9 ASSESSMENT OF ERGONOMIC RISK FACTORS

Ergoniza Intelligent can assess different ergonomic risk factors associated with posture, physical exertion, and the mechanical interaction between the body and its environment. Among other aspects, the system can estimate the joint exertions required to maintain a posture or support a load, the discomfort associated with unsuitable or sustained postures, postural load using observational methods such as REBA or LUBA, the compression and shear forces acting on the L4/L5 intervertebral disc, and the risk associated with lifting or lowering loads. It can also analyze postural stability, the possibility of slipping, and weight distribution among the different supports.

These results should not be interpreted as alternative measures of the same quantity, but as complementary approaches to different dimensions of ergonomic risk. Each corresponds to a specific mechanism and is calculated using its own models, assumptions, and criteria. For example, joint-exertion analysis estimates the mechanical demand required to maintain a posture or support a load; postural-discomfort analysis assesses the deviation of body segments from functional or comfortable zones; and lumbar-compression analysis estimates the mechanical loads on the L4/L5 region. Stability analysis checks whether the projection considered by the model remains within the polygon defined by the supports, while slipping analysis compares the required horizontal reactions with the available friction capacity. Weight distribution provides additional information about the load supported by each support, but does not by itself constitute a direct measure of risk.

Although these factors are calculated separately, they are not strictly independent. In many situations, relationships exist among them. A posture involving pronounced trunk inclination can simultaneously increase postural discomfort, moments in the lumbar region, and compression force on the intervertebral discs. A heavy load held with the arms away from the body can increase exertion at the shoulders, elbows, and wrists, change the position of the center of pressure, and affect stability. Similarly, a postural change intended to reduce the joint moment in one area of the body may increase the load or postural demand on other segments.

For this reason, Ergoniza Intelligent does not reduce the assessment to a single overall risk indicator. Combining all factors into a single score could conceal relevant information about the source of the ergonomic problem and make it more difficult to identify appropriate corrective measures. Two tasks with the same overall value could have very different risk profiles: one dominated by overexertion, another by extreme postures, another by lumbar compression, and another by instability. The value of the analysis lies precisely in distinguishing these dimensions and allowing the assessor to identify which factors contribute to the observed risk.

Assessing the indicators separately also facilitates technical interpretation of the results. If the main problem is joint exertion, preventive measures can focus on reducing the load, bringing it closer to the body, modifying the grip, or introducing mechanical aids. If the dominant factor is postural discomfort, improvements can focus on redesigning working heights, reaches, work orientations, or rest-break requirements.

If the main factor is lumbar compression, particular attention should be given to the magnitude and position of the loads, trunk flexion and asymmetry, and, where applicable, the conditions under which lifting or lowering is performed. If instability or a highly asymmetric weight distribution is detected, it may be necessary to modify the base of support, posture, or point of application of the forces. When a slipping risk exists, the applied horizontal forces, coefficient of friction, and condition of the footwear and support surface should also be reviewed.

Consequently, the results provided by Ergoniza Intelligent should be interpreted as a structured set of biomechanical and ergonomic results and estimates, not as an automatic decision. The system helps identify, quantify, and compare risk factors, but the final ergonomic assessment remains the responsibility of the professional analyzing the task. The assessor must consider the results together with observation of the actual activity, the duration and frequency of exposure, the characteristics of the worker population, organizational conditions, and any other relevant information about the job.

The absence of high values for a particular indicator does not necessarily imply the absence of overall risk. Similarly, a high value in a specific dimension must be interpreted in its context and in relation to the other factors. The role of Ergoniza Intelligent is to provide information that supports professional judgment, facilitates comparison among design alternatives, and guides preventive decision-making.

The following chapters address the assessment of each risk factor independently. Nevertheless, the assessor must understand the relationships among them and consider them together when forming a technical judgment.