Menu

Physiology & Rehabilitation MCQs

Practice Set 20 of 26

This practice set contains high-yield board review questions covering key concepts in Physiology & Rehabilitation. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 381

Topic: Physiology & Rehabilitation

During a postoperative rehabilitation protocol, a patient uses a Cybex machine that maintains a constant speed of movement regardless of the force applied. What type of muscle contraction does this represent?

. Isometric
. Isotonic concentric
. Isotonic eccentric
. Isokinetic
. Plyometric

Correct Answer & Explanation

. Isokinetic

Explanation

Isokinetic exercises involve muscle contraction where the speed of movement is kept constant by a dynamometer machine throughout the range of motion. This allows for maximal mechanical resistance at every point in the arc of motion.

Question 382

Topic: Physiology & Rehabilitation

Which of the following physiological or biochemical characteristics is true regarding Type I (slow-twitch) skeletal muscle fibers compared to Type II fibers?

. Higher glycogen content
. Lower mitochondrial density
. Rely primarily on anaerobic glycolysis
. Higher concentration of myoglobin
. Faster rate of fatigue

Correct Answer & Explanation

. Higher concentration of myoglobin

Explanation

Type I muscle fibers are 'slow oxidative' fibers designed for endurance. They are highly fatigue-resistant and rely on aerobic metabolism. Consequently, they possess a high density of mitochondria and a high concentration of myoglobin (giving them a red appearance) to facilitate oxygen transport.

Question 383

Topic: Physiology & Rehabilitation

To maximally decrease the joint reaction force across an osteoarthritic hip during the stance phase of gait, a patient should be instructed to hold a cane in the contralateral hand. Biomechanically, this intervention reduces the hip joint reaction force primarily by:

. Shifting the patient's center of gravity laterally away from the affected hip
. Providing a counter-torque that decreases the required force generation by the ipsilateral hip abductors
. Increasing the lever arm of the body weight relative to the center of rotation
. Decreasing the lever arm of the abductor muscles
. Directing the ground reaction force anteriorly

Correct Answer & Explanation

. Providing a counter-torque that decreases the required force generation by the ipsilateral hip abductors

Explanation

Using a cane in the contralateral hand produces an upward ground reaction force that generates a torque acting in the same rotational direction as the hip abductors (opposite to the torque of body weight). This drastically reduces the force the abductor muscles must generate to keep the pelvis level. Because the pull of the abductors constitutes the largest component of the hip joint reaction force, decreasing their required force dramatically offloads the joint.

Question 384

Topic: Physiology & Rehabilitation

During a prolonged endurance event, such as a marathon, the athlete's skeletal muscles predominantly rely on muscle fibers characterized by which of the following physiological profiles?

. High myosin ATPase activity, low oxidative capacity
. Low myosin ATPase activity, high myoglobin content
. High glycogen content, fast twitch speed
. Fast contraction, high glycolytic capacity
. Large motor neuron size, easily fatigued

Correct Answer & Explanation

. Low myosin ATPase activity, high myoglobin content

Explanation

Endurance athletes rely predominantly on Type I (slow-twitch) muscle fibers. These fibers have a low myosin ATPase activity, high myoglobin content, high oxidative capacity, and are highly resistant to fatigue.

Question 385

Topic: Physiology & Rehabilitation

Which type of joint lubrication predominates in healthy human articular cartilage during the normal walking cycle when the joint surfaces are undergoing relative motion at high speeds and low loads?

. Boundary lubrication
. Elastohydrodynamic lubrication
. Weeping lubrication
. Squeeze-film lubrication
. Hydrostatic lubrication

Correct Answer & Explanation

. Elastohydrodynamic lubrication

Explanation

Elastohydrodynamic lubrication (a form of fluid film lubrication) predominates under dynamic conditions of high speed and low load (such as the swing phase of gait). The deformation of the elastic articular cartilage increases the surface area and maintains a continuous thin fluid film, minimizing friction.

Question 386

Topic: Physiology & Rehabilitation

Compared to isometric and concentric muscle contractions, what is the biomechanical and metabolic profile of an eccentric muscle contraction?

. Generates the least force and requires the most ATP
. Generates the most force and requires the most ATP
. Generates the most force and requires the least ATP
. Generates less force than concentric but uses more ATP
. Force generation and ATP consumption are equal across all types

Correct Answer & Explanation

. Generates the most force and requires the least ATP

Explanation

Eccentric contractions (muscle lengthening under tension) can generate the highest maximal force of the three contraction types. They also do so more efficiently, consuming the least amount of ATP.

Question 387

Topic: Physiology & Rehabilitation

During the normal human gait cycle, the gluteus maximus exhibits its peak electromyographic (EMG) activity during which phase?

. Initial contact (heel strike) to loading response
. Mid-stance
. Terminal stance
. Pre-swing
. Initial swing

Correct Answer & Explanation

. Initial contact (heel strike) to loading response

Explanation

The gluteus maximus peaks in activity from initial contact to early loading response. It acts eccentrically to decelerate the forward momentum of the trunk and prevent hip flexion collapse.

Question 388

Topic: Physiology & Rehabilitation

During the normal gait cycle, which muscle undergoes an eccentric contraction at initial contact (heel strike) to prevent foot slap?

. Gastrocnemius
. Tibialis posterior
. Peroneus longus
. Tibialis anterior
. Extensor hallucis longus

Correct Answer & Explanation

. Tibialis anterior

Explanation

The tibialis anterior contracts eccentrically during initial contact to slowly lower the foot to the ground. Weakness or denervation of this muscle results in a foot slap or steppage gait.

Question 389

Topic: Physiology & Rehabilitation

During the lowering phase of a heavy bicep curl, the biceps brachii muscle produces force while lengthening. This type of muscle contraction is defined as:

. Isometric
. Concentric
. Eccentric
. Isokinetic
. Plyometric

Correct Answer & Explanation

. Eccentric

Explanation

An eccentric contraction occurs when a muscle develops tension while simultaneously lengthening (e.g., the lowering phase of a bicep curl). A concentric contraction involves muscle shortening during force production. An isometric contraction involves force production without a change in muscle length. Eccentric contractions generate the highest forces and are most commonly associated with delayed-onset muscle soreness (DOMS).

Question 390

Topic: Physiology & Rehabilitation
During a muscle biopsy, fibers are identified that are highly resistant to fatigue, depend on aerobic metabolism, and contain large amounts of myoglobin. These fibers are most characteristic of which type of skeletal muscle?
. Type IIa
. Type IIb
. Type IIx
. Type I
. Type III

Correct Answer & Explanation

. Type I

Explanation

Type I muscle fibers are slow-twitch, aerobic, fatigue-resistant fibers with high mitochondrial density and myoglobin content. They are predominant in postural muscles such as the soleus.

Question 391

Topic: Physiology & Rehabilitation

A marathon runner sustains a mild hamstring strain. Which muscle fiber type is predominant in the hamstring muscles adapted for long-distance endurance running, and what is its primary metabolic pathway?

. Type I; anaerobic glycolysis
. Type I; oxidative phosphorylation
. Type IIa; anaerobic glycolysis
. Type IIb; oxidative phosphorylation
. Type IIb; anaerobic glycolysis

Correct Answer & Explanation

. Type I; oxidative phosphorylation

Explanation

Type I (slow-twitch) muscle fibers are built for endurance and possess high numbers of mitochondria and abundant myoglobin. They rely primarily on oxidative phosphorylation for sustained, aerobic energy production.

Question 392

Topic: Physiology & Rehabilitation

During the normal human gait cycle, which of the following muscles undergoes primarily eccentric contraction at heel strike to prevent the clinical phenomenon of 'foot slap'?

. Tibialis anterior
. Gastrocnemius
. Quadriceps femoris
. Hamstrings
. Gluteus medius

Correct Answer & Explanation

. Tibialis anterior

Explanation

At heel strike (initial contact), the foot is rapidly plantarflexing. The tibialis anterior, which is a dorsiflexor, fires eccentrically to control the rate of plantar flexion and gently lower the foot to the ground. Failure of this eccentric contraction results in a 'foot slap' gait.

Question 393

Topic: Physiology & Rehabilitation
A patient suffers a penetrating trauma to the spinal cord resulting in Brown-Séquard syndrome. Clinical examination below the level of the lesion will typically demonstrate:
. Ipsilateral loss of pain and temperature, contralateral loss of motor function
. Ipsilateral loss of motor function and proprioception, contralateral loss of pain and temperature
. Bilateral loss of motor function, preservation of dorsal columns
. Contralateral loss of proprioception, ipsilateral loss of pain and temperature
. Bilateral loss of pain and temperature, preservation of motor function

Correct Answer & Explanation

. Ipsilateral loss of motor function and proprioception, contralateral loss of pain and temperature

Explanation

Brown-Séquard syndrome (hemisection of the spinal cord) causes ipsilateral loss of motor function (corticospinal tract) and proprioception/vibration (dorsal columns), and contralateral loss of pain and temperature sensation (spinothalamic tract, which decussates 1-2 levels above entry).

Question 394

Topic: Physiology & Rehabilitation

During the normal human gait cycle, at which specific phase is the anterior tibial muscle maximally active?

. Midstance
. Terminal stance
. Heel strike to foot flat
. Midswing
. Toe-off

Correct Answer & Explanation

. Heel strike to foot flat

Explanation

The tibialis anterior acts eccentrically from heel strike (initial contact) to foot flat (loading response) to decelerate plantar flexion and prevent the foot from slapping the ground. This eccentric contraction represents its period of peak electrical activity during the normal gait cycle.

Question 395

Topic: Physiology & Rehabilitation

A muscle contraction in which the muscle generates tension while actively lengthening is defined as which of the following?

. Concentric
. Eccentric
. Isometric
. Isokinetic
. Isotonic

Correct Answer & Explanation

. Eccentric

Explanation

An eccentric contraction occurs when a muscle lengthens while generating force, often acting to decelerate a joint. This specific type of contraction generates the highest maximum force compared to isometric or concentric contractions.

Question 396

Topic: Physiology & Rehabilitation

Which type of joint lubrication is most heavily relied upon by human articular joints during the stance phase of normal walking, when loads are highest and sliding speeds are relatively low?

. Elastohydrodynamic lubrication
. Boundary lubrication
. Hydrodynamic lubrication
. Squeeze-film lubrication
. Weeping lubrication

Correct Answer & Explanation

. Boundary lubrication

Explanation

Boundary lubrication is the primary mechanism under high loads and low speeds, depending on molecules like lubricin attached to the articular surfaces to prevent direct cartilage-to-cartilage contact. Fluid-film (elastohydrodynamic) lubrication dominates at higher sliding speeds.

Question 397

Topic: Physiology & Rehabilitation

Skeletal muscle fibers are differentiated based on their functional and metabolic capabilities. Which of the following characteristics accurately describes Type I skeletal muscle fibers?

. They rely primarily on anaerobic glycolysis for energy production
. They fatigue rapidly during sustained physical activity
. They have a high density of mitochondria and myoglobin
. They are recruited primarily during explosive, high-power movements
. They exhibit a fast-twitch mechanical response

Correct Answer & Explanation

. They have a high density of mitochondria and myoglobin

Explanation

Type I muscle fibers are slow-twitch, oxidative fibers uniquely adapted for endurance and sustained postural control. They possess a high density of mitochondria, myoglobin, and capillaries, allowing them to rely on aerobic metabolism and strongly resist fatigue.

Question 398

Topic: Physiology & Rehabilitation

Understanding the dynamic joint reaction forces across the hip is critical for arthroplasty design and rehabilitation. During a normal gait cycle, the greatest joint reaction force across the hip occurs during which specific phase?

. Heel strike
. Mid-stance
. Toe-off
. Mid-swing
. Terminal swing

Correct Answer & Explanation

. Mid-stance

Explanation

The maximum joint reaction forces across the hip joint occur during the stance phase, particularly around mid-stance. During this phase, the abductor musculature must fire forcefully to balance the pelvis against the body weight, generating forces that can exceed three times body weight.

Question 399

Topic: Physiology & Rehabilitation

During the single-limb stance phase of normal gait, what is the approximate force transmitted across the hip joint, expressed as a multiple of body weight (BW)?

. 1 x BW
. 1.5 x BW
. 2.5 to 3 x BW
. 5 to 6 x BW
. 7 to 8 x BW

Correct Answer & Explanation

. 2.5 to 3 x BW

Explanation

During single-limb stance, the hip joint reaction force is approximately 2.5 to 3 times body weight. This force is a combination of the body weight acting on the lever arm of the pelvis and the counteracting force of the hip abductors.

Question 400

Topic: Physiology & Rehabilitation

During a drop jump exercise, the quadriceps muscle actively resists gravity to decelerate the body. What type of muscle contraction is occurring in the quadriceps?

. Isokinetic
. Isometric
. Concentric
. Eccentric
. Plyometric

Correct Answer & Explanation

. Eccentric

Explanation

An eccentric contraction occurs when a muscle generates force while actively lengthening to decelerate a joint. Eccentric contractions generate the highest peak forces and are heavily implicated in muscle strain injuries.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page