Training bras

Okay, so it's called a training bra. A training bra. I don't get it. What is the girl being trained for? It's not like training wheels on a bike where she completely loses it after a while. From that point forward, she has to always wear a bra. So it's not training. She actually NEEDS it at that point, and will continue to need it for the rest of her life.

In that case, we could have training shoes, training underwear, and apparently what's needed now (given guys not being able to pull their pants up all the way so that I have to see the poka dot boxers), training jeans and khakis.