Answer:
The run on sentence here is, "Sprained ankles are common injuries for athletes, a sprain may not even need treatment."
Explanation:
A run-on sentence happens when two or more independent clauses are fused incorrectly. There are two types of run-on sentences. There are fused sentences and comma splices.
A fused sentence transpires when independent clauses work collectively with no signs of punctuation or correlating conjunctions to distribute them. A comma splice befalls when two or more independent clauses are linked exclusively by a comma.
When talking about, "Sprained ankles are common injuries for athletes, a sprain may not even need treatment." The part that is wrong here is the comma before "a." This is wrong because this is a massive voice missue.
The comma would mean to take a pause, which is a missue in human beings voice.
To correct this you would put a period for a full stop in that sentence and continue with the subject afterwords.
"Sprained ankles are common injuries for athletes. A sprain may not even need treatment.
You subsitute the comma with a period and make the lowercase an uppercase A.