A wearable assistive device such as an exoskeleton may include a main frame that support a hip joint of a user. The main frame may have a predetermined curvature and structure that closely conforms to and remains in contact with a hip of the user at or near the hip joint so that the main frame may stably support both hip joints. While the user wears the exoskeleton and walks, bends, or lifts, the exoskeleton may stably and efficiently provide a force to assist a movement originating at the hip joint of the user, thereby aiding the user in stably walking, bending, or lifting.