Knowing body composition is a highly valid tool to help inform both athletes and non-athletes of their health and what they may need to improve on. Such information can be used to identify weight issues such as being over weight or underweight and to track fat and muscle mass growth or loss. One number on a scale is not enough to have an overview of body composition.
Let´s look into the pros and cons of the most commonly used body composition tools.
What is body composition?
Body composition divides your body weight into seperate elements of fat, muscle, bone, water and minerals. A proper body compposition examination can show how muscle and fat is disributed around the body, the density of bones (even bone health such as risk of osteoporosis) and changes in muscle and fat formation or loss over time. Due to this, it is important to not define weight as one number from a scale but rather a combination of multiple measurements.
What do body composition tools do?
Body composition measurement tools are divided into different compartments (e.g. 2C, 3C, 4C). This is the number of compartments a tool can measure. Compartments are the different bodily elements that body weight can be divided into. The more compartments that are measured, the smaller the rates of error can occur.
2C divides body weight into fat mass and lean body mass
3C divides body weight into fat mass, lean body mass & bone mineral content
4C includes multiple tools to measure multiple compartments
What are the different measurement strategies?
Skin calipers
- assesses skinfold thickness only with a steel pincher that contains a measuring compass.
Bioelectrical impedance analysis
- an electrical scale with a handle that uses an electrical current to measure body weight, an estimated fat mass and lean body mass.
Air-displacement plethysmography (BodPod)
- an computerized egg-shaped chamber that measures body weight, fat mass and lean body mass.
Hydrostatic or underwater weighing
- a swing-like device is used for a person to sit on and is lowered into water. The person´s body volume is measured and divided into body weight, fat mass and lean body mass.
Dual-energy x-ray absorptiometry (DXA)
- a high-tech scanner that uses x-rays to divide a person´s body weight into fat mass, lean body mass and bone mineral density.
This graphic shows the populatirty of the various body composition measurement tools:
Graphic: Yan Lemur infographics
What are the pros & cons of 2-, 3-, & 4-compartment body composition measurement tools?
2-compartment:
(e.g. BodPod, skinfold, BIA and hydrostatic weighing)
Pros:
Most commonly used in clinical and sport settings due to ease of operation & accessibility
Affordable
Some provide regional fat mass (e.g. skinfolds)
Cons:
Over- and underpredictions of body fat percentage have been identified
Highly dependant on accuracy of tester
Must be done by same tester
Assume constant properties of fat free mass
Can be invasive to some (skinfolds & hydrostatic weighing)
High validity & reliability
3-compartment:
(e.g. DXA)
Pros:
Most accuracy and reproducibility of the currently available tools
Higher validity & reliability
Provides regional BC
Estimates BMD
Low radiation (sequential measurements safe)
Non-invasive & fast (5-15 min)
Cons:
Suitable for most (potentially less for lean athletes)
Subject to debate on accuracy with differences in hydration, glycogen & muscle creatine levels
Expensive
Trained technician required
Must use same machine (limits location)
Not portable
4-compartment:
Requires multiple BC methods to be used in combination with each other.
Pros:
Most accurate (at the moment)
Higher validity & reliability
Provides info on all aspects
Provides regional body composition (i.e. measurements of specific body parts)
Potentially more accurate for leaner subjects
Cons:
Time-consuming
Requires access to expensive technology
Often out of reach for practical applications in sport
Not always portable
Consider the following when deciding on a tool to use:
Technician´s experience
Accessibility of the tool
Who the tool is being used on (e.g. athlete or non-athlete)
Goal of the study or what you want to achieve by using the tool
Pros and cons of each tool
Is there a gold standard body composition measurement tool for an athletic population?
At the moment there is not one specific tool that is considered the gold standard for measuring body composition, as all have their pros and cons and suit different situations. Combining multiple tools to minimise the rate of error is the closest thing to it.
For example this woould include combining 2C models such as BW, skinfolds and waist circumference with photographs or the DXA scan with skinfolds. However, keep in mind that this strategy can become complicated when analysing the results.