Special attention was paid to the analysis of support patterns and the duration of support phases. The animals used almost exclusively (in 88 to 99% of steps) the 3-2-3-2-3-2-3-2 support pattern in which phases of support on three limbs alternated with phases of support on two limbs, homolateral and diagonal. The relative duration of support phases showed a tendency to decrease with increased locomotor velocity, except for the supports on diagonal limbs which slightly increased. The mean duration of the majority of support phases was similar and ranged between 12.2 and 14.5% of the step cycle. Phases of support on both hind- and one forelimb were somewhat (about 5%) shorter. It is concluded that the relative stability of support patterns and of the duration of support phases during walking observed in the present experiment may serve as a template for comparing changes in the gait produced by various CNS lesions.