Muscle fibre types and fatigue — practice questions

Question 1 · difficulty L1 · recall

Which pigment gives red skeletal muscle fibres their characteristic colour?

• A. Myoglobin
• B. Haemoglobin
• C. Melanin
• D. Keratin

Question 2 · difficulty L1 · recall

Which muscle fibre type generally contains more mitochondria?

• A. White muscle fibres
• B. Red muscle fibres
• C. Both always contain identical numbers
• D. Only cardiac fibres contain mitochondria

Question 3 · difficulty L2 · understanding

Why are red muscle fibres better suited for prolonged activity than white fibres?

• A. They contain no actin
• B. They lack mitochondria and use only glycolysis
• C. They have more myoglobin and mitochondria and rely strongly on aerobic metabolism
• D. They cannot fatigue under any condition

Question 4 · difficulty L2 · understanding

Which feature is most typical of white skeletal muscle fibres?

• A. Inability to contract rapidly
• B. High myoglobin content and abundant mitochondria
• C. Exclusive use of oxidative phosphorylation
• D. Low myoglobin content and greater reliance on anaerobic metabolism

Question 5 · difficulty L3 · application

A sprinter relies heavily on fibres that produce rapid, powerful contractions but fatigue quickly. Which fibre type is most involved?

• A. White muscle fibres
• B. Red muscle fibres
• C. Smooth muscle fibres only
• D. Cardiac muscle fibres

Question 6 · difficulty L3 · application

A postural muscle must remain active for long periods with minimal fatigue. Which combination of properties would best support this function?

• A. Low myoglobin, few mitochondria and strong anaerobic dependence
• B. High myoglobin, many mitochondria and strong aerobic capacity
• C. No capillary supply and no oxidative enzymes
• D. Absence of ATP-dependent cross-bridges

Question 7 · difficulty L3 · application

Repeated intense contractions occur faster than oxygen can be supplied adequately. Which metabolic change is associated with muscle fatigue in this situation?

• A. Complete cessation of ATP use
• B. Immediate conversion of all white fibres into red fibres
• C. Greater reliance on anaerobic metabolism with lactate accumulation
• D. Permanent destruction of actin filaments

Question 8 · difficulty L4 · analysis

Muscle sample P has abundant myoglobin and mitochondria, while sample Q has less myoglobin and fewer mitochondria. Which performance pattern is most likely?

• A. Q cannot generate ATP
• B. P fatigues faster, while Q is specialised for endurance
• C. Both must have identical endurance because both are skeletal muscle
• D. P is more fatigue-resistant, while Q is better suited to brief powerful activity

Question 9 · difficulty L5 · analysis

Two athletes have similar muscle mass. Athlete X has a higher proportion of oxidative, myoglobin-rich fibres, while athlete Y has more glycolytic, low-myoglobin fibres. Which event profile best fits them?

• A. X is favoured in endurance events and Y in short explosive events
• B. X is favoured only in sprinting and Y only in distance events
• C. Both should perform identically because muscle mass is equal
• D. Y cannot perform voluntary movement