In terms of competition rules and physical demands, long-distance track races have much in common with middle-distance races, except that pacing, stamina, and race tactics become much greater factors in performances. However, a number of athletes have achieved success in both middle- and long-distance events, including Saïd Aouita who set world records from 1500 m to 5000 m. The use of pace-setters in long-distance events is very common at the elite level, although they are not present at championship level competitions as all qualified competitors want to win.