What Is an InBody Scan and What Does It Measure?

What Is an InBody Scan and What Does It Measure?

An InBody scan is a body composition test that takes about 60 seconds and splits your bodyweight into three things the bathroom scale cannot see: muscle mass, fat mass and body water. It measures each of those segmentally, so you get separate readings for your left arm, right arm, torso, left leg and right leg. That is the whole point. Two people can weigh exactly the same and have completely different bodies, and one number on a scale will never tell you which direction you are actually moving in.

I have been coaching in Amsterdam Noord for over ten years, and the InBody scan is the single tool that has changed the most conversations I have with clients. Not because the machine is magic, but because it ends the argument. When someone tells me nothing is happening after eight weeks of training, we pull up the numbers, and usually something very specific is happening — it just was not visible on the scale.

What an InBody scan actually measures

A standard InBody scan gives you:

• Skeletal muscle mass — the muscle you can actually train and grow.
• Body fat mass and body fat percentage — separated from everything else, not estimated from weight and height.
• Total body water, split into intracellular and extracellular water. Useful for hydration and, over time, as a rough recovery and inflammation signal.
• Segmental analysis — muscle and fat readings per limb and torso. This is where imbalances show up.
• Basal metabolic rate — an estimate of the energy your body uses at rest.
• Visceral fat level — an estimate of fat around the organs rather than under the skin.

The segmental breakdown is the part most people ignore and the part I use the most. If your right arm carries noticeably more muscle than your left, that shows up in your pull-ups and your push-ups long before you feel it. We program around it instead of guessing.

How the InBody scan works

You stand barefoot on the platform, hold the two handles, keep your arms slightly away from your body, and stay still. A very low, painless electrical current passes through your body and the machine measures how easily it travels through different tissue. Muscle holds a lot of water and conducts easily. Fat holds much less and resists. The machine reads that resistance across multiple frequencies and calculates your composition from it.

The whole thing takes around a minute. You do not undress, you do not get in a tank of water, and you do not get pinched with calipers by someone guessing at your skinfolds.

Why the scale lies and the InBody scan does not

This is the conversation I have most often. Someone trains hard for two months, eats better, feels stronger, and the scale has not moved. They are ready to quit.

Then we scan. Muscle mass up, fat mass down, weight identical. That is not a plateau. That is exactly what is supposed to happen, and without an InBody scan they would have walked away from a program that was working.

The reverse happens too. Weight drops fast on a crash diet, and the scan shows most of the loss came from muscle rather than fat. That is a result nobody actually wants, because losing muscle drops your resting metabolism and makes the whole thing harder to hold onto. I would rather catch that in week four than in month six. If body composition is your main goal, I have written more about how that works in calisthenics for weight loss.

How accurate is an InBody scan?

Honest answer: it is very good at showing change, and reasonably good at absolute numbers. Bioelectrical impedance is affected by hydration, food, alcohol, and hard training in the previous 24 hours. A gold-standard DEXA scan will be more precise on any single measurement.

But precision on one day is not what you need. What you need is a reliable trend line, and for that the InBody scan is excellent — as long as you scan under the same conditions every time. That consistency is worth more than chasing decimal points.

How to prepare for your InBody scan

To make your numbers comparable session to session:

• Scan at roughly the same time of day, ideally morning.
• Do not eat a large meal in the two hours before.
• Skip alcohol the night before.
• Do not scan straight after a hard session or a sauna.
• Use the toilet first.
• Take your shoes and socks off, and remove heavy jewellery.

Nobody gets this perfect. Just do not compare a Monday-morning fasted scan to a Friday-evening post-dinner scan and draw dramatic conclusions from it.

How we use the InBody scan at Calisthenics Amsterdam

Every new client at our gym in Amsterdam Noord starts with a Starter Package: four to six personal training sessions, a physical assessment, and an InBody scan on day one. That first scan is the baseline. Without it, everything afterwards is opinion.

From there, we rescan at your Goal Review Session. Your coach sits down with you, we put the new numbers next to the old ones, and we look at three things: is muscle mass going in the right direction, is fat mass going in the right direction, and does the training plan need to change. Sometimes the answer is that the program is fine and your sleep is the problem. The data makes that conversation concrete instead of vague.

This is also why we coach rather than just hand out access to a room full of bars. Progress in bodyweight training is genuinely harder to track than adding a plate to a barbell — I have written about that trade-off in calisthenics pros and cons. The InBody scan closes that gap, and your coach interprets it for you rather than emailing you a printout.

What realistic change looks like

Most clients who train two to three times a week and make basic improvements to their eating see a clear directional shift on the InBody scan within eight to twelve weeks: muscle up, fat down, weight often barely moving at first. Strength usually moves faster than the scan does — you will feel it in your pull-ups before you see it in the numbers.

Anyone promising you a dramatic body composition transformation in four weeks is selling you something. Bodies change on a timescale of months, and the InBody scan is most useful when you treat it as a quarterly checkpoint rather than a weekly verdict. If you are still figuring out what a sensible training week looks like, start with how to start calisthenics.

Who an InBody scan is not for

Two groups:

If you have an implanted electronic medical device such as a pacemaker, do not use an InBody machine — the current is tiny, but it is not worth the risk. Tell your coach and we will track your progress through strength markers, measurements and photos instead. If you are pregnant, check with your doctor or midwife first.

And if you already have a difficult relationship with numbers on a scale, be honest with your coach about that before we scan you. For some people, more data helps. For others it becomes something to obsess over, and in that case we will happily track your progress through what your body can do instead. The scan is a tool. It works for you, not the other way round.

Book a free strategy session

If you want to know where you actually stand rather than what the scale guesses, book a free 20-minute strategy session at our gym at Metaalbewerkerweg 11 in Amsterdam Noord — a short ferry ride from Central Station. We will talk through your goals, show you the machine, and if it makes sense, get you started with a Starter Package that includes your first InBody scan.

You will leave knowing your real starting point. That is worth a lot more than another six months of guessing.