In an initial attempt to assess the applicability of Weiner's (1972) attribution model to sport-related behavior, the effects of ability (high versus low), effort (high versus low) and outcome (success versus failure) on causal attributions were investigated. After riding a bicycle ergometer, subjects were asked to attribute the cause of their increased or decreased performance to ability, effort, task difficulty and/or luck. The results indicated that successful outcomes were attributed to both ability and effort and that unsuccessful outcomes were attributed to a lack of ability but not a lack of effort. While the task was seen as easier following success, the perception of low effort mediated this relationship. The results were interpreted to support a situationally specific conceptualization of sport achievement. First, whereas a motivational bias appears to preclude low ability attributions in intellectual pursuits, such is not the case with a novel physical task contingent on strength and muscular endurance. It was suggested that physiologically related ability may be viewed as relatively unstable. Second, relative to intellectual tasks, sport-related effort may be more salient and more quantifiable and may exert a greater influence on subsequent attributions for sport achievement. Finally, support was obtained for the assertions that affect is codetermined by both effort and ability and that expectancy discrepant performance is accounted for largely by perceptions of task difficulty.