Midterm 2 Flashcards
1
Q
developmental changes
A
- changes are based on optimizing principles of motion and stability
- changes can be seen across a variety of motor skills
- changes often produce more force, velocity, or accuracy
- occur according to biomechanics principles
2
Q
biomechanics
A
the study of forces acting on and generated within the body and the effects of these forces on the tissues, fluids, or materials used for diagnosis, treatment or research purposes
- motion and stability are two principles within the larger field of biomechanics, known as the physics of movement
3
Q
force
A
strength or energy exerted, as an attribute of physical action or movement, measured in newtons
4
Q
mass
A
the mass of a body refers to the amount of substance that it is made up of and is measure in weight
5
Q
velocity
A
the rate of change of position of an object in a particular direction
6
Q
acceleration
A
any time velocity changes, if you are not changing speed, you are not accelerating
7
Q
inertia
A
- the idea that an object will continue its current motion (whether moving or stationary) until some force causes its speed or direction to change
- resistance to change in speed or to get moving
- opposing change in direction or speed
8
Q
momentum
A
- the product of mass and velocity
- mass in motion
- how much motion something or someone has
9
Q
we must exert force to
A
- move objects
- move ourselves
10
Q
more inertia/momentum
A
- it is harder to move
- more force application is required
11
Q
to move an object farther or faster
A
- increase the force delivered to the object
- increase distance over which force is applied
12
Q
newton’s first law
A
- an object at rest stays at rest, and an object in motion stays in motion until acted upon by a force
- any object that is moving will continue moving unless an external force is applied to stop it from moving
- this law is about inertia
- once a ball is struck in tennis, its forward trajectory would continue indefinitely if the forces of gravity, friction from the air resistance or striking the ground and the force of the opposing player’s racket did not stop it
13
Q
newton’s second law
A
- Force = mass x acceleration
- object’s acceleration is related to force applied and inversely related to mass
- acceleration is the rate of change of the velocity of an object with respect to time
- mass is how much matter the object contains
- tennis serve: the mass of the ball remains constant, therefore the more force you apply to the constant mass of the ball, the greater the acceleration of that serve will be until it reaches top speed
14
Q
newton’s third law
A
- to every action, there is an equal and opposite reaction
- when you push on something, it pushes back on you
15
Q
force and time
A
- to make an object move, increase force application for a given time
- to make an object stop, increase time over which a given force is applied
16
Q
balance
A
- a person’s ability to control their equilibrium in reaction to gravity only
- equilibrium is a state of rest of the body either at a stationary or moving position
- equilibrium is a state of no acceleration and can be static or dynamic
17
Q
stability
A
- your body’s ability to return to a desired position or trajectory following a disturbance to equilibrium
- if acceleration is occurring, we’re talking about stability
- as our body needs to respond to acceleration and return to a desired position or trajectory
18
Q
increasing stability
A
- stability = ability to resist movement
- increase base of support
- lower center of gravity
19
Q
increasing balance
A
- balance = ability to maintain equilibrium
- increase stability
- improve strength, coordination, and proprioception
20
Q
proprioception
A
ability to sense movement, action and location
21
Q
stability-mobility trade-off
A
- new movers adopt stability strategies that maximize stability and balance but hinder quick movement
- with development and improvement in ability to maintain upright posture during movement, movers shift to mobility strategies so they can move faster
22
Q
what is locomotion?
A
- the ability to move from one place to another
- often focus on early acquisition of locomotor skills
- locomotion is a lifelong movement activity
- changes occur in walking, running, galloping, and other motor skills as individual, environmental and task constraints change
23
Q
senior runners
A
- at the 2018 USA Track ad Field Masters Championships, there were two world records set in the 60m dash
- in the women’s 100+ age group, Julia “Hurricane” Hawkins, at 102, set a new world record with a time of 24.79 seconds
- Orville Rogers set a world record in the mens 100+ 60m race with a time of 19.13 seconds, Rogers held seven world records in the 95-99 bracket
24
Q
locomotion
A
- moving from place to place
- moving on one, two, or four limbs: crawling, walking, running, hopping, skipping, galloping, using other modes
25
constraints
- discourage or limit certain movements
- encourage or permit other movements
- "shape" movements, channel away from some movements while toward others
26
individual constraints
- unique physical, mental characteristics
- structural: related to the body's structure: height, muscle mass
- functional: related to behavioural function: attention, motivation, fear
27
environmental constraints
- properties of the environment, external
- global, not task specific
- physical: gravity, surfaces
- sociocultural: gender roles, cultural norms
28
task constraints
- specific task requirements or goals, external to the body and not related to the individual
- related specifically to tasks or skills: goal of task, rules guiding task performance, equipment
29
rate controller/limiter
- an individual constraint or lack of development of a system that holds back the development of a motor skill
- a toddle may be strong enough to hold herself up, but its a lack of balance that limits the progression from standing to walking
- a 5 yr old shooting a basketball, lack of muscular strength to get it to the 10ft hoop, strength is then the system that is the rate limiter/controller
30
study of locomotion
- falls within many fields, from medicine to psychology
- across the lifespan, individuals use various methods of locomotion
- the type of locomotions they use depends on interacting constraints
31
locomotion across lifespan
- childhood years: height, weight, and lengths change dramatically and act as rate controllers
- during much of the lifespan, other types of constraints, such as motivation or even perceived gender association of a skill may encourage or discourage behaviour
- as one approaches old age, structural constraints such as physical characteristics may return as important rate controllers, however functional constraints such as fear of falling or loss of balance capability, may acts just as strongly to discourage locomotion
- environmental constraints such as weather changes (eg. ice and snow) also impact older adults
32
early locomotion of crawling
the following progression of skills leads to creeping and crawling:
1. crawling with the chest and stomach on floor, commando crawling
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. crawling with the legs and arms working alternately
33
walking
- walking is the first form of upright, bipedal locomotion
- walking is defined by the following:
- 50% phasing between the legs, individuals alternate their legs so that the left leg is halfway through its motion as the right leg begins its own
- period of double support followed by period of single support
34
early walking
- stability and balance are maximized over mobility
- arms are in high guard
- feet are out-toed and spread wide apart
- independent steps are taken
- rate controllers are strength (to support body on one leg) and balance
35
rate limiters in early walking
- infants have the ability to move their legs in an alternating pattern from birth onward, yet they cannot walk for at least 7 months
- critical levels of development required to overcome these rate-controlling factors:
- legs must be able to move alternately, and must have enough strength to support themselves on a single limb -> muscle strength in the trunk and extensor muscles to allow them to maintain an upright posture on a small base of support
- must also balance on one leg while transferring weight to other foot
36
proficient walking (1)
- stability is traded for mobility
- stride length increases
- base of support is reduced
- pelvis is rotated
- opposition (arms to legs) occurs
- double knee-lock is adopted: knee extends at heel strike, flexes slightly as the body weight moves forward over the supporting leg, and then extends once more at foot push-off, because the knee extends twice in one step cycle we call this double knee-lock
37
proficient walking (2)
- by age 4, most children have the essential ingredients of an advanced walk
- the length of time for which one foot supports the body weight while the other swings forward increases, especially from 1.0 year to 2.5 years
- stride length increases throughout mid-adolescence, partly because of fuller ROM at the hips, knees, and ankles and partly because of the increase in leg length resulting from growth
- velocity of walk also increases, especially between 1.0-3.5 years of age
- rhythm and coordination of a child's walk improve observably until age 5 or so, beyond this age improvements are subtle
38
developmental changes in walking in older adulthood
- stability is maximized
- out-toeing increases
- stride length decreases
- pelvic rotation decreases
- speed decreases
- objects are used as balance aids
39
rate controllers in later walking
- structural constraints may result from osteoarthritis in the joints or from a decline in muscle mass, a disease sate must progress to a critical level before it will discourage all walking
- more often, older adults modify their gait to accommodate pain or changes in balance
- functional constraints, such as balance and fear, can also affect walking patterns
- often, two types of individual constraints will interact, and their sum will act as a rate controller
- a decrease in walking leads to a decrease in muscle mass and flexibility, which in turn affects walking patterns
40
running
- occurs 6-7 months after walking starts
- for a gait to be considered a run it must include a flight phase
- an infant's earliest attempts to run are actually fast walks
41
early running
- stability over mobility: return of old "behaviours"
- arms in high guard, limited ROM, short stride length, little rotation
- infants running for the first time may exhibit some of the characteristics of an early walk, even though the infant no longer uses these in their walk
42
rate limiters for early running
- running requires a flight phase
- strength: to propel themselves into the air, toddlers must have sufficient strength in each leg to lift themselves off the ground
- balance: once in the air, infants must catch themselves on the other leg and then balance on that leg while shifting their weight forward
43
proficient running
- less stability, more mobility
- increased stride length
- planar movement: heel strike then forefoot
- narrow base of support
- trunk rotation
- opposition
44
developmental changes in runningin older adulthood
- many of the rate controllers mentioned for later walking also affect running
- because running requires greater generation of force and greater ability to balance, considerably smaller changes in these constraints may lead to the disappearance of this skill
- may have the ability to run but not the desire or the opportunity; in other words, an older adult may only run in an urgent situation
45
jumping
- person propels self off ground with one or two feet; lands on two feet
- children attempt jumping at a young age ad often achieve the simplest form before age 2
46
leap
- person propels self off ground with one foot, extends flight period, and lands on opposite foot
47
hop
person propels self off ground with one foot and lands on same foot
48
early jumping, hopping, leaping
- by school age, children can usually perform all of these jumps
- early jumping occurs by 18 months, a combination of achievements and strategies occur
49
jumping type and difficulty
1. jumping down from one foot to the other foot
2. jump up from two feet to two feet
3. jump down from one foot to two feet
4. jump down from two feet to two feet
5. run and jump toward one foot to the other
6. jump forward from two feet to two feet
7. run and jump forward from one feet to two feet
8. jump over object from two feet to two feet
9. jump from one foot to the same foot rhythmically
50
proficient jumping
- preparatory crouch maximizes takeoff force
- both feet leave ground at the same time
- arm swing used during jump
- for vertical jump, force is directed downward; body is extended
- for horizontal jump, force is directed down and backward; knees are flexed during flight
51
developmental changes of jumping
- continual growth in body size and strength contribute to quantitative improvements
- it is not guaranteed that every child will eventually master jumping
- inefficient jumping characteristics including limited arm swing and incomplete leg extension at takeoff
52
rate limiters in jumping
- development of enough force to bring own body into the air from a still position
- unlike in walking and running, they cannot take advantage of a "fall and catch" motion but rather must project their entire bodies into the air
53
hopping
- adults rarely use hopping to move around, yet to become a skillful mover, an individual should develop hopping skills during childhood
- to hop, especially repeatedly, one must project and absorb body weight with just one limb and maintain balance on the small base of support that one foot provides
- complex sport and dance skills often incorporate these movement abilities
54
early hopping
- starts later than jumping
- few children under 3 can hop repeatedly
- early characteristics include: support leg is lifted rather than used to project body, arms are inactive, swing leg is held rigidly in front of body
55
rate controller in hopping
- depend on the postural system's 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, and quickly generate enough force to hop again
56
galloping, sliding, skipping
- involve a combination of skills previously obtained: stepping, hopping, leaping
- gallop and slide are asymmetric
- gallop: forward step on one foot, leap on the other
- slide: sideways step on one foot, leap on other
- skip is symmetric: alternating step-hops on one foot then on the other
57
early galloping, sliding, skipping
- children's early attempts at these skills are usually arrhythmic and stiff
- the arms are rarely involved in projecting the body off the ground
- children might hold their arms stiffly in the high guard position or out to the side to aid their balance
- their stride or step length is short, and they land flat-footed
- little trunk rotation is used, and they exaggerate vertical lift
- in early galloping attempts, a child's trailing leg may land ahead of the lead leg
58
proficient 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
59
emergence of galloping, sliding, skipping
- galloping is the first to emerge (around 2-3 years of age)
- sliding comes next
- skipping is usually the last to emerge (around 4-7 years)
60
rate limiters for galloping, sliding, skipping
- galloping: rhythm because one or more elements are used repeatedly in a certain pattern
- the two legs are performing different tasks ( step vs. leap-step); therefore they require different amounts of force, which requires changing force coordination
- sliding: coordination (turning to one side)
- skipping:
- coordination (ability to perform two tasks with one leg)
- not limited by generation of force because children hop before they skip, nor is balance a rate limiter because it is more difficult to balance while hopping than skipping
- skipping is the most complex fundamental locomotor pattern
- skipping might not appear until the individual's neuromuscular system can coordinate the two limbs as they performs different tasks at the same time.
61
ballistic skills
- performer applies force to a object to project it forward
- examples include throwing, kicking, and striking
62
throwing
- forms: underhand (one or two hand), sidearm (most advanced), overarm (one or two hand)
- assessment:
- product measures (outcome): accuracy, distance, ball velocity
- process measures (movement pattern): developmental sequences
63
early overarm throwing
- throw involves mostly arm action
- elbow is pointed up
- throw is executed by elbow extension alone
- not trunk rotation, step forward or follow-through
64
beginning throwing
- trunk flexion (leaning forward) not rotation
- steps into throw
- hand follows behind elbow
65
proficient overarm throwing for force
- thrower uses prepatory windup, weight shifts and trunk rotates back; arm swings
- thrower uses opposite leg, long step and differentiated trunk rotation (DTR)
- the forearm lags behind the trunk and upper arm during the forward swing, while the upper trunk is rotating forward, the forearm and hand appear to be stationary or to move down and back. The forearm lags until the upper trunk and shoulders actually rotate in the direction of the throw
- wrist flexion during follow-through
66
sequence of proficient throwing
1. forward step and pelvic rotation
2. upper spine rotation and upper arm swing
3. upper arm inward rotation and elbow extension
4. release
5. follow-through
67
developmental changes in overarm throwing: childhood
- forceful overarm throw is a complex skill due its dedicated sequence
- not everyone reaches the highest step in each component
- difference are observed between the sexes in throwing skill
68
throw like a girl?
- research over the past century has shown that girls do not develop the same overarm throwing ability as boys, but maybe that was just a sign of the times from a culture that discouraged girls from throwing overarm
- in a 2008 study looking at 6-8 year olds:
students were recorded before and after four instruction and practice classes
- boys were more likely than girls to take a contralateral step, use trunk rotation and have forearm lag
- girls showed more advanced patterns after instructional classes
- still saw gender difference, instruction and practice can help girls in their skill development and narrow the gender gap
69
why has there not been a narrowing of the gender differences in sport?
- girls are being given more opportunities to participate in ball sports, more coaching, and more motivation to succeed in sport (eg. college scholarships, professional careers)
- likely a mix of biological and environmental factors
- environmental explanations: cultural expectations, opportunities for training/skill development
- biological explanations: anthropometric variables such as body size, physique, and proportions, and neuromuscular coordination
70
developmental changes in overarm throwing: adulthood
- differences are observed between the sexes
- ball velocities are moderate
- one or more body systems might regress, causing a slowing or limitation of movement, then reach a critical point at which the movement pattern must change such as shoulder arthritis
71
throwing for accuracy
- the developmental sequences constructed for overarm throwing specially address a throw for distance rather than for accuracy
- thrower may use lower developmental steps for accuracy throws than for forceful throws
- of course, in sports and games, throws are rarely made for distance without some accuracy constraint, or for accuracy without the need for force
- what this research demonstrates is that different movement patterns arise for different task constraints, even for the same person in the same environment
- when required to throw a greater distance, difference between throws are minimal
72
shooting for accuracy case study
- basketball free throw: regular shot or two handed underhand shot
- Rick Barry: 10 years in the NBA (8 time all-star), average 24 points per game
- a 0.900 shooting percentage from the line, using two hand underhand shot
- he said fluid motions made him so successful
- no one else in the NBA shoots this way
73
kicking
- kicker strikes ball with foot
- kicks must have perceptual abilities and eye-foot coordination to make contact
- kicking a moving ball is difficult for children
74
early kicker
- no step is taken with the non-kicking leg
- kicking leg pushes forward, may retract right after
- only motion is knee extension
75
intermediate kicker
- steps froward, putting the leg in a cocked position, but the leg swing is still minimal
- the knee is bent at contact, and some of the momentum of the kick is lost due to the bent knee
76
proficient kicking
- typically leaping or running at ball (max force)
- preparatory windup is used (trunk rotated back, kicking leg cocked, knee bent)
- trunk rotates forward
- movement is sequential: thigh rotates forward, the lower leg extends
- full range of motion at hip
- arms move in opposition to legs
77
developmental changes in kicking
- movement pattern changes are not well documented compared to throwing
- children do not automatically achieve proficient kicking
78
striking
- although many sports and physical activities incorporate striking, research date on the development of striking is sparse
- it can be done with various implements in various orientations such as swinging a bat sidearm,. a racket overhand, or a golf club underhand
- we focus on one-hand sidearm, striking with an implement and one-hand overarm striking with an implement
79
sidearm striking
- implements can be used
- mechanical principles are similar for all striking tasks
- striking involves the most difficult perceptual judgement
80
early sidearm striking
- success in meeting a moving object in limited in early childhood
- teachers often adapt striking tasks for young children by making the ball stationary
- chopping motion (elbow extension)
- little leg and trunk movement
81
proficient sidearm striking
- sideways preparatory stance and long step
- trunk rotation
- horizontal swing through large range of motion (arm extended before contact)
- linking movements together to produce the greatest force
- the sequence is as follows: backswing and forward step, pelvic rotation, spinal rotation and swing, arm extension, contact and follow-through
82
developmental changes in sidearm striking
- chop: plane of swing progresses from vertical to horizontal
- trend is toward use of trunk rotation (none, then blocked, the differentiated), shoulders and hips move together then move separately
- grip changes from power grip to "shake-hands" grip
- elbows are held away from the body and extended before contact
83
overarm striking
- overarm striking is a form of striking where the arm travels above the shoulder level
- without an implement, eg. volleyball serve
- with an implement, eg. tennis serve
84
early overarm striking
- limited pelvic or spinal movement
- striker swings with collapsed elbow
- there is little to no lag with swing forward, doesn't let racket or hand lag behind the arm during the forward swing
- movement looks like early throwing
85
proficient overarm striking
- pelvis and spine are rotated more than 90 degrees
- elbow is held between 90 and 119 degrees at start of forward movement
- racket lags behind arm in forward swing, forearm lags behind humerus
- movement is sequential
86
striking: older adults
- many older performers can be as accurate a younger performers when strength and flexibility demands are not high, eg. iron shots
- well-practices movement patterns might be well maintained over the life span
87
summary of ballistic skills
1. developmental trends are toward proficient mechanical performance, maximizing force and speed
- performer uses forward step and more trunk rotation
- trunk rotation is differentiated
- projected limb shows increasing lag
2. not all people reach highest developmental steps
3. intervention programs for young children can be beneficial
4. older adults appear to maintain coordination of ballistic movements fairly well
88
Are human hands more primitive than chimpanzees?
Yes, it is argued our hands were similar shortly after the chimp-human evolutionary split, the human hand retains more primitive proportions
- we have a longer thumb and shorter fingers, allowing us to easily grasp objects using precision grip
- chimps have much longer fingers and shorter thumbs which is better for swinging on branches
89
hand transplant info
- Matthew Scott celebrated the 19th anniversary of his hand transplant in 2018, which was the first in the US
- he lost his hand from a firecracker accident, but received the transplant from a cadaver in a 15-hour surgery
- a year and a half after the surgery he was able to sense temperature, pressure and pain in his new hand, as well as tie shoelaces, turn pages and trow a baseball
- by year 8, he could pick up a 15-pound weight
90
grasping
- when a skilled adult wants to obtain an object the reach and grasp form a smooth movement
- prehension is the grasping of an object
91
grasping development
- a transition occurs from power to precision grips
- the first year sees a transition from power grips to precision grips
- at 2 months, infants can grasp with the entire hand, called the power grip
- at 9 months, infants hold objects between the thumb and one or more fingers, called the precision grip
92
learning to reach
- infants are good at reaching in the dark, so matching vision of the hand with the movement or reaching to grasp is not a fit
- learning to reach is more than anything else a problem of learning to control the arm
- infants are more likely to learn to control their arms by doing, eg. repeated reaching for objects
93
hand-mouth movements
- at 3-4 months old, infants become consistent in moving the hand to the mouth
- by 5 months, they open the mouth in anticipation of the hand's arrival
94
bimanual reaching and manipulation
- around 4.5 months, infants reach for objects with both arms, usually one hand reaches and grasps the object first
95
manipulation
- later in the first year, infants learn to hold two objects, one in each hand, and often bang them together
- by 12 months, they can pull things apart and insert one object into another
- infants early in their second year can use objects as tools such as utensils
- not until the end of the second year can infants perform complementary activities with the hands, eg. holding a lid open with one hand while withdrawing an object with the other
96
role of posture
- reaches improves when infants can maintain postural control
- by 4 months, infants can adjust their posture as they reach
97
manual performance in adulthood
- the ability to reach and grasp remains an important motor skill throughout the lifespan
- many careers involve manipulation
- in older adults the ability to perform some activities of daily living - such as bathing and dressing, preparing meals, and making phone calls - can dictate whether the individual is able to live independently
98
manual performance in older adults
- Kauranen & Vanharanta (1996) found that manual performance declined after age 50 and movements slowed; coordination scores declined
- Hughes et al. (1997) found that strength declined and more individuals exceeded time thresholds
- some loss in coordination of handwriting occurs
- accuracy is maintained, especially in well-practiced tasks
99
catching
- catching is difficult as a developmental task
- during early childhood we see children throw and kick, even If their movement patterns are not yet proficient
- but if young children catch a ball, it often reflects the skill of the thrower in getting the ball to arrive in outstretched arms
- a child may start to attempt catching at around 18 months
- early catching may not happen until age 3, late compared to other motor development milestones
100
some catches are better than others
- the goal of catching is to retain possession of the object you catch
- it is better to catch an object in the hands than trap it against the body or opposite arms because if the object is caught in the hands, the catcher ca quickly manipulate it - often by throwing it
101
early catching
- children initially position their arms and hand rigidly, sometimes trapping the ball against the chest
- children sometimes turn their heads away or close their eyes
- moderate levels of catching performance are reached in mid-childhood
102
proficient catching
- hands "give" with the ball to gradually absorb the force
- catcher moves side to side or forward and back to intercept the ball
- fingers are pointed up for high balls and down for low balls
103
anticipation and interception
- anticipation is involved in many manipulative tasks and interception skills
- the ball or other moving object can approach at different speeds, from different directions, and along different trajectories and may be of varying size and shape
104
development of catching
- interception success is often related to ball size, speed, trajectory,and interception location
- children's accuracy decreases if the interceptions is farther away
- performances can be well developed by the teens if the environment promotes it
105
how do children learn to arrive at the right place?
- children must learn to make more precise calculations to become proficient catchers
- errors made in early attempts serve as informative feedback that can be used to refine the calculation process
- experience is crucial in learning to move to catch
- parents, teachers, and coaches can manipulate the task during practice
106
catching in older adulthood
- little research is available
- catching might be influenced by factors affecting movement speed or ability to reach
- older adults can improve with practice
107
aspects that affect catching (7)
- bimanual reaching and fast manipulation for throwback
- anticipation
- force absorption
- locomotion
- jumping
- environmental constraints
- task constraints: goals, rules and equipment
