Unit 4: Movement analysis Flashcards
Explain the role of neurotransmitters in stimulating skeletal muscle contraction
Acetylcholine: it is vital to allow us to move, as it send a signal to our muscle receptors to generate muscle contraction
1. An electrical impulse opens calcium channels and let calcium in
2. They push the vesicles containing acetylcholine, releasing it in the surface
3. It attaches to sodium channel receptors, letting sodium in the muscle tissue –> this transports the impulse from the neuron to the muscle
Cholinesterase: catabolic enzyme that breaks down acetylcholine to generate muscle relaxation
1. When trying to relax, the acetylcholine left in the synaptic cleft is broken down by cholinesterase
2. So no impulse is transmitted to the muscle
3. Muscle relaxation happens
Explain how skeletal muscle contracts by the sliding filament theory
- Start at the neuromuscular junction
- Allows sodium into the cell, impulsing an electric charge on the motor end plate
- Calcium is released from the sarcoplasmic reticulum into the muscle, arriving at each sarcomere in each myofibril.
- Every muscle fiber and myofilament is stimulated.
- Calcium binds to troponin on the tropomyosin which causes it to move
- ATP on the Mysoin head is hydrolyzed to form ADP + Phosphate
- Myosin grabs hold of actin –> Cross bridge formed. (cross bridge formation will continue until maximum contraction of the muscle fiber is reached.)
Why are muscles striated?
Because the sarcomeres of muscle fibers are visible
Outline the movement of flexion and extension. Give examples.
Flexion: decrease the angle on the sagital plane
–> ex.
- Flexion of the forearm at the elbow
- Flexion of the arm at the shoulder
- Flexion of the thigh at the hip
- Flexion of the knee
Extension: increase the angle on the sagital plane
–> ex.
- Extension of forearm at the elbow
- Extension of arm at the shoulder
- Extension of leg at the knee
- Extension of thigh at the hip
Outline the movement of pronation and supination. Give examples.
Pronation: medial rotation of forearm on transverse plane
–> ex. thumbs in radius and ulna
Supination: lateral rotation of forearm on transverse plane
–> ex. thumbs out radioulnar joint
Outline the movement of abduction and adduction. Give examples.
Abduction: increase angle on the frontal plane
–> ex.
- Abduction of the arm at the shoulder
- Abduction of the thigh at hip
Adduction: decrease angle on the frontal plane
–> ex.
- Adduction of arm at shoulder
- Adduction of thigh at hip
Outline the movement of elevation and depression. Give example.
Elevation: Elevating bones
–> ex. elevating shoulders
Depression: Lowering bones
Outline the movement of rotation and circumduction. Give examples.
Rotation: Joint rotates
–> ex. in football rotate hip to throw the ball and in swimming you rotate forearm to do backstroke
Circumduction: Combination of flexion, extension, abduction, and adduction (going through all the ranges of motion to create movement)
–> ex. butterfly technique in swimming
Outline the movement of dorsi flexion and plantar flexion. Give examples.
Dorsi flexion: upwards flexion of the foot on the sagital plane
–> ex. toes up
Plantar flexion: downwards flexion of the feet on the sagital plane
–> ex. toes down
Outline the movement eversion and inversion. Give an example.
Eversion: foot is turned medially outwards
Inversion: foot is turned medially inwards
–> ex. when passing the ball in football
Outline the types of muscle contraction
Isotonic: the tension and stress remains the same
- concentric= muscle is constricting
- eccentric= muscle is lengthening
–> ex. lifting or lowering dumbbells
Isometric: the length remains the same, no shortening, the dimensions stay the same
–> ex. doing a plank or ski sit
Isokinetic: the energy remains the same. Done with machines.
Explain the concept of reciprocal inhibition.
Whenever a muscle contracts to produce a movement, an opposite one relaxes.
The muscle that contracts is called AGONIST MUSCLE and the one that relaxes is called ANTAGONIST MUSCLE.
Explain DOMS in relation to muscle contractions
Delayed Onset Muscle Soreness
–> Muscle pain that starts 24-48 hours after a very intense work out
CAUSES:
- Overtraining
- No progression in exercise
- Excess of eccentric contractions
- Overstretching
CONSEQUENCES:
- Inflammation
- Pain
HOW TO PREVENT:
- Reducing eccentric contractions during early training
- Start at low intensity and gradually increase
- Warm up or Cool down
Define the term force
The mechanical interaction that goes on between two objects. It is a vector.
Define the terms speed and velocity
Speed: distance/time. It is a scalar.
Velocity: distance changed/time. It is a vector.
