development of human locomotion

locomotion

the act of moving or the capability to move from place to place

which type of locomotion we use depends on…

interacting constraints

the first voluntary locomotion

1. crawling with chest & stomach on floor

2. low creeping with stomach off floor but legs working together (symmetrically)

3. rocking back & forth in high creep position

4. creeping with legs & arms working alternatively

learning to crawl

• no strict progression

• multiple positions

• belly crawling

• experience predicts future forms

• smaller, slimmer infants crawl earlier

crawling on stomach

• prone progression

• belly on supporting surface

• arms & legs move reciprocally

creeping

• prone progression

• belly lifted off supporting surface

• arms & legs move reciprocally

quadrupedal

walking on hands & feet

supported cruising

• after standing is accomplished

• 1st bipedal locomotion

• hands supporting on furniture

• generally sideways

stand alone

• 1 month before onset of unsupported walking

• sensory constraints

  • vestibular

  • visual

  • proprioceptive

first steps alone

• 11 months

• “high gaurd” arm position

• wide base of support

early walking

• 10-15 months

• muscle mass at 6 months is predictor

  • larger = delayed acquisition

  • smaller = earlier acquisition

characteristics of early walking

1. balance easily lost, frequent falls → large base of support & short steps

2. little-no trunk rotation

3. flat-footed contact with ground, one knee locked, other bent

4. each step independent

5. out-toeing → minimal ankle movement, sight pelvic tilt

6. high-guard position → limbs fixed, do not swing (lack of coordination → inefficient)

at approx 1 year…

• locomotion on 2 legs & maintain balance during squat positions

• 1st time doing 2 complex things at once

• extended environmental exploration

• squat & reach (12m)

walking

a locomotor phasing relationship between the legs, as well as a period of double support (when both feet are on the ground), followed by a period of single support

interlimb coordination

• timing b/w legs/feet at this point of footfalls

• stand/stance: time when foot is on ground

• swing: time that foot is in air

• ~ 50/50

Clark et al. (1988)

• variability in gait as defined by “temporal phasing”

• high values = instability

• increasing proficiency as we age

characteristics of proficient walkers

• give up some stability for additional mobility & speed

• increase stride length

• flat-foot → heel-to-toe (plantigrade gait)

• reduction of base of support

• pelvis begins to rotate

• oppositional arm swing

• mature pattern at ~4-5 years

walking becomes more efficient as:

• stride width decreases

  • ↓ based of support, ↑ mobility, ↑ stride length

• flat footed steps disappear

  • plantigrade gait / heel-to-toe pattern

  • 60% in stance, 40% in swing

• eversion of foot decreases

  • feet point straight ahead

• pelvic rotation increases

  • full leg motion + oppositional upper body movement

• high-guard position decreases

  • replaced by reciprocal arm swing

walking: arm swing

• new walker

  • fix arm position important for reducing degrees of freedom

• proficient walker

  • arm swing counterbalances trunk rotation around the vertical axis

  • degrees of freedom released

onset of walking

3-5 continuous steps

walking

• 1st form of upright, bipedal locomotion without support

• nearly equal phasing b/w legs

• period of double support followed by period of single support

developmental changes in walking: early childhood

by age 4, essential components of an advanced walk are present

developmental changes in walking: older adulthood

• maximizing stability

• ↑ out-toeing

• ↓ stride length

• ↓ pelvic rotation

• ↓ speed

• objects used as balance aids

rate limiters in later walking

• any changes associated with aging process

• changes in structural constraints

• strength (to support body on the leg) & balance

running

• 6-7 months after walking starts

• 50% phasing b/w legs

• flight phase followed by single support

early running: stability over mobility

• return of “old behaviour”

• arms in high guard

• limited ROM

• short stride length

• little rotation

proficient running

• less stability, more mobility

• increased stride length

• planar movement

• narrow base of support

• trunk rotation

• opposition

developmental changes of running: early running

• as children grow, qualitative changes in running patterns

• progressed physical growth & maturation → improved quantitive measures of running

developmental changes of running: later running (seniors)

• patterns help increase stability & balance

• decreases in stride length, ROM, # of strides, speed

• rate controllers: balance & strength

rate controllers in later running

• running requires greater generation of force & ability to balance

• smaller changes in constraints can affect later running

• individual may have ability to run but not opportunity to do so or chooses not to

jump

person propels self off ground with one or two feet; lands on two feet

hop

person propels self off ground with one foot; lands on same foot

leap

person propels self off ground with one foot, extends flight period, and lands on opposite foot

early jumping

• simple jumping before age 2

• jumping only vertically

• one-foot takeoff or landing

• no or limited preparatory movement

proficient jumping

• preparatory crouch maximizes takeoff force

• both feet leave ground at same time

• arm swing

• vertical: force directed down; body extended

• horizontal: force directed down & backward; knees flexed during flight

developmental changes of jumping

• continuous growth in body size & strength → quantitive improvements

• not every child will master jumping

• rate limiters: development of enough force to bring own body into air from still position

early hopping

• starts later than jumping

• support leg lifted rather than used to project body

• arms inactive

• swing leg held rigidly in front of body

proficient hopping

• swing leg leads hip & moves through full ROM

• support leg extends fully at hip

• oppositional arm movements generate force

• support leg flexed on landing

rate controllers in hopping

• depends on postural systems’ ability to balance body

• ability to generate force to lift body with one limb, recover, & quickly generate force to hop again

galloping, sliding, skipping

• combination of stepping, hopping, leaping

• gallop & slide are asymmetric

• skip is symmetric

gallop

• forward step on one foot, leap on other

• first to emerge (2-3 yrs)

• rate limiter: coordination (uncoupling legs), differential force production (legs performing different tasks)

slide

• sideways step on one foot, leap on other

• second to emerge

• rate limiter: coordination (turning to one side)

skip

• alternating step-hops on one foot, then on the other

• last to emerge (4-7 yrs)

• rate limiter: coordination (ability to perform 2 tasks with 1 leg)

early galloping, sliding, skipping

• arrhythmic & stiff movements

• little or no arm movement

• little or no trunk rotation

• exaggeration of vertical lift

• short stride or step length

proficient galloping, sliding, skipping

• arms no longer needed for balance

• skipping: arms swing rhythmically in opposition to legs + provide momentum

• can use arms for other purpose during galloping & sliding