Scaling: Partitioning out Differences in Size

In his “Editor’s Notes,” Rowland (15) raised an issue that is fundamentally important but frequently appears to be misunderstood. The issue is scaling, that is, the means of partitioning out differences in size. Because physiological variables are often dependent on size, an adjustment has to be made to “normalize” for body dimensions and assess more precisely a particular characteristic. These adjustments have four main applications: (a) to an individual who is compared against standards for the purposes of assessment; (b) in comparisons between groups; (c) in longitudinal studies, especially with children, in which for instance the effects of training have to be disentangled from the effects of growth and development; and (d) in studies that explore the relationship between physiological variables and performance. The purpose of this review is to assess the most appropriate means of scaling and demonstrate how well-intentioned, but nevertheless incorrect, scaling techniques have probably produced misleading results and retarded progress in our understanding of the physiology of exercise.