Using Skulpt Chisel for Body Composition Measurement


For many people, reaching their health and fitness goals means reducing their body fat or gaining muscle mass. In all likelihood, there is greater interest in the former. So, what’s the best way to go about measuring it? The major ways to measure body fat percentage are as follows:

1. Visual Changes: Look at your body over time.
2. Skin Calipers: Use measurement calipers to measure “pinch-able” fat at different locations of your body.
3. DEXA: X-ray beams are used to assess lean and fat mass.
4. Hydrostatic Weighing: Body fat composition determined from your dry weight and weight when submerged in water.
5. Air-Displacement Plethysmography: Similar to hydrostatic weighing, but using air displacement instead.
6. Electrical Impedance: Using tiny electrical impulses to measure signal return rates, which are specific to different tissues.

There are drawbacks to each of the above. Visual changes can be hard to see if you are losing small amounts of fat mass or if the fat is being reduced more heavily in certain body parts than others. Skin calipers have a fair bit of user error and can only take measurements from certain body parts (not necessarily the ones where you have most of your body fat). DEXA, Hydrostatic Weighing and Air-Displacement Plethysmography have the major drawback of being expensive.

Given the above, I tried to settle on a method that I would regularly use to assess body fat on myself (I do a lot of experimenting with training programs and nutrition plans). I started with Hydrostatic Weighing at a time when I was carrying the most fat (May 2015) and the results told me I had 9.5% body fat. I don’t have a picture from that time, but it really didn’t make sense. Hydrostatic Weighing is often considered a gold standard because the science behind it is robust. However executing the technique is somewhat tricky as user/subject error can skew the results. Indeed, something must have went wrong. Perhaps I didn’t expel enough air when under the water. Perhaps it wasn’t calibrated right. Whatever the reason I knew I had to be around 13-15% fat and I didn’t want to keep spending money to sort it out.

Instead, I backed the Skulpt Chisel on Kickstarter which uses electrical impedance. Typical electrical impedance devices (which are generally scales) send a signal through your entire body and read the signal once it returns…after having taken the shortest route to get there. Thus, these devices are susceptible to changes in body hydration, how fed you are, etc. The devices also base their calculation on how tall you are, how much you weigh, and so on. The Skulpt Chisel doesn’t make these kinds of estimations. It sends and receives its signals locally as they passes through specific parts of your body (biceps, thigh, abdominals). Thus, the signals pass through the muscle and the fat of your area of interest. Comparisons made by the Skulpt Chisel team demonstrated that the Chisel was 5 times more accurate than regular impedance scales and deviated from DEXA measurements (the more expensive gold standard) by less than 1.5%.

For my interests, I wasn’t that concerned with absolute accuracy. I wanted a device with accuracy for sure, but I wanted one that could track changes (sometimes small ones) consistently over time. So, once my device came, I decided to try it out. Here’s how it went:

Age: 38
Testing Period: April 2016 to October 2016 (6 months)
Training Regimen: 5 days per week. CrossFit and High Intensity Conditioning classes with some supplemental maintenance strength training on the side.
Nutrition: Not regulated. A handful of meals each day were Paleo, others were not. However, I knew based on prior information that the calories and macronutrients I was consuming were appropriate for me to lose fat.
Visual Changes:

April 2016

October 2016

As you can see, I was reasonably lean when I started the experiment, but managed to get even leaner by the end. The reduction in fat mass was therefore not major, but that’s exactly what I wanted to experiment with; I wanted to see how well the Skulpt Chisel would pick up on a relatively small change. Below I highlight the specific data the Skulpt Chisel gave me.
img_3969-edit summary-edit
Note that the graphs above are a bit different do to a change in software version that happened during my experiment. You can see that my body fat percentage dropped from 14.7% to 12.1%. Note the starting body fat percentage of 14.7% made much more sense than the 9.5% that hydrostatic testing gave me (which was measured when I was carrying even more fat than I am in the picture shown on the left).
Shown above is also a readout for muscle quality. Skulpt Chisel measures this based on the fact that higher quality muscles will have less stored fat and, if bigger, will demonstrate greater electrical charge storage capacity and greater time delays as the signal returns. I wasn’t too concerned about this measurement given that my muscle size (visual appearance) and how much weight I can lift is what’s most important to me, but it’s a nice feature to have.
To close, I want to highlight what I really love about the Skulpt Chisel and that is how you can get a readout of your body fat percentage in specific areas of you body. This is crucial because 1) most of us want to look leaner in a specific area (i.e., Abdominals) and 2) our bodies tend to collect more fat in certain areas than others. For me I tend to carry more weight in my abdominal region and my buttocks (over my gluteal muscles). Of the two it’s my glutes that carry the most fat by far. So, did the Skulpt Chisel pick this up?
img_3972-edit fat-back-edit
Again, the summary figures above look a bit different due to the software versions, but you can see quite clearly a large amount of fat in my Glutes at the start (21.8%, 24%) which is then reduced, but still somewhat high at the end (13.5%, 14.3%). So, yes, the Skulpt Chisel picked up on this key site-specific difference and its change over time.

So there you have it. The Skulpt Chisel can be purchased for $99. It interfaces with your smart phone, so that’s all you need. Given the information offered by the device and how reasonable the price is, I can’t recommend it enough. I’ve been recommending this device to all my clients that are serious about tracking their body composition changes, so if you too are interested in the information it has to offer, check it out.

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