The art, practice and science of Feldenkrais®
Director: Robert J. Burgess BEd, PT, PhD, Feldenkrais Practitioner

the evolution of human locomotion
vertebrate locomotion - trunk action

fish locomotion

Undulating trunk side bending of the fish body and tail propel the animal. Pitch (nose down and up) and roll (roll of body as a whole) are also possible but flexion/extension and rotation of the body as we know it are not possible.

reptilian locomotion

Alternate trunk side bending action in tune with leg action. Trunk muscles contraction phasically. Energy costs and strain is minimised. In reptiles, notice how the head moves side to side.

cheetah locomotion

Alternate trunk flexion and extension extend the action of the limbs making for greater power and speed. The head is maintained with minimal deviation side to side or up and down. The assists with vision and audition.

The cheetah flexes its trunk or rounds its spine in preparation for striding during gallop.

Here with the striding limbs, the trunk arches to extend the power and length of the stride. It would be hard to imagine the cheetah developing any speed without its powerful trunk action.

whale and dolphin locomotion

Whales and dolphins went back to sea maintaining their terrestrial trunk motion of flexion and extension for propulsion.

human locomotion

Humans evolved to an upright stance with straightened knees (unlike the apes that can't straighten knees). The shift in orientation of the "axial skeleton" or trunk, from the horizontal to the vertical with respect to gravity necessitated some changes to our gait pattern.

Instead of major side bending trunk action for locomotion, humans evolved to use a counter rotation of the spine. Not forgetting some remnants of side bending (reptiles and fish) and also trunk flexion and extension (whales, dolphins and quadripeds).

To experience trunk rotation used in gait, try walking on your "butt". Imagine having no legs and your feet are attached to the pelvis. This is how you would locomote. Now add legs but retain the action of the trunk. This rotation and side bend from the pelvis is a key to the power and coordination of human locomotion.

We don't walk only with legs, we walk with legs and body. One major body action for gait is rotation. Counter rotation because as the pelvis rotates in one direction the shoulders go opposite.

The other major action is a side bending of the pelvis and trunk. The pelvis drops on the side of the swinging leg. That whole side lengthens like a spring (recall the newt trunk and leg action!).

Both of these actions extend the swing of the leg, increase energy efficiency and lessen strain at the hip and knee.

Like the cheetah, the head in human locomotion deviates little in the horizontal and frontal planes. To have a head that glides forward unimpeded in perceiving the environment while the powerful and legs propel the human animal, the thorax or chest is flexibile enough to accomodate this demand. Without this flexibility something else must accomodate the simultaneous demand for a steady head position while the pelvis and legs power propulsion.

Interestingly, one researcher proposed that the arch in human spine is critical to locomotion. Any structure with an arch that is then bent to one side will rotate. Gracovetsky (1986)* proposed this as the source of intitiation and power of human locomotion. So as well as muscles being a source of power, proper organization of the skeleton will allow muscular power to excel. Gracovetsky's ideas fit well with a Feldenkrais view of gait as being powered and inititiated from the pelivs. Many other authors attritbute power to the calf or hip flexor muscles.

Much can be learned about movement and movement issues from each individual's gait pattern. Planning movement learning around components of gait is a powerful way to enhance the power and ease of walking and to lessen any pain syndrome in the back and legs.

What you see here is a simple introduction to some components of gait action that can be explored/exploited in movement lessons of Feldenkrais FI or ATM.

Assessment of gait and the tranfer of any movement effects to our walking pattern is very central to all Feldenkrais lessons. This is a very general introduction to gait mechanics and its affect on spinal and limb function.

Relevance: The origins of locomotion are with the trunk. The fish without legs powers through the sea with trunk action. Even reptiles still clearly use their trunk to power locomotion. Quadrupeds like the cheetah also have a powerful contribution from their trunk.

Remnants of side bending coupled with rotation drive human locomotion along with the obvious leg action.

Trunk action is a major contributor to powerful and strain free human locomotion. Trunk components of action in locomotion can be not only inhibited but also observed, felt, practiced, restored and enjoyed. Mobility, motor control of the trunk and coordination with the legs are always components in all back and leg pain syndromes.

And there is much more! Connection and coordination of the foot with leg and trunk action is critical to normal function and pain syndromes of the back and legs.

For a little more detail (but some repitition) from an old newsletter on human gait parameters see:
Human Locomotion.

More later on leg (hip, knee and foot) syndromes.

*Gracovetsky S (1986): Function of the spine. J Biomed Eng 8(3): 217-23.
*Gracovetsky S and Farfan H (1986): The optimum spine. Spine 11(6): 543-73.