I'm not asking about chest protection or serious downhill armor.

Various websites sell shoulder supports. It's basically a compression sleeve combined with a strap that goes around your chest and back. There are unilateral and bilateral versions.

My biggest injuries over the last few years have been getting my arm whipped back in a crash. Nothing broken, nothing torn, but just kinda hurts and doesn't feel good for months.

I wonder if these things would help prevent these kind of injuries? I would imagine I'd lose some range of motion, but that's kinda the point. I'm talking about mountain bikes, not rock climbing.

Has anyone tried these? Pictures is one version but there are a few different ones I've seen.