Speaking of bloomers – I remember wearing genuine old-fashioned ones for gym class in some early grade somewhere. They were made of a thin light brown material, that, if I remember right, gathered BELOW THE KNEES.
A few years later,the gymsuits we were required to buy ($2.50? $3? -- or you could have a pattern to sew your own) were more modern snappy one-piece affairs. They still had bloomer-type elastic hems for modesty, but up where today’s shorts are likely to end. In one school I attended, each class wore a different solid color, and in another school the gymsuits had striped fabric for the top sections.
But everywhere, it seemed in those days, the material used was tough plain Indian Head cotton. Raise your hand if you remember Indian Head cotton! It required ironing, of course, but it bore a label bragging that it was SANFORIZED.
Whatever that meant.