An exerciser includes one handle having an inner thread formed in one end and includes another handle having a bolt extended from one end for engaging with the inner thread of the one handle and for allowing the two handles to be rotated relative to the other. A spring is engaged on the bolt and biased between the handles for applying a biasing force against the handles and for resisting the rotation between the handles. A cap or one or more weights may be attached to the other end of each of the handles for exercising the arms of the user.