Midterm #2 Flashcards
(104 cards)
1
Q
what is tissue mechanics
A
mechanics of materials of human connective tissue
2
Q
human connective tissue
A
bones
ligaments
cartilage
tendons
3
Q
load
A
an externally applied force
4
Q
what does the respond of an object to a load depend on
A
magnitude location direction duration frequency variability rate
5
Q
types of load
A
axial (tension, compression) bending shear torsion combined loading
6
Q
axial force - compression
A
push or squash molecules of a material otgether
deformation by shortening
7
Q
what is compression/tension response proportional to
A
body´s cross sectional area
8
Q
axial force - tension
A
pull apart object´s molecules
deformation by stretchng or elongating
9
Q
shear
A
transverse force
force that causes one part of body to move parallel past another part
10
Q
what can shear loading lead to
A
on skin - blisters
on tibia and femur - tension in ligaments
11
Q
torsion
A
rotational load
twisting around axis
depends on distribution of material around axis
12
Q
bending
A
compression on one side
tension on the other side
loading applied perpendicular to longitudinal axis
13
Q
what determines the effects of bending on the body
A
cross sectional area
distribution of material
length of the body
14
Q
what causes injury
A
load > tissue tolerance
load > tissue strength
15
Q
biological material quantitiy
A
size -> amount of material distribution
16
Q
bilogical material quality
A
ingredients of the tissue
17
Q
factors affecting tissue strength
A
material
amount of tissue
distribution of tissue
18
Q
what is distribution of tissue
A
how tissue is soread
area of moment of inertia - a measure of a body´s resistance to bending
19
Q
tissue tolerance
A
relationship between load imposed (external force) and the amount of deformation (internal reaction) of material
20
Q
load deformarion
A
effects of load on different tissue sizes and materials
chnage of shape of tissue
21
Q
stress strain
A
stress = load/size
effects of stress on material and tissue
change in length normalized to original length
22
Q
stress
A
property of object under pressure
force over small area will cause larger stress
e.g. tennis shoes vs. spike heels
23
Q
unit of stress
A
N/mm(squared)
24
Q
relation of load/stress on vertebrae
A
load: increases from cervical -> lumbar
stress: decreases from cervical -> lumbar
25
descriptors of strength
```
ultimate strength
yield point
stiffness
deformation
energy
failure point
ductility
brittleness
```
26
different types of injury
acute load injury
repretitive load injury
prolonged load injury
27
what factors contribute to injury
```
age
gender
genetics
physical condition
fatigue
environment
...
```
28
stiffness
relates load and deformation
29
elastic region
no permanent change in tissue
recovers all energy
used to deform tissue
30
plastic region
energy used to permanently change the shape of the tissue
31
yield strength
load/stress at which plastic deformation begins
32
ultimate strength
max load/stress
33
fracture strength
load/stress at point of fracture
34
ductility
amount of strain material can undergo before fatigue
35
brittleness
minimal (no plastic) deformation of tissue
36
toughness/energy under the curve
work required to produce deformation
37
types of bones
```
cortical bone (solid)
trabecular bone (has holes)
```
38
bone mass over time
males have greater peak bone mass
males have greater rate of gain for BMC
females have decrease in bone mass around menopause age 45-60
39
bone cells
osteoblasts - bone formation
osteoclasts - take away of old damaged bone
osteocytes - mature osteoblasts during formation
40
steps of bone formation
activation
resorption
reversal
formation
41
exercise for bone strengthening
weight bearing activities
short duration
mderate to intense magnitude
long rest periods
42
why is summer good for bones
increase in vitamin D
| more physical activity
43
bone content
65% inorganic substance (clacium)
| 35% organic substance (collagen)
44
responsibility of calcium in bones
many functions
heartbeat
conducting nerve impulse
muscle contraction
45
parts of female athlete triad
low energy availability/disordered eating
bone loss/osteoporosis
menstrual disturbances/Amenorrhea
46
areas of bone cross section
```
periosteal merimeter
endocortical perimeter
endocorticol perimeter
total area
cortical bone area
periosteal diameter
endocortical diameter
```
47
law of inertia in angular kinetics
body remains at rest or constant anular velocity around an axis of rotation unless external torque changes its state
48
mass moment of inertia (I)
body´s resistance to a change in angular velocity
49
what does the mass moment of inertia (I)depend on
mass and distribution
50
in what unit does the mass moment of inertia get measured
kgm(squared)
51
claculation of mass moment of inertia (I)
I = m r(squared)
52
law of acceleration in angular kinetics
angular acceleration of body is directly proportional to the torque causing it
takes place in same rotary direction as torque acts
inversely proportional to mass moment of inertia of the body
53
torque in angular kinetics
torque = mass moment of inertia x angular acceleration
| will cause acceleration of body around axis of rotation
54
angular momentum -> rotating disk (extended object)
L = I x angular velocity
55
angular momentum tether ball (pointy object)
angular momentum = radius x linear velocity
| L = r x p (linear momentum m x linear velocity)
56
conservation of angular momentum
when gravity is only force acting on object, angular momentum will stay the same even if radius of object changes
57
maximal efort
range of motion
| speed of motion
58
hat is maximla performance a reult of
max effort
summation of joint torques
continuity of joint torques (usage of kinetic link principle)
59
goal of the kinetic link principle
achieve max angular velocity of distal segment
60
what does the kinetic link principle say
beginning movement with large segments, smaller segments initiate contraction at the point of maximal angular velocity and zero angular acceleration
timing is important
taking torque of one joint into movement of another joint
61
angular impulse to momentum relationship
angular impulse = angular momentum
| T x delta t = I x angular velocity
62
law of action reaction in angular kinetics
for every torque there is a equal and opposite directed torque
63
what kind of objects experience centripedal force
any that move in circular path
| includes forces that push or pull objects towards center of circle
64
centripedal force
describes direction of force
| alters the direction of the object without altering its speed
65
what can a muscle tendon complex act at as
motor, brake, rubber-band, strut
66
phases of a jump
propulsive phase
braking phase
both phases are on the ground
67
propulsive phase
upward phase
| from initiation of upward movement to the instant of takeoff
68
braking phase
downward phase from the instant of landing to the max dorsiflexion
69
concentric contraction in upward phase of a jump
MTC develops greater force than external force
muscle shortens
force and displacement same direction, MTC - positive work
MTC increases energy of skeletal system
MTC acts as energy source or motor
70
eccentric contraction in downward phase of a jump
MTC develops less forc ethan external force
muscle lenghtens
force and displacement opposite directions
body is losing energy
MTC acting brake, absorbing the energy
71
what is a stretch shortening cycle (SSC)
an eccentric contraction followed by an immediate concentric contraction of a muscle
72
Isometric contraction
```
motion
MTC develops equal force to external force
muscle length does not change
no displacement -> no work
MTC acts as a stabilizer
```
73
functional unit of muscle
sarcomere
74
what does sarcomere include
```
contractile protein (actin, myosin)
non-contractile protein (titin and desmin)
```
75
resting length of sarcomere
2 micrometer
| from z line to z line
76
muscle structure
acting myosin are myofilaments -> myofilaments active parts of sarcomere -> string of sarcomere = myofibril ->multiple myofibril = muscle fiber -> group of muscle fiber = fasicle -> group of fasculi = muscle belly
77
titin and desmin
in sarcomere
| a series of elastic components (SEC)
78
extracellular connective tissue (PEC)
```
made of collagen and elastin
endomysium wraps one muscle fiber
perimysium wraps one fascicle
epimysium wraps muscle belly
parallel elastic components (PEC)
continous with tendons on both ends
```
79
elastic property of PEC and SEC
provide force only when stretched
| force transmitted to bone
80
viscous prperty of PEC and SEC
increased velocity of stretch increases the passive force produced
81
when do non-contractile (passive) components develop tension
when muscle is lengthended beyond resting length
82
theory for muscle as brake - eccentric contraction
titin increases stiffness -> contributes to force production as muscle lengthens
small contribution from elastic elements of cross bridges
83
theory of muscle as a strut - isometric contraction
muscle shortens, tendon lengthens
| greatest isometric force as mid range of muscle length
84
load-deformation relationship in non-contractile components
linear
85
interaction of muscle and tendon
independently
can work in different directions or velocities
short tendons work at same displacement and velocity as muscle
86
what does the force produced in a muscle depend on
```
# of cross bridges formed
length of muscle
```
87
what does the ability to form cross bridges depend on
muscle length
too long -> actin is out of range
too short -> overlapping, less force to produce
88
when does passive tension contribute to force production
only when muscle is stretched beyond resting length
89
what oes the combination of active and passive tension allow
large range of muscle forces over a wide range of muscle length
90
active indufficiency of two joint muscles
muscle force is limited due to short length (length tension curve)
91
passive insuffiviency of two joint muscle
A muscle will limit range of motion at a joint because it is over-stretched over two joints
92
force velocity curve/relationship
max force during high eccentric velocity
lowest force during high concentric velocity
medium force during isometric contraction
93
power
force x velocity
| peak at intermediate velocity
94
muscle actions
```
agonist
antagoinst
synergist
stabilizer
neutralizer
isokinetic
isotonic
```
95
agonist
prime mover
| muscle that produces motion
96
antagonist
opposite of motion creating
| get stretched
97
synergist
muscle that work together to produce motion
| when working alone they produce different motion
98
stabilizer
muscles that support movement
99
neutralizer
shoulder extensor neutralizes biceps shoulder flexion during biceps curl
100
isokinetic muscle action
constant velocity of contraction
| concentric and eccentric contraction
101
isotonic muscle action
constant load throughout contraction
free weights
torque changes throughout motion
102
what does bone remodeling include
bone formationa nd bone resorption
103
what does bone modeling refer to
large changes in bone during normal growth
104
one thing we can do to combat female athlete triad
balanced diet - including calcium and enough energy for growing active athlete
provide enough rest periods
