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Topic 4 - Movement analysis :check: - Coggle Diagram
Topic 4 - Movement analysis :check:
Neurotransmitters
Neurotransmitters are chemicals which allow for the communication between neurons and another cell.
What role do neurotransmitters play in stimulation of muscle contraction?
Neurotransmitters, such as acetylcholine, aid in the process of muscle contraction
For example, acetylcholine causes the release of calcium into the sarcoplasmic reticulum during muscle contraction.
An enzyme called cholinesterase hydrolyses acectylcholine into acetic acid and choline, this is a necessary reaction for a neuron to return to its resting place after excitement.
Explain the signal detection process
Brain detects a stimulus - intense noises or other senses are better recognised by the brain
The stimuli is processed by the brain and is interpreted from information from external stimuli
Compares the stimuli to past memories and knowledge
Stimulus is recognised and matched to a memory store so it can be understood
Long term v Short term memory
Short term sensory
= large capacity
= Less than a second duration
= Filters out irrelevant information
Short = 7+-2 bits of information at a time
Long = unlimited store of information
Short = 10 seconds duration
Long term = Very long time but not forever due to neural pruning
Short = consciuosly analysed
Long = stores information from past memories
Skeletal muscle contraction (SFT)
Explain the 10 steps of the sliding filament theory
1) An action potential is generated by the brain or a reflex
2) This travels across the motor neuron to the neuromuscular junction of the motor unit.
3) Acetylcholine is released into the synaptic cleft from vesicles in the pre-synaptic neuron and are received by nicotinic receptors
4) The acetylcholine then triggers the release of calcium into the sarcoplasmic reticulum
5) This causes the troponin-tropomyosin complex to change shape
6) Allows myosin heads to attach to previously blocked actin binding sites
7) The ATP from the myosin heads is broken down into ADP and a phosphate with the net release of energy
8) This allows the myosin to pull the actin filaments in
9) Shortening the H-zone and the A-band - hence shortening the muscle
10) This continues to happen with every myofibril in the muscle cell
Outline the different types of muscle contraction
Concentric - muscle contraction when the muscle shortens - raising phase of a bicep curl
Eccentric - muscle contraction when the muscle lengthens - lowering phase of a bicep curl
Isometric - muscle contraction without shortening - plank
Isokinetic - muscle contraction with movement at a constant speed - squat
Isotonic - muscle contraction involving movement
Extension occurs at the knee when the quadriceps contract
Hyperextension occurs at the hip when the gluteus maximus contracts
Plantar flexion occurs at the ankle when the gastrocnemius contracts
Explain DOMS in relation to concentric and eccentric muscle contractions
DOMS is known as delayed onset muscle soreness and is the result of intense eccentric exercise
DOMS occurs hours to days after the exercise and is due to the structural muscle damage caused by the exercise and the inflammatory reactions in the muscle
DOMS can be prevented by warming up and cooling down directly before and after training at a high intensity
OR, by training at a lower intensity then gradually increasing exercise intensity while keeping the eccentric muscle contraction component low
Explain the concept of reciprocal inhibition
Idea that when one muscle within an antagonistic muscle is contracting, the other is relaxing
For example if the agonist is contracting then the antagonist is relaxing
This is caused when the motorneuron in the agonist is stimulated
The motorneuron in the antagonist is inhibited which prevents it from contracting strongly
Fast v Slow twitch muscle fibres
Fast has:
Less mitochondria
Faster ATP resynthesis
Lower capillary volume
Lower endurance
Explosive
Anaerobic respiration
Lower blood supply
Small but fast energy supply
Low myoglobin
Faster ATP resynthesis
Biomechanics
Vector
Force - the accumulation of an objects weight and speed
Impulse - a wave of excitement over a nerve or muscle
Velocity - the measure of an objects speed in any given direction
Displacement - the overall change in start position and end position
Acceleration - the rate at which an object is increasing its speed
Momentum - the combination of an objects mass and velocity
Scalar
Speed - the measure of an objects change in distance in regards to time
The centre of mass is the point at which all of an individuals weight is evenly distributed, the point could at some point be external to the body
As a high jumper arches their back to get over the bar, the fosbury flop, they move their centre of mass to outside of their body to allow them to clear the bar.
The greater the arch, the further the centre of mass moves from their body
1, 2, 3, F, L, E
1st class - neck when raising the head
2nd class - gastrocnemius
3rd class - bicep
Newtons first law - Law of inertia - any object will stay stationary or in constant motion until acted upon by an external force
Newtons second law - F = m x a
Force = mass x acceleration
Newtons 3rd law - opposite reactions
Every force has an equal and opposite reaction force
Angular momentum = the momentum of inertia x angular velocity
Angular velocity is the rate at which the body rotates through an angle
Moment of inertia is needed for angular acceleration around a rotational axis and it determines torque (force that causes rotation)
Ballerina moves adducts arms towards the body to decrease the moment of inertia, thereby increasing toruque and they are able to spin about a rotational axis, increasing angular velocity
Then they move their arms back out wide to increase moment of inertia and thereby decrease angular velocity
Factors affecting projectile motion upon takeoff/release
Trajectory - increase in height of trajectory affects distance of the object being thrown in an inverted U correlation - ideal angle is 45 degrees depending on the sport
Height of release - the higher the object is released from at takeoff/release increases distance
Speed is directly proportional to distance as it increases horizontal and vertical trajectory
Bernoulli's principle - inverse relationship between space and pressure in a fluid
Lift force is always perpendicular to direction of flow - which is usually towards the area of low pressure
For example, a golf swing puts back spin on the golf ball which decreases pressure above the golf ball and increases pressure underneath the ball, thereby sending it up higher into the air.