Skeletal System’s
Response to Exercise
Includes
Article
Questions (10 multiple choice, 2 open-ended)
Answer Key
Your Skeletal System's Response to Exercise
Your skeletal system has 206 bones (more at birth, such as the skull, which
fuse together as the body matures) that work with your muscles to allow movement
with the bones serving as an anchor point for the muscles to attach to. This system
gives your body its shape and form. Physically active people generally have higher
bone density than inactive people. Your skeletal system responds to exercise like
your muscles in that stress (good stress in the form of exercise such as lifting a new
heavier weight) forces the body to adapt and grow to respond to this new found
stressor. Higher levels of physical activity may reduce your risk of age-related
bone loss. Regular exercise may provide lifelong benefits, particularly for skeletal
systems in children, adolescents and young adults.
Bone Mass
Calcium is the most abundant mineral in your body; with 99% stored in the
skeleton. Calcium is also one of the minerals used to send the signal to the
working muscles, telling them to contract. Your skeletal system responds to
exercise by taking in more calcium. Osteoblasts are cells that bring calcium into
bones; think osteoBlasts, build (B = Build). Osteoblasts slow down and transport
less calcium from your blood to your bones during inactivity, but exercise has the
opposite effect and increases osteoblastic activity. Exercise that requires force
through a particular bone strengthens that bone. Examples of exercise that require
force through a bone would be jumping/landing, running, cutting in a game or any
other form of impacts on the body. Exercise helps you increase the density and
strength of your bones, especially exercising regularly during the first three
decades of life. These forces create tiny micro-fractures (micro = small) in the
bones which then are repaired and heal back stronger through a process called
‘ossification.’ Ossification allows the bones to actually heal back STRONGER
(due to the extra calcium brought in by the osteoblasts) than before the microfractures.
Weight Bearing
Your skeletal system responds to weight-bearing exercise more than
nonweight-bearing exercise. Weight-bearing exercises include activities such as
weightlifting, jogging, climbing stairs, tennis, and dancing. These exercises force
your skeletal system to work against gravity; any weight bearing exercise stresses
the skeletal system and as a response to this new stress, the bones become more
dense (again, microfractures and the response of ossification). Non weight-bearing
exercises include swimming and cycling. Your skeletal system gradually loses
bone mass after age 30. Therefore, performing more weight-bearing exercise
before age 30 increases the amount of bone you can loose and may reduce your
risk of developing problems with low bone density. Weight-bearing exercise after
age 30 may help you maintain bone density. Osteoporosis is a bone loss disorder
in which the bones become porous, brittle and susceptible to fractures.
Osteoporosis is caused by a loss of calcium and other bone building minerals as
well as a lifestyle without adequate weight bearing exercise to improve or maintain
bone density.
Overtraining
Exercising too much may trigger negative responses from your skeletal
system. You can lose bone density if you exercise too much and do not take
enough calcium and vitamin D. One such example of overtraining or overuse
injuries would be stress fractures. Stress fractures do not occur as the result of a
single traumatic event (for example, a hit in football, falling off a ladder) rather too
much use which does not give the body sufficient time or resources to properly
heal from the last workout. Stress fractures are typically seen in the lower
extremities (such as feet, lower legs) and even the vertebrae, rather than upper
extremities such as the humerus or shoulder girdle. Fluoride, iron, manganese and
phosphorus are also important for healthy bones. Young women who exercise too
much may not experience menstrual periods. This may indicate low estrogen
levels, which may lead to brittle bones and osteoporosis. Weightlifting is generally
healthy for young skeletal systems, but intense and heavy weightlifting, such as
one-rep max workouts, may lead to injuries that damage growth plates in children
and adolescents. Growth plate injuries can stunt normal growth.
Soft Tissue Support
Your skeletal system may become less susceptible to bone fractures in
response to exercise, because exercise strengthens soft tissues that protect your
bones. Physical activity, such as running, playing sports and plyometrics, increases
your muscular coordination and balance. Plyometric exercises include various
forms of jumping, skipping and medicine ball throws. This reduces your risk of
skeletal injury from falling, because your muscles adapt better to sudden obstacles
and unstable surfaces through improved neuro-muscular coordination. In other
words, exercises such as jumping or medicine ball throws improve the
communication between the nervous system and muscular system, allowing the
nervous system to send messages more quickly to the muscular system. This
improved coordination can increase the likelihood of catching yourself if you slip
or fall (improved reactions or coordination); resulting in protecting your skeletal
system. Muscle-building exercises reduce your risk of skeletal injury by
increasing the size and strength of tissues that protect your bones.
Skeletal System’s Response to Exercise Article Questions
1) Which mineral is the most abundant nutrient in the body?
a. Magnesium
b. Calcium
c. Phosphorous
d. Iron
2) Which best describes the job of osteoblasts according to the article?
a. Cells that rid the bones of excess calcium
b. Increases bone’s use/intake of iron
c. Cells which increase bone marrow production
d. Cells which bring calcium into bones
3) Which of the following is not an example of weight bearing exercise mentioned in the article?
a. Jogging
b. Weight lifting
c. Swimming
d. Tennis
4) The prefix ‘osteo-‘ (osteoblast, osteoporosis) means
a. Calcium
b. Bone
c. Density
d. Lacking density or mass
5) As used in the article, what does the word ‘brittle’ mean?
a. Strong, hard to break
b. Easily broken
c. Lacking density and/or mass
d. Resilient
6) According to the article, what can result from growth plate damage?
a. Broken bones
b. Deformed joints
c. Stunted growth
d. Poor posture
7) Osteoporosis is a communicable (contagious) bone disease.
a. True
b. False
8) As used in the article, what does the prefix ‘micro-‘ (micro fractures) mean?
a. Large
b. Small
c. Frequent
d. Irregular
9) As used in the article (paragraph titled ‘Bone Mass’); what does the word ‘abundant’ most
nearly mean?
a. Sparse, lacking in quantity
b. In great quantity, large amount
c. Lightest weight
d. Heaviest, largest mass
10) According to the article, which two vitamins/minerals are essential to consume for bone health?
a. Calcium, Vitamin A
b. Vitamin A, Iron
c. Vitamin D, Calcium
d. Vitamin D, Vitamin A
Do you believe your current lifestyle includes adequate weight bearing activities to promote bone
density? If yes, support with at least two examples. If not, provide two example of activities you
could participate in to promote bone density.
Summarize the above article in three to five sentences. Briefly address each of the following
components – who, what, when, where, why and how of the article in your summary.
Skeletal System’s Response to Exercise – Multiple Choice Answer Key
1) Which mineral is the most abundant nutrient in the body?
a. Magnesium
b. Calcium
c. Phosphorous
d. Iron
2) Which best describes the job of osteoblasts according to the article?
a. Cells that rid the bones of excess calcium
b. Increases bone’s use/intake of iron
c. Cells which increase bone marrow production
d. Cells which bring calcium into bones
3) Which of the following is not an example of weight bearing exercise mentioned in the article?
a. Jogging
b. Weight lifting
c. Swimming
d. Tennis
4) The prefix ‘osteo-‘ (osteoblast, osteoporosis) means
a. Calcium
b. Bone
c. Density
d. Lacking density or mass
5) As used in the article, what does the word ‘brittle’ mean?
a. Strong, hard to break
b. Easily broken
c. Lacking density and/or mass
d. Resilient
6) According to the article, what can result from growth plate damage?
a. Broken bones
b. Deformed joints
c. Stunted growth
d. Poor posture
7) Osteoporosis is a communicable (contagious) bone disease.
a. True
b. False
8) As used in the article, what does the prefix ‘micro-‘ (micro fractures) mean?
a. Large
b. Small
c. Frequent
d. Irregular
9) As used in the article (paragraph titled ‘Bone Mass’); what does the word ‘abundant’ most
nearly mean?
a. Sparse, lacking in quantity
b. In great quantity, large amount
c. Lightest weight
d. Heaviest, largest mass
10) According to the article, which two vitamins/minerals are essential to consume for bone health?
a. Calcium, Vitamin A
b. Vitamin A, Iron
c. Vitamin D, Calcium
d. Vitamin D, Vitamin A