Okay, you quite often mentioned the "petite" shape of these Warrior-Women. Well, I'm not convinced. Take this one Girl of the "Ending-Times" of Amazon culture, that Michael Schulz from Goettingen inspected. She has had the muscles of a today's male Bodybuilder... and with 1,6 meters height she was 10 centimeters taller than the average Greek guy those days. She, riding one of these little horses you discovered would look like Arnold Schwarzenegger, riding a Shetland-Pony ;-)
If you can't inspect the bones of these Women, a good indicator for big muscles is also the size of the arrowhead-to-shaft-joints. If the holes do only measure about 4 millimeters, it's for a barreled shaft. These shafts are used for 80+ pound Bows, because "normal" Shafts would simply explode before leaving the Bow (happened to me once with my 55 pound Assyrian Bow - wasn't funny). In my Shooting-Club, we only have 2 guys that can handle such amount of power. Both of them look like Hercules (well, one like Hercules who ate too much LOL)