WeeWhiteWabbit

Have your thyroid checked. Mine last that long and that's my cause

Run, endurance runners have very low muscle bulk and I have noticed my thighs shrink with running (I'm a horse rider too). But you need to build slowly to long distances. Stuff that you can't do fast. You will probably always have muscular thighs but this just strips them down a bit.

Congratulations! And the success is all down to you so revel in every pound lost