IMO Practice Test — Locomotion and Movement
6 Questions • 15 min • Olympiad level
15:00
Question 1 of 6
Muscles are arranged in antagonistic pairs because a muscle can only:
Pull, not push
Push, not pull
Grow, not shrink
Rest, not work
Explanation: Since a muscle only pulls, an opposing muscle is needed to move the bone the other way.
Question 2 of 6
During contraction the sarcomere shortens even though the filaments stay the same length. This is explained by:
The filaments sliding past each other
The filaments dissolving
Bones bending
Loss of calcium
Explanation: The sliding filament theory: overlap increases as filaments slide, shortening the sarcomere without changing filament length.
Question 3 of 6
A blow to the head is less likely to damage the brain because the skull is made of:
Immovable joints forming a protective case
Hinge joints
Ball-and-socket joints
Soft muscle
Explanation: The fixed, immovable joints of the skull form a rigid protective box around the brain.
Question 4 of 6
Older people are more prone to fractures partly because of osteoporosis, in which bones:
Lose minerals and become brittle
Gain extra calcium
Turn into muscle
Become more flexible
Explanation: Loss of bone minerals like calcium makes bones weak and easy to break.
Question 5 of 6
The shoulder allows a wider range of movement than the elbow because it is a:
Ball-and-socket joint
Hinge joint
Fixed joint
Slightly movable joint
Explanation: A ball-and-socket joint permits movement in all directions, unlike the one-plane hinge elbow.
Question 6 of 6
Without enough ATP, a muscle cannot relax properly (as in cramps) because ATP is needed to:
Detach the filaments and reset the sarcomere
Make more bone
Add calcium forever
Stop the nerve
Explanation: ATP is required both for contraction and to release the cross-bridges so the muscle can relax.