InBody at the box: what a body-composition analyser measures and how to read it

There is an InBody 120 body-composition analyser at our box. Scales only tell you how much you weigh. The analyser tries to split that number into parts: muscle, fat, water. It is not a medical test or a health assessment, but it can be a good point of reference if you train regularly and want to see what is changing.

How the scan works

InBody uses bioelectrical impedance analysis (BIA). A weak current passes through the body and the device measures the resistance it meets. From that, the analyser estimates what your mass is made of.

According to the manufacturer’s documentation, the 120 has eight touch electrodes (two for each hand and each foot), measures impedance at two frequencies (20 and 100 kHz), and the scan itself takes about 17 seconds. You stand barefoot on the device and hold the handles. People with a pacemaker or any other implanted electronic device must not use it, because a current passes through the body.

What the result shows

According to the documentation, the InBody 120 printout gives:

• body weight,
• skeletal muscle mass,
• body fat percentage,
• BMI,
• basal metabolic rate (BMR), an estimate of your resting energy needs,
• WHR, the waist-to-hip ratio,
• visceral fat level.

The full report, which you open in the manufacturer’s software, also has total body water, protein, minerals, body fat mass and a breakdown for the limbs and trunk.

In the manual, WHR, visceral fat level and BMR are listed as research parameters. The analyser does not measure your waist or hips with a tape, so WHR is a calculation, not a measurement of circumference. Treat these numbers as a guide.

What the number tells you, and what it does not

BIA is convenient, quick and painless, but it is an estimate. The result depends on how much water is in your body at that moment, and that changes during the day, after a meal, after training and in hot weather. So a single scan is not an exact description of your body.

What works best is comparison: the same person, the same device, similar conditions. Then the changes between results say more than the absolute numbers. If you scan every few weeks, at the same time of day and after similar preparation, you can see a trend. One scan done after training or after lunch means little.

How to prepare

These recommendations come from the manufacturer’s InBody 120 manual.

• In the morning, if you can. Water in the body shifts downwards during the day, and that affects the result.
• Do not eat before the scan. After a meal, wait at least two hours. Food counts towards body weight and can distort the result.
• Go to the toilet. Urine and the contents of the bowel count towards body weight, so they affect the result. They are not “counted as fat”; they just add kilos that are not body composition.
• Do not exercise before the scan. Even light effort can briefly change body composition in the reading. So scan before class, not after.
• Stand for about 5 minutes. After lying or sitting for a long time, water settles differently and the result shifts a little.
• Wipe your hands and feet. The manufacturer recommends the InBody Tissue, because very dry hands or calloused feet make the measurement harder.
• Take your socks off. The scan needs skin contact with the electrodes. Take off heavy clothing and metal accessories too, because their weight goes into the result.

How it works at our box

A body-composition scan is part of starting with OPEN. After your first class, if you choose OPEN, you get a coach who looks after you, and Dawid Kowalski leads your start. The first meeting includes a body-composition scan, setting a goal and a plan, and over 12 weeks there are three consultations with a scan. After a month we come back to it together. What happens in those 12 weeks is in CrossFit for beginners: the first 12 weeks.

You can also book a scan on its own, without a membership: call reception, arrange a time, come in and pay on the spot. A scan is also part of personal training if you are working on body composition with a coach. We do not list the price on the website; reception will tell you.

The result is not there to judge you but to talk about: where you are starting, what you want to change and how we will know it is working. If you do not know what the numbers on the sheet mean, ask the coach. If you need more than a conversation, our coaches also run personal training, and the scan is then part of the work towards your goal. A meal plan is a job for a dietitian, not for the analyser or the coach.

Sources

• InBody 120 user manual (PDF, InBody): electrodes, measurement method, scan time, printout parameters, precautions before the test
• 510(k) summary K130777 (FDA), InBody 120: eight touch electrodes, 20 and 100 kHz, indicated “for healthy individuals only”
• InBody: InBody 120 result interpretation: definitions of WHR, visceral fat level and BMR