Chapter 5: Loco 1 and 2 Flashcards
Locomotion
Is the act of moving or the capability to move from place to place
What affects the type of locomotion that can be complete?
interacting constraints
The first voluntary locomotion: 4 steps
- Crawling with the chest and stomach on the floor
- Low creeping with the stomach off the floor but the legs working together (symmetrically)
- Rocking back and forth in the high creep position
- Creeping with the legs and arms woking alternately
Is there a strict progression for crawling?
No
How many crawling positions observed?
multiple
Do some infants skip directly to hand and knees?
Yes
What does the amount of experience in early forms of crawling predict?
The speed and efficiency of later forms
What kind of infants crawl earlier?
Smaller, slimmer, more well-proportioned infant crawl earlier than do larger, chubbier infants
Crawling on stomach:
Prone progression
Belly on the supporting surface
Arms and legs move in a reciprocal pattern
Creeping:
Prone progression
Belly lifted off the supporting surface
Arms and legs move reciprocally
Quadrupedal:
walking on hands and feet
Bipedal locomotion:
Two legs for walking
After standing is accomplished what comes after?
supported cruising
What is supported cruising?
First bipedal locomotion
Hands supporting on furniture (awareness of affordance?)
Generally sideways, both arms and legs provide support
When does unsupported walking happen compared to standing alone?
1 month after infant cant stand alone
Sensory contraints at the phase of unsupported walking?
vestibular, visual and proprioceptive
How many months old does an infant usually take 1st steps alone?
11 months
When is early walking usually achieved?
Achieve independent walking generally between 10-15 months
What can predict the onset of independent walking?
Muscle mass at 6 months may predict the onset of independent walking:
Larger muscle mass may delay a acquisition
Also, infants who are smaller boned or have linear frames may acquire this milestone
A beginner walker: movement patterns
short stride and high- guard arm position
The high arm guide is because Moment of inertia, what is that?
a measure of resistance of the body (a body’s tendency to resist angular acceleration)
Characteristics of early walking (6)
- Balance easily lost, frequent falls. Compensate, large base of support, short steps
- little if any trunk rotation
- contact with ground is flat footed. One knee locked, other bent
- each step independent of other
- out-toeing. Minimal ankle movement, slight pelvic tilt
- High guard position. Limbs fixed do not swing
At approximately 1 years old what happens with locomotion?
Has locomotion on two legs and maintain balance during squat positions
This is important because
First time doing two (reasonably complex) things at once
Allows for extended environmental exploration (squat and reach (12m))
Walking: define
Is defined by a 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
Inter-limb coordination:
timing b/w the legs/feet at this point of footfalls (steps quickly with other foot… then slowly in stepping with the other)
stand/stance:
time when the foot is on the ground
swimg
time the foot is in the air
clark et al. (1988) study of walking shows?
variability in gait as defined by temporal phasing, increasing proficiency with age
Characteristics of proficient walkers
Proficient walkers tend to give up some stability for additional mobility an speed
Increase in stride length
Flat-footed changes to heel-to-toe (plantigrade gait)
Reduction of base of support
Pelvis begins to rotate
Oppositional arm swing, and well as arm-leg movements
Mature walking patter at what age?
~4-5 years
How does walking become more efficient?
- Stride width decreases
Base of support os decreased to within the approximate lateral dimension of teh trunk, which increases mobility by allowing for greater stride length - Flat - footed steps disappear (foot contact)
Eventually replaced by plantigrade gait
Heel - to - toe pattern
Heel strike in front of body with toes in the air, followed by toe contact, with the heel lifting during the maintained toe contact
Each leg spends 60% of time in stance, 40% in swing phase) - Eversion of the foot decreases (foot angle)
Feet evenly point straight ahead - Pelvic rotation increases
Allows full leg motion and oppositional movement of the upper body - High-guard position decreases
Eventually replaced by a reciprocal arm swing
Walking: Arm swing of a new walker
fixed arm position important for reducing degrees of freedom
Walking: Arm swing of a profiecnt walker?
arm swing counterbalances truck rotation around the vertical axis, degrees of freedom are released
what is the first form of upright, bipedal locomotion
walking
Walking is defined by:
Nearly equal phasing between the legs
Period of double support (both feet on the ground followed by a period of single support)
Characteristics of early walking:
Maximizes stability and balance over mobility
Arms are in high-guard
Feet are out-toes and spread wide
Independent steps are taken
Characteristics of proficiency walking:
Trading stability for mobility Stride length increases Base of support is reduced Pelvis is roasted Opposition (arms to legs) occurs
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 increases Stride length decreases Pelvic rotation decreases Speed decreases Objects are used as balance aids
Rate limiters in later walking:
Any of the changes associated with the aging process can act as rate limiters
Most obvious, changes in structural constraints can influence walking
Rate limiters are strength (to support the body on the leg) and balance
When does running occur?
Occurs 6-7 months after walking starts
Running is defined by?
50% phasing between the legs
Flight phase followed by single support
Early Running:
Stability over mobility Return of old behaviours Arms in high guard Limited range of motion 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 and maturation, generally result in improved quantitative measures of running
Developmental changes of Running: Later Running
Patterns help increase stability and balance
Decreases appear in: stride length, range of motion, # of strides, speed
Rate controllers: balance and strength
Rate controllers in later running:
Running required greater generation of force and ability to balance
Smaller changes in constraints can affect later running
An individual may have the ability to run, but may not have the opportunity to do so, or chooses not to
Jump:
person propels self off ground with one or two feet; lands on two feet
Hop?
Hop: person propels self off ground with one foot; lands on same foot
Leap:
Leap: Person proels self off ground with one foot, extends flight period, and lands on opposite foot
When does jumping begin?
Children often begin simple jumping before age 2
Early Jumping:
People can perform either vertical or horizontal (standing long) jump Early Characteristics: Jumping only vertically One-foot takeoff or landing No or limited preparatory movements
Proficient Jumping:
preparatory crouch maximizes takeoff force
Both feet leave ground at the same time
Arm swing used during jump
Vertical jump: force is directed downward ; body is extended
Horizontal jump: force is directed down and backward; knees are flexed during flight
Developmental changes of jumping:
Continuous growth in body size and strength contribute to quantitative improvements
It is not guaranteed that very child will eventually master jumping
Rate limiters for Jumping:
developmental of enough force to bring own body into the air from a still position
What level of difficulty is a standing long jump?
6- standing long jump
What level of difficulty is a running long jump?
7
When does hopping start?
After jumping
Early characteristics of hoping:
Support leg is lifted rather than used to project body
Arms are inactive
Swing leg is held rigidly in front of the body
Proficient hopping:
Swing leg leads hip and moves through full range of motion
Support eg extends fully at hip
Oppositional arm movement generates force
Support leg is flexed on landing
Developmental changes in Hopping:
Few children under 3 can hop repeatedly
Adaptations of the neuromuscular system that moderates the force of landing
This is due (at least in part) to an interaction of the individual constraints in the body, and within the framework of the principles of motion
Rate controllers in hopping:
Depends on the postural systems ability to balance the body on one limb for a succession of hops
Ability to generate enough force to lift the body with one limb, recover and quickly generate enough force to hop again
What do Galloping, sliding and skipping involve?
A combination of stepping, hopping and leaping
Gallop and slides are?
Asymmetric
Gallop?
forward step on one foot and leap with the other
Slide?
sideways step with one foot, lead with the other
Skip?
Symmetric, alternating step hops on one foot then one on the other
Early Galloping, sliding, skipping:
The arms are no longer needed for balance
In skipping, the arms swing rhythmically in opposition to the legs and provide momentum
Child can use the arms for another purpose during galloping and sliding such as clapping
Developmental changes in Galloping, sliding, skipping:
galloping is the first to emerge (around 2-3 years old)
sliding comes next
skipping is usually last to emerge (around 4-7 years old)
Rate limiters for Galloping, sliding, skipping:
coordination
