Eowyn was, of course, disguised as the male rider Dernhelm, and we are told she blended-into the mass of other riders, indistinguishably.
These pictures therefore inform us that the Riders of Rohan fought the Battle of Pellennor Fields wearing metal basques with twin conical 'breast'-plates, that fully revealed their legs and buttocks...
I must admit that this was not how I personally saw the Riders of Rohan with my minds eye; and I rather wish I hadn't discovered the fact.