Muscular System in Sport Practice Quiz (24 questions)

1. Which classification correctly describes voluntary control of the three muscle types?

A. Smooth muscle is voluntary, while cardiac and skeletal muscles are involuntary.

B. Cardiac muscle is voluntary, while skeletal and smooth muscles are involuntary.

C. Skeletal muscle is voluntary, while cardiac and smooth muscles are involuntary.

D. Skeletal and cardiac muscles are voluntary, while smooth muscle is involuntary.

Answer: (C)

Explanation

Skeletal muscle is under conscious control, whereas cardiac and smooth muscles act involuntarily. A common confusion is to classify cardiac muscle as voluntary, but its contractions are involuntary.

2. Which statement describes cardiac muscle in a healthy heart?

A. It lines the intestines, contracts involuntarily, and does not fatigue.

B. It forms the walls of the heart chambers, contracts involuntarily, and does not fatigue.

C. It attaches to bones, contracts voluntarily, and maintains posture.

D. It forms the walls of the heart chambers, contracts voluntarily, and does not fatigue.

Answer: (B)

Explanation

Cardiac muscle makes up the walls of the heart chambers, works involuntarily, and does not fatigue when the heart is healthy. Skeletal muscle attaches to bones and is consciously controlled, so that description does not fit cardiac muscle.

3. During a standing exercise, which combination of functions can skeletal muscles perform?

A. Move substances through organs, supply cells with nutrients, and control involuntary contractions.

B. Pump blood through the body, maintain posture, and contract without conscious control.

C. Enable conscious movement, line the heart chambers, and prevent fatigue during healthy activity.

D. Maintain posture, enable conscious movement, and generate heat that helps regulate body temperature.

Answer: (D)

Explanation

Skeletal muscles enable conscious movement and strength, help maintain posture, and generate heat that supports normal body temperature. Moving substances through organs is a function associated with smooth muscle.

4. Which muscle type helps move substances through the intestines and blood vessels without conscious control?

A. Cardiac muscle, which forms the walls of the heart chambers.

B. Skeletal muscle, which generates heat during conscious movement.

C. Smooth muscle, which works involuntarily in and around organs.

D. Skeletal muscle, which attaches to bones and controls posture.

Answer: (C)

Explanation

Smooth muscle acts involuntarily in and around organs, helping move substances through the body. Cardiac muscle also acts involuntarily, but its defining location is the walls of the heart chambers.

5. Which named muscle is located on the front of the lower leg?

A. Gastrocnemius

B. Tibialis anterior

C. Gluteals

D. Hamstrings

Answer: (B)

Explanation

The tibialis anterior is one of the major skeletal muscles and is located at the front of the lower leg. The gastrocnemius is a calf muscle, while the hamstrings and gluteals are located around the thigh and hip.

6. Which pair consists of major skeletal muscles associated with the upper arm?

A. Quadriceps and hamstrings

B. Gastrocnemius and soleus

C. Pectorals and abdominals

D. Biceps and triceps

Answer: (D)

Explanation

The biceps and triceps are major skeletal muscles of the upper arm. The pectorals and abdominals are associated with the torso, while the other pairs are in the legs.

7. While lowering a weight under control, a muscle lengthens but remains responsible for controlling the movement; what role does it have?

A. Synergist, because its main role is to stabilize a joint and its origin.

B. Antagonist, because any muscle that lengthens produces the opposite movement.

C. Fixator, because the prime mover is responsible for the lowering phase.

D. Agonist, because the prime mover can control a lowering phase while lengthening.

Answer: (D)

Explanation

The agonist is the prime mover and can remain responsible for a movement during a controlled lowering phase while lengthening. An antagonist opposes the agonist's movement rather than defining the prime mover in that phase.

8. What is the role of an antagonist in relation to an agonist at a joint?

A. It relaxes and produces the opposite movement, with the pair positioned on opposite sides of a joint or bone.

B. It stabilizes the joint and controls the muscle's origin while producing the agonist's movement.

C. It assists the agonist in controlling direction, with the pair positioned on the same side of a joint.

D. It contracts as the prime mover while the agonist relaxes and produces the opposite movement.

Answer: (A)

Explanation

An antagonist relaxes and produces the movement opposite to the agonist, and antagonistic partners lie on opposite sides of a joint or bone. A synergist assists the agonist rather than opposing its movement.

9. When an antagonistic pair reverses a movement, what happens to the two muscles?

A. Their actions swap: one contracts and shortens as the other relaxes and lengthens, because muscles pull rather than push.

B. Both muscles contract and shorten together, then push the joint in the opposite direction.

C. The first muscle relaxes and lengthens while the second also relaxes and lengthens to reverse the movement.

D. One muscle contracts and shortens while its partner contracts and shortens to pull the joint back.

Answer: (A)

Explanation

In an antagonistic pair, one muscle contracts and shortens while its partner relaxes and lengthens; they swap actions to reverse the movement. The idea that muscles push the joint back is incorrect because muscles pull but cannot push.

10. What happens to a muscle during a concentric contraction while it generates force?

A. It lengthens, as when lowering a weight.

B. It shortens, as when raising a weight.

C. It relaxes as the load is removed.

D. It remains the same length while holding a load.

Answer: (B)

Explanation

A concentric contraction produces force while the muscle shortens, such as during the lifting phase of a weight. An eccentric contraction is the related but different action in which the muscle lengthens while producing force.

11. During the lowering phase of a controlled weight movement, which type of contraction generates force as the muscle lengthens?

A. An eccentric contraction

B. An isometric contraction

C. A concentric contraction

D. A passive stretch

Answer: (A)

Explanation

An eccentric contraction generates force while the muscle lengthens, as it does when lowering a weight. A concentric contraction produces force while the muscle shortens, which describes the lifting phase instead.

12. A person holds a load steady without changing the working muscle's length; what type of contraction is occurring?

A. A concentric contraction

B. An eccentric contraction

C. An isometric contraction

D. A rapid contraction

Answer: (C)

Explanation

An isometric contraction generates force while the muscle stays the same length, as in holding a load still. An eccentric contraction also generates force, but the muscle lengthens during it.

13. Which classification correctly describes the broad types of skeletal muscle fibres and the subdivisions of Type II?

A. Type I fibres are slow-twitch, while Type II fibres are fast-twitch and include Type IIA and Type IIB.

B. Type I fibres are slow-twitch, while Type II fibres are fast-twitch and include IIa and IIx.

C. Type I fibres are fast-twitch, while Type II fibres are slow-twitch and include Type IIa and Type IIx.

D. Type I fibres are fast-twitch, while Type II fibres are slow-twitch and include IIa and IIx.

Answer: (B)

Explanation

Skeletal muscle fibres are broadly grouped as slow-twitch Type I or fast-twitch Type II, with Type II subdivided into IIa and IIx. The common confusion reverses the twitch-speed labels for Type I and Type II.

14. Which muscle-fibre profile best fits an athlete preparing for a long-distance swim?

A. Type IIx fibres, which contract rapidly, produce high force, and suit brief anaerobic efforts.

B. Type IIa fibres, which contract quickly, produce high force, and suit repeated powerful efforts.

C. Type I fibres, which contract slowly, resist fatigue, and have high aerobic capacity.

D. Type I fibres, which contract rapidly, produce high force, and fatigue quickly.

Answer: (C)

Explanation

Type I fibres contract slowly, resist fatigue, and have high aerobic capacity, making them suitable for long-duration activities such as distance swimming. Type IIx fibres are associated instead with short, high-intensity efforts and fatigue more quickly.

15. A runner needs repeated speed and power efforts, while retaining more fatigue resistance than Type IIx fibres provide; which fibre type best matches this profile?

A. Type IIx fibres, suited to rapid, forceful efforts that fatigue more quickly than Type IIa.

B. Type I fibres, suited to brief anaerobic efforts through rapid contraction and high force.

C. Type IIa fibres, suited to quick, forceful efforts with more fatigue resistance than Type IIx.

D. Type I fibres, suited to sustained aerobic efforts through slow contraction and high fatigue resistance.

Answer: (C)

Explanation

Type IIa fibres contract quickly, produce high force, and resist fatigue more than Type IIx fibres; they support speed and power activities. Type IIx fibres also produce high force, but they fatigue faster and are better suited to brief, intense efforts.

16. Which fibre type is most suited to a short, high-intensity 100-metre sprint because it contracts rapidly and produces high force but fatigues quickly?

A. A mixed Type I and Type IIa profile

B. Type IIa fibres

C. Type IIx fibres

D. Type I fibres

Answer: (C)

Explanation

Type IIx fibres contract rapidly, produce high force, and fatigue faster than Type IIa fibres, fitting short, high-intensity anaerobic activity such as a 100-metre run. Type IIa fibres also support speed and power, but they resist fatigue more effectively.

17. How does an acute muscular response differ from a chronic response to exercise?

A. An acute response occurs after repeated sessions, whereas a chronic response develops during a single session.

B. An acute response occurs during or immediately after one session, whereas a chronic response develops over a longer period.

C. An acute response occurs during exercise, whereas a chronic response develops only immediately after one session.

D. An acute response develops over a longer period, whereas a chronic response occurs during or immediately after one session.

Answer: (B)

Explanation

Acute muscular responses happen during or immediately after a single exercise session, while chronic responses develop over a longer period. The key distinction is the timescale, not whether the response happens during a session or after it.

18. During exercise, how does the body meet the increased oxygen and glucose demand of working muscles?

A. It lowers muscular metabolic activity to match the existing blood supply.

B. It increases blood supply to resting muscles to divert oxygen from working muscles.

C. It increases blood supply to the working muscles as their metabolic activity rises.

D. It reduces blood supply to the working muscles as their metabolic activity rises.

Answer: (C)

Explanation

Exercise raises muscular metabolic activity and oxygen and glucose demand, which is met by increased blood supply to the working muscles. Reducing blood supply would not provide the needed delivery of oxygen and glucose.

19. What change defines muscle hypertrophy after regular overloaded resistance training?

A. Muscle fibres develop small injuries during strenuous exercise.

B. Muscle fibres enlarge as their protein content increases.

C. Muscle fibres contract more strongly without changing size.

D. Muscle fibres gain more capillaries for oxygen delivery.

Answer: (B)

Explanation

Hypertrophy is an increase in muscle size as fibres enlarge and their muscle-cell protein content rises with regular overloaded resistance training. Microtears are exercise-related fibre injuries, not the definition of hypertrophy.

20. How can muscle hypertrophy contribute to improved aerobic energy production?

A. It creates more room for mitochondria, whose increased number and size can improve aerobic energy production.

B. It raises muscle glycogen storage, which prevents mitochondria from using oxygen during exercise.

C. It increases fibre protein content, which directly replaces the need for mitochondrial aerobic energy production.

D. It increases capillary density, which causes mitochondria to shrink while improving aerobic energy production.

Answer: (A)

Explanation

Hypertrophy provides more room for mitochondria, and increases in mitochondrial number and size improve the muscle's capacity to produce aerobic energy. Greater capillarisation can also benefit performance, but it is a distinct adaptation rather than the mechanism described here.

21. An endurance-trained athlete can sustain a higher exercise intensity with less lactate accumulation. Which adaptation best explains this effect?

A. Increased capillarisation improves oxygen and nutrient delivery and waste removal, supporting greater fat and oxygen use.

B. Increased muscle protein content gives fibres more room for mitochondria and directly clears lactate.

C. Thicker cartilage improves blood delivery to muscle fibres and delays lactate accumulation.

D. Greater tendon strength improves joint stability, reducing the muscles' need to use aerobic energy.

Answer: (A)

Explanation

Endurance training increases capillarisation, improving delivery of oxygen and nutrients and removal of waste; better use of fat and oxygen helps muscles work harder with less lactate and delays fatigue. Greater tendon strength can support joints, but it does not explain the described lactate-related effect.

22. Under the all-or-none law, what happens when a nerve impulse is sufficient to activate a motor unit?

A. One fibre contracts first, then the remaining fibres contract if the impulse continues.

B. The strongest fibres in that motor unit contract while weaker fibres remain relaxed.

C. The motor unit contracts in proportion to the strength of the nerve impulse.

D. All muscle fibres in that motor unit contract, or none of them do.

Answer: (D)

Explanation

Once a motor unit is activated, all of its muscle fibres contract together, or none do. The graded response applies to recruitment across motor units, not partial contraction of fibres within one activated unit.

23. Which statement accurately describes age-related muscle loss and the stated rate for inactivity?

A. Sarcopenia begins around age 30, and inactive people may lose 3% to 5% of muscle mass per decade after age 50.

B. Sarcopenia begins around age 30, and active people may lose 3% to 5% of muscle mass per decade after age 50.

C. Sarcopenia begins around age 50, and active people may lose 3% to 5% of muscle mass per decade after age 30.

D. Sarcopenia begins around age 50, and inactive people may lose 3% to 5% of muscle mass per decade after age 30.

Answer: (D)

Explanation

Sarcopenia begins around age 50, while physically inactive people can lose 3% to 5% of muscle mass per decade after age 30; active people also experience some muscle loss. The stated percentage applies to inactive people, not to active people.

24. A person experiences a sudden, painful muscle contraction they cannot control during exercise. What is this most likely to be?

A. A voluntary contraction, a deliberate movement typically initiated to control skeletal muscles.

B. Sarcopenia, an age-related reduction in muscle mass that occurs as a sudden contraction.

C. A cramp, an involuntary contraction that may be associated with exercise, dehydration, or inadequate blood supply.

D. A muscle tear, a structural injury that is defined by persistent loss of muscle control.

Answer: (C)

Explanation

A cramp is a sudden, involuntary muscle contraction that can be painful and may be associated with exercise, dehydration, or inadequate blood supply. A voluntary contraction is a controlled action, unlike the involuntary event described.