Athleticism doesn't matter an iota for running backs. Could be nice to find a diamond in the rough...sure...say Aaron Jones from UTEP a few years back, but then you also have Phil Lindsey, Dalvin Cook, Elijah McGuire, etc that are productive and are all below average to terrible testing athletes.
Aaron Jones was not a diamond in the rough. He was CUSA best back for 2 years on a TERRIBLE UTEP squad.