a long sentence is not always a run on sentence.

a sentence is sometimes defined as "a complete idea"

so "Run" can be a sentence.

but some idea's are more complex.. and require more words.

a run on sentence is 2 or more ideas.

so, in theory, "Run, skip, jump!" could be a run on.(most wouldn't think so, but...

edit to "Run, skip, jump, jog, do anything, but get your self moving!" and it expresses one idea (activity)

where as "Run, skip, jump, jog, do anything, but get your self moving, you'll be healthier and so will your heart." is a run on.

2 idea's-- (1 get moving, 2 health) (and the health aspect has 2 ideas, general good health and cardiac health!) that a lot to cram into mone sentence!)

my other obsession