## 4 Discussion  
The key features of the introduced load cell in this study are (a) the possibility of measuring a resulting triaxial force and its components with respect to each reference axis and (b) its configuration, which makes it versatile to be used in different tasks. To provide the output forces, an analytical model was developed based on linear elasticity theory and solid mechanics models. The model is a combined tension, axial load, bending and torsion problem. The position of the points instrumented with strain gauges has an essential role, first, because the value of the output signal (strains) is required to be relevant for each component of the triaxial force, and second, because the instrumented points, on two sides of the element and in a central position, avoid unwanted signals that could significantly alter the ideal value of the output signal, caused by: the torsion phenomenon, temperature changes or deviations generated by irregularities in the geometry of the mechanical element, or due to effects caused by the strain gauge installation process. The load cell prototype can be integrated into the structure of the machine where the force is to be measured without affecting the worker's movements through a welding, gluing or screwing process, such as the case presented in this work. Other important characteristics are that, unlike those on the market (cylinder, \"S\"-type, membrane, etc. ), the cell body is easy to manufacture (\"L\" shape and rectangular section); the instrumentation is clearly defined in this work and its calibration is relatively simple, which may be relevant in engineering applications. Thus, its application can be crucial in situations where commercial triaxial cells, due to their geometric configuration and operating principles, are not feasible to install and apply, making the proposed cell a possible option. However, for some applications, the necessary geometric dimensions and their implementation to the work system may have possible limitations. Once the calibration factor of the cell was obtained and to evaluate its efficiency, various tests were carried out applying a variety of weights with different orientations, Table 3 and Appendix B. A demonstrative case of the functionality of the load cell to measure the triaxial forces that are produced when the thumb triggers the cigarette lighter in three directions during the movement of a hand accurately defines the high-risk level associated with the task and the likelihood of developing WMSDs. Eight people (four men and four women) activated a cigarette lighter adapted to the triaxial load cell to measure the AF as a case study. In this first stage, the tests were carried out to seek repeatability and reproducibility of the tests. That is, the same test was repeated with eight different people, activating the lighter under the same laboratory conditions. This made it possible to monitor the triaxial load cell sensitivity and precision with respect to using it as a biomechanical tool to define EH. For example, test P3 female and P4 male had standard deviations of 3.22 and 3.06, respectively, and P1 female, P5 female and P6 male had standard deviations of 5.16, 4.65 and 4.92. These results show that the AF behaviour is too similar between them, despite