Seated posture

Ergoniza Intelligent lets you indicate that the model is in a seated posture. This matters because a seated posture is not interpreted biomechanically in the same way as a standing posture.

When the model is considered seated, the system can change how it interprets supports, exertion, floor contact, postural discomfort, and certain stability or biomechanical-load analyses.

There are two ways to set this condition:

automatic seated-posture detection;
explicit activation with Seated in the left-side menu.

Ways to define seated posture

Activation method	Where it is configured	Intended use
Automatic detection	Model parameter settings panel	Lets the system use heuristics to determine whether the model appears to be seated.
Explicit activation	Seated button in the left-side menu	Manually identifies the current posture, or a selected set of postures, as seated.

Automatic seated-posture detection

Enable automatic detection with Automatically detect seated posture under Model parameter settings.

Ergoniza Intelligent then uses heuristics to identify whether the model is seated. This can simplify configuration for tasks performed while seated.

Use this feature carefully. Heuristic detection can produce false positives, incorrectly interpreting the model as seated when the actual posture is not.

After enabling it, visually inspect the model and verify that the system’s interpretation matches the assessed task.

For more information, see Model parameter settings.

Explicit activation with Seated

The second method uses Seated in the left-side menu.

When enabled, Ergoniza Intelligent considers the model seated regardless of its geometric posture. This option therefore forces a seated interpretation.

Use explicit activation when you know that the situation is seated and want to state this directly, especially when automatic detection does not identify it correctly or you want to avoid relying on a heuristic.

Application in Single posture mode

In Single posture mode, Seated applies to the current posture.

When enabled, the posture is considered seated. When disabled, that explicit condition ceases to apply, and the system uses its general configuration, including automatic detection if enabled.

Use this option to state unambiguously that the single posture being assessed must be analyzed as seated.

Application in Multiple postures mode

In Multiple postures mode, the seated condition can apply to the current posture or a selected set of postures.

If no timeline interval is selected, Seated applies to the posture at the current time.

If an interval or group of postures is selected, the system lets you apply the seated condition to all selected postures or only the current posture.

This represents activities in which only part of a sequence is performed while seated—for example, an activity with standing, seated, and transition phases. Apply the seated condition only to postures that actually represent sitting.

Effect on biomechanical exertion

The seated condition can change calculated supports and exertion. The system considers detected contact regions, such as the feet, knees, thighs, or pelvis, according to the posture.

Backrest has a more specific effect. When the model is seated on a chair, the flexion component of the torso moment is unloaded. Lateral-flexion and rotation components remain, and an extension moment is not removed.

The backrest is not added as a contact region and does not generate its own reaction force. Enabling it therefore does not directly change the distribution of reactions among supports.

Lumbar moments and L4/L5 compression are recalculated from the remaining components. Results can therefore change, but they are not necessarily eliminated or reduced by the same proportion in every case.

Before interpreting a seated posture, verify:

that the posture is correctly identified as seated;
that the system recognizes chair sitting when the backrest is to be used;
that Backrest corresponds to actual posterior support;
that detected contact regions represent the task correctly.

Effect on postural discomfort

The seated condition also affects postural-discomfort calculation.

A seated posture is not necessarily assessed by the same criteria as a standing posture. Certain movements or degrees of freedom can be interpreted differently, and some movements may not apply in the same way.

Ergoniza Intelligent therefore uses criteria specific to seated postures when calculating discomfort. The result can differ from that for the same geometry assessed as not seated.

This is particularly important when comparing design alternatives or reviewing work in a chair, on a bench, in an industrial seat, in a cab, or at a control station.

For technical details, see the Technical foundations sections on postural discomfort and the distinction between standing and seated postures.

Effect on stability and supports

Seated posture can also affect how supports and stability are interpreted.

In a standing posture, the system generally treats the feet as the primary floor contacts. In a seated posture, other supports can be involved, such as the seat, pelvis, thighs, or knees, depending on the represented posture.

This can affect:

interpretation of floor contact;
location of supports;
display of reactions;
stability analysis;
interpretation of partial-support or seated situations.

Visually inspect seated postures and verify that represented supports are consistent with the real situation.

When to use automatic detection

Use automatic detection when you want the system to generally identify whether the model appears seated, especially during tasks where this condition varies.

It can be useful when:

several postures are analyzed;
the seated posture is clear;
less manual intervention is desired;
the system can reasonably identify supports in a sequence.

Always review automatic detection; do not assume that it will identify sitting correctly in every case.

When to use Seated

Use Seated when you need to explicitly identify a posture as seated.

This is recommended when:

automatic detection does not recognize the posture correctly;
there is a risk of a false positive or false negative;
a single posture is being assessed;
only specific postures in a sequence should be seated;
more precise manual control is required.

Seated must represent the task’s actual condition. Do not enable it merely to alter a result when the person is not actually seated.

Recommendations for use

Before running an analysis for a seated posture, review:

whether the posture actually represents sitting;
whether to use automatic detection or explicit activation;
whether Backrest should be enabled;
whether model supports are consistent with the real scene;
whether seated posture should apply to one posture or several selected postures;
whether biomechanical or discomfort results change substantially when seated posture is enabled or disabled.

When in doubt, explicitly enable seated posture only for postures that clearly represent sitting and review the results before completing the assessment.

Relationship with the Technical foundations

This page describes operational use. For methodological details, see:

These sections explain how sitting is identified, how supports are modeled, how the backrest is considered, and why a seated posture can produce different results from one assessed as not seated.