Motor Development - Chapter 7

Degree of Arm Action

No arm action → limited arm swing → extension → partial flexion → extension → complete arm swing overhead

Jumping

Occurs when individuals propel themselves off the ground with one or both feet and then land on *both feet*

Locomotion: Key Point

-After infancy, most humans move from place to place using upright bipedal locomotion -A particular pattern of locomotion is called a gait -Upright bipedal gait patterns include walking running, galloping, skipping and hopping

Rate Limiters in Early Running

-Coordination is not likely to be a rate limiter (patterns are similar to walking) -Strength is a very important rate limiter since it is required for the flight phase -Balance is also important to catch themselves upon the landing of the flight phase

Skipping: Observing Patterns

-Observe whether the child skips with one leg and runs with the other or if they skip with either leg -Both Legs: look at the height of the hop and the knee lift (lower height = proficient and smooth) -Note whether the arms are bilateral (beginner) or oppositional (proficient)

Hopping Introduction

-Once again, hopping is when someone propels themselves with one foot and lands on the same foot -Not used commonly by adults but should be developed to become a skillful mover -Requires projection and absorption with just one limb and balance on a small base of support

Locomotion: Explained

-Requires the interaction of many systems and constraints -Type of locomotion locomotion depends on the interaction of constraints -During childhood years, height, weight, and length act as weight controllers -Constraint Examples: motivation & perceived gender association (+ or - behavior) -Functional Constraint Examples: fear of falling or loss of balance capability -Env. Constraint Example: weather changes

Galloping, Sliding, and Skipping: Rate Limiters

-Rhythmic or coordination changes are required for the 50% phasing -Two legs perform different tasks and require different forces (force coordination) -Galloping Rate Limiter: force coordination -Sliding Rate Limiter: neuromuscular system -Skipping: most difficult requiring the neuromuscular system to coordinate the two limbs as they perform asymmetric tasks

Developmental Changes: Early Running

-Running speed and time in flight increase due to increased body size, increased strength, and improved coordination [studies between 1.5 & 10 years] -Not all achieve improvements as children, many refine running as teenagers (age alone does not guarantee perfect running form) -Out-toeing, lateral leg movements, and limited stride may persist in individual runners (may be associated with skeletal & muscular imbalances)

Running Across the Life Span

-Running typically ensues 6-7 months after walking -Early attempts of running are typically fast walks (no flight period) -Learning to run: wide base, flat-footed landing, leg extension at mid-support, high-guard arm position

Proficient Hopping

-Swing leg must lead the hip -The support leg must fully extend -The arms must move in opposition to the legs -The support leg must flex at landing to absorb force and to prepare for next takeoff

Locomotion

-The act of moving, or the capability to move, from place to place -Performed everyday with little thought

Skipping: Developmental Changes

-The final of the three bipedal patterns to emerge (coordination in each leg is asymmetrical) -4-7 Years of Age [a little more than 1/2 of 5 year olds] -At first, a child might perform a unilateral step-hop (skip with the dominant leg and just a running step with the other) -When beginning, the child may have occasional breaks with steps or gallops in the middle -Develops in girls first

Progression of Skills for Creeping & Crawling (4)

1) Crawling with the chest and stomach on the floor 2) Low creeping with the stomach off the floor but the legs working together (symmetrically) 3) Rocking back and forth in the high creep position 4) Creeping with the legs and arms alternating

Proficient Jumps for Height

1) Direct force downward and extend body through flight (extend dominant arm up and opposite arm swings down with a lateral tilt of the shoulders if aiming for a target) 2) Keep trunk upright 3) Flex the ankles, knees, and hips on touchdown to reduce force absorption Figure 7.10 (Page 142)

Observation Plan for Hopping: Legs

A) Active Swing Leg → swing leg leads with fully extended support leg (step 4; projection delay and swing leg leads) OR takeoff leg extends only (step 3; projected takeoff) B) Inactive Swing Leg → minimal extension at take off (step 2; fall and catch) OR high & inactive swing leg (step 1; momentary flight)

Chapter 7

Development of Human Locomotion

Vertical Jump vs. Standing Long Jump

Differ by (A) Position and (B) Movement Speed Vertical Jump: knees and ankles extend faster Standing Long Jump: hips are more flexed, hips extend faster

Developmental Changes in Jumping

Horizontal: +3-5" per year during elementary school years Vertical: +2" per year during elementary school years -Clark & Phillips found that movement patterns differ, most notably in arm movement -Standing long jump:

Jumping Observation Plan (Figure 7.12)

Leg Action: both feet leave at the same time... knees extend at the same time or after heels come off the ground... heels come off the ground before the knees extend and trunk moves forward Arm Action: the arms swing at takeoff... the arms swing back before they swing forward at takeoff... arms then swing forward to a position over head at takeoff

Summary and Synthesis

Page 154

Developmental Sequence for Hopping

See Table 7.6 Page 146 Leg Action: Momentary flight, fall and catch, projected takeoff, projection delay Arm Action: bilateral inactive, bilateral reactive, bilateral assist, semi-opposition, opposing assist

Table 7.4

Whole Body Approach of Jumping Page 139

Adolf (1997) on the Environment

"The surface must provide a continuous path to support the body, must be large enough to allow passage as the body moves forward, must be sturdy enough to support body weight, and must be firm enough, flat enough, and have sufficient friction to maintain balance as weight shifts from limb to limb

Clark Study: Difference Among Age Groups

-3-, 5-, 7-, 9- year-olds and adults use the same leg pattern of coordination and same pattern for horizontal and vertical jumps -Specifically, the timing of the hip, knee, and ankle joint extension at takeoff was similar in all groups (reflects the mechanics of lifting the body off of the ground) -Neuromuscular system must use a leg coordination pattern that gets the body off the ground but... the limb positions and movement speeds change as the jumper is better able to optimize jumping distance or adapt the jump to a specific task

Rate Controllers of Later Walking

-A disease state must progress to a critical level before it will discourage all walking -Often, older adults modify their gait to accommodate pain or balance changes -Functional constraints such as balance and fear may influence walking patterns -Fear of falling results in a gait designed to assist with balance (wider stance/base, short step -Less walking decreases muscle mass and flexibility, thereby reducing walking ability and patterns

Developmental Changes in Walking During Early Childhood

-Age 4: advanced walker -Pelvic Rotation: 13.8 months -Knee Flexion at Mid-support: 16.3 months -Trunk-Width Base of Support: 17.0 months -Synchronous Arm Swing: 18.0 months -Heel-then-Forefoot Strike: 18.5 months

Assessment of Running: Observation Plan

-Allows one to make quick judgments about the developmental level of a particular runner Steps of Leg Action: presence of flight, knee flex to at least 90 degrees, leg in forward-back plane Steps of Arm Action: arms are active, true opposition to legs, forward-back movement

Jumping Progression: Beginner

-Begin a vertical jump, even if attempting to jump horizontally -Preparatory crouch is slight and legs do not fully extend at liftoff -Lack symmetrical/two-foot takeoff and landings -Trunk is too erect during horizontal jump -Lack of coordinated arm action (asymmetrical, stationary, and/or in high guard position for potential falls) -Arms may wing ineffectively during flight or parachute during landing

Galloping, Sliding, and Skipping: Characteristics of Early Skill Patterns

-Beginners are usually arrhythmic -Stiff with arms in high guard position rarely involved with projecting the body off the floor (seek balance) -Stride/step length is short and they land flat-footed -Minimal trunk rotation and exaggerate vertical lift (do not project forward) -Early galloping: trailing leg may land in front of leading leg

Sliding: Observing Patterns

-Best from the front since the movement is lateral -Focus on knee stiffness (stiff = beginner; relaxed = skilled with spring characteristic) -Focus on arms in guard position or relaxed and free -Note whether they can slide to both sides or just the dominant

Developmental Changes in Walking During Older Adulthood: Schwanda Study

-Confirmed shorter stride length and velocity -Remained the same: stride rate, swing time of recovering leg, time of support, vertical displacement of center of gravity

Developmental Changes in Walking During Older Adulthood

-Constraint interactions and walking patterns may change due to wt. gain/loss, strength, balance, injury, or gait training -Older adults experience a recalibration to the environment and the task based on biological/ind. constraints -Study by Murray detected 4 changes with age -Schwanda confirmed shorter stride length and velocity -Key Point: Rate controllers in walking during older adulthood may be caused by factors such as disuse and fear of falling and therefore may be altered and improved

Hopping Rate Controllers

-Depends on the postural system's ability to balance the body on one limb for a succession of hops -To hop repeatedly, the individual must be able to generate enough force to lift the body with one limb, recover, and quickly generate enough force to hop again -Unlike running, the leg stays extended and requires more effort... making the ability to generate force the rate controller

Whole-Body Approach

-Describes all characteristic positions of various body components in a step (Table 7.4) -E.g. Jumping: view jumping as a whole

Characteristics of Early Jumping

-Development gauged by age for certain kinds of jumping, distance/height of jump, and jumping form/pattern -Stepping down off a higher surface from one to to the other before jumping is achieved -Learn to jump down from progressively greater heights -Begin to master jumps, jumps over objects, and hopping a few times on one foot -School Age: children can perform all jumps -Gradual process of refining skills -Development is based on the standing long jump

Addressing Atypical Walking Development in Down Syndrome

-Down syndrome delays motor milestone attainment and may significantly delay the onset of walking -Study placed children over treadmill to facilitate walking -The treadmill intervention was successful: rose to a standing position and began walking sooner (with and without assistance)

Characteristics of Early Running

-Early characteristics reflect the changes in speed (task constraint) b/w walking and running -Begins with a short stride length and limited ROM (rear leg does not fully extend; momentarily in flight) -Arm swing is to accompany the trunk's rotation, not to drive forward and back -Elbows unnecessarily extend during the swing back -Arm swings too much to the side -Early runners may swing arms across the body to ensure balance

Hands and Feet Gait

-Emergence of this gait pattern resulted from infrequently occurring interactions b/w constraints -Env. Constraints: crawling surface may make knee support uncomfortable [e.g. gravel] → feet support -Also, the reinforcement/response of the parent may facilitate this movement -Lastly, avg. or above-avg. strength and health must interact with env. factors to allow hands-and-feet gait -Hands and feet gait is rarely seen b/c these factors do not exist and interact to encourage this quadruped movement

Introduction

-Examines various locomotor skills across the life s;pan, how they change systematically, and how individual constraints act as rate controllers -Locomotor skills change throughout one's lifespan based on constraints

Developmental Changes in Hopping

-Few children under 3 can hop repeatedly -Proficient hopping usually occurs during preschool years (But Hlaverson and Williams showed half of 3,4, & 5 year olds were at step 2 in the arm/leg action) -In order to prepare for landing, the neuromuscular system prepares before landing to moderate the force of the landing by allowing the leg to give/flex... once reaching step 2 the child may land hard enough that force reaches a critical value to cause potential damage, causing the neuromuscular system to change for a softer/cushioned landing

Galloping: Developmental Changes

-First of the three bipedal patterns to emerge [first asymmetrical locomotor pattern learned b/c walking/running are 50-50] -2-3 Years of Age (after running at age 2 and before hopping at age 3-4) -Two Timing Patterns: (1) steps takes ~2x as long as the leap step [66%-33% phasing] (2) step takes ~3x as long as the leap step [75%-25% phasing] -Learn to lead with the dominant leg much sooner

First Step: Characteristics of Early Walking

-First, steps tend to be independent of the next; short steps; little leg and hip extension; flat feet; toes point outward; spread feet for lateral balance; no trunk rotation; toddler holds arms up -Characteristics above improve balance -Then, hands drop to waist level (middle guard) and then extended down side (low guard) -Preliminary arm swing is unequal and and irregular (both hands may swing together)

The Component Approach

-Follows each separate body component through whatever number of steps accounts for the qualitative changes observed over time (Table 7.5) -E.g. Jumping: view the arms and legs separately

Galloping, Sliding, and Skipping

-Galloping and Sliding: asymmetric gaits that consist of a step on one foot and a leap-step on the other foot (same leg always leads with the step) -Galloping: individual moves forward -Sliding: individual moves sideways -Skipping: a step and hop on the same foot with alternating feet (step-hop on rt., step-hop on left, step-hop on rt., etc.)

Observing Hopping Patterns

-Halverson's systematic pattern of observation focusing on the body parts one at a time -Pay attention to the swing leg (active vs. inactive) and then the support leg (extend vs. flex) -Pay attention to arm action from side and front (bilateral or opposing) (inactive, reactive, or backward)

Running

-Has a 50% phasing relationship between the legs -Unlike walking, running has a period of flight (neither foot touching the ground; no double support) -More advanced than running

Walking

-Is defined by a 50% phasing relationship b/w the legs as well as a period of double support (when both feet are on the ground) followed by a period of single support -Individuals alternate their legs so that the left leg is halfway through its motion as the right leg beings its own

Jump Progression: Skilled Horizontal Jump

-Leaks trunk forward at least 30 degrees (and tip forward at the start of takeoff) -Age 3: can change their trunk angle at takeoff to make either a vertical or horizontal jump -Heels usually come off the ground before the knees start to extend -KEY STEP: The leg action in which "heels up" begins the takeoff is the most advanced step in the developmental sequence for the leg action of the horizontal jump -Arms are used symmetrically to lead the jump from a preparatory extended position to an overhead swing Image on Page 143

Developmental Changes in Walking During Early Childhood: General Changes

-Length of time for one foot supporting wt. while the other swings forward increases (especially year 1-2.5) -Stride length increases through adolescence (increased leg length and ROM) -Walk velocity increases (especially year 1-3.5) -Rhythm and coordination improve until age 5

Zimmerman on Inefficient Jumping Characteristics

-Limited arm swing and incomplete leg extension at takeoff

Degree of Leg Action

-Lowest: a one-foot takeoff -Asymmetrical takeoff -To improve: (1) make a symmetrical two-foot takeoff, flight and landing with (2) full extension of ankles, knees, and hips at takeoff after a deep preparatory crouch

Early Hopping

-Minimal leg extension -Inactive swing leg (do not project it upward, it stays stationary and flexed) -Inactive arm (do not shoot them up for elevation)

The First Voluntary Locomotor Efforts: Creeping and Crawling

-Motor milestones must be achieved (lifting the head in the prone position) -Requires strength and limb uncoupling -Environment must allow for infant locomotion and the infant must evaluate the env. to see how well it matches their ind. constraints -Leads to creeping and crawling

Developmental Changes: Later Running

-Nelson analyzed the transition from walking to running in older women -Increased walking speed by lengthening stride but increased running speed by increasing stride frequency -Major Differences: older women did not tuck their recovering leg completely, had a shorter stride length, and took fewer strides [absolute jogging and running speed slower than young women as well]

Developmental Changes in Walking During Older Adulthood: Gabell and Nayak Study

-No significant differences b/w the walking patterns of the 32 older adults compared to younger adults -Some changes might be due to disease and injury (especially involving muscle loss) -In short, since older adults merely walk slower, they tend to mimic the walking gait of young adults walking slowly

Creeping and Crawling

-Occur when all four limbs are in contact with the supporting surface -In crawling: the infant's chest and stomach also touch the surface -In creeping: only the hands and knees touch the surface

Proficient Walking Patterns

-Proficient walking relates to finding a medium between balance and mobility and further recalibration Developmental Changes: 1) Increased stride length (greater force application) 2) Heel-then-forefoot pattern (increased ROM) 3) Reduced out-toeing with narrowed based (keeps feet & force in the forward-backward plane) 4) Double knee-lock pattern (full ROM due to knee extending at heel strike, flexing as body wt. moves forward, and extends once more at push-off) 5) Pelvis rotates 6) Oppositional movement of upper/lower body segments 7) Balance improves (reduced forward trunk inclination) 8) Coordinates oppositional arm swing with the movement of the legs (relaxed arm swing; unison)

Rate Limiters in Early Walking

-Rate limiters are muscular strength and balance -Walking requirements: legs must be able to alternate, strength to support self on one limb, balance on one leg while transferring his weight to his other foot -Thelen, Ulrich, and Jensen: infants must have trunk and extensor muscle strength for upright posture on a small base of support... and develop balance or an erect posture/body position to compensate for weight shifts

Galloping, Sliding, and Skipping: Proficient Skill Patterns

-Rhythmical and relaxed -Arms no longer needed for balance -Arms swing rhythmically in opposition to the legs, providing momentum -Child can use the arms for another purpose during movement (e.g. clapping) -Forefoot or heel-to-forefoot landings prevail -The knees "give" on landing, remaining flexed while they support the body's weight, and then extend at takeoff, especially when the child is traveling quickly

Jumping Introduction

-Simple jumps are often achieved by age 2 -Specialized forms of jumping (i.e. hopping and leaping) are also achieved during childhood

Rate Controllers in Late Running

-Smaller changes in strength and balance may lead to the disappearance of running -Many restrict running for only required situations

An Integrated Approach to Understanding Hopping

-Stage 2: the swing leg is held in front and motionless, not contributing or preventing a hop when light -When gaining weight a motionless swing leg inhibits a hop and the child must recalibrate the landing (newton's 3rd law) due to new individual constraints [safer hop in step 3 with change in both legs] -Graphs illustrate the development step based on age with greater progression in the preferred leg and an increase in step progression with age

Developmental Changes: Proficient Running

-Stride length increases due to greater force (rear leg is fully extended at push off, heel is tucked close to the buttocks, and the thigh swings forward with greater acceleration, and the thigh comes parallel to the ground before foot strike) -When the recovery led is swung forward in a tuck position, conserving the runner's effort -Runner eliminates lateral leg movements -Foot strikes the ground with heel first and then forefoot strikes the ground in an approximately flat pattern [extended running] -Out-toeing is eliminated and base is narrowed -Support leg flexes at the knee as the body's wt. comes over the leg -Trunk rotation increases to allow for a longer stride and better arm-leg opposition (trunk leans forward) -Arms swing forward and back in opposition to the legs (elbows approach right angles)

Galloping: Observing Patterns

-The trailing foot lands alongside or behind the lead foot -The flight pattern is low -Arms are free to swing rhythmically or to perform an alternative task -Note whether they can lead with both legs or just the dominant

Walking Across the Life Span

-Walking, unlike other motor behaviors, does not change much over the life span -Relative walking timing does not change across one's lifetime -50% phasing, double support and single support -Based on ind. and env., an individual may change absolute timing and placement

Observing Motor Skill Performance

1) Analysis - must know the sequence to examine the critical features of a skill pattern 2) Planning - plan or use observation guidelines [organized by body component or sequence component] 3) Positioning - watch from several angles Tools: description/characteristics of desired sequence, plan for observing to place one at a step/level, and a recording sheet

Proficient Jumps for Distance

1) Direct force down and back by beginning the takeoff with the heels leaving the ground before the knees extend (trunk appears to tilt forward) 2) Flex the knees during flight, then bring the thighs forward to a position parallel with the ground 3) Swing the lower legs for a two-foot landing 4) Let the trunk come forward in reaction to the thigh flexing, putting the body in a jackknife position 5) Flex the ankles and knees when the heels touch the ground to absorb the momentum of the body over distance as the body continues to move forward Figure 7.11 (Page 143)

Proficient Jumping

1) Preparatory crouch that will stretch the muscle and allow the legs to apply maximal force as they fully extend at the moment of liftoff 2) Take off for a horizontal jump with the heels coming off the ground and with both feet leaving the ground at the same time 3) Extend the arms backward, then initiate takeoff with a vigorous arm swing forward to a position overhead

Hopping Steps

1) Support leg is pulled for momentary flight and arms are not working in opposition 2) Some leg extension is used to leave the group but swing leg is still inactive 3) Swing leg leads the hop 4) Range of the swing leg completely behind the support leg and both arms move in opposition to the legs

Galloping, Sliding, and Skipping: Observing Patterns

1) Use a side view to note the trailing foot in relation to the leading foot 2) View the vertical lift 3) View the arms

Observation Plan for Hopping: Arms

A) Opposing → opposing assist (step 5) or slight opposition (step 4) B) Bilateral → active with bilateral assist & pump (step 3) OR active with bilateral reaction (step 2) OR bilateral inactive (step 1; slight movement and held to side)

Table 7.5

Component Approach of Jumping (components are arms and legs) Page 140

Other Locomotor Skills

Jumping, hopping, galloping, sliding, and skipping

Skipping: Progression

Legs -Beginner uses a high hop and knee lift (appears jerky) -Child partially extends the leg on the hop and uses a lower but smoother knee lift (more smoother, efficient, and rhythmic) Arms -Arms are used inconsistently, swinging one or both arms up and laterally -Begin to use arms bilaterally (sometimes forward and back in circles... sometimes forward and down) -Skilled skippers use their arms in opposition to their legs

Leaping

Occurs when individuals propel themselves with one foot and land on the *other foot*

Hopping

Occurs when individuals propel themselves with one foot and then land on the *same foot*

Developmental Changes in Walking During Older Adulthood: Murray Study

Older men exhibit: 1) Step length ~3 cm shorter 2) More toed out ~3 degrees 3) Reduced ankle extension 4) Diminished pelvic rotation

Developmental Sequence for Running: Arm Action

Step 1: High or middle guard (both arms are held b/w waist and shoulder and move very little) Step 2: Bilateral arm swing (arms swing but are coupled... moving together) Step 3: Opposition, oblique (arms drive forward in the opposition pattern but possess some lateral movement) Step 4: Opposition, sagittal (arms swing forward and backward in the opposition pattern and stay nearly sagittal)

Developmental Sequence for Running: Leg Action

Step 1: minimal flight with a short and flat-footed running step with a stiff leg upon return Step 2: Crossover swing with a long stride, recovery knee above a right angle, and legs move laterally Step 3: Direct/forward projection where the stride is long & recovery leg tucks to swing forward