Grouping of runners during marathon competition.

Marathon runners tend to form clusters during competition, possibly as a means of improving their performance. Studies of international competitors in Fukuoka and Tokyo races have shown a density of 0.44 to 0.80 runners.m2 among those maintaining a pace of 4.8-5.6 m.s-1, clustering being most marked among elite performers. Some 95% of clustered runners maintained a minimum distance of 0.5-1.5 m from other competitors; moreover, such competitors avoided occupying an angle of +/- 15 degrees either before or behind other runners. The phenomenon merits closer study by those interested in the bettering of marathon performance.