Why Hydrostatic

Why Hydrostatic (Underwater) Body Fat Testing?

As body fat testing, rather than simple scale weight, has become "the standard" in this new millennium, Hydrostatic Testing (Underwater Weighing) has become universally regarded by industry experts as the "Gold Standard" in body fat testing. Renowned author and fitness expert Covert Bailey, in the phenomenal best seller "Fit or Fat", states: "That hydrostatic testing (underwater immersion) is the most accurate method for body fat determination."

FitnessWave's hydrostatic method uses a two component model which separates the body in two distinct pieces:
  • Bone, muscle, and connective tissue collectively known as lean mass sinks (More Dense than Water).
  • Body Fat-floats (Less Dense than Water). 

By obtaining your land weight and water weight (based on buoyancy) our specialized computer program can scientifically calculate your body fat as a percentage of your total weight. The ordinary land scale cannot tell you if weight loss is muscle or fat, while getting dunked with FitnessWave can tell you to the ounce of what took place with you body during your weight loss regiment.

Clinically speaking, the hydrostatic testing method has been around for over 50 years and is based on Archimedes principle which states "that when a body is submerged in water, there is a buoyant counter force equal to the weight of the water which is displaced". Again, because bone and muscle are denser than water, a person with a larger percentage of lean body mass will weigh more in the water and ultimately have a lower body fat percentage versus someone with less lean muscle mass. A person with more body fat will be lighter in water because body fat floats and lean tissue, muscle, connective tissue, bones, etc. sink.

Hydrostatic Body Fat Testing (Hydro-Densitometry): According to research, "Hydrostatic Body Fat Testing "is still the "Gold Standard" to which all methods of body fat testing still compare themselves. FitnessWave has been the pioneer in hydrostatic testing for nearly twenty years and we strive to provide accurate and affordable hydrostatic testing to our clients with a professional touch. FitnessWave makes hydrostatic body fat testing a fun experience for the whole family.

Recommended Body Fat Percentages

You may be asking yourself why is knowing my body fat percentage is so important?

Traditional scale weight can not determine how much muscle (lean mass) or fat mass one idividual has versus another. And if you are working out this can become very frustrating especially if the scale isn’t moving. The reason the scale may not be moving is because as you lose fat you may be gaining muscle and this will counterbalance the scale.
Body fat percentage has become a standard for doctors, and health professionals alike.

  • BMI is another number that is being used to rate peoples health. BMI stands for “Body Mass Index”. BMI is based on a chart that goes by a persons height, weight and then gives you a number based on this chart.Over the past 50 years the average height and weight for mankind has increased approximately 20 percent. There are many factors for this, one is the steroids in the food we eat, and another factor is weight training and the use of supplements in our diets.
  • These factors taken over time have had a huge impact on our society. Once again, land weight scales cannot determine the lean to fat ratio of that weight. An individual can be "over weight" and not "over fat". For example, a body builder may be 4% body fat an two hundred and fifty pounds and yet may be considered "overweight by BMI or Body Mass Index.
  • When the BMI was developed by insurance companies in the 1950's and 1960's it was meant to be used as a health guideline that was based on height and weight. It is our opinion that these guidlines are getting more and more outdated due to the fact that people in general have more muscle than they did years ago. Therefore, these charts are not a good indication of a person's ideal body weight for optimal health. A true body fat reading is the only real way of knowing where you stand. So come and "Get Dunked" we know you will love it.

Why a healthy body composition is important?

Whether you are overweight or of normal body weight you should be aware of the impact body composition has on your health! Even if your scale weight is within a normal range, you can still have unhealthy or altered body composition.

What is unhealthy body composition?

Generally speaking, it refers to carrying too much or excess body fat in comparison to your lean muscle mass. As your body fat-to-lean ratio increases, so does your health risks. In fact, more often than not an unhealthy body composition can lead to obesity (commonly defined as 30 pounds or more overweight) a condition associated with many critical health concerns, including some of the following:

  • Heart disease
  • Stroke
  • High blood pressure
  • High Cholesterol
  • Type 2 diabetes
  • Certain forms of cancer
  • Excess fatigue

Some Factors that Contribute to Unhealthy Body Composition:
  • A high-fat, high-sugar diet
  • Lack of exercise 
  • Overeating
  • Excess alcohol intake

Did you know?
  • More than 60% of the U.S. adult population is overweight, with over 25% considered obese.
  • Almost 30% U.S. children and teens aged 6 to 19 years old are categorized as overweight.Overweight adolescents have a 70% chance of becoming overweight or obese adults.
  • In America, approximately 47% of those who are overweight and 71% of those who are obese have high blood pressure.
  • Half of all overweight and obese American adults have cholesterol levels higher than they should (greater than 200 mg/dl).
  • Approximately 25% to 33% of Americans have insulin resistance, which left unchecked, may develop in to type 2 diabetes. About 70% of people with type 2 diabetes are overweight.

According to the National Institute of Health the following are considered to be benefits of a Healthy Body Composition:
  • Increase energy and endurance.
  • Promote healthy blood pressure.
  • Improve quality of sleep.
  • Relieve some strain placed on your knees, hips, and lower back which can lead to reduced pain.
  • Improve mood and self confidence.
  • Reduce the risk of certain pregnancy related complications.
  • Improve blood circulation in all parts of the body, thereby reducing the risk of heart disease and stroke.
  • Reduce respiratory infections and breathlessness, and improve lung function.
  • Improve insulin sensitivity and glucose tolerance.

The Bottom Line is a healthy body composition can not only improves your general health but it can also change your whole quality of life for the better!

Health Risks Associated With Too Much Body Fat Include The Following:
  • Increased blood pressure
  • Increased total cholesterol level
  • Increased LDL (bad) cholesterol
  • Increased risk of cardiac problems
  • Increased risk of Diabetes
  • Hardening of the arteries
  • Aggravation of osteoarthritis
  • Promotes blood clots and varicose veins
  • GI disorders
  • Increased predisposition to some cancers
  • Decreased reaction time
  • Reduced balance and coordination
  • Increased susceptibility to infections
  • Decreased circulation
  • Delayed wound healing

Who We Test?


Our "Gold Standard" technology has withstood the test of time year after year and is an essential component in beginner as well as seasoned athletes fitness programs


FitnessWave schedules test locations with health club facilities which are OPEN TO THE PUBLIC. The fitness trainers combine their expertise in conjunction with our testing method, which gives individuals an advantage on reaching their fitness goals.

  • Referrals from Existing Members

Friends and family share positive results, which can result in new faces coming to your facility for testing.

  • Increase Your Training and/or Nutrition Consulting

The test data is crucial to a well-formed training and nutrition plan, and individuals will look to your facility resources for follow up information and services.

  • Retention of Existing Members

By providing state of the art technology, your members are receiving "extra" benefits to their existing membership.


Corporations and public agencies recognize the importance of health and wellness programs, and the benefits these programs can provide. FitnessWave works in conjunction with health and wellness programs to optimize the goals of these corporate and public agency programs. Our mission is to enable your organization to improve the health of your employees, control insurance costs, lower health claims and absenteeism, and increase productivity.

Did you know that 70% of healthcare costs in the United States are preventable? According to the American Heart Association, we lose $32 BILLION a year because of premature illness associated with cardiovascular diseases like high blood pressure, diabetes, and obesity.



It is vital to implement programs to help our youth get healthy and stay healthy. At FitnessWave, our technology is used in conjunction with programs to achieve that goal.

  • Monitor and track the effectiveness of nutrition, rehabilitation, and training programs
  • Develop individual, sport, and/or position-specific body composition ranges
  • Assess Resting Metabolic Rate (RMR) and Total Energy Expenditure (TEE)
  • Provide athletes with additional motivation and knowledge on proper training principles
  • Accommodate a wide range of subjects (size, race, and gender)

FitnessWave provides a safe protocol to manage and track both fat and fat-free mass, rather than the overall weight of athletes.

How do other methods compare?

Hydrostatic Body Fat Testing (Hydro-Densitometry):

According to research, "Hydrostatic Body Fat Testing" is still the "Gold Standard" to which all methods of body fat testing still compare themselves. However, for informational purposes we would like to share other methods that are being used within the health, fitness, and medical community.


  • The "Gold Standard" in body fat testing
  • What other methods still compare to
  • Fast test time (5-10 minutes)
  • Most accurate technology available today
  • Provides the best repeatability from test to test (tracking changes)
  • Error rate around 1.5%
  • Low equipment maintenance
  • Has been the most accurate method for over 30 years


  • Requires knowledge to administer test
  • Being submerged underwater might be a little difficult for some (elderly)
  • Must be able to blow out your air

Duel Energy X-Ray Absorptiometry Body Fat Testing (DEXA):

DEXA uses two x-ray energies to measure body fat, body fat percentage, muscle and bone mineral. One must lie down on an x-ray table while the machine scans the body. It takes the machine about 10 to 15 minutes to produce the image of the tissue.


  • Under proper conditions it provides accurate results
  • Error Rate is less than 2% under proper conditions
  • Radiation exposure is relatively low but it is still new technology


  • Very expensive equipment
  • Costly
  • Uses X-Rays
  • Not easily accessible, or mobile
  • Different DEXA equipment can produce different results
  • X-Ray license required to use machine
  • Frequent testing may be of concern due to radiation exposure

Caliper Body Fat Testing:

This is a small pinching device that measures subcutaneous body fat on your body. It has a +/- 3-8 percent error ratio based on technician skill, quality of caliper used, and number of sites pinched. Although it's quick and relatively easy to get it's more of an estimate of body fat this is because it only measures a few areas on your body and not the whole thing. Plus, it is very subjective to each person that does the testing.


  • Easy to use once skill is mastered
  • Does not require much time
  • Noninvasive method
  • Inexpensive way of estimating body fat percent
  • Portable


  • Technical sources of error
  • Error rate up to +/-8%
  • Mostly concerned with subcutaneous fat (under the skin)
  • May not be an ideal measurement for those who are obese, or very lean.
  • Reliability is highly dependent upon skill and the type of calipers used

Bio-Impedance (BIA) Body Fat Testing:

This measurement is done by hooking up an electrode to your foot or hand. An electrical low voltage impulse is then shot up one leg or arm and down the other to estimate body fat percentage. It measures the resistance in your body. Since body fat is a poor conductor of electricity, a lot of body fat will impede the current more so then lean mass.


  • Fast and simple


  • Error ratio +/-5 to 8 percent
  • Results effected by hydration levels, food intake, and body temp
  • Subjectivity is high
  • Higher percentage of error than most people desire
  • Overestimates lean people and underestimates obese people 

Bod Pod Body Fat Testing:

This method tries to compare itself to the Hydrostatic method of body fat testing and it is based on similar principles. However, instead of using water it uses air displacement instead. This method has conflicting research reported on its results. Humidity, temperature, body hair and other environmental issues have been reported to negate the results of its body fat readings. According to Georgia State University, if each body fat test is performed correctly to the recommended guidelines, there is a +/-3% error. Likewise, a study done by McCrory, etal.* the bod pod has a validity of .93 using hydrostatic weighing as the criterion measure body fat percentage. Medicine and Science in Sport and Exercise, 27 (12): 1686-1691, 1995


  • Fast 5 -10 minutes
  • Not difficult to operate


  • Error ratio +/-3 percent
  • Results effected by h body temp of muscles
  • Hydration levels can effect results
  • Body hair can have an effect on the results
  • Very expensive equipment
  • Breathing pattern might affect the results
  • Can have an Claustrophobic feeling

Futrex Body Fat Testing:

This method of assessing body fat is based on the principles of light absorption, reflectance, and near infrared spectroscopy. This is an infrared laser that is shot into your bicep muscle that emits an infrared light which passes through both fat and muscle and is reflected back to the probe. The test results change depending on what you program into the machine. Hydration levels can also dramatically change the results of the body fat readings.


  • Non-invasive
  • Fast
  • Convenient


  • Error ratio +/-5 to 6 percent
  • Results effected by hydration levels, food intake, and body temp
  • Subjectivity is high
Read 240207 times Last modified on Thursday, 23 July 2015 19:13

Get in touch with us

For equipment sales or business opportunities

Phone (Text or Call): 480-964-9283

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.