BodPod vs Ultrasound (BodyMetrix)

BodPod vs Ultrasound (BodyMetrix)

You may have heard of BodPod. It looks a bit like a space shuttle that measures body composition using plethysmography. Lets put BodPod vs ultrasound to the test.

Plethysmography measures changes in volume within the body using air displacement. It’s a lot like hydrostatic weighing but using air instead of water.

A metal cylinder goes into the BodPod to calibrate before a measurement, then a swim cap donned, semi-naked individual climbs inside and begins the test.

Considered a Gold Standard, this high tech looking bit of kit has a hefty price tag of about £40,000. Yes, that’s forty thousand British pounds.

What interests me beyond body fat measurement is measuring muscle tissue. There’s plenty of good fat monitors on the market, but few muscle measurement systems. Even the BodPod can’t measure muscle directly. In fact, the systems measure fat-free mass instead shown by the screenshot from the BodPod website.


I talk a lot about measuring muscle as part of body composition measurement. There are many benefits to doing it. Knowing that any weight loss is from fat and not water or muscle is powerful. It can help intervene if needed and then make subtle changes to maximise client progress. The BodyMetrix screenshot below shows actual muscle thickness in millimetres.

BodyMetrix ultrasound, BodPod vs Ultrasound

Because Fat-free mass measurements include organs, bones and muscle. The ability to identifying real muscle changes with BodPod is near impossible.

When taking a body fat measurement, I take note of the muscle tissue thickness too. Referring to the measurement, I can confirm weight loss was from fat tissue. At the same time, I can see that there was little to no loss of muscle tissue. Powerful stuff.

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