Tracking body composition changes

Human body is composed of several materials, some of which are muscle, fat, bone, blood, urine… So measuring or tracking changes in body composition with weight scale is pretty much like observing total points scored in basketball games – 153 baskets scored doesn’t tell you who won and by how much! And when you factor also gut contents, gut microbioma (over 1kg in adults!), glycogen content (with all bound water), urine volume, hydration status… into body weight, the picture becomes quite messy.

Body fat caliper

Body fat caliper

So while I do track my body weight on daily basis (I am data geek, who thinks that even bad data is better than no data at all!), I now mostly rely on body fat measurements with skin caliper to track my body composition changes. The skinfold estimation method is based on measuring the skinfolds at several standardized body points to determine the subcutaneous fat layer. These measurements can then be converted into estimated body fat percentage by various equations. Although this method may not give you an accurate reading of real body fat percentage, it is very useful for tracking composition changes over a period of time. I mainly compare the skinfolds values (individual or the sum of values) over time and do not pay much regards to the estimated body fat percentage. All in all, the main goal is to reduce the subcutaneous body fat, so why not measure it directly!

The calipers are very cheap; you can even get electronic calipers for very reasonable prices! As previously described, I use mechanical caliper on 10 body locations (Chest, Abdominal, Thigh, Bicep, Tricep, Subscapular, Suprailiac, Lower Back, Calf and Midaxillary).

Skinfold measuring sites

Skinfold measuring sites

I made Excel spreadsheet for tracking my skinfolds, with body fat estimates from various equations from literature. The formulas used are from Parillo (9 sites), Jackson Pollock (7 sites), Jackson Pollock (4 sites), Ball (7 sites for general population), Faulkner (4 sites for athletes) and Wilmore (7 sites for athletes). But as stated earlier, I mainly check the skinfolds values.

On the next graph are represented my values from July 2013, when I started using caliper. I had average skinfold of 5 mm, and at just above 71 kg body weight the formulas estimated my body fat percentage to be in the range of just over 7%. Going into my A race of the year, Hawaii in October, I had a racing weight between 71 and 72 kg with 3,4 mm average skinfold (around 5,5% body fat). In my offseason (November, December) I gained back some weight to just over 75 kg and my average skinfold increased to just over 5mm. This indicates that most of my weight gain was due to muscle mass gain, in the range of 2 – 3 kg. Naturally, I also gained approx. 1 kg of body fat, mostly for insulation purposes 🙂 The increase in weight is intentional, as I am emphasizing strength work in this training period by performing a lot of leg and upper body strength work along with core strength exercises. The underlying reason is to build a solid foundation for demanding training sessions that will come later in the season.

My skinfold data with average body weight (red line) and average skinfold (green line)

My skinfold data with average body weight (red line) and average skinfold (green line)

So to summarize, I think the caliper is superior tool in comparison to weight scales for tracking body composition changes and far more useful in daily practice. That is if you are quite ambitious athlete, and need to lose only couple kg of body fat for that optimal race performance. When I will return to “normal” life without racing ambitions, I will gladly ditch the use of both weight scale and caliper and replace them with another proficient measuring device: my eyes!

So if you are an ambitious athlete, you can download my Excel spreadsheet for tracking body composition changes here:

Download “Body composition tracking spreadsheet” Body-Composition-Tracking.xlsx – Downloaded 1601 times – 69 KB


And  here are the preprinted notes for easier measurements:

Download “Skinfold measurement” Skinfold-measurement.doc – Downloaded 865 times – 509 KB


Leave a Reply

Your email address will not be published. Required fields are marked *