PAS Biomechanical Analysis & Movement 2 — Questions and Answers
Question 1: Which plane of motion does a lateral trunk bend (side flexion) primarily occur in?
- Sagittal plane
- Frontal plane (Correct answer)
- Transverse plane
- Oblique plane
Correct answer: Frontal plane
Lateral trunk flexion occurs in the frontal (coronal) plane, dividing the body into front and back halves.
Question 2: The center of gravity in a standing adult is typically located at approximately what vertebral level?
- T12
- L2
- S2 (Correct answer)
- L5
Correct answer: S2
The center of gravity in a typical standing adult is located just anterior to the second sacral segment (S2).
Question 3: Which term describes the rotational force produced by a muscle acting at a joint?
- Vector
- Torque (Correct answer)
- Impulse
- Inertia
Correct answer: Torque
Torque is the rotational force a muscle generates about a joint axis, calculated as force multiplied by the moment arm.
Question 4: During gait, which phase involves the foot making initial contact with the ground?
- Midstance
- Terminal stance
- Loading response
- Initial contact (Correct answer)
Correct answer: Initial contact
Initial contact is the very beginning of the stance phase when the heel (or foot) first touches the ground.
Question 5: Excessive anterior pelvic tilt is most commonly associated with tightness in which muscle group?
- Hamstrings
- Hip flexors (Correct answer)
- Gluteus maximus
- Tibialis anterior
Correct answer: Hip flexors
Tight hip flexors (iliopsoas) pull the anterior pelvis downward, causing an anterior pelvic tilt and increased lumbar lordosis.
Question 6: Which type of muscle contraction occurs when the muscle generates force while lengthening?
- Concentric
- Isometric
- Eccentric (Correct answer)
- Isokinetic
Correct answer: Eccentric
Eccentric contraction occurs when a muscle produces force while elongating, such as the quadriceps controlling descent during a squat.
Question 7: Pronation of the subtalar joint is described as a combination of which three motions?
- Dorsiflexion, eversion, and abduction (Correct answer)
- Plantarflexion, inversion, and adduction
- Dorsiflexion, inversion, and abduction
- Plantarflexion, eversion, and abduction
Correct answer: Dorsiflexion, eversion, and abduction
Subtalar pronation is a triplanar motion consisting of dorsiflexion, eversion, and abduction occurring simultaneously.
PAS Biomechanical Analysis & Movement 2
Which plane of motion does a lateral trunk bend (side flexion) primarily occur in?