Research overview: spinal flexion and the double-suspension gallop

The cheetah uses a rotary gallop with two airborne suspension phases per stride, one with limbs gathered and one with them extended. This overview examines how dorsoventral flexion and extension of the lumbar spine lengthen each stride by swinging the hindlimbs far forward beneath the body and then flinging them back. Comparative anatomy of the vertebral column, the long epaxial muscles, and elastic structures suggests the trunk acts almost like a spring loaded and released each cycle. Investigators study this with marker-based motion capture and skeletal modelling, comparing felid spines with those of less flexible cursors. Why it matters: the spine contributes stride length that the limbs alone cannot, so it helps explain the cheetah top-speed advantage and the trade-offs that come with such a flexible, lightly built back.