Segmental Lean Analysis

• The measured part: the impedance of each of the five segments. The device takes 40 impedance readings — 8 frequencies from 1 kHz to 3 MHz for each of the five segments. The trunk is measured separately because it is shorter and wider, so its impedance is low, while according to the manufacturer its muscle makes up almost half of total muscle mass.
• The derived part: body water in that segment is established from segment impedance. The manufacturer presents body water as derived from measurement rather than as an estimate.
• The calculated part: the lean mass value in kilograms. The specific equation the manufacturer uses for this does not appear in the manual.
• The reference comparison: both percentages. The upper bar relates the kilograms to ideal weight, calculated as ideal BMI × height². The lower bar relates them to the actual measured weight. One hundred percent is a reference point, not a ceiling.
• Age, sex and ethnicity do not enter the body composition calculation itself. The manufacturer uses them only for reference ranges and scores by which the result is evaluated.

• Sort out the sides first. Right arm and right leg mean your right arm and right leg, not the ones you see on the right of the picture. The same for the left side.
• The chart axis is drawn in the manual across 70 to 150 percent with ten-percent divisions. The 100 percent mark is a reference point, not a maximum or a limit you must not exceed.
• The upper bar answers the question of how much lean tissue you carry relative to the ideal weight for your height. The lower bar answers a different question: whether that lean tissue is enough for the weight you actually carry.
• The manual illustrates this with a right leg: 7.5 kg of lean mass equals 100 percent against ideal weight but only 88 percent against current weight. There is enough lean tissue for the ideal weight, but not for the current one.
• The relationship between the two bars depends on how far your weight is from the ideal. When they are close, both bars are of similar length. When current weight is above ideal, the lower bar is shorter. When it is below, the lower bar is longer.
• The manual states that in the long run the goal is to be at 100 percent or above — particularly for the lower bar, because that one relates to the weight the body actually carries.
• A difference between the right and left side is an observation, not a diagnosis. The manual connects it with one-sided loading (it gives tennis for arms and football for legs as examples) or with injury, but frames these as possible explanations. The device cannot establish muscular imbalance, injury, oedema or inflammation.
• The manual gives no specific threshold in kilograms or percent above which a difference between sides counts as large. For the balance evaluation it describes only the comparison method, not numeric boundaries.
• When the bars sit within or above the range while the segmental ECW Ratio is raised, the manual says lean mass in that segment may be overstated. That is a prompt to check the other value, not a conclusion about health.

• Always compare the same segment under comparable conditions: similar time of day, no training or sauna immediately beforehand, similar fluid intake.
• Follow both bars separately. During weight reduction the upper bar may shorten slightly (some lean mass goes too), while the lower bar lengthens, because the same lean tissue now carries less weight. The manual describes this as the desirable course.
• The opposite case is both bars falling at once. That means more lean mass was lost than the drop in weight would account for.
• Differences of a few tenths of a kilogram between two measurements are not a reliable signal. Lean mass includes water, so part of any swing falls to hydration.
• For targeted training or rehabilitation of one segment, count on a horizon of months rather than weeks. A change visible after a week is very likely a fluid shift.
• When the difference between sides narrows over time, that is useful feedback on what you are doing. When it widens, it is a prompt for a conversation with a trainer or physiotherapist, not for a self-diagnosis.

General principles: how to read change between measurements →

• The segmental ECW Ratio – distinguishes a value genuinely backed by lean tissue from one that may be overstated by a higher share of extracellular water.
• Segmental body water – shows how much water is in that segment; muscle acts as a water reservoir, so the two values move together.
• Whole-body skeletal muscle mass – the overall context the segments add up to.
• Skeletal Muscle Index – comparison of the amount of muscle with an age group, which a single segment cannot provide.
• Segmental fat – shows the other component in the same segment, so it is visible whether the volume of an arm is lean tissue or fat.
• Hand grip strength – a functional measure. The amount of lean mass in an arm says nothing about how strong that arm is.

• Sides are read from the point of view of the person being measured. Left arm means your left arm, even though the silhouette shows it on the right. Swapping sides is the most common error in reading segmental analysis.
• A difference between sides is not a diagnosis of muscular imbalance, injury, oedema or inflammation. It is an observation about the distribution of lean mass, which has many possible explanations including simply being right- or left-handed.
• One hundred percent is not a ceiling. The axis in the manual runs to 150 percent, and a value above 100 percent means more lean mass relative to the reference, not an error.
• The two percentages for one segment are not two different measurements. They are one figure in kilograms related to two different bases: ideal weight and current weight.
• Lean mass is not pure muscle. It contains water and other non-fat tissue, which is why it moves even without training.
• A high trunk value does not mean strong abdominal muscles. The trunk is one large segment covering chest, abdomen and back, and the device does not distinguish individual muscles within it.
• Segments cannot be compared with each other in kilograms. A leg naturally carries more lean mass than an arm; what makes sense is comparing left with right and comparing against the reference.

• Hydration, because lean mass is derived from body water.
• Training shortly before the measurement — it raises perfusion and shifts fluid, typically in the segments that were loaded.
• Time of day: the manual notes that water shifts towards the lower half of the body during the day, which shows up mainly in the leg values.
• Posture before the measurement — the manual recommends standing for at least 5 minutes, because moving from lying to standing changes fluid distribution.
• The quality of electrode contact: dry hands and feet need wiping, otherwise electrical contact worsens.
• Stance during the measurement — arms straight and not touching the trunk, thighs apart. An incorrect stance affects segmental values most of all.
• Food and drink shortly before the measurement, room temperature outside the recommended 20 to 25 °C, showering or sauna beforehand.
• The menstrual cycle, during which the amount of retained water fluctuates.

• It does not diagnose muscular imbalance, injury, oedema or inflammation. A difference between sides is an observation, not a finding.
• It does not measure the strength or function of a segment.
• It does not distinguish individual muscles within a segment; the trunk is a single unit covering chest, abdomen and back.
• Lean mass includes water, so the value responds to hydration even without a real change in muscle.
• The manufacturer publishes neither numeric band boundaries nor thresholds for the balance evaluation.
• The manual gives no equation for calculating lean mass from impedance, so the value cannot be independently recalculated.