Experimental results of dynamic modulus and internal friction, measured directly during creep deformation, and back-stress data from dip test measurements are considered for an explanation of the power law of creep. The explanation is essentially based on the assumption that stationary creep depends on dislocations in the subgrain interior with zones of accumulation near to the subboundaries which are conditioning for the emission processes. The power law is related to the tendency, of the dislocation segments, to approach to the lengths of superior backstress limit, the more the higher the applied stress.