What is the relation between the emergence of locomotion and postural control?

1. Reflex stepping

2. Static phase: stepping can’tbe elicited

3. Transition phase: stepping under reflex and volitional control

4. Deliberate stepping: voluntary control but infant
requires support

5. Independent stepping

6. Heel-toe progression

7. Integrated walking

 * Stepping tends to disappear in most infants by about 2 months, and will reappear with the onset of self-generated locomotion.

* It's disapearence is assumed to be mainly the result of inhibition by maturing higher neural centers. (hierachical model).

* Dynamic systems approach: view locomotion as an emergent property of many interacting complex processes. according to this approach moving and developing systems have certain self-organizig properties. The disappearence of the neonatal stepping pattern at about 2 months of age results from changes in the number of components of the system that reduce the likelyhood of seeig this behavior.

* Weight Hypothesis: Supine kicking during the period when new born stepping disappears. One explanation for the persistance of supine kicking is that it does not require the same strength as stepping, since they are not workign against gravity.

* From slides: Stepping is a classic example. Its disappearance attributed to a phase where higher brain structures suppressed primitive brain/spinal centers, then brought stepping back under cortical (perceptual) control. Stepping does not disappear if practiced

Describe the development of the perception of affordances for locomotion.

* (slides) Adolph’s work suggests that the affordances for locomotion are perceived posture by posture with little transfer from one posture to another

* (Book) with experience, this behavior decreased, with their perceptual judgments becoming simliar to their actual motor ability, such that attemps to navigate a slope matched the infants porbability of success.

     Example: infants who were new walkers avoided a 36 degree descent in crwaling but would plunge down the same slope when walking.

What are the characteristics of early walking patterns?

*Characteristics of early walking
1.High step frequency

2.No reciprocal swinging between
upper and lower limbs

3.Flexed knee during stance

4.Increased hip flexion

5.Pelvic tilt and hip abduction during
swing

6.Ankle plantar flexion at foot strike

7.Decreased ankle flexion during
swing

In what order do different locomotion abilities emerge?

• Locomotor patterns emerge in the following sequence:
– Run

– Gallop

– Hop

– Skip

– Others?
• Transfers are also important mobility skills