Which of the following best represents the causes of stiff muscles?
a. stiff muscles only result from overwork.
b. stiff muscles only result from prolonged periods of inactivity.
c. stiff muscles result from both over- and underworking them.
d. stiff muscles are mostly the result of painful injuries.

The most probable answer to this question would be C. Stiff muscles result from both over- and under working them. Stiff muscles don't just come from overwork but also in prolonged periods of inactivity. When overworking, they stiffen to prevent the muscle to be to used that might result to far graver injuries including it snapping into two. Under worked muscles or muscles that have remained dormant for prolonged periods usually become stiff. This is because of that it may become to weak to support your body when the time comes for it to be used again. Painful injuries, on the other hand, sometimes result to a stiff muscle and sometimes not, is solely depends on the kinds of injury that happened.