# Ergonomic Design of a Workplace Using Virtual Reality and a Motion Capture Suit
## 4 Methodological Basis for an Ergonomic Rationalisation  
Based on the expert group method and conversations with experts, we propose a method that is straightforward, but which has still not been described in the relevant literature, probably because it requires the hardware and software resources described above.  
Generally, and firstly, we need to identify and select a referential workplace and identify the working procedure decomposed into operations. The measurement method itself must first be divided into two phases, which were also examined in the study (Figure 4).  
The diagram shows the four phases of the study: **VRb**, **VRa**, **NonVR**, and **Classic** which are described in more detail below.  
* **VR phase**  
\(\bigcirc\) **VRb--Measurement of working positions using the MoCap suit in a virtual environment.  
\(\bigcirc\) **VRa--Measurement of working positions using MoCap suit in a virtual environment after rationalisation.  
* **Real world phase**  
\(\bigcirc\) **NonVR--measurements using the MoCap suit in a real environment after rationalisation.  
\(\bigcirc\) **Classic--measurements using classical methods on the real environment after rationalisation.  
The proposed method is piloted in an experimental study. There are some limitations of the method and also of this study:  
The ergonomics of the workplace was evaluated according to the current legislation of the Czech Republic NV361 which evaluates working positions according to their acceptability as described in [36; 37]. The method of evaluation according to the current legislation was chosen because it is more stringent than global ergonomic methods such as the RULA or REBA [14; 38]. Therefore, any assessment carried out will be valid even within the framework of these worldwide methodologies. At the same time, the measurement is necessary for categorising the workplace in terms of physical load.  
This method is suitable only for an assembly workplace.  
Figure 4: The method of ergonomic rationalisation.  
Only workers with no previous VR experience are considered.  
Hardware--HMD (Oculus Quest 2) and MoCap suit (Perception Neuron Studio)  
Software--Software necessary to control the hardware, and proprietary software.  
These limits can easily be broken during follow-up research and the possibilities of the method could be broadened.  
The following working positions were observed and measured in all phases of the working process (VRb, VRa, NonVR, and Classic):  
Head rotation greater than 15\({}^{\circ}\)--conditionally acceptable position.  
Head tilt greater than 25\({}^{\circ}\)--unacceptable working position.  
Torso tilt greater than 60\({}^{\circ}\)--unacceptable working position.  
40\({}^{\circ}\) to 60\({}^{\circ}\) trunk tilt--conditionally acceptable working position.  
Upper limb flexion greater than 60\({}^{\circ}\)--unacceptable working position.  
Upper limb flexion 40\({}^{\circ}\) to 60\({}^{\circ}\)--conditionally acceptable working position.  
According to the legislation: a worker may spend a cumulative 160 min in an average 8-h shift in a conditionally acceptable work position; a worker may spend a cumulative 30 min in an unacceptable work position.  
Special attention should be paid to lower back pain during the evaluation. Lower back pain is a very common symptom. It occurs in high-income, middle-income, and low-income countries and all age groups from children to the elderly [39]. Due to the type of activity performed here, where bending, stooping, or rotation of the trunk is eliminated, and the weight of the load being handled, back position and low back pain are not important risk factors. The maximum cumulative weight of loads handled is 3600 Kg per shift, which complies with working limits [36] for men and women.