The Effects of Muscular Fatigue on the Kinetics of Sprint Running

Abstract

Abstract In order to compare the kinematic and kinetic effects of fatigue on the mechanics of sprint running, 15 male subjects were filmed in the saggital plane while performing a short (50 meter) maximal exertion sprint and a long (400 meter) fatiguing sprint. The short sprint was filmed at 40 meters, while the long sprint was filmed at 40 and 380 meters. The films were reduced utilizing a digitizer coupled to a computer terminal. Analysis results were generated via a human motion analysis program. Kinematic and kinetic results were entered into the statistical analysis as differences between non-fatigued and fatigued values. Initially, quality of the performance (measured by the change in horizontal velocity of the body center of gravity) was statistically related to change in the kinetic variable of integrated muscle moment at each of the body joints. The kinetic variables found to be significant were then statistically compared to logically related changes in kinematic variables (temporally adjacent or concurrent). Changes in the generated moments about the hip and knee during ground contact were found to be related to the quality of the performer. Kinematic changes related to the significant moment changes indicated that, while the better sprinter (smaller velocity loss) closely maintained the kinetic and kinematic patterns, the poorer sprinter (larger velocity loss) inefficiently deviated in both areas. The lack of significance between the changes in upper limb moments and change in average velocity indicated that productive arm effort does not affect the level of performance in the fatigued condition.