Surely the image of the spartiates created by pop culture has to be based on some "real" stuff.
You might want to check out the answer by /u/Iphikrates to the question:
/u/Iphikrates also talked a lot about the Spartans on the Askhistorians podcast:
AskHistorians Podcast 061 - Hoplite Warfare and the Battle of Nemea.
He also collaborated with Invicta to make a YouTube video on this subject:
Misunderstood Moments in History - The Spartan Myth