Academy / Anthropometry
The phantom stratagem
Ross & Wilson’s 170.18 cm unisex phantom — why we scale girths before we talk about ‘small’ or ‘large’. · 7 min read
The problem
A 190 cm basketball athlete with a 38 cm calf is not ‘the same’ as a 165 cm runner with a 38 cm calf. Absolute girth confounds size with tissue. The phantom stratagem scales every length and girth by 170.18 / stature so subjects can be compared on a common skeleton.
Kineos KRS-27 stores sex-specific phantom means and SDs at that stature. A z-score of 0 is the reference envelope, not an aesthetic ideal. Positive z is more tissue than the reference; it is not automatically ‘better’.
ISAK
The International Society for the Advancement of Kinanthropometry defines landmarks, fold directions, and a restricted profile of eight skinfolds, nine girths and two bone breadths (plus mass and stature). Z25 is a teaching superset of girths, including posterior sites that ISAK does not require. When you publish, say so.