Question 1

Which of the following factors directly increases the force generated by a single skeletal muscle fiber?

Accepted Answer

Increasing the frequency of activation (action potentials)

Question 2

A patient is undergoing physical therapy after muscle injury. Which cellular process is most responsible for muscle hypertrophy during recovery?

Accepted Answer

Activation and fusion of satellite cells to existing muscle fibers

Question 3

During a sustained muscle contraction, calcium ($$Ca^{2+}) $$remains elevated in the sarcoplasm. What is the physiological consequence of this?

Accepted Answer

Increased cross-bridge cycling and force production

Question 4

Which type of muscle contraction occurs when the muscle generates force but does not change length?

Accepted Answer

Isometric contraction

Question 5

A weightlifter performs repeated maximal lifts, leading to muscle hypertrophy. Which adaptation is LEAST likely to occur in their skeletal muscle?

Accepted Answer

Decrease in myofibril number

Question 6

Which equation best represents the relationship between muscle force ($$F$$), cross-sectional area ($$A$$), and specific tension ($$T$$)?

Accepted Answer

$$F = T 	imes A$$

Question 7

A muscle fiber is stimulated at a frequency that does not allow complete relaxation between stimuli. What is this pattern of contraction called?

Accepted Answer

Unfused tetanus

Question 8

Which motor unit type is recruited first during a gradual increase in muscle force according to the size principle?

Accepted Answer

Slow-oxidative motor units

Question 9

A runner experiences muscle fatigue during a marathon. Which muscle fiber type is most resistant to fatigue?

Accepted Answer

Type I (slow-oxidative)

Question 10

Which of the following best explains why large-diameter motor neurons are recruited last during voluntary muscle contraction?

Accepted Answer

They have higher cytoplasmic resistance and require greater stimulus to reach threshold

Question 11

Which adaptation is most likely to occur in skeletal muscle following endurance training?

Accepted Answer

Increase in capillary density

Question 12

During an eccentric contraction, what happens to the muscle?

Accepted Answer

It lengthens while generating force

Question 13

Which process is primarily responsible for muscle atrophy?

Accepted Answer

Protein degradation exceeds protein synthesis

Question 14

A muscle fiber is exposed to a rapid series of action potentials, resulting in maximal, sustained tension. What is this phenomenon called?

Accepted Answer

Fused tetanus

Question 15

Which of the following is a neural adaptation to resistance training?

Accepted Answer

Reduced inhibitory input from Golgi tendon organs

Question 16

Which of the following best describes the role of series elastic elements during isometric contraction?

Accepted Answer

They stretch, allowing sarcomeres to shorten without changing overall muscle length

Question 17

Which of the following is NOT a determinant of whole muscle force production?

Accepted Answer

Type of neurotransmitter released at the neuromuscular junction

Question 18

Which of the following statements about muscle plasticity is correct?

Accepted Answer

Muscle mass increases primarily through hypertrophy rather than hyperplasia in humans

Question 19

A patient with muscle atrophy is found to have decreased contractile protein content. Which equation best describes the relationship between muscle mass ($$M$$), protein synthesis ($$S$$), and protein degradation ($$D$$)?

Accepted Answer

$$M \propto S - D$$

Question 20

Which of the following is a characteristic of fast-glycolytic muscle fibers?

Accepted Answer

Large diameter and rapid force production

Skeletal Muscle Plasticity, Force Development, and Adaptation

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