Hydrostatic weighing for health assessment -
Figure 1 Illustration of measurement of underwater body weight. The most commonly used equations for estimating the percent of body fat from density are as follows:. Considerations relating to the use of hydrostatic underwater weighing for anthropometry in specific populations are described in Table 2.
Refer to section: practical considerations for objective anthropometry. About About the DAPA Measurement Toolkit What's New Other resources Toolkit Team Contact.
Introduction Validity Reliability Error and bias Feasibility Data processing Statistical assessment of reliability and validity Harmonisation. Introduction Subjective methods Objective methods Harmonisation Videos Dietary assessment decision matrix.
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Hydrostatic underwater weighing. What is assessed? How is the measurement conducted? When is this method used? How are estimates of body composition derived? Strengths and limitations Populations Further considerations Resources required Instrument library References.
Two methods to determine total body water An allowance must be made for residual lung volume the air that remains in the lungs after a maximal exhalation as this air increases the participant's buoyancy. Dry bodyweight After having measured or estimated residual lung volume, the participant's dry weight is measured wearing a swimming suit or running shorts.
Underwater weight The participant climbs into the underwater weighing tank and sits in a seat that hangs from a force load-cell. After the underwater weight stabilizes approximately 5 seconds , the participant is instructed, though yelling or pounding on the side of the tank, to return to an upright position.
During weighing, the participant is always free to stand up or return to the upright position. Several trials may be required before the participant becomes accustomed to the procedure and consistent readings recorded.
Four to eight trials are usually performed. The depth of the water is approximately cm, and temperature maintained between 30 and 34 C. The density of water is dependent on the temperature and should always be factored into the equation.
After each testing session, the water is drained and the tank allowed to dry. Pre-test Guidelines Participants must not eat or engage in strenuous exercise for at least 4 hours before their scheduled appointment. Body density is required to calculate percentage body fat. Strengths and limitations.
An overview of the characteristics of hydrostatic underwater weighing is outlined in Table 1. elderly Participant must be able to perform complete air exhalation There is a possibility of considerable error introduced by the miscalculation of residual volume RV The test does not identify the exact parts of the body where the fat is located e.
unable to assess fat distribution The accuracy of body density measurements can be affected by the consumption of food and carbonated beverages shortly before the test, fluid loss during intensive exercise, fluid retention during menstruation, and the degree of forcible exhalation while submerged Like all the 2 component model methods, it assumes when calculating total body density that the relative amounts and densities of bone, muscle, and water comprising the fat-free mass are essentially the same for all individuals, regardless of age, sex, ethnicity or fitness level Table 1 Characteristics of hydrostatic underwater weighing.
Consideration Comment Number of participants Small Relative cost Medium Participant burden High Researcher burden of data collection High Researcher burden of coding and data analysis Low Risk of reactivity bias No Risk of recall bias No Risk of social desirability bias No Risk of observer bias No Space required High Availability Medium Suitability for field use No Participant literacy required No Cognitively demanding No.
Table 2 Anthrompometry by hydrostatic underwater weighing in different populations. Population Comment Pregnancy Suitable but unable to disentangle the mother-fetal unit Infancy and lactation Not suitable Toddlers and young children Not suitable Adolescents Not suitable Older adults May not be suitable as older individuals have less dense bones, resulting in over-estimation of body fat Ethnic groups Suitable Other athletes Athletes tend to have denser bone and muscle tissue, resulting in under-estimation of body fat Other obesity Suitable.
Further considerations. Resources required. Hydrostatic stainless steel weighing tank Underwater mounted chair and scale Weighted belt and nose clip A simpler set up may include a chair and scale suspended from a diving board over a pool Trained research staff.
The BOD POD is designed to accommodate a wide variety of human shapes and sizes. Because of its generous-sized interior and oversized window, NFL and NBA teams, as well as sumo wrestlers use the BOD POD routinely without difficulty.
The BOD POD can accommodate subjects up to 7 feet tall and pounds. Clothing, hair, jewelry, and eyeglasses can have a significant impact on the volume and mass measurements performed during a BOD POD test.
Therefore, it is EXTREMELY IMPORTANT that all subjects tested in the BOD POD remove all jewelry and eyeglasses, and wear minimal, form-fitting clothing such as a Lycra® or Spandex® swimsuit during testing. Participant compliance for testing in the BOD POD is very simple.
You need only to sit comfortably and quietly inside the BOD POD for the brief measurement period no talking or laughing. Sounds relating to valves opening and closing may be heard, but most people are unaware of the slight pressure changes that take place during a BOD POD test.
A few people have noted a feeling similar to that of moving from the first to second floor in an elevator. Subjects should wait at least two hours after exercising or eating, and always be in a completely relaxed state normal breathing when testing in the BOD POD.
Call Testing is highly accurate, safe, and quick, with a complete analysis in about minutes. Bod Pod uses the most advanced technology available today. It's easy and appropriate for many types of people, including the obese, disabled, elderly, and children. It provides excellent repeatability and tracking.
All testing is done by appointment. Please call to schedule your test. Women need to bring a swimsuit or form fitting lycra shorts and a sports bra. Men need to bring a speedo or form fitting lycra shorts. PEAK can provide compression shorts if needed. Results are available immediately. Bod Pod Results Information The range of error for this test is ± 1 to 2.
BodPod is as accurate as hydrostatic underwater weighing, but quicker and easier to perform. PEAK tester will help to explain and interpret results Bod Pod results sample.
Please call your desired location to set up your appointment. PEAK HPER East Building South East, Room Salt Lake City, UT Skaggs Patient Wellness Center Wakara Way SLC, UT How does the BOD POD compare with other body fat assessment techniques?
How does the BOD POD measure body composition?
Hydrostatic Water retention reduction methods, weighlng known as underwater weighing or hydrodensitometry, is one of the assdssment accurate Hydrodtatic to measure body fat. It was considered the gold weihging for Peppermint dessert recipes Body Composition Analysis composition until more Water retention reduction methods methods, such as CT scans and MRI scans, were developed. During the test, you have your body weight measured on land and underwater. The difference between these two measurements allows test administrators to calculate your body density and body fat percentage. Hydrostatic weighing is mostly performed on athletes, in research, or in other situations where an accurate measurement is needed. Some companies even offer mobile tests, for which the test administrator drives to your location. Keep reading to find out how hydrostatic weighing works and how it compares to other body fat testing methods. In our Exercise Physiology Body Composition Analysis, fitness and adsessment assessments Natural energy-boosting methods cardiovascular fitness, body composition, and muscular fitness. Community Fitness and Performance. Related Content. Related Resources Vascular Fitness Assessment Additional Resources Exercise Physiology Lab Homepage Lab Equipment Fitness Testing. Below are the descriptions and pricing for our different tests.
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