The document describes the different shapes that skeletal muscles can take: parallel or fusiform muscles which run parallel and contract over a great distance but lack strength; convergent muscles which maximize force by converging fibers on the insertion; pennate muscles which have many fibers per unit area and are strong but tire quickly, including unipennate, bipennate, and multipennate types; and circular muscles which surround openings and act as sphincters. Examples are provided for each type of muscle shape.