Resistance exercise

Question 1

define resistance exercise

Answer 1

Any exercise that causes the muscle to contract against an external resistance, with a primary aim of improving muscle strength

Question 2

State the 3 types of muscle contractions

Answer 2

• Concentric: muscle shortens
• Eccentric: muscle lengthens
• Isometric: no length change

Question 3

State the process of a muscle contraction

Answer 3

1. Action potential arrives at the neuromuscular junction
2. Acetylcholine is released causing depolarisation by binding to receptors in my-ocyte membrane
3. Calcium is released from the sarcoplasmic reticulum
4. Calcium binds to troponin, changing its shape, and moving tropomyosin from the active site of the actin filament
5. Myosin can now attach to actin forming a cross-bridge at the binding site
6. ATP attached to the myosin head is broken down to release energy for a power stroke of the myosin filament
7. This moves the Z-lines towards each other, reducing the length of the sarco-mere- contracting
8. A new ATP molecule binds to the myosin head, causing it to release from the actin binding site
9. If calcium I still present in the myocyte, the myosin head will attach to the next available binding site
10. Whilst the nerve impulse persists, this process will repeat until either no calci-um or no ATP are present
11. Once the nerve impulses stops the calcium is pumped back to the sarcoplas-mic reticulum and the muscle relaxes and lengthens

Question 4

State how of the muscle cross sectional area increases

Answer 4

Muscle fibre hypertrophy-cells get bigger
- Myofiber hypertrophy happen through myofibrillar splitting/hyperplasia

Increased number of cross bridges which can form
- muscles grow and become stronger

Question 5

Explain what a motor unit is

Answer 5

• The final functional portion of the pathway in the nervous system
• Basic functional units of skeletal muscle

Question 6

What is a motor unit measure in

Answer 6

• Measured in fibres per unit & linked to function

Question 7

What effect does resistance exercise have on action potential firing frequency

Answer 7

Increases firing rate, there is a ceiling to this !

Question 8

State the 3 neural adaptations of resistance training

Answer 8

1. Motor unit recruitment patter (efficiency)
2. Frequency of action potential firing (summation)
3. Threshold of activation changes (morphological)

Question 9

Describes the relationship between hormones & exercise

Answer 9

• Exercise leads to an acute rise in anabolic hormones e.g. insulin, growth hormone, testosterone
• Increases satellite cell activation & MPS stimulation