A resistance trainer that provides for rotational movement, balance training and strength building. The device is an integral one-piece fabricated from wood or plastic that includes a deck that is detachable from the base. The base in includes two separate dome-shaped reservoirs wherein the domes provide instability when in contact with the ground due to the curved surface. Inside of the domed reservoirs is space to add a weighted component, such as standard plate weights or sand or water or other replaceable means of weighting the device. The user can rotate the board using the torso muscles used when surfing or snowboarding and can also balance in a heel to toe direction or a front to back direction for balance and strength building.