Which method commonly used for body composition assessment is non-invasive and quick?

Skinfold measurements are a widely used method for assessing body composition that is both non-invasive and quick. This technique involves using calipers to measure the thickness of skinfolds at specific anatomical sites on the body. The data collected can then be used to estimate body fat percentage by utilizing established equations.

The process is straightforward; it typically takes just a few minutes to perform the measurements on a subject, making it an efficient choice in various settings, such as fitness assessments or health screenings. Skinfold measurements require minimal equipment and can be performed with little training, making them accessible for many practitioners.

Other methods mentioned, such as blood tests, X-ray imaging, and magnetic resonance imaging (MRI), do not share the same characteristics. Blood tests require a sample and analysis to provide information about body composition indirectly, while X-ray imaging and MRI are both imaging techniques that can be time-consuming, costly, and may require special facilities or training to perform and interpret. Hence, among the options provided, skinfold measurements stand out as the optimal choice for a quick non-invasive assessment of body composition.