Changes in fat or muscle mass can affect sports performance. If you have read What is body composition and how is body fat calculated?, you will know that anthropometry and bioimpedance are two practical ways to assess it.
Here we focus on anthropometry, a familiar technique in sport, and compare it with bioimpedance scales for body composition.
What is anthropometry, and what is it for?
Anthropometry analyses body composition and proportions to help understand their relationship with performance.
Body-composition information can inform nutritional planning, goals and outcomes. It establishes a starting point, but is especially useful for tracking change over time. One isolated measurement has limited value. Nutritionists look at trends across repeated assessments.
Body composition also influences energy expenditure: more muscle generally increases resting needs, among other factors. Watch this video on building muscle for more detail.
What does an anthropometric assessment measure?
Key measurements include height, weight, circumferences and skinfold thickness. Equations can use these in a 4-component model estimating muscle, fat, bone and residual mass; these are model-based estimates, not direct scans of each tissue.
The muscle component represents the body’s skeletal muscle tissues.
The fat component includes:
- Subcutaneous fat. Fat beneath the skin, assessed indirectly through skinfold measurements.
- Visceral fat. Fat within the abdomen around organs. Excess visceral fat can be a health concern, but skinfolds do not measure it directly.
The bone component is an estimate of bone mass, not a measurement of bone mineral density.
The residual component represents other tissues and structures, such as organs, blood vessels and connective tissues.
Anthropometry versus bioimpedance
Now you know what anthropometry involves, how does it differ from bioimpedance testing for body composition?
Here is an overview.
What is a bioimpedance assessment?
It uses a device, often a body-analysis scale, that passes a small electrical current through the body and measures impedance.
It relies on differences in electrical properties between tissues, influenced largely by their water and electrolyte content.
Because it measures impedance and uses equations rather than directly weighing each tissue, it is a doubly indirect assessment.
Each device may use a different equation to estimate the proportions of body components.
The accuracy of bioimpedance scales and anthropometry depends on the device, protocol, equation and practitioner. Standardising conditions can improve repeatability; our bioimpedance post explains how.
One useful habit is using the same scale. The original article highlights the Surface Precision 10600 Smart Healthy Pro as an affordable option.
How can anthropometry help me?
Compared with bioimpedance, anthropometry gives a practitioner direct access to individual measurements, helping interpret where changes occurred. Neither method is universally more accurate for every purpose.
Correct measurement needs appropriate interpretation. The judgement of a sports nutritionist can help.
What measurements are included?
Alongside height and weight, there are 3 broad groups:
Circumferences
Tape measurements help track changes in body size, including muscle-related changes and waist circumference, though they are not direct measurements of muscle mass.
Common sites include the abdomen, relaxed and flexed arm, mid-thigh, calf and hips.
Breadths
These are distances between anatomical landmarks and can contribute to bone-mass estimates. They require a suitable bone breadth calliper.
Common breadths include the wrist (bistyloid), knee (biepicondylar femur) and elbow (biepicondylar humerus).
Skinfolds
Skinfolds assess a compressed double layer of skin and subcutaneous tissue using a skinfold calliper. Their sum can help track changes in subcutaneous fat.
Different equations estimate body-fat percentage for different populations, including athletes and the general population.
The original illustration shows 9 possible skinfold sites; protocols differ, and the standard ISAK profile uses its specified measurement sites.
Reliability and limitations
Anthropometry can be a reliable technique when standardised. It should be performed by appropriately trained practitioners. At the time of writing, INDYA assessments were performed by sports nutritionists with ISAK level 1 or level 2 accreditation.
Measurement quality varies with the practitioner and equipment. Calibration and regular technique practice matter.
Direct complications are uncommon, but obtaining some landmarks and skinfolds can be more difficult in people with severe obesity, increasing measurement uncertainty.
What types of assessment are available?
Assessments differ according to their measurements. At the time, INDYA offered 2 types:
1. Short anthropometric assessment
Weight, height, abdominal circumference and three skinfolds: iliac crest, supraspinale and abdominal. It can establish an initial reference before a more complete follow-up.
2. Full anthropometric assessment
In addition, this includes biceps, triceps, subscapular, front-thigh and medial-calf skinfolds; relaxed and flexed arm, mid-thigh, calf and hip circumferences; and wrist, femur and humerus breadths.
Anthropometry for athletes
Seeing the same number on the scale can make progress seem stalled. An anthropometric assessment may reveal changes in body composition despite stable weight.
It is another tool for monitoring an athlete’s progress and considering whether the current strategy is appropriate or a different approach is needed.
To take these recommendations further and adapt them to your goals, training and actual needs, INDYA offers a sports nutritionist to design and adjust a personalised nutrition plan.
To complement your online nutritional planning with anthropometry, visit the INDYA centre in Valencia where we will have the callipers ready ;)
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