Abstract: A portable aquatic/land weight training system and method comprises a plurality of collapsible weight chamber members. Each of the collapsible weight chamber members includes a pair of flexible end members joined by first and second flexible band members forming a water- and air-tight chamber. The first band member forms an opening through the collapsible weight chamber member. The opening has a diameter D so as to pass a bar therethrough. Each weight chamber has a water valve and water valve closure member for filling the weight member with water and an air valve and air valve closure member for filling the weight chamber member with air. Each weight chamber member has a peripheral edge and the water valve is located near the peripheral edge of the weight chamber member so that the water valve closure member and the peripheral edge can be grasped by a pair of fingers to close the water valve to sealing relation without significant expulsion of water.