week 2 lesson 2- Muscle Activity Flashcards

1
Q

what is a motor unit

A

A neuron; plus the muscle fibres it supplies

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2
Q

What is the difference between a large and small motor unit

A

Large motor units are one neuron which innervated many single muscle fibres
Small motor units have fewer muscle fibres

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3
Q

What is the relationship between the intensity of force generated in a muscle contraction to the number of motor units recruited

A

Greater the force, the more the motor units are activated

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4
Q

What is the difference in response of the muscle fibres between isotonic and isometric muscle contractions

A

Isotonic: change in force generated, and change in length
Isometric: change in force generated, no change in length

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5
Q

Where is the biggest gain in tension (force) in the muscle

A

Ascending curve from points 2 to 1 on graph. From where muscle sarcomwrws are at their shortest to where they are approaching optimum length

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6
Q

Name the factors affecting the strength and power of the skeletal muscle

A

Morphology
Neural
Architecture

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7
Q

Define morphology

A

Muscle size
Fibre type and size

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8
Q

Define neural

A

Motor unit firing frequency
Motor unit recruitment

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9
Q

Define architecture

A

Muscle fibre attachment
Muscle fibre length
Pennation angle

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10
Q

Name types of contractions

A

Concentric
Eccentric

Isometric
Isokinetic

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11
Q

Explain concentric contraction

A

Force generated is sufficient to overcome the resistance
Muscle shortens as it contracts

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12
Q

Explain eccentric contraction

A

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

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13
Q

Explain isometric contraction

A

Muscle remains same length
Holding an object up without moving it.
Muscle force mastched load

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14
Q

Explain isokinetic contraction

A

Muscle contraction velocity remains constant while force force can vary

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15
Q

Define strength

A

Max amount of force that a muscle can exert against some form resistance

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16
Q

Define power

A

Muscle force x velocity of muscle contraction

17
Q

Explain the length- tension relationship

A

Amount of tension generated by muscle and the force of contraction depends on length of sarcomeres within a muscle before contraction occurs

18
Q

What does the strength of skeletal muscle depend on

A

Skeletal muscle size

19
Q

Explain muscle twitch

A

Single Muscle contraction in response to a brief stimulation
Quick contraction and relaxation response

20
Q

Explain summation

A

Muscle fibres are re stimulated whilst there is still contractile activity

21
Q

Explain tetanus (incomplete)

A

Muscle fibres partially relax between contraction time for ca2* to be recycled

22
Q

Explain tetanus (complete)

A

No relaxation between contractions as result of rapid stimulation

23
Q

What happens to muscle length ad tension when it undergoes an isotonic eccentric contraction

A

Muscle lengthens under contraction