By Marla Kaminsky, AFS Community Expert

Data is the new black.  The calorie counter on the elliptical is no longer cutting it.  Members want quantitative results.  Showing a client their entire body composition (body fat, muscle, etc...) is an effective way to show progress and motivate members. 

My goal is to educate you on the different types of body composition available.  I’ll also touch on the importance of presenting body composition in a way that motivates progress, rather than distracting from goals.

Outside of old-school calipers (which are not accurate at all because they only measure the fat under the skin), there are three primary categories of body composition I am going to focus on.  These are the ones being used most often in the fitness community.

  • DEXA (dual energy x-ray absorptiometry)
  • Displacement (air or water)
  • Bio Impedance

DEXA- dual energy x-ray absorptiometry:  DEXA uses x-ray radiation in very low doses to determine the body’s composition and remains the gold standard and what all other technology is compared against for accuracy.

BIA (bio impedance analysis)- This technology uses a very low voltage of electricity.   From there, sophisticated calculations give you the results.  Clinical grade BIA machines have reliable accuracy.  The benefit of BIA is that it is relatively inexpensive (starting at under $3,000) and it measures the body’s water content, which is important to overall fitness performance. 

Air or water displacement- this used to be the most popular way to test for body composition.  Now with other methods, these are seen less frequently.  Water and air Displacement is when the subject gets into a unit that measures the body composition based on the displacement of water or air.

Now that you have a basic knowledge of the different types of body composition, what do you do with it?  Here are some pointers when looking to make a purchase.

  1. Don’t get caught up in looking for the absolute “most” accurate.  All of these clinical grade methods are accurate.  
  2. Set a budget.  You are going to be spending about $3,000, for the most basic BIA device. 
  3. Decide what information is most important to you. 

Here are some recommendations for presenting body composition to your clients:

  1. Look for changes over time (usually a month apart), Most of the body is water and can change up to 7 pounds throughout the day.  You need enough time between each test that water isn’t a factor.
  2. I always recommend providing two positives and an improvement.  Providing an overly detailed analysis will confuse your members.
  3. Work with a company that will help you beyond your purchase.  It often takes time to have a clear understanding of the data and how to present it.

When done right, body composition is key to unlocking measurable results and creating long term motivation.


Marla Kaminsky is the owner of Spartan Wellness Technology.  Ms. Kaminsky has extensive knowledge in the implementation of bio impendence analysis in the fitness and wellness industry.  Her expertise extends into training and educating individuals and business owners in how fitness testing can improve member engagement.  If you are interested in learning how SWT can help you improve your business model she can be reached at  For a more detailed explanation of the different types of body composition, click HERE.

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