The following is my IMHO, but I have been thinking about this subject also since I recently scratched the ground on a speed bump while driving with 3 passengers, also at a very low speed.
Option 1: I think those bars are some sort of protection from touching the ground. I had similar bars on my Mazda 3 and touched the ground on speed bumps on a number occasions.
Option 2: Alternatively this is where you put that thing (hoisting jack?) that keeps the car in the air while you are changing a wheel - at least that what my Mazda 3 instruction said (I read it when I had to change a wheel).
Had another look at the picture - it looks like it is a lateral bar, so I think it is option 1, because the bars for option 2 (for hoisting jack) are on sides of the car, going from the front wheel to the rear one.
Russian, it's not a bar and not used for support in any way. It's made of plastic and I too have scraped one of mine once. I wonder if it's there to warn you so you don't scrape your front end of the car? Doubt that though, the other thought is some sort of aerodynamic device, as they're in front of each wheel?