EFFECTS OF WINDS ON WORLD CLASS LONG JUMP PERFORMANCE

Abstract

INTRODUCTON - Since 1936 there has been a rule in track and field events applied to the sprints, hurdles and horizontal jumps regarding the maximum wind assistance for record purposes. The value of this has been consistently +2msm1a l though there has been considerable debate over the magnitude of the effects of wind speed on track and field events. There have been a number of scientific studies on wind assistance and wind measurement e.g. Hill (1 927), Heidenstrom(1982), Ward-Smith (1 985), Murrie (1 986),Dapena and Feltner (1 9871, Behncke(1992) and Linthorne (1994). There is statistical evidence for the 100m that athletes do not gain the full benefit of wind assistance predicted in these theories. Some studies have been done on Bob Beamon's world record long jump, Brearley (1 977),Burghes et. al. (1 982), Frohlich (1 985) and Ward-Smith (1986). The aim of this study’s to determine the effects of wind on long jump performances and develop a computer program for converting world class pe-formances in known wind conditions to equivalent performances in still air. Quadratic regression analysis and extrapolation are applied to the best, non-altitude, long jump performances of Carl Lewis, in known wind conditions. These were 20 of the top30 performances up to 1991. Analysis was also carried out on the best long jump performances of Heike Drechsler and Jackie Joyner Kersee. RESULTS - Wind adjustment can be ex-pressed as Ss = Sc - 0.031 w + 0.0027 wZ(S.E. 0.05), where Ss = distance achieved in still air, Sc = distance recorded in competition and w = recorded wind speed. The legal wind limit of +2ms1 gives an improvement in performance of 0.05m (0.6%). The optimum wind assistance is +5.5ms-'. A wind of +5.5ms-I gives an improvement in performance of O.09m. Above +5.5ms1 the improvement in performance decreases, ultimately to 0 at +I1 .5ms-I. A wind speed of +9.5ms1 gives the same advantage asa wind speed of +2ms-I. Winds above+ll.Srns-l are a detriment to performance. These results show similar values to analyses of Carl Lewis's lOOm and 200m performances. CONCLUSION - A direct relationship between assisting wind speed and improvement in performance is demonstrated, how-ever the effects of wind velocity on performances in competition are less than one third of those predicted in the theories of Ward-Smith (1 986) and others. The women's performances exhibit less consistency and less dependency on wind speed than those of Lewis. The research provides further evidence that athletes either, are not able to take full advantage of the theoretical assistance provided by the wind and/ or the measurement of wind speed tends to overestimate the wind experienced by an athlete. A computer program, to run under the Microsoft Windows environment, for converting performances to equivalent times in still air for the men's long jump, lOOm and200m has been developed from Lewis'sbest performances when at his peak between1981 and 1989.REFERENCESFrolich, C. (1 985), Effect of Wind and Altitude on Record Performance in Foot Races, Pole Vault and Long Jump, American Jour-nal of Physics 53, 726-730Ward-Smith, A.J. (1986), Altitude and Wind Effects on Long Jump with Particular Reference to the World Record Established by Bob Beamon, Journal of Sports Science 4,89-99