Physiology & Rehabilitation MCQs

Which of the following best describes the normal 'screw-home' kinematic mechanism of the knee as it moves from active flexion into terminal extension in an open kinetic chain?

During the single-leg stance phase of gait, the abductor muscles must generate sufficient torque to balance the body weight. If the distance from the body's center of gravity to the center of the femoral head is exactly three times the distance from the abductor insertion to the center of the femoral head, what is the approximate abductor muscle force required to maintain a level pelvis?

Which type of muscle contraction generates the greatest force per unit of muscle cross-sectional area, but is also most strongly associated with the highest risk of delayed onset muscle soreness (DOMS) and musculotendinous injury?

A 30-year-old male weightlifter feels a tear in his anterior chest while performing a heavy bench press. Which segment of the pectoralis major muscle is most commonly torn in this mechanism, and where does it insert on the humerus?

In skeletal muscle physiology, which type of muscle contraction is capable of generating the maximum peak force?

Skeletal muscle fibers are classified based on their metabolic and contractile properties. Which of the following biochemical and functional profiles is characteristic of Type I (slow-twitch) muscle fibers?

During muscle contraction, the maximum force generated by a single motor unit depends heavily on the type of contraction performed. Which type of muscle contraction is capable of generating the greatest absolute peak force?

Which of the following best characterizes Type I muscle fibers compared to Type IIb fibers?

During an active concentric muscle contraction, the sarcomere actively shortens. According to the sliding filament theory, which of the following statements regarding the structural bands is correct?

During the normal adult gait cycle, the absolute highest compressive joint reaction forces experienced by the hip joint typically occur during which specific phase?

A marathon runner predominantly relies on specific muscle fibers during a race. Which of the following characteristics best describes the primary muscle fiber type utilized during this endurance activity?

During a rapid, forceful eccentric contraction, a protective neural mechanism acts to inhibit the agonist muscle to prevent musculotendinous rupture. Which receptor is responsible for this autogenic inhibition, and what parameter does it primarily sense?

Which of the following physiologic and structural characteristics best differentiates Type IIb (fast-twitch glycolytic) muscle fibers from Type I (slow-twitch oxidative) muscle fibers?

During the normal human gait cycle, which muscle undergoes a critical eccentric contraction at initial contact (heel strike) to decelerate the foot and prevent it from slapping against the ground?

During the stance phase of normal human gait, the peak compressive loads across the articular cartilage of the knee can exceed several times body weight. Under these high-load, high-motion conditions, what is the primary mode of joint lubrication?

When evaluating muscle fiber types in an elite long-distance runner, one would expect a higher proportion of Type I fibers compared to a sprinter. Which of the following is a key physiological characteristic of Type I muscle fibers?

During normal human walking, the articular cartilage of the knee is subjected to varying loads and sliding speeds. Which lubrication mechanism is most predominant during the swing phase of the gait cycle, when the joint experiences high sliding speeds and relatively low loads?

Bupivacaine is commonly used for regional anesthesia and postoperative pain control in orthopedics. Its primary mechanism of action involves the blockade of which of the following neuronal ion channels?

During a heavy eccentric contraction, such as the lowering phase of a bicep curl, the muscle generates active tension while lengthening. Which of the following describes the fundamental structural and functional unit of the muscle fiber that lengthens during this process?