# Position-Specific Kinanthropometric Traits of Professional American Football Players: A Study of Mexican LFA Players

## TL;DR

This study describes the body characteristics of Mexican professional American football players based on their positions on the field.

## Contribution

The study provides position-specific kinanthropometric data for Mexican professional American football players.

## Key findings

- Offensive and defensive linemen had higher adipose, muscle, and bone mass compared to other positions.
- Arm relaxed girth, biiliocristal breadth, and sitting height were the most important variables for positional differentiation.
- The overall somatotype was a balanced endomorphic mesomorph (3.8–7.0–0.8).

## Abstract

Background: This cross-sectional observational study aimed to describe the position-specific kinanthropometric characteristics of Mexican professional American football players competing in the 2019–2020 seasons of the Liga de Fútbol Americano. Methods: A total of 189 athletes were assessed following International Society for the Advancement of Kinanthropometry standards. Twenty-six anthropometric variables were measured to estimate body composition (five-way fractionation), somatotype, proportionality indices, and tissue-specific masses. Positional differences were examined using ANOVA or Kruskal–Wallis tests with corresponding effect sizes (η2 or ε2). An exploratory stepwise discriminant analysis identified the anthropometric dimensions contributing most to positional differentiation, and classification accuracy was calculated. Results: Offensive and defensive linemen showed the greatest absolute size and higher adipose, muscle, and bone mass compared with other positions. The overall somatotype corresponded to a balanced endomorphic mesomorph (3.8–7.0–0.8), with wide receivers and defensive backs presenting lower endomorphy. The discriminant model identified arm relaxed girth, biiliocristal breadth, and sitting height as the variables contributing most to positional differentiation, achieving a classification accuracy of 57.7%. Given its exploratory nature and the absence of cross-validation, the discriminatory capacity of the model should be interpreted with caution. Somatotype Attitudinal Mean indicated greater interpositional heterogeneity among linemen. Conclusions: This study provides population-specific reference data for Mexican professional American football players, highlighting clear positional morphological characteristics. These findings may support talent identification and positional profiling; however, the exploratory discriminant model and league-specific sample limit generalization to other populations.