An apparatus for tensioning spring arms used in conjunction with a weight distribution hitch. The apparatus may comprise a mechanical linkage that may be operable to multiply an input force provided by a jack to an output force of sufficient magnitude to tension the spring arms. The mechanical linkage may comprise a pair of rigid arms that are linked to a support post of a trailer jack. The pair of rigid arms may automatically be raised in conjunction with the support post being operated from a lowered position to a raised position. The rigid arms may exert a force on a cross-piece member extending between the spring arms. Alternatively, the mechanical linkage may comprise a flexible member for placing the spring arms under tension.