Muscle Atrophy and Strengthening

Question 1

What is muscle atrophy?

Answer 1

The loss of skeletal muscle mass, typically due to disuse, resulting in reduced size, strength, and function.

Question 2

What are common causes of muscle atrophy?

Answer 2

Disuse, bed rest, immobilisation, splinting, neurological issues, ageing, pathology, and malnutrition.

Question 3

What happens during disuse muscle atrophy at the cellular level?

Answer 3

Lack of contraction leads to protein loss, apoptosis, and degradation exceeding synthesis, with Type 1 fibres affected most.

Question 4

What is muscle strength?

Answer 4

The ability of a muscle to generate force.

Question 5

What are the three aspects of muscle performance?

Answer 5

Strength (force), power (force over time), and endurance (repeated contractions over time).

Question 6

What is the Medical Research Council (MRC) Scale for muscle strength?

Answer 6

0 = no contraction, 1 = flicker, 2 = movement with gravity eliminated, 3 = movement against gravity, 4 = movement with resistance, 5 = full function.

Question 7

What are the phases of physiological strengthening?

Answer 7

Neural activation (0–2 weeks), hypertrophy (6–8 weeks), and cellular/circulatory adaptations (10–12 weeks).

Question 8

What occurs during neural activation in strengthening?

Answer 8

Improved motor unit recruitment and coordination, leading to increased force production without structural changes.

Question 9

What is muscle hypertrophy?

Answer 9

An increase in muscle fibre cross-sectional area due to protein synthesis and satellite cell activity, primarily in Type 2 fibres.

Question 10

What late adaptations occur in muscle with training?

Answer 10

Increased capillary density, myoglobin, enzyme activity, and mitochondrial density supporting endurance and strength.