Challenge her to a posedown, but do it really loudly so everybody in the cardio area can hear you. Then when she doesn't get off the treadmill, scream "You fucking pussy!!!!" as loud and shrill as humanly possible, tear your shirt off a la HUlk Hogan and jump right into an Abs & Thighs pose, then a double bi. When you strike the double bi, spit on your own chest and smile.