... confounder. Third, the two primary determinants of performance are strength and body mass. Therefore, a sample of powerlifting world record holders would be heterogeneous in body mass and weight ... (same for SU). For the distance run (DR), the scaling index is derived as follows (Vanderburgh & Mahar, Vanderburgh & Crowder, 2006; Vanderburgh & Laubach, 2007): Since distance run ... account for body weight differences in determining race performance (Vanderburgh & Laubach, 2007). Despite the additional credit for larger body mass, these models have also been determined to...