What method is commonly used by personal trainers to assess body composition?

Girth measurements are commonly used by personal trainers to assess body composition because they are relatively simple, quick, and non-invasive. This method involves measuring the circumference of various body parts, such as the waist, hips, and limbs, which allows trainers to gather information about fat distribution and body composition. It can be particularly effective in monitoring changes over time, making it a practical tool for both trainers and clients.

Additionally, girth measurements do not require specialized equipment or extensive training, making them accessible for personal trainers in various settings, such as gyms or fitness studios. This method may not provide the detailed insights into body fat percentage or lean mass that more advanced techniques like hydrostatic weighing or dual X-ray absorptiometry offer, but its ease of use and effectiveness for tracking progress make it a popular choice among fitness professionals.