Free MBLEx Test Kinesiology and Biomechanics Questions and Answers — Questions and Answers
Question 1: A client is performing a bicep curl. The action of lowering the weight in a controlled manner involves which type of muscle contraction in the biceps brachii?
- Isometric
- Concentric
- Eccentric (Correct answer)
- Isokinetic
Correct answer: Eccentric
An eccentric contraction occurs when a muscle lengthens under tension. In the case of lowering a weight during a bicep curl, the biceps brachii is actively engaged to control the movement, but it is elongating rather than shortening. Concentric contractions involve muscle shortening (lifting the weight), and isometric contractions involve tension without a change in muscle length.
Question 2: A client is standing and performs abduction of the hip by lifting their leg out to the side. This movement occurs primarily in which cardinal plane?
- Sagittal
- Transverse
- Oblique
- Frontal (Correct answer)
Correct answer: Frontal
The frontal (or coronal) plane divides the body into anterior and posterior (front and back) halves. Movements in this plane are side-to-side, such as hip abduction and adduction. The sagittal plane involves forward and backward movements (flexion/extension), and the transverse plane involves rotational movements.
Question 3: During a proprioceptive neuromuscular facilitation (PNF) stretching technique, a therapist asks the client to contract the quadriceps to encourage the hamstrings to relax. This physiological principle is known as:
- Reciprocal inhibition (Correct answer)
- Autogenic inhibition
- Stretch reflex
- Post-isometric relaxation
Correct answer: Reciprocal inhibition
Reciprocal inhibition is the neuromuscular process where muscles on one side of a joint relax to accommodate the contraction of muscles on the other side of that joint. When the agonist muscle (quadriceps) contracts, the antagonist muscle (hamstrings) is neurologically signaled to relax, allowing for a deeper stretch.
Question 4: Which of the following describes a closed kinetic chain movement?
- Leg extension on a machine
- Throwing a baseball
- Performing a squat (Correct answer)
- Bicep curl with a dumbbell
Correct answer: Performing a squat
In a closed kinetic chain exercise, the distal segment (hand or foot) is fixed and remains in constant contact with a surface. During a squat, the feet are fixed to the floor, and the rest of the body moves. The other options are open kinetic chain movements, where the distal segment moves freely in space.
Question 5: For upward rotation of the scapula to occur efficiently, the upper trapezius, lower trapezius, and serratus anterior must work together synergistically. This type of muscular teamwork is known as a:
- Reversal of action
- Force couple (Correct answer)
- Prime mover action
- Fixator contraction
Correct answer: Force couple
A force couple refers to two or more muscles pulling in different directions on an object to create a rotational movement. For upward rotation of the scapula, the upper trapezius pulls up, the lower trapezius pulls down, and the serratus anterior pulls forward, all contributing to the same rotational motion.
Question 6: A client presents with an anterior pelvic tilt. Which pair of muscles is most likely tight and short, contributing to this postural deviation?
- Rectus abdominis and hamstrings
- Hip flexors and erector spinae (Correct answer)
- Gluteus maximus and external obliques
- Adductor longus and quadratus lumborum
Correct answer: Hip flexors and erector spinae
An anterior pelvic tilt is created by a force couple where the hip flexors (e.g., iliopsoas, rectus femoris) pull the front of the pelvis down, and the lumbar erector spinae pull the back of the pelvis up. This results in the characteristic forward-tilted position. Conversely, the rectus abdominis and hamstrings would be lengthened and are responsible for a posterior pelvic tilt.
Free MBLEx Test Kinesiology and Biomechanics Questions and Answers
A client is performing a bicep curl.
The action of lowering the weight in a controlled manner involves which type of muscle contraction in the biceps brachii?