The four competitive strokes are the butterfly, backstroke, breaststroke, and freestyle. These strokes can be swum individually or together in an individual medley (IM). The IM order is: 1) butterfly, 2) backstroke, 3) breaststroke, and 4) freestyle. There are two types of relays: medley and freestyle. The medley relay order is: 1) backstroke, 2) breaststroke, 3) butterfly, and 4) freestyle. Each of the four swimmers in the relay swims a predetermined distance, dependent on the overall length of the relay. The three relay lengths are 200 meters or yards, 400 meters or yards, and 800 meters or yards (which is only swum freestyle). In a 50 meter pool, each swimmer swims one length for the 200 relay, two lengths for the 400 relay, and four lengths for the 800 relay. In a 25 meter or yard pool, each swimmer swims two lengths for the 200 relay, four lengths for the 400 relay, and eight lengths for the 800 relay. Many full-size competition pools in the United States have a length of 50 meters and a width of 25 yards (the Olympic pool size, allowing both short course (25 m or 25 yd pool) and long course (50 m pool) races to be held.
Special Olympics Aquatics is a collection of swimming events in which all competitors have a physical or mental disability. Special Olympics aquatics is comprised of a number of swimming events meant for athletes with physical or mental disability. Because of the wide array of swimming events offered, aquatics is appropriate for a range of ages and ability levels. Aquatics competition events are based on a variety of strokes. Special Olympics also offers events for lower ability level athletes to train and compete in basic aquatics skills. The development of these key skills is necessary prior to advancing to longer competitive events. As in all Special Olympics sports, athletes are grouped in competition divisions according to ability level, age and gender.
Aquatics was an event at the first Special Olympics International Games held in Chicago, Illinois, USA in 1968. At the 2003 Special Olympics World Summer Games held in Dublin, Ireland, 573 athletes representing 97 Special Olympics Programs competed in aquatics. As of the 2005 Special Olympics Athlete Participation Report, 159,100 Special Olympics athletes compete in aquatics.