Exam 3 Flashcards
(213 cards)
1
Q
Compared to adults, a child’s stride length is
A
Shorter
2
Q
Compared to an adult, a child’s cadence is
A
Higher
3
Q
Compared to an adult, a child’s gait speed is
A
Lower
4
Q
If we wanted to compare stride length in children and adults, how would we do it?
A
Normalize it by height and look at stride length as a % of height
5
Q
What was the goal of the Chester, Tingley and Biden study?
A
Examine kinetic and kinematic differences in kids 3-13
6
Q
How is cadence measured?
A
Steps per second
7
Q
What is the relationship between cadence and cycle time?
A
Cadence is the INVERSE of cycle time
8
Q
Cycle time =
A
1/cadence
9
Q
How would you describe gait kinetics?
A
Moments
10
Q
How would you describe gait kinematics?
A
Osteokinematics of gait
11
Q
What were the results of the Chester, Tingley and Biden study?
A
There is very little difference between the kinematics of the 3-4 yr olds, 7-8 yr olds, and 9-13 yr olds.
BUT there is a difference in max hip flexion between the 3-4 yr old group and the 9-13 group (but not statistically significant)
12
Q
At what age does a child’s gait kinematics look like an adults?
A
3-4 years old
13
Q
Are joint moments between 3 year olds and older kids the same?
A
No
14
Q
Sutherland says that gait “stabilizes” by what age and matures at what age?
A
Stabilizes by 3
Matures by 7
15
Q
GRF behind the ankle’s center of rotation will cause what?
A
Plantarflexion
16
Q
GRF behind the center of rotation at the knee will cause what?
A
Flexion
17
Q
GRF in front of the hips center of rotation will cause what?
A
Flexion
18
Q
GRF behind the hips center of rotation will make it want to do what?
A
Extension
19
Q
GRF in front of the knees center of rotation will push the knee into
A
Extension
20
Q
GRF in front of the ankle’s center of rotation will cause what?
A
Dorsiflexion
21
Q
What are we talking about when we say joint moments?
A
The moments that the muscles are creating, NOT the moments that gravity or acceleration are creating
22
Q
What do joint moments act against?
A
GRF
23
Q
What is GRF made up of?
A
Forces against gravity and the forces accelerating the body through the gait cycle
24
Q
How does gravity not make us fall down?
A
Muscles counteract gravity
25
Gravity and acceleration create a moment about the ____ and our muscles counteract that moment in the _____ direction
Hip
| Opposite
26
What equipment do you need to record joint moments?
3D motion analysis system and force plate
27
The older children had greater
Peak plantarflexion moment
28
The younger children had the
Least plantarflexion moment
29
How do you measure kinetics?
(N*m)/kg
30
Are kinetics normalized? How?
yes- normalized to body weight. that's why its / by kg
31
What did Chester, Bingley, and Biden use for their statistical analysis?
MANOVA
32
Which age group DOES have different kinematics?
Toddlers (1-3)
33
Children at age 1 have a (higher/lower) step frequency than adults
Higher- 180 steps/min
34
Do toddlers age 1 have reciprocal arm swing?
No- they hold their arms in "high guard"
35
What is the position of the hips, knees, and ankles during toddler (1 yr) gait?
Hip- externally rotated
Knees- remains flexed
Ankles- PF at heelstrike, DF during swing phase dominished
36
What three things at the hip are all increased during swing phase for a toddler? (1)
Hip flexion
APT
Hip abduction
37
Single-limb stance is (increased/decreased) for toddlers
Decreased
38
Toddlers have a (wide/narrow) BOS
Wide
39
Where is our center of mass?
Slightly in front of S2
40
What is the definition of COM, according to Neumann?
Each body has a point where the COM is evenly distributed
41
What happens to COM when subjected to gravity?
COM of a body closely coincides with its center of gravity
42
What is COG?
Point at which the effects of gravity are completely balanced
43
What is the point where all of the mass of the object is concentrated?
Center of mass
44
Will an object rotate when supported at its COM?
No- there is no net torque acting on the body and it will remain in static equilibrium
45
An object balances on its
COM
46
How will an object move when kicked in line with its COM?
Without rotating
47
How will an object move when kicked above or below its COM?
Will rotate around COM
48
The exact point of COM will be in the center of
Rotation
49
Are COM and COG synonymous?
Yes
50
Is there only one COM in our entire body?
No- each body segment has its own COM, but we sum them all up when considering COM
51
The COM of the entire body moves relative to what?
The body segments
52
When someone falls, they are doing what?
Rotating around the COM/COG
53
What is the importance of the Fosbury flop?
COM goes underneath the body during a high jump
54
What is the equation for potential energy?
Mass x gravity x height
55
What is potential energy?
Energy that could be converted into acceleration if the object fell to the groun
56
What is kinetic energy?
Energy created by the acceleration of a moving body
57
When is kinetic energy greatest during gait?
When the COM is at it's lowest point
58
When during gait is the COM at it's lowest point?
IC or opposite IC
59
When is potential energy at it's greatest point?
When the COM is at the highest point
60
When is the COM at it's highest point during the gait cycle?
Feet adjacent
61
Why isn't the COM at exactly 50% of body height?
The top half of the body weighs more than the bottom half
62
Where does COM reside along the M-L axis?
Right in the middle because the body is symmetrical in the frontal plane
63
Where does COM reside along the vertical axis?
Height of S2
64
Where does COM reside along the AP axis?
Right in front of S2
65
If someone has a R side above knee amputation, what does that do to their COM?
COM will move higher and to the L side because w/o the leg, the mass is concentrated higher and on the left
66
What did the data from Orendurff suggest?
Relationship between vertical and ML displacement of COM excursions changes substantially with walking speed
67
What is a sinusoidal pattern?
Sine wave
68
As speed increases, vertical displacement of COM
Increases
69
As speed increases, ML displacement of COM
Decreases
70
What test could Orendurff use for within subject data?
Paired t test or repeated measures ANOVA
BUT they should use repeated measures ANOVA with Bonferroni
71
What is postural sway?
constant displacement and correction of the COG within the BOS
72
Are COM and COP the same thing?
NO
73
What is COP?
The location of the GRF where your feet are pushing on the ground to control your COM
74
Which leads which? (COP/COM)
COP leads COM
75
(COM/COP) oscillates about the (COM/COP) to keep the person balanced
COP oscillates about the COM
76
What happens to COP during quiet standing?
COP falls almost directly under COM because the accelerations are very small. GRF very close to vertical
77
Does COM need to stay within the BOS at all times?
No- only during quiet standing
78
Does the COM need to stay within the BOS during movement?
No- dynamic stability can be preserved despite short periods in which the body is unsupported
79
How do you measure COP?
Force plates
80
If we are standing still and only looking at the transverse plane, will the COM and COP be far apart?
No
81
What are the 3 functions of the gait cycle?
PT intervention
Surgical intervention
Document change
82
What 2 things make gait?
Controlled fall + recovery
83
What creates momentum to set the body up for a fall?
Swinging limb
84
During which phase does the outstretched limb catch the body?
Early stance
85
What is the interval between IC of each foot?
Step length
86
What are your double limb support phases?
IC, LR, Preswing
87
What are the 3 functional tasks of gait?
Weight acceptance (stance)
Single limb support (stance)
Swing limb advancement (swing)
88
What is the fxn of weight acceptance?
Stability
Shock absorption
Forward progression
89
What is the fxn of single limb support?
Stability
| Forward progression
90
What is the fxn of swing limb advancement?
Foot clearance
| Limb advancement
91
Which phases are weight acceptance?
IC, LR
92
Which phases are single limb support?
Midstance
| Terminal stance
93
Which phases are swing limb advancement?
Preswing
| Initial, mid, terminal swing
94
What are the 3 critical events that help normal gait?
ROM
Torque demand
Muscle activity
95
What is ROM of the hip during IC?
20 degrees flexion
96
What is ROM of the knee during IC?
5 degrees flexion
97
What is ROM of the ankle during IC?
Neutral
98
Which phases have your heel rocker?
IC, LR
99
What is ROM of the hip during LR?
20 degrees flexion
100
What is ROM of the knee during LR?
15 degrees flexion
101
What is ROM of the ankle during LR?
5 degrees PF
102
What is ROM of the hip during midstance?
Neutral
103
What is ROM of the knee during midstance?
5 degrees flexion
104
What is ROM of the ankle during midstance?
5 degrees DF
105
Which phase do you have the ankle rocker?
Midstance
106
What is ROM of the hip during terminal stance?
20 deg apparent hyperextension
107
What is ROM of the knee during terminal stance?
5 degrees flexion
108
What is ROM of the ankle during terminal stance?
10 degrees DF
109
During which phases do you have the forefoot rocker?
Terminal stance
110
What is ROM of the hip during preswing?
10 deg apparent hyperextension
111
What is ROM of the knee during preswing?
40 deg flexion
112
What is ROM of the ankle during preswing?
15 deg PF
113
What is ROM of the hip during initial swing?
15 deg flexion
114
What is ROM of the knee during initial swing?
60 deg flexion
115
What is ROM of the ankle during initial swing?
5 deg PF
116
What is ROM of the hip during midswing?
25 deg flexion
117
What is ROM of the knee during midswing?
25 deg flexion
118
What is ROM of the ankle during midswing?
Neutral
119
What is ROM of the hip during terminal swing?
20 deg flexion
120
What is ROM of the knee during terminal swing?
5 deg flexion
121
What is ROM of the ankle during terminal swing?
Neutral
122
What is the critical event during IC?
Heel first contact
123
What is the critical event during LR?
Hip stability
Controlled knee flexion
Ankle PF
124
What is the critical event during midstance?
Controlled tibial advancement
125
What is the critical event during terminal stance?
Controlled ankle DF with heel rise trailing limb
126
What is the critical event during preswing?
Passive knee flexion to 40
| Ankle PF
127
What is the critical event during initial swing? (in terms of knee flexion and hip flexion)
Knee flexion to 60
| Hip flexion to 15
128
What is the critical event during midswing?
Further hip flexion to 25
| Ankle DF to 0
129
What is the critical event during terminal swing?
Knee extension to neutral
130
What muscle activity is occurring during IC at the ankle?
Pretibials (ant tib)
131
What muscle activity is occurring during LR at the ankle?
Pretibials
132
What muscle activity is occurring during midstance at the ankle?
Calf
133
What muscle activity is occurring during terminal stance at the ankle?
Calf
134
What muscle activity is occurring during preswing at the ankle?
None
135
What muscle activity is occurring during initial swing at the ankle?
DF
136
What muscle activity is occurring during midswing at the ankle?
DF
137
What muscle activity is occurring during terminal swing at the ankle?
DF
138
What muscle activity is occurring during IC at the knee?
None
139
What muscle activity is occurring during LR at the knee?
Quads
140
What muscle activity is occurring during midstance at the knee?
Quads then none
141
What muscle activity is occurring during terminal stance at the knee?
None
142
What muscle activity is occurring during preswing at the knee?
None
143
What muscle activity is occurring during initial swing at the knee?
2 jt flexors
| Short biceps
144
What muscle activity is occurring during mid swing at the knee?
Short head biceps
145
What muscle activity is occurring during terminal swing at the knee?
Quads
146
What muscle activity is occurring during IC at the hip?
Hip extensors
147
What muscle activity is occurring during LR at the hip?
Hip extensors
| Hip abductors
148
What muscle activity is occurring during midstance at the hip?
None
149
What muscle activity is occurring during terminal stance at the hip?
None
150
What muscle activity is occurring during pre-swing at the hip?
Minimal add. longus
151
What muscle activity is occurring during initial swing at the hip?
2 jt flexors
| Hip flexors
152
What muscle activity is occurring during mid swing at the hip?
Flexors then extensors
153
What muscle activity is occurring during terminal swing at the hip?
Hamstrings then glutes
154
What three movements make up pronation?
DF
Eversion
Abduction
155
What three movements make up supination?
Inversion
Adduction
PF
156
What position is the calcaneus in during rearfoot valgus?
Eversion
157
What position is the calcaneus in during rearfoot varus?
Inversion
158
What are you looking for with rearfoot varus/valgus?
How the calcaneus lines up with talus, tibia, fibula
159
What are you looking for with forefoot varus/valgus?
How the forefoot lines up with the calcaneus
160
Rear foot inverted (rearfoot varus) means the medial side of the ____ will be elevated
Heel
161
Forefoot varus and rear foot normal means the medial side of the ____ is elevated
Forefoot
162
How do we compensate for rearfoot and forefoot varus?
STJ pronation, leaves the foot in an unstable position
163
Where in the gait cycle do we see the most pronation?
LR going into midstance
164
Where in the gait cycle do we see supination?
Preswing
165
What are the normal biomechanics of the foot during the LR of gait?
Eversion of calcaneus
Inward rotation of talus
Medial rotation of ankle joint axis
Internal rotation of tibia
166
What happens to the patellofemoral mechanics during excessive pronation?
Increasing IR of tibia
167
Where is the greatest pressure on the foot at heel strike?
Heel
168
Where is the greatest pressure on the foot at midstance?
Midfoot
169
Where is the greatest pressure on the foot at toe off?
First toe
170
Where do you have greater ground reaction forces on the foot when walking?
Heel (heel strike) and metatarsal heads (push off)
171
Why is there a small peak in force when the foot initially hits the ground?
Rearfoot striking
172
What are the three rockers of normal gait?
Heel (first)
Ankle (second)
Forefoot (third)
173
What is the heel rocker characterized by?
Heel strike at IC and ankle PF
174
What is the ankle rocker characterized by?
Tibial advancement over the foot and DF
175
What is the forefoot rocker characterized by?
Heel rise, forefoot DF, and ankle PF
176
What is directional stability?
Stability of a moving body about an axis that is perpendicular to its direction of motion
177
If a vehicle is directionally stable, what is produced in a direction opposite to the rotational disturbance?
Restoring moment
178
What does stability mean?
That after a perturbation the system will return to baseline
179
What is the opposite of stability?
Chaos
180
What does instability mean?
The system will deviate further from baseline (fail/blow up)
181
What are examples of unstable systems?
Things that grow exponentially (population growth)
182
Define postural stability
The ability to maintain the position of the body and COM within the stability limits
183
True or false- the term stability can be equated with balance or equilibrium
True
184
True or false- stability limits do not change according to the task
False- stability limits change according to the individual's biomechanics/environment
185
What are 3 ways you can increase the stability of an object?
Increasing the base of support
Lowering the COM
Increasing the mass of the system
186
Is the area of COP excursion during standing sway considered to be a valid and reliable measure of balance?
Yes
187
What is a more valid measure of balance in older adults?
Sway with a closed base of support
188
What does closed BOS mean?
Feet together
189
What does an open BOS mean?
Feet shoulder width apart
190
Sway is a valuable measure of what?
Static balance
191
Area of sway (eyes closed) is _____ than the area of sway (eyes open)
Larger
192
What are some ways to measure sway path?
Sway path length
Sway path length (AP or ML)
AP or ML sway range
193
Why do we study balance with perturbations?
Because perturbations are repeatable in an experimental setting
194
What would a greater COP distance or COP velocity following perturbation indicate?
Poorer balance
195
What are the three strategies used to control standing balance?
Ankle strategy
Hip strategy
Step strategy
196
What is important to note about both the ankle and hip strategy?
They can both turn into the step strategy
197
Motion of the platform backwards during the Horak study would cause the subject to sway
Forward
198
If the ankle muscles turn on after the hip muscles, which strategy does this indicate?
Hip strategy
199
Motion of a platform forward would cause a subject to sway
Posteriorly
200
What sway occurred in the young adult group?
Posterior sway causing ankle PF
201
What sway occurred in aging group 1?
7/12 were normal, but proximal & distal muscles were significantly delayed sompared to young adults
202
What sway occurred in aging group 2?
5/12 shows REVERSALS of distal proximal respose. Quads fired before anterior tib.
203
What does the quads firing before the ant tip indicate in aging group 2?
A hip strategy instead of an ankle strategy
204
Older adults have (shorter/longer) muscle latency responses (especially distal responses)
Longer
205
True or false- younger adults use the hip strategy more
False- older adults use the hip strategy more
206
What does EMG activation look like in late independent walking for children?
Ankle strategy pattern
| EMG activations take place quickly after perturbation
207
How does EMG activity look different in a child with CP?
Antagonist and agonist muscles activated during the isometric test.
Neurotypical showed only agonist muscles activating during isometric test
208
What is it called (in a child who has CP) when their agonist and antagonist muscles activate isometrically at the same time?
Co-contraction
209
What is a typical pattern of EMG activity in a baby in regards to trunk extensors?
Trunk extensors activate earlier to anterior deltoid
210
At what points in the walking gait cycle are the ground reaction forces the greatest?
LR, terminal stance
211
What was the THM of the Chester Tinglet and Biden study?
Kinematics between groups were not different but kinetics WERE significantly different
212
How much does the COM move up and down during neurotypical gait?
5 cm
213
How much does the COM move from side to side during neurotypical gait?
4 cm
