Topic 4
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Lable the diagram of a motor unit
• Dendrite • Cell body • Nucleus • Axon • Motor end plate • Synaspse • Muscle
Expalin the role of neurotransmitters in stimulating skeletal muscle contraction
Neurotransmitters-chemicals that are used communication between hevron at the end of the synapse and another cell Acetylcholue -transfers the action potential from the motor unit to muscles cells vin a chemical transfer to contract the muscle · At the end of the motor endplate acetylcholine changes electrical impulse into a chemical stimulus · it increases membrane permeability to sodium ions ↳ causing calcium to be released into the muscle tell cholinesterase -an enzyme which breaks down acetylcholine · breaking down acetylcholine will depolarize the membrane which will stop the muscle from contracting
Explain how skeletal muscles contracts by the sliding filament theory
· A. P travels along sarcolemma and through +-tubules · A. P stimulates Sarcoplasmic-reticulum release (22t Into muscle cells · Ca’t binds to troponin which then moves tropomyosin and opens the binding sites on actin · myosin binds to actin forming In cross-bridge myosin head undergoes a power stroke sliding actin across If pulling 2 lines closer together · Cross-bridge is broken from the breakdown of energy released from ATP to ADP myosin head is re-excited from energy released from the breakdown ATP to ADP + P · The cross-bridge cycle continues until muscle is no longer stimulated
Explain how fast and slow twitch fiber types differ in structure and function
Fiber Types Type I fibers Type II A fibers Type II B Fibers · contraction speed · Slow · fast · very high - Size of motor neuron. Small · large · very large - Resistance to fatigue high · intermediate · low · Activity used for · nerobic · large term anaerobic · short terp anaerobic · Force production · low · high · very high · Efficiency · highly · Intermediate · low · Number of Mitochondria high · high · low · Capillary density high · Intermediate · low · oxidative capacity high · intermediate · low
Outline the types of movement of synovial joints
Outline the types of muscle contractions
sotonic -the muscle contract changing size and causes body movement There are two types of Isotonic contractions · Concentric= muscle shortens · Eccentric muscle lengthens sometric -no change in length when muscle contracts ex: carrying an object Isokinetic-contractions that produce movements at a constant speed ex: rehealing Injury/dynamometer
Explain the concept of reciprocal inhibition
Analyse movements in relation to joint action and muscle contraction
Explain delayed onset muscle soreness in relation to eccentric and concentric muscle contractions
Define the terms force, speed, velocity, displacement, acceleration, momentum, impulse
velocity -The rate at which a body moves from one location to another in a specific direction impulse -The effect of force over time acceleration -The rate at which velocity changes over time distance -The length of a path a body follows force -A pushing or pulling action that causes a change of state (rest/motion)of a body Scalar -A quantity that only has magnitude displacement -The length of a straight line joining the start and finish points Vector -A quantity that has magnitude and direction momentum-A vector describing a ‘quantity of motion’and is the product of mass and velocity mass x velocity ↳ heavier object = heavier momentum
Anaylse velocity-time, distance-time, and force-time graphs of sporting actions
Define the term centre of mass
The point at which the body is balanced in all directions
Explain that a change in body position during sporting activities can change the position of the centre of mass
The centre of mass can change when the body is moving dynamically. The centre of mass is not always Inside the body, it can be outside of the body depending on positions Why is it important to know where center of mass Is? Determines the stability of static position. 2. it provides the axis of rotation. CofM remains in body CofM outside body erunning -> Diving -walking · high Jump swimming -> Long Jump -> Somersalt
Distinguish between first, second and third class levers
Fulcrum -> The joint Resistance -body part to be moved 123 FRE >What is In the middle Effort muscle pull at the muscle insertion f First class lever -fulcrum in middle EX: Nodding head L second class lever -Load Is In the middle EX: Heel up and down = Third class Lever -Effort In middle EX: blcep curl
Label anatomical representations of levers
Define newtons three laws of motion/ Explain how newtons three laws of motion apply to sporting activities
Newtons first law an object will remain at rest or constant velocity unless acted upon by an external force Ex: An athlete at a starting block will not move unless a force acts upon them. The external force comes from the blocks and this propels the sprinter out of the blocks when exert a downward and backward force against the blocks Newtons Second law The rate of change of acceleration of an object is proportional to the force applied and acts in the direction of the force Example: two athletes at starting block, one is lighter-accelerate faster. Two athletes same mass, the one who applied more force = accel fast Newtons third law For every action there is an equal and opposite reaction Ex: Sprinter applied downwards/backwards force on Immorable block, they exert back with a forward/upward reaction force on the sprinter, pushing the sprinter forwards. The harder the sprinter pushes, the greater the reaction force will be
State the relationship between angular momentum, moment of inertia and angular velocity
angular momentum: The product of the body’s moment of interfa, and its angular velocity. M = IxV moment of Inertia: its determines the torque (force that causes rotation)needed for a desired angular acceleration about a rotational axis. It depends on the mass of the object, its shape, and its relative point of rotation - Example -> ⑳ · The first object the mass is evenly distribution high moment of Inertim e The second object the d moment of Inertice Center point Angular Velocity: Is a ratio of a change of angular displacement and the time during which the change occured. The rate at which a body spins/rotates/turns through an angle. Angular Velocity = angular displacement time [ 96
Explain the concept of angular moment in relation to sporting activities
High moment of Inertia small moment of Inertia ⑳ open arms = > Pulling arms and legs together O O —(high)moment of Inertia · · decrease (low)moment of Inertia I -> Decrease In angular velocity I · increase in angular velocity L ↳ = decrease speed L ↳ = Increases speed
Explain the factors that affect projectile motion at take-off or release
Projectiles -are objects or athletes that are propelled in the air Influences -> 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
Outline the Bernoulli principle with respect to projectile motion in sporting examples