We report on the magnetoresistance R(H) measurements on high Tc YBa2Cu3O7/PrBa2Cu3O7 multilayers. A phenomenological theory based on single vortex motion (where R(H,T) = H/(aexp(U/T) p(H/Rn))) was used to fit the experimental data. This theory, which fits the magnetoresistance data quite well in both the low and the high resistance part contains three parameters: U, p and a. For the activation energy U we used the field dependence: U ? H-0.53 which was obtained from a fit of the resistive transition R(T) with the relation for thermally activated flux flow (TAFF): R = R0exp(-U/T). The parameter p determines the relative strength of the flux flow and is found to decrease with decreasing temperature. The parameter a, which characterizes the TAFF, increases with decreasing temperature, thus demonstrating the dominance of this mechanism at lower temperatures.