A biomechanical evaluation of the role of fatigue in middle-distance running.

Eight college level runners were filmed using high speed photography at the 500 m, 1,300 m, 2,100 m and 2,900 m stages of a 3,000 m time trial. Kinematic and spatio-temporal data were obtained through an interfaced digitiser computer system. Mean horizontal velocities of 5.18 m/s, 5.17 m/s, 5.18 m/s and 5.16 m/s indicated that minimal variations occurred from the four stages of the trial. No significant changes in biomechanical data were apparent between the first three stages of the trial; however, changes were evident when Stage 4, the 2,900 m mark, was compared to the earlier sections of the trial. With the development of fatigue stride length decreased while stride rate increased to maintain the constant velocity. There was also a small shift to increase the period of support and correspondingly decrease the period of non-support. The leg was more angled at foot strike, the thigh was less extended at the end of the support phase, and the trunk was carried further forward during the running cycle. Success in middle-distance running requires the athlete to maintain an efficient co-ordinated movement pattern over the entire race. The coach who can identify the changes in movement patterns over a race increases the likelihood of success for his athletes.