Hot-housing and red-shirting

[Deepurple]

The "Hot-Housing" Syndrome
Does holding children back help or humiliate?
Yet not everyone agrees that such a delay is beneficial. In public schools, the practice of allowing children to repeat kindergarten--"red-shirting" or "hot-housing," to borrow the slang for holding college athletes back so they will be more formidable wrestlers or football players--has been attacked as a waste of scarce resources. Some observers argue that it takes a psychological toll, saddling children with the humiliation of having "flunked."

What do hot-housing and red-shirting mean in the above paragraph? Where did they come from? Thanks with appreciation.

 

[Tdol]

They both refer to holding smeone back in sports so that they will be better players later, so they have an analogy of sorts with making students repeat classes if they fail.

 

[BobK]

This is a new meaning of "hot-housing" for me. I've always met it in the context of giving someone extra tuition/attention so that they develop earlier. (Of course, my use of "develop" is open to interpretation. A gymnast who wins Olympic gold at 14 may have developed in one way at the expense of other development).

This usage is presumably taken from the world of horticulture. If you want a summer-flowering plant to flower early - say, for a show - you put it in a hot-house (a greenhouse that is heated rather than simply magnifying the sun's warmth) and do other things (such as using artificial light to trick it into 'thinking' the days are longer than they really are).

b