4 - Movement analysis Flashcards
Label a diagram of a motor unit
- dendrite
- cell body
- nucleus
- axon
- motor end plate
- synapse
- muscle
Dendrites
link the neuron to other neurons and allow information o flow between different nerves.
Axon
is the main component of nerve signal transmissions. It is similar to the electrical wire and is made of myelin
Myelin
A protein that makes sure the electrical signal is insulated from from surrounding tissues. The myelin has holes in it called Nodes of Ranvier which help aid the transmission of information.
Synapse
transmission of electric nerve impulses between two nerve cells
Explain the role of neurotransmitters in stimulating skeletal muscle contraction
Neurotransmitters are chemicals which are released at the end of a nerve fiber by a nerve impulse. They are used for communication between a neuron and the synapse and another cell.
Acetylcholine is the primary neurotransmitter for the motor neurons that innervate skeletal muscle.
Cholinesterase is an enzyme that catalyzes the breakdown of acetylcholine into choline and acetic acid which is necessary for the neuron to return to its resting state.
Explain the difference in fast and slow twitch muscle fibers
Slow twitch
Type 1 – Slow twitch
They are associated with endurance sports as they produce ATP more slowly and reley on aerobic respiration
- Take longer to contract
- Give long sustained muscle contractions
- Not as powerful
- Have more mitochondria
- Have a good oxygen supply
- Suited to activities which require long term energy
Fat switch
Type IIa – Fast twitch
*Have a greater resistance to fatigue due to endurance training
- Contract quickly
- Give sharp powerful muscle contractions
- Don’t use oxygen
- Have fewer mitochondria
- Suited to activities with burst of strength and power
- Tire quickly
Type IIb – Fast twitch glycolic
Outline the 14 movement types at a synovial joint
- flexion
- extension
- adduction
- adduction
- pronation
- supination
- elevation
- depression
- rotation
- circumduction
- dorsi flexion
- plantar flexion
- eversion
- inversion
Outline the 14 movement types at a synovial joint
- flexion
- extension
- adduction
- adduction
- pronation
- supination
- elevation (the upward movement)
- depression (a downward movement)
- rotation
- circumduction
- dorsi flexion
- plantar flexion
- eversion
- inversion
Axis
A straight line in which an object rotates around.
Axes and planes of movement
- Sagittal axis - Passes horizontally from posterior to anterior
- Frontal plane
- Frontal axis – Horizontally left to right
- Sagittal movement
- Vertical axis – From inferior to superior
- Transverse plane
Isometric contraction
The muscle stays the SAME length, the muscle force balances resistance
- Generally, no movement
- Pushing against a fixed position
Example: Plank
Isotonic contraction
A CHANGE in muscle length due to the increase in load.
Concentric contraction
Part of Isotonic contraction
Muscle shortens
Decrease in angle joint
Pulls against gravity
Causes joint movement
Eccentric contraction
Part of Isotonic contraction
Muscle lengthens
Increase in muscle joint
Works with gravity
Controls joint movement
Isokinetic contraction
Is can be:
- Isokinetic concentric contraction
- Isokinetic eccentric contraction
It’s basically means the velocity of muscle contractions remains constant while the muscle length changes (can either shorten or lengthen)
Reciprocal inhibition
describes the process of muscles on one side of a joint relaxing (antagonist) to accommodate contraction on the other side of that joint (agonist).
DOMS
the pain and stiffness felt in muscles several hours to days after strenuous exercise. It is brought on by eccentric contractions.
It can be reduced by starting training at low intensity and gradually increasing it thus reducing the eccentric contractions. In addition to this warming up and cooling doesn’t is important.
Scalar
A measurement that only has size
Vector
A measurement that has both size and direction
Force
A push or a pull
Displacement – Distance measured in a stated direction
Speed
Maximum rate at which a person is able to move their body
Velocity
Rate at which an object changes position
Acceleration
The rate of change in velocity
Momentum
mass x acceleration
Impulse
force x time
List 5 scalar and vector examples
scalar-
• Length • Mass • Area • Volume • Speed • Density - Pressure
vector -
• Displacement • Velocity • Direction • Acceleration • Momentum • Force • Impulse Weight
Velocity time graph
- if the line goes up it is constant acceleration
- if the line is straight it is constant velocity
- If the line is coming down it is deceleration
- if the line is at 0 the object is a rest
Distant time graphs
- line goes up it is moving
- Line is flat it is stationary
Center of mass
The point at which the body is balanced in all directions
Explain how a change in body position can change the position of the center of mass
The scissor kick :
- The center of mass is within the pelvic girdle and is within the body.
- The action involves clearing the bar one leg at a time
- Since the center of the mass is within the body it is more likely that the bar will be hit and the jump will be invalid
Frosbery Flop :
- The center of mass in this jump is externally placed
- The arch in the back allows the mass to be shifted to the outside of the body for a greater opportunity of clearance
- The greater the arch of the back the lower the center of mass
Fulcrum
The joint
Resistance
Body part being moved
Effort
Muscle pull at the muscle insertion
Explain the three types of levers
First class lever - Fulcrum in the middle
Second class lever - Load is in the middle
Third class lever -
Effort is in the middle
Newtons 1st law
1) First law – Law of inertia
“An object will remain at rest or at constant velocity unless acted upon by an external force”
Newtons 2nd law
1) Law of acceleration
“Acceleration depends on two things force and mass” (Force = mass x acceleration)
Newtons 3rd law
1) Third law – Law of reaction
“ Every action has an equal and opposite reaction”
Moment of inertia
how difficult a body/ object is to rotate about an axis and is measured
Angular velocity
ratio of the change in angular displacement and the time during which the change has occurred. The rate of which a body spins through an angle.
Angular velocity = angular displacement / time
Angular momentum
the quantity of rotation
Angular momentum = inertia x angular velocity
Explain the factors that affect projectile motion at take off or release
• height of release
1. the higher the release = the greater distance covered
2. the higher the release = the longer spent in the air
3. the higher the release = the longer the horizontal component will be acting
• angle of release
1. ideal angle of release is 45 degrees
2. the angle changes the relationship between the horizontal and vertical components of projectile
• speed of release (most influential)
1. speed is directly related to the distance
2. greater the speed = greater the distance
3. initial vertical velocity increases the height of the trajectory, creating a longer flight path
4. initial horizontal velocity will increase the length of flight time and distance
Projectile
objects or athletes that are propelled through the air
Bernoullis principle
The pressure difference around a ball causes it to spin.
Lower pressure is on the top of the ball where as high pressure is on the bottom of the ball.This causes a lift force.
