Deep Winter here, and as one does, I dream of Spring.
According to Classicist M. L. West, “Swinging is a recurrent feature of Indo-European springtime and midsummer festivities.”
Sure enough: in Hindu India, in ancient (and modern) Greece and Rome, in Russia, in the Balkans, in the Baltics: springtime (often Easter) is when you hang a swing from the leafing-out branch of a tree and jump on for a ride (and better it be if it's with a buddy). Half the Latvian Easter dainas that I've seen focus on swinging. There's said to be a sympathetic correlation between how high one swings and how high the crops will stand in the coming growing season.
ty!