Detecting Low Fat-free Mass Index From Anthropometric Z-scores In Female College Athletes

Body composition assessment is often included in the athlete’s program. Detecting low levels of some components, like the fat-free mass (FFM), may help identify female athletes at risk of developing hormonal problems from training- or diet-related issues. In this regard, a fat-free mass index (FFMI) below 16 kg/m2 has been suggested to identify a low FFMI in women. Some laboratory methods, like DXA, can assess FFM with relatively acceptable precision; however, those methods are impractical in field settings. Conversely, anthropometry is an accessible method and can be used to estimate “Phantom” z-scores to assess body size. However, whether the Phantom-derived z-scores can be used to identify a low FFMI is still to be determined. PURPOSE: To determine whether the Phantom-derived z-scores could be used for detecting a low FFMI in female college athletes. METHODS: The sample comprised 58 women participating in different sports at the national competitive level. We took anthropometric measurements according to the ISAK protocol. Similarly, the body composition was analyzed with a whole-body DXA scan to get the FFMI. We calculated the Phantom z-scores for the arm, thigh, and calf corrected circumferences (corrected for the triceps, anterior thigh, and medial calf skinfold, respectively) and the uncorrected forearm circumference. Next, we calculated the arithmetic mean from these four z-scores (ZC) to predict the DXA-derived FFMI and determine the ZC equivalent to a FFMI of 16 kg/m2 using linear regression. Data are presented as mean ± SD or median [25th, 75th percentile]. RESULTS: The descriptives were the following: age 21.2 ± 2.1 y, weight 60.9 ± 8.7 kg, height 164.0 ± 7.0 cm, FFMI 16.2 ± 1.4 kg/m2, and ZC 0.34 [-0.23, 0.77]. The ZC was a statistically significant predictor of FFMI (FFMI = 15.8 + ZC * 1.3) (r = 0.79, SEE = 0.86, p < 0.001). The ZC cut-off point was 0.1; however, after considering one SEE, the equivalent lower and higher cut-off points were -0.5 and 0.8 ZC CONCLUSIONS: The Phantom-derived z-scores help set cut-off points to identify low FFMI in female college athletes, serving as a screening tool in field conditions. We propose that the desirable ZC should be >0.8, and a ZC < -0.5 would imply a higher probability of low FFMI.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.