Unit 5: Movement Analysis Flashcards
Synovial Joint (2)
- most common joint
- where space between bones allows substantial movement
What movements can the synovial joint make? (8)
- flexion
- extension
- abduction
- adduction
- medial rotation
- lateral rotation
- elevation
- depression
Flexion
decreases the angle between body parts
Extension
increases angles between body parts
Abduction
away from midline
Adduction
towards midline
medial rotation
rotational movement towards midline
lateral rotation
rotation movement away from midline
elevation
superior movement
depression
inferior movement
What synovial joint movements are possible in the joints of the feet? (4)
- eversion
- inversion
- dorsi flexion
- plantar flexion
eversion
medial rotation of ankle joint
inversion
lateral rotation of the ankle joint
dorsi flexion
flexion at ankle, so the foot point more superiorly
plantar flexion
extension at the ankle, so the foot points inferiorly
What synovial joint movements are possible in the radioulnar joint? (2)
- pronation
- supination
Pronation
medial rotation of the radioulnar joint so palm is upward
Supination
lateral rotation of radioulnar joint so palm is downward
What are some combinations of movement? (3)
- circumduction
- pronation of foot
- supination of foot
Circumduction
circling at joint that combines hyperextension, abduction, extension, and adduction
Where does circumduction occur? (5)
- shoulder
- hip
- wrist
- ankle
- thumb
Pronation of the Foot
combines dorsi flexion, eversion, and abduction
Supination of Foot
combines inversion and adduction
What are the 3 types of skeletal muscle fibers?
- Type I
- Type IIa
- Type IIb
What is the contraction speed of a type I muscle fiber?
slow
What is the muscle force of a type I muscle fiber?
small
What is the fatigue resistance of a type I muscle fiber?
high
What is the glycogen content of a type I muscle fiber?
low
What is the mitochondrial density of a type I muscle fiber?
high
What is the color of a type I muscle fiber?
red
What is the primary function of type I muscle fiber?
endurance
What is the contraction speed of a type II a muscle fiber?
fast
What is the muscle force of a type II a muscle fiber?
large
What is the fatigue resistance of a type II a muscle fiber?
low
What is the glycogen content of a type II a muscle fiber?
high
What is the mitochondrial density of a type II a muscle fiber?
low
What is the color of a type II a muscle fiber?
white
What is the primary function of a type II a muscle fiber?
increased intensity
What is the contraction speed of a type II b muscle fiber?
fastest
What is the muscle force of a type II b muscle fiber?
largest
What is the fatigue resistance of a type II b muscle fiber?
lowest
What is the glycogen content of a type II b muscle fiber?
high
What is the mitochondrial density of a type II b muscle fiber?
lowest
What is the color of a type II b muscle fiber?
white
What is the primary function of a type II b muscle fiber?
increased intensity
What are the characteristics of slow and fast twitch muscle fibers? (7)
- contraction speed
- muscle forces
- fatigue resistance
- glycogen
- mitochondria
- color
- primary function
What do fiber types play a role in determining and how so? (2)
- athletic abilities
- they are genetically pre-determined
Isotonic Contractions
muscle length change and causes movement of body
What are the two types of isotonic contractions?
- concentric
- eccentric
Concentric
muscle shortens while developing tension
Eccentric (2)
- muscle lengthens while developing tension
- most efficient method to build muscle
Isometric Contractions (2)
- muscle length remains constant with no joint movement
- muscle force balances resistance which results in no joint movement
Isokinetic Contractions (3)
- muscle contracts so body segment to which it is attaches moves at a constant speed around the joint
- used in physical therapy setting
- required specialized equipment
What produces the most DOMS?
eccentric contractions
DOMS (3)
- soreness that peaks 24-28 hours after exercise
- causes inflammation, stiffness, and pain
- negatively affects performance
What causes the feeling of soreness from DOMS? (3)
- microscopic tears of muscle
- overstretching of muscle
- muscle spasms
What are the roles of muscles in joint movement? (2)
- agonist
- antagonist
Agonist
muscles that provides the major force to complete the movement
Antagonist
muscles that oppose the agonist by relaxing or lengthening by eccentric contraction
Reciprocal Inhibition (2)
- when an agonist muscle contracts, the agonist muscle relaxes
- an automatic action controlled by neurons
What does reciprocal inhibition ensure?
the agonist is not being opposed by a muscle acting in the opposite direction of motion
What are examples of reciprocal inhibition? (2)
- bicep curl
- bending of knee
How is reciprocal inhibition involved in the upward phase of a bicep curl? (2)
- agonist: biceps brachii cocentrically contracts
- antagonist: triceps brachii relaxes
How is reciprocal inhibition involved in the downward phase of a bicep curl? (2)
- agonist: biceps brachii eccentrically contracts
- antagonist: triceps brachii is still relaxed
How is reciprocal inhibition involved in flexion at the knee? (2)
- agonist: hamstring group
- antagonist: quadriceps
How is reciprocal inhibition involved in extension at the knee? (2)
- agonist: quadriceps
- antagonist: hamstring
How do the muscles control movement?
by moving bones and joints
How does brain control movement?
through nerves
Nerves
run from the brain through the spinal cord to the muscle
Central Nervous System (CNS)
brain and spinal cord where most sensing and muscle control takes place
Peripheral Nervous System (PNS)
nerve cells extending from spinal column to limbs and other parts of the body
neuron
electrically excitable cells of the nervous system
motor neurons
carry information from CNS to muscles signaling contraction or relaxation
sensory neurons
carry signals to CNS from receptors throughout body
What are the structures in a neuron? (4)
- dendrites
- cell body
- axon
- myelin
Dendrites
receive information from other neurons
Cell Body
cell’s support center that makes proteins and contains nucleus with DNA
Axon
relays electrical signal from cell body to muscle using myelin
Myelin
protein that helps conduct electrical signal down axon
How does a signal move through a neuron?
dendrites –> cell body –> axon
How does the brain communicate with muscle?
motor unit
Motor Unit
single motor neuron and muscle fibers it innervates
What are the structures of a motor unit? (2)
- motor end plate
- synapse
Motor End Plate
where branches of motor neuron axon synapse with target muscle cell
Synapse (2)
- gap between neuron and muscle fiber
- electrical nerve signal must cross synapse to stimulate the muscle
Neuromuscular Junction (3)
- where a motor neuron and muscle cell meet
- no direct contact across the synapse
- site of chemical communication
Neurotransmitter
chemicals that transmit signals across gap/synapse between motor neurons and muscle
What is an example of a neurotransmitter?
acetylcholine
Acetylcholine
neurotransmitter at neuromuscular junction
What is the process of releasing acetylcholine from the brain to the muscle? (6)
- made in ends of the motor neuron axon and stored in vesicles
- transmits signal from nerve to muscle across synapse
- Diffuses across synaptic
- Binds with receptors at motor end plate and stimulates calcium release
- Spreads impulse over whole muscle fiber
- Broken down by enzyme cholinesterase to end muscle contraction
Myofibril
Contractile fibers that extend length the striated muscle fibers
Sarcomere
Smallest contractile units of myofibril made of actin and myosin
Actin
Thin, contractile protein that slides past myosin causing contraction
Myosin
Thick contractile, protein with protrusions called myosin heads
What are the structures within skeletal muscle cells? (7)
- myofibril
- sarcomere
- actin
- myosin
- Z line
- H zone
- A band
Z Line
separate sarcomeres and attaches actin
H Zone (2)
- center of sarcomere that shorten during contraction
- only myosin
A Band (2)
- length of myosin filament where actin and myosin interact
- same length during contraction
What happens to the sarcomere length during contraction? (2)
- sarcomere shortens
- Z lines closer
What happens to sarcomere length during relaxation? (2)
- sarcomere lengthens
- Z lines further apart
What happens to stimulate muscle contraction? (4)
- acetylcholine binds to muscle receptors
- an electric signal passes inside the muscle through T-tubules
- sarcoplasmic reticulum releases calcium ions
- Ca2+ bind to troponin
What are the steps of skeletal muscle contraction? (5)
- ATP binds myosin head and it detaches from actin binding site
- ATP is broken down to recock myosin to new position
- Myosin forms cross-bridge with actin
- ADP + P are released and myosin head drags along (power stroke)
- Repeated power strokes will happen if Ca 2+ is present
What is the role of ATP in Skeletal Muscle Contraction? (4)
- present at myosin head
- only source of energy for muscle contraction
- broken down to ADP and loss of P initiates power stroke
- reusable
What is needed to stop muscle contraction? (2)
- Ca 2+ is pumped back into sarcoplasmic reticulum
- Cholinesterase breaks down acetylcholine in the synaptic cleft allowing muscle relaxation
Biomechanics
examines forces caused by body (muscles) and those that act on body (gravity and other athletes) to affect body’s motion
What are the two areas of biomechanics?
- kinematics
- kinetics
Kinematics
dealing with motion of bodies and objects
Kinetics
dealing with force of bodies/objects
Scalar
measurement that only has size
Vector
measurement that has both size and direction
Position
location of object is given by its coordinates
Displacement (2)
- change in position from original
- has size (how far) and direction (vector)
Distance (2)
- amount traveled
- size & no direction
Velocity (3)
- displacement/time
- has size and direction vector
- can be linear or angular
What is the unit for displacement?
meters
What is the unit for velocity?
meters per second
Speed (2)
- distance/time
- size and no direction
What does the slope reveal in distance v time graphs?
the speed
Acceleration (3)
- change in velocity/time
- size and direction vector
- change in speed, direction, or both
What is the unit for acceleration?
meters per second per second
What does the slope reveal in velocity v. time graphs?
the acceleration
Force (2)
- push/pull that tries to change the motion of an object
- can involve contact or act at distance
Gravity
force that attracts body toward center of earth or toward other physical body with mass
What is another name for Newton’s 1st Law?
law of inertia
What does Newton’s 1st Law mean?
objects stay where they are or keep moving unless acted on by a force
What is the formula for Newton’s 2nd Law?
F = ma
What does Newton’s 2nd Law mean?
object’s acceleration is directly proportional to the size of the force producing it and inversely proportional to object’s mass
What is an example of Newton’s 2nd Law of motion?
heavier object will accelerate less for the same force. To accelerate heavy objects, a large force is needed
What is another name for Newton’s 3rd Law?
law of reaction
Newton’s 3rd Law
for every action there is an equal and opposite reaction
What are important aspects to consider about Newton’s 3rd Law? (2)
- forces on object are same size, regardless of the masses of objects
- forces happen at exactly same time
Levers
- simple machine used to provide a mechanical advantage
- allow small force to move big weight)
What is the mechanical advantage formula?
length of the effort arm divided by load arm
What in the body can be described as levers?
movement of bones at joints using muscles
What does a lever consist of? (4)
- rod
- fulcrum
- load
- effort
What is the equivalent to a rod in our body?
bone
What is the equivalent to a fulcrum in our body?
joint
What is the equivalent to a load in our body?
body weight
What is the equivalent to an effort force in our body?
muscle force
First Class Lever
effort & load on opposite sides of fulcrum
Second Class Lever
effort & load on same side of fulcrum with load closer to fulcrum
What is the benefit of a second class lever?
↓ effort lift ↑ weight
Third Class Lever
effort and load on same side of fulcrum with effort closer to fulcrum
What is the benefit of a third class lever?
↑ range motion & speed
What is an example of a first class lever in the body?
muscles of neck provide effort to lift head (load)
What is an example of a second class lever in the body?
calf muscles provide effort to lift body (load) when standing on the toes
What is an example of a third class lever in the body?
biceps brachii
provides effort at
elbow joint to hold
weight at hand
Torque
force applied to object that causes it to rotate
What does the size of torque depend on? (3)
- size of the force
- direction of the force
- how far the force is applied from axis of rotation
What does torque from muscles cause?
bones to rotate around joints
Center of Mass (2)
- point around which mass of a body is evenly distributed
- isn’t always within body
What does center of mass depend on?
distribution, density and shape of material in the body
Why is center of mass important? (3)
- It determines stability of static positions
- It’s the axis for airborne rotations
- It’s the reference point for whole body translation.
What is an example of center of mass in sport?
Fosbury Flop
Fosbury Flop (2)
- athlete bends their body like a banana around the bar and their center of mass is below and outside body
- jumper using Fosbury technique will not have to raise their center of mass as high
Momentum
measure of mass in motion
What is the formula for momentum?
p=mv
What happens to momentum during collision?
- total momentum of 2 objects is conserved
- momentum lost by object 1 = momentum gained by object 2
What must happen for an object’s momentum to change?
a force must be applied over a period of time
Impulse
force multiplied by the time it acts for J = Ft
Angular momentum (2)
- measure of amount of rotation
- once generated, it stays constant
What is the formula for angular momentum?
L = moment of inertia x angular velocity
Moment of Inertia
difficulty in rotating object
What influences moment of inertia? (3)
- object’s mass and its distribution around axis of rotation
- mass further away from axis = ↑ moment of inertia (difficult to rotate)
- mass near axis = easier to rotate
What is angular momentum important for?
creating rotation
What is an example of angular momentum in gymnastics?
A gymnast “tucks” to rotate faster (↓MI & ↑ AV) and “opens out” to decrease rotation (↑MI and ↓ AV) to land
What is an example of angular momentum in sprinting? (4)
- moment of inertia is larger when leg is extended and smaller when leg is bent
- smaller moment of inertia with bent knee = easier to move & higher angular velocity
- recovery time is shorter & runner can take next
stride quickly/more strides per time - angular velocity is reduced as the runner extends knee
Projectile
object thrown/dropped into air and acted on by only forces of gravity, air resistance and lift.
Projectile motion
The propelling force
starts its motion
What are factors that determine range of projectile? (3)
- speed
- projection angle
- projection height
How does speed determine the range of a projectile?
small increase in projection speed will drastically increase range
How does projection angle determine the range of a projectile?
more important for height of flight and accuracy
How does projection height determine the range of a projectile?
maximizes range of values possible for projection speed & angle
What does the optimum projection angle depend on?
projection height
When should the projection angle be below 45º?
with increased projectile landing area (shot-put)
When should the projection angle be above 45º?
with decreased projectile landing area (free throw)
When should projectile landing area be 45º?
when projectile release height is equal to landing height
Drag (3)
- force in direction opposite to object’s motion
- ↑ drag at ↑ speeds
- due to molecules of substance resisting motion
Surface drag
interaction between object surface & molecules resisting motion
Form drag
caused by shape of object
Bernoulli Principle
pressure exerted by air/water reduces as its velocity increases
How does the Bernoulli Principle apply to ball movement? (3)
- When an object is rotating through the air (spinning ball), the air is dragged around by rotation of the ball.
- This increases air velocity on one side (↓ pressure) & decreases velocity on other side (↑ pressure).
- The ball will move towards the low pressure region
How does the Bernoulli Principle apply to topspin in tennis?
spin is in the same direction as the movement of air particles at the bottom of the ball, this increases velocity at the bottom of the ball ( ↓ pressure)
Topspin in tennis
hit the ball with speed and see it land within the boundary designated by the court
