How low should sackpacks hang?

I have one adidas one that has longer thin strings. When I put it on the bag hangs just on my bottom.

I just got a new Fila one its a bit smaller and the strings is flat and fabric. When I put it on it is just on the middle of my back not too low and high.

Can sackpacks hang lower or can they also hang higher on the back?
thanks!