Types Of Muscle Contraction

Question 1

What are the three groups of agonist muscle contractions?

Answer 1

• Isometric
• Isotonic (concentric)
• Isotonic (eccentric)

Question 2

Isometric contraction:

Answer 2

• Isometric contractions occur when there is no change in the length of the contracting muscle. For example, carrying an object in front of you.

• The amount of force a muscle is able to produce during an isometric contraction depends on the length of the muscle at the point of contraction.

• Each muscle has an optimum length at which the maximum isometric force can be produced.

Question 3

Isotonic concentric contraction:

Answer 3

• Concentric contractions are those which cause the muscle to shorten as it contracts.

• Concentric contractions are the most common type of muscle contractions and occur frequently in daily and sporting activities.

Question 4

Describe the all or none law of muscle contraction.

Answer 4

• For a motor unit to contract it must receive a nerve impulse

• So once activated, all muscle fibres will contract

• Or none of the muscle fibres will contract.

Question 5

How does the all or none law link to a motor unit?

Answer 5

• For a muscle to contract it must receive a nerve impulse.

• This stimulus must be sufficient to activate at least one motor unit which contains the motor neuron and the attached muscle fibres.

Question 6

Isotonic eccentric contraction:

Answer 6

• This occurs when the muscle lengthens as it contracts.

• This usually involves the control or deceleration of a movement.