Research

Mixed

Ultrasound measurement of vastus lateralis (VL) muscle thickness, combined with body mass, provides a statistically accurate and ecologically valid prediction of whole-body and thigh fat-free mass (FFM) in resistance-trained men, serving as a viable alternative to DXA.

If you are a resistance-trained man, you can track your muscle gains using a portable ultrasound device focused on your vastus lateralis (side thigh) and your body weight. The study provides a specific formula: Whole Body FFM = -1.657 + (0.719 * Body Mass in kg) + (0.416 * VL Thickness in mm). This method is as accurate as DXA for this group and can be done in a gym setting, allowing you to monitor progress without expensive medical imaging.

GoodSupportsHIGH confidence
The present study introduces a statistically robust and ecologically applicable mathematical model based on US measurements, specifically on the VL-MT, for assessing FFM in resistance-trained men.
Maria J. Valamatos et al. · Ultrasound in Medicine & Biology · 2025

Why this rating

Cross-sectional study with a moderate sample size (n=79), rigorous validation using PRESS, CCC, and Bland-Altman against a gold standard (DXA).

Source

Is Ultrasound an Accurate Method for Predicting Fat-Free Mass in Resistance-Trained Men?

Maria J. Valamatos et al. · Ultrasound in Medicine & Biology · 2025

DOI 10.1016/j.ultrasmedbio.2025.10.001

cross_sectional · n=79
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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