The measurement uses the principle of B.I.A., Bioelectric Impedance Analysis. With this process, an imperceptible, completely safe and harmless current enables the determination of body tissue proportions within seconds. With the inclusion of constants and/or individual values (age, height, sex, activity levels) this procedure can be used to determine the percentage of fat, water and muscle in the body. Muscle tissue and water have good electrical conductivity, and therefore a lower resistance. On the other hand, fatty tissue has a low conductivity, as the fat cells hardly conduct the current due to their very high resistance.

A high percentage of body fat indicates a higher risk of disease and cannot be visually assessed. Even people who appear slim may have a high percentage of body fat. The following body fat levels provide you with a guideline (for further information, please consult your doctor!).



A lower level is often found in athletes. Depending on the type of sports, the intensity of training and the person's physical constitution, levels can be achieved that are even lower than the specified guidelines. Please note that very low fat percentages may pose a danger to health.

The normal percentage of body water is in the following ranges:


 
Body fat has a relatively low percentage of water. Persons with a high body fat percentage may have a body water percentage under the guidelines. Endurance athletes may exceed the guidelines because of their low fat percentage and high muscle percentage.

The body water percentage measured with standard personal scales is not suitable for drawing medical conclusions on items such as age-related water accumulation. If in doubt, consult your doctor.

A high body water percentage is generally desirable.

Close monitoring of body fat and body water is particularly important with diets. Short-term weight fluctuations within a few days are usually only due to a loss of liquid. If your weight and percentage of body fat drop simultaneously, your diet is working and you are losing fat mass. Ideally, you can support your diet with physical exercise, fitness or power training. This can result in a mid-term increase in the percentage of muscle in your body.

Well-trained muscles have many functions. They support the spine and relieve pressure on discs. They help to relieve and prevent tension. They help with improving posture. Muscles also consume more energy than other tissues and make an important contribution to burning fat. Improving musculature is therefore an important factor in reducing weight over the long term.

The normal percentage of muscle is in the following ranges:

Our bones, like the rest of the body, are subject to natural building, degeneration and ageing processes. The bone mass rapidly increases in childhood and reaches its maximum at 30 to 40 years of age in both men and women. As our age increases bone mass tends to decrease. This decrease can be countered with healthy nutrition (with minerals such as calcium and vitamin D) and regular physical activity.  Targeted exercise can be used to improve the stability of your bones.

Note that a standard personal scale does not show the calcium content of the bone but the weight of all constituents of the bone (organic substances, inorganic substances and water).

Important: Please do not confuse bone mass with bone density. Bone density can only be measured by a medical examination (computed tomography, ultrasound). Conclusions about changes in bones and bone hardness (such as osteoporosis) are impossible with a standard personal scale.

It is virtually impossible to influence the bone but it does vary slightly within the factors that affect it (weight, height, age, sex).

Important: body fat, body water and muscle percentage cannot be added together (muscle tissue also contains constituents of body water).

Scales with the "vibration-on" function have an integrated vibration sensor. Audibly, briefly and firmly tap the scale with your foot to activate the vibration sensor. Step on the scale when the display shows 0.0.

The "tap-on" function describes switching on the scale by tapping the platform lightly with the foot. The user must tap the scale and wait until the display show 0.0. Then step on the scale and wait for the measurement.

Body fat scales must not be used with electrically operated implants (e.g. cardiac pacemalers, medication pumps).

Persons with electrically conducting implants (e.g. bone screws, hip replacements) can use the scales. However, incorrect measurements can occur because of the better electrical conductivity of the implant compared to the tissues.

The body fat scales should not be used during pregnancy. Because of the amniotic fluid, incorrect measurements can occur.

• Anatomical variations (e.g. considerably longer or shorter leg length)
• Volume of calves and/or thighs
• Training condition of the muscles
• Bone structure
• Fat distribution in the body
• User’s state of health
• Poor contact between soles of the feet and electrodes
• Severe sweating
• Use of medications
• Oedema of the legs
• Haematomas in the legs
• Fever
• Measurement after physical effort
• Measurement at different times of the day
• Fluctuating body weight
• Pregnancy (amniotic fluid)
• Metal implants
• Calloused skin on the soles of the feet

Different weights may have different causes. For example, the person did not stand perfectly still on the scale, the scale was moved or lifted between measurements, the scale was not set to zero or not initialised correctly or the person stood in a different position on the scale.

Technical tolerances may also result is a difference as much as +/- 0.5 kg between two measurements. The repetition accuracy of weight measurements on a scale is +/- 0.3 kg. If several scales are compared, the maximum tolerance at 40 kg is +/- 0.5 kg and for 100 kg +/- 1.1 kg.

Different body fat values may be the result of varying results in weight measurement, the effect of external factors (dry feet), motion artefacts or if the user stands differently on the electrodes between measurements. The tolerance of body fat or body water measurements is +/- 1%.

Different manufacturers use different evaluations of measurement results in their software. The evaluations may result in differences in the measurement results. The body fat should always be measured by the B.I.A. method as a trend and not as an absolute measurement, because the overall measurement depends on many other factors. For example, the change in body fat percentage can be easily followed on a diagnostic scale with a person on a diet.

Sports mode is an additional function for adjusting the body fat measurement for the individual characteristics of a user group. A number of fixed parameters are used by the scale software to calculate the body fat percentage (apart from the actual measurement of the body resistance) for the body fat analysis. In standard mode these constants reflect averages derived from medical studies of the "normal population". Because the distribution of the various body parts (muscle tissue, bone, fat etc.) is different for athletes, the sports mode is also included. This mode uses constants derived from medical studies with athletes. The different values are therefore the result of the different constants in the software.