A three-link planar manipulator is a representative example of redundant actuation. Using this redundancy in actuation, the distributed actuation mechanism (DAM) was recently proposed to enhance the end-effector force. In this paper, dual-mode operation of a DAM-based three-link planar manipulator is proposed through evaluating its maximum achievable velocity and force at a target position. For this purpose, the end-effector velocity and force are mathematically derived. Design optimization is then performed to determine the maximum achievable velocity and force and to draw the allowable velocity and force polygons. In order to demonstrate the effectiveness of the proposed dual-mode operation, a human gait-like cycle is numerically analyzed and experimentally validated.