Easy
Health & Fitness
Training, Food & Rest
The settled basics of exercise, nutrition and recovery.
Sample question
Start quiz
Cardiovascular exercise primarily strengthens which systems?
The Body Under Load
Bone thickens where it is loaded, cartilage has no blood supply, and sweat only cools you if it can evaporate. General physiology, no advice.
About this topic
Living tissue is not passive material. Bone lays down more where it is repeatedly loaded and thins where it is not, which is why long spaceflight is a problem for the skeleton and why the racket arm of a career tennis player has measurably denser bone than the other. Tendon stores and returns elastic energy. Muscle adds contractile protein. The whole structure is continually being rebuilt around the demands placed on it. A few structures are exceptions, and the exceptions matter. Articular cartilage has no blood supply of its own and heals poorly for that reason. Cooling depends on evaporation rather than on sweat itself, so humid air defeats it. These questions cover that mechanical and thermal side of physiology — how the body handles load and heat, described rather than prescribed.
Questions & answers
The Body Under Load: all 10 questions and answers
Every question in this quiz is listed below with its correct answer and the reasoning behind it. Play first if you would rather not see the answers — or read through as a study sheet.
Play it insteadShow all answers and explanationsHide answers
-
1Wolff's law describes what?
- A The rate at which muscle is lost with age
- B How joints lose fluid overnight
- C The relationship between height and weight
- D Bone remodelling itself in response to the loads placed on it Correct
Answer: D. Bone remodelling itself in response to the loads placed on it
Why: Julius Wolff set the idea out in the nineteenth century. It is why extended weightlessness in orbit reduces bone density and why loading is central to keeping it.
-
2Sweating cools the body by which mechanism?
- A Widening of blood vessels in the gut
- B Reducing the amount of heat the body produces
- C Evaporation from the skin, which carries heat away with the departing water Correct
- D The sweat itself being cooler than the body
Answer: C. Evaporation from the skin, which carries heat away with the departing water
Why: This is why humid air feels so much harder to work in. When the surrounding air is close to saturated, sweat runs off instead of evaporating and does almost nothing.
-
3Articular cartilage inside a joint has which notable property?
- A It is composed mainly of calcium
- B It has no blood supply of its own Correct
- C It is packed with nerve endings
- D It regrows rapidly after injury
Answer: B. It has no blood supply of its own
Why: Nutrients reach it by diffusion through joint fluid as the joint moves. That slow supply is a large part of why damage to it heals so poorly.
-
4Agonist and antagonist muscles are best described as what?
- A A pair that act in opposition across the same joint Correct
- B Two muscles that produce the same movement
- C The muscles of the heart and the gut
- D The largest and the smallest muscles in the body
Answer: A. A pair that act in opposition across the same joint
Why: The biceps and triceps are the standard pairing. Smooth movement depends on the antagonist releasing in step rather than simply switching off.
-
5What does the diaphragm do during breathing in?
- A It contracts to push air out
- B It filters dust from the incoming air
- C It warms blood returning to the heart
- D It contracts and flattens, drawing air into the lungs Correct
Answer: D. It contracts and flattens, drawing air into the lungs
Why: The lungs contain no muscle of their own. All the mechanical work of quiet breathing comes from the diaphragm and the muscles between the ribs.
-
6The hip and the shoulder are examples of which joint type?
- A Pivot
- B Saddle
- C Ball and socket Correct
- D Hinge
Answer: C. Ball and socket
Why: The shoulder trades stability for range of movement, since its socket is shallow. That is why it dislocates far more readily than the hip does.
-
7Spending weeks at high altitude produces which change in the blood?
- A Thicker white blood cells
- B More red blood cells, raising oxygen-carrying capacity Correct
- C Fewer red blood cells
- D A permanent fall in blood volume
Answer: B. More red blood cells, raising oxygen-carrying capacity
Why: The kidneys release more erythropoietin when oxygen is scarce. The adaptation takes weeks rather than days, and it reverses on return to sea level.
-
8Staying balanced while standing still depends chiefly on which combination of inputs?
- A The inner ear, vision, and sensors in muscles and joints Correct
- B The lungs and the diaphragm
- C The liver and the kidneys
- D Temperature receptors in the skin
Answer: A. The inner ear, vision, and sensors in muscles and joints
Why: Because the three sources are pooled, losing one is usually manageable and losing two is not. That is why closing the eyes on an unstable surface is far harder than closing them on firm ground.
-
9A plyometric movement is one that does what?
- A Holds a fixed position without moving
- B Moves a joint through its range very slowly
- C Involves no ground contact at all
- D Uses a rapid stretch immediately followed by a shortening contraction Correct
Answer: D. Uses a rapid stretch immediately followed by a shortening contraction
Why: Tendon stores elastic energy during the brief stretch and returns it. That is why a countermovement jump goes higher than one begun from a still squat.
-
10Warming up raises muscle temperature, which does what?
- A Empties the muscles of stored fuel
- B Permanently increases lung volume
- C Speeds the chemical reactions supplying energy and makes tissue more pliable Correct
- D Lowers heart rate back toward resting levels
Answer: C. Speeds the chemical reactions supplying energy and makes tissue more pliable
Why: Blood flow is redistributed toward working muscle at the same time. That redistribution takes a couple of minutes to settle, which is part of why the first minutes of hard effort feel worst.
Frequently asked questions about The Body Under Load
How many questions are in The Body Under Load?
The Body Under Load has 10 questions and takes about 6 minutes to finish. It is rated Medium and sits in our Health & Fitness category.
How is The Body Under Load scored?
Each of the 10 correct answers adds 10 XP, up to 100 XP for a clean run. Wrong answers cost you nothing, and your full question-by-question review is shown at the end.
Are the answers to The Body Under Load explained?
Yes. All 10 questions carry a written explanation of why the correct answer is right, so the quiz works as a study sheet as well as a test.
Can I replay The Body Under Load?
Yes, as often as you like. The questions and the answer options are reshuffled on each run, and you can use Practice Mistakes afterwards to retry only the ones you missed. No account is needed to play.
QuizKite Quality Guarantee
Every quiz on QuizKite is researched, written and fact-checked by hand against reliable references, with an explanation for each answer. Read our full Editorial Policy to learn more about our content standards.
Keep going
More Health & Fitness
Medium
Health & Fitness
Muscles, Oxygen and Effort
Fibre types, lactate, motor units and what actually happens inside a working muscle.
Sample question
Start quiz
Skeletal muscle fibres are conventionally divided into which two broad types?
Medium
Education & Learning
School Systems Around the World
Selection, apprenticeships, entrance exams and how differently countries organise schooling.
Sample question
Start quiz
The word kindergarten was coined in which country?
Easy
General Knowledge
Everyday Origins
Where ordinary words and objects actually came from.
Sample question
Start quiz
The English word "salary" comes from the Latin word for which substance?
Easy
Food & Drink
From the Kitchen
What familiar dishes are made of, and where they came from.
Sample question
Start quiz
Which spice is harvested from the stigmas of a crocus flower?
Medium
Economics & Money
Money, Markets & Meaning
What the words in every economic headline actually mean.
Sample question
Start quiz
What is the currency of Japan?