week 2 lesson 2- Muscle Activity Flashcards
what is a motor unit
A neuron; plus the muscle fibres it supplies
What is the difference between a large and small motor unit
Large motor units are one neuron which innervated many single muscle fibres
Small motor units have fewer muscle fibres
What is the relationship between the intensity of force generated in a muscle contraction to the number of motor units recruited
Greater the force, the more the motor units are activated
What is the difference in response of the muscle fibres between isotonic and isometric muscle contractions
Isotonic: change in force generated, and change in length
Isometric: change in force generated, no change in length
Where is the biggest gain in tension (force) in the muscle
Ascending curve from points 2 to 1 on graph. From where muscle sarcomwrws are at their shortest to where they are approaching optimum length
Name the factors affecting the strength and power of the skeletal muscle
Morphology
Neural
Architecture
Define morphology
Muscle size
Fibre type and size
Define neural
Motor unit firing frequency
Motor unit recruitment
Define architecture
Muscle fibre attachment
Muscle fibre length
Pennation angle
Name types of contractions
Concentric
Eccentric
Isometric
Isokinetic
Explain concentric contraction
Force generated is sufficient to overcome the resistance
Muscle shortens as it contracts
Explain eccentric contraction
Force generated is insufficient to overcome external load on muscle and muscle fibres lengthen as they contract
Decelerating a body part of lowering a load gently
Explain isometric contraction
Muscle remains same length
Holding an object up without moving it.
Muscle force mastched load
Explain isokinetic contraction
Muscle contraction velocity remains constant while force force can vary
Define strength
Max amount of force that a muscle can exert against some form resistance
