Lecture 9 Flashcards

1
Q

What do differences in torque influence?

A

The direction and range of motion of the muscle motion.

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2
Q

Why are variable resistance strength machines beneficial?

A

Provide a constant load (force) but different torques requirements. This means the machine adjust strength depending on where the muscle is.

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3
Q

What is moment of inertia? When does it have a smaller value?

A

Resistance to Angular Motion. Smallest when object has a small mass and is able to rotate.

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4
Q

What happens to the moment of inertia if the mass is located closer to the axis of rotation?

A

It becomes smaller.

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5
Q

Name factors that affect the ability for muscles to generate force.

A
  • Cross-sectional area
  • Muscle fiber orientation
  • Muscle length and velocity
  • Prior activity (fatigue)
  • Muscle fiber and motor unit composition.
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6
Q

Why do bigger muscles typically produce more force and therefore torque?

A

They have a bigger cross-sectional area and therefore have more muscle fibres and contract more and produce more force.

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7
Q

What is the difference between parallel and serial muscle fibres?

A

Serial means they are attached at different points and the more fibres there are, the muscles don’t get necessarily stronger. Fibres are attached to the same point and have a lot more resistance. The amount you can shorten and lengthen is always the same.

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8
Q

What is the difference between active and passive components of total force development.

A

Active: attachment of myosin cross bridges to actin filaments with a sarcomere.
Passive: stretching of connective tissue (sarcolemma, connective tissue).

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9
Q

In plantar flexion, what muscle does not change in length?

A

Soleus

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10
Q

Why do we still activate weaker muscles?

A

Because we can’t always activate muscles that their optimal length.

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11
Q

What do EMG do?

A
  • Tell us which muscles are active and when.

- the amplitude increases as the intensity of the muscle contraction increases.

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12
Q

What type of concentric make the muscles stronger?

A

Slower contractions.

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13
Q

Can we activate all muscles to 100%

A

Depends, the will is somewhat more physiological than physical.

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