Lance Armstrong’s Era of Performance: Part III: Demonstrating the Post Hoc Fallacy

HFM Lodewijkx

    Research output: Contribution to journalArticleAcademicpeer-review


    In consequence of USADA’s charges, Lance Armstrong conceded he doped during his cycling career. The logic proposed in the post hoc fallacy entails that Armstrong’s sportive feats are therefore ‘caused’ by his doping use. This fallacy generalizes to the belief put forward in the doping debate that the progress in speed over time in professional cycling is determined by riders’ use of progressively potent doping agents. To examine this fallacy, the current study compared Armstrong’s mountain time trial wins, realized in the Tour de France (2001, 2004), to victories demonstrated by riders in similar races uphill in the French race (1958–1996, N = 17). The fallacy expects that riders will race faster over time and that Armstrong’s achievements will be far superior to other riders. However, if these expectations are disconfirmed the fallacy will be refuted. We developed a climbing index to evaluate riders’ km/h performances: ClI = (Corrected altitude climb / Distance trial) ● 100. Higher values indicate more demanding races. Mediation regression analyses showed that, over time, the trials became less demanding, b = -.0076 (∆R2 = .201, p ≤ .05), and that riders raced b = 0.201 km/h faster per year (∆R2 = .234, p ≤ .05). The index had a robust influence on riders’ speed (r = -.97) and they raced b = -2.302 km/h slower per unit of the index (∆R2 = .932, p ≤ .0001). The significant mediating influence of the index, b = 0.175 km/h (p ≤ .05), subsequently reduced riders’ progress in speed to a nonsignificant b = 0.026 km/h per year (p = .38, ∆R2 = .003). Furthermore, Armstrong’s performances did not prove to be outliers. Findings invalidate the reasoning employed in the post hoc fallacy, since the CLI and not the year in which riders competed constitutes the main determinant of riders’ performances. They also entail that Armstrong’s modern doping agents may not have given him the proposed advantage over his forerunners who won trials before the 1990s, i.e., the years in which these potent aids were not yet rampant in professional road racing.
    Original languageEnglish
    Pages (from-to)63-70
    Number of pages8
    JournalAmerican Journal of Sports Science and Medicine
    Issue number4
    Publication statusPublished - 2013


    • Sport performance. Professional road racing


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