the purpose of this thesis was to examine the effects of cognitive strategies on the performance of three female swimmers. the independent variables were the three strategy conditions that were used by the subjects. the major dependent variable was the time taken by each subject to swim the 400 metre effort. questionnaires also generated information on a number of factors. treatment conditions were randomly assigned according to a 3 x 3 latin squares format. an analysis of performance data emphasized the individual nature of athletic performance. two of the athletes appeared to be able to use cognitive strategies to improve performance, while the other did not demonstrate this ability. questionnaire data revealed that improved performances did not appear to be related to reduced discomfort or altered pain perception. a phi coefficient analysis indicated that expectation to perform well or poorly was not related to actual performance. the ability of the subjects to concentrate on the prepared strategy was generally high. two of the three subjects swam their best under their preferred condition. ratings of discomfort and assessment of performances varied with the individuals. the performance of each subject appeared to be affected differently by measured factors with confounding potential.