CLKD, any muscle you put under stress with resistance/weights will build/strengthen. There are two different issues here. One is fat, the other is muscle.
We all have muscle underneath our fat tissue. It's depends on how much fat tissue you have as to whether you can clearly see the muscle or feel the definition. I do leg workouts with squats, biceps triceps, back, hamstrings, all of it. My muscles are very, very solid. Some are certainly covered in a layer of fat (my butt/thighs), but the muscle is strong and I can see some definitions still.
We'll see how that goes in the future.

Much like any form of exercise, retaining or building muscle depends on how much you work at it and how dedicated and consistent you are.
Ah.... thank you for explaining the apron reference!

Here in the US, we more talk about boobs going south and sitting on the waistline. I've never had much of a bust line, so there wasn't much of anything to go south!!
In all of this discussion, I try to keep reminding myself that the most important part is just to feel healthy, and know that I'm doing things that are benefiting my health, even if we aren't seeing our shapes be what they used to be.
It can be hard to let go of that desire to retain our more youthful shape, but best to foster acceptance and appreciation for the things that we do have still. I try hard to embrace that, not always successfully I might add. We live in a very youth-obsessed (at all costs) culture. But I am realizing that it's all in our mindset and where we choose to put our energies. xxxx