Table 1.

Terms used in this study to compare mechanical patterns of the center of mass to gait patterns of the limbs

Whole-body mechanics (patterns of center-of-mass fluctuation)a
Pendular mechanicsInverted pendulum-like mechanism
Spring mechanicsSpring-mass mechanism
Gaits (patterns of footfalls)b
WalkDuty factor >50% (includes several possible walking gaits*)
RunDuty factor <50% (includes several possible running gaits*)
TrotLimb phase 50±10% (diagonal couplet gait)
Walking trotLimb phase 50±10% (with >50% duty factor)
Running trotLimb phase 50±10% (with <50% duty factor)
AerialSteps separated by periods with no limb contact with the ground
Non-aerialSteps overlapping — continuous ground contact by at least one limb
  • a Cavagna et al., 1977.

  • b Hildebrand, 1976.

  • * Determined by duty factor and limb phase.