Validity of Self-Reported Running Distance

Dideriksen, M, Soegaard, C, and Nielsen, RO. Validity of self-reported running distance. J Strength Cond Res 30(6): 1592-1596, 2016 - It is unclear whether there is a difference between subjective evaluation and objective global positioning systems (GPS) measurement of running distance. The purpose of this study was to investigate if such difference exists. A total of 100 participants (51% men; median age, 41.5; body mass, 78.1 kg ±13.8 SD) completed a run of free choice, then subjectively reported the distance in kilometer (km). This information was subsequently compared with the distance derived from a nondifferential GPS watch using paired t-tests and Bland-Altman's 95% limits of agreement. No significant difference was found between the mean paired differences between subjective evaluations and GPS measurements (1.86%, 95% confidence interval -1.53%; 5.25%, p 0.96). The Bland-Altman 95% limits of agreement revealed considerable variation (lower limit -28% and upper limit 40%). Such variation exceeds the clinical error range of 10%. In conclusion, the mean running distance (km) is similar between self-reporting and GPS measurements. However, researchers should consider using GPS measurements in favor of subjective reporting of running distance because of considerable variation on an individual level.