I bought these thermals for my g-son who plays on a flag football team.  The uniform is just shorts, long socks, and the numbered jersey.  I decided that the long underwear would hide well under the uniform for those really cold mornings.  So I ordered and had them ready, but did not show them to him until he had a cold weather game (just in case he would balk at the idea).

He actually liked the idea of the long underwear and he was very pleasantly surprised at how warm they kept him.
I have noticed that several of the boys now seem to be wearing them too -so either my idea was not at all original, or the boys have exchanged notes.  ;-)

He likes these so much that he wants to wear them every time he plays outside  -football or not.

They fit well and are apparently very comfortable.