In the peloponnesian war why did the athenians not want to fight sparta on land?

In the peloponnesian war Athenians don't want to fight Sparta on land because they had naval supremacy over the Spartans.    

Explanation:

The Peloponnesian war was the Greek war which was fought between the Delian league which was led by the Athens and the Peloponnesian league which was led by the Spartans. This was fought from 431 to 404 BC.

The war resulted in the Athens losing to the Spartans in the war. In the war, the Athens were not in a favor of fighting the war on the land because the Athens had upper hand over the Spartans in the naval region.