# The State of the Art of Biomechanics Applied in Ergonomic Furniture Design
## 3 Findings and Discussions
### Biomechanics Utilized in Different Types of Furniture
#### 3.1.3 Transportation Vehicle Seats  
In the automotive industry, customer demand for vehicle performance and comfort is increasing. As a result, car manufacturers consider car seats or interior comfort as an important selling point and as a way to differentiate themselves from their competitors [57; 58]. However, these seats are currently designed mainly based on user experience, traditional knowledge, and extensive, time-consuming, and expensive prototyping and experimental or field testing [59; 60]. For example, experimental tests are first conducted to obtain a fatigue analysis view. Road tests are then conducted using seat pressure distribution (SPD) and electromyography (EMG) to elaborate the fatigue process [61]. Comfort in mass-produced vehicles can be measured using digital human models (DHMs) [59]. The advent of the human hip finite element (FE) model enables the prediction of the pressure distribution between the human body and the seat surface through its detailed and realistic geometric description [57]. Biomechanical methods have emerged to analyze fatigue more accurately and to design more comfortable car seats. [PERSON] et al. [58] utilized musculoskeletal modeling and simulation techniques to investigate the primary factors contributing to fatigue in long-distance truck drivers. The study finds that interaction factors between the driver and the car seat, including the backrest angle, coefficient of friction at the interface between the body and the car seat, longitudinal track position, and availability of lumbar support, impact both driver fatigue and comfort [58; 61]. The use of biomechanical knowledge is more scientific and objective than subjective comfort assessment and less costly and more efficient than experimental testing. In addition, torso posture and biomechanical logic should be introduced into seat design and evaluation, incorporating seat geometry into comfort, safety and ergonomic design solutions. As the market shifts from human driven to autonomous vehicles, the need to account for postural variation in seat design increases [62; 63; 64]. As in the automotive seat industry, comfort has been an important factor for passengers in choosing an airline and the aircraft for many years, and it makes sense to design a comfortable interior and seat to attract passengers. Some studies show that a seat pan design using spring-foam technology can be lighter and more comfortable than conventional foam cushion materials [60; 65]. Comfort is established by six factors: anthropometry, climate, sound, vibration, illumination, and smell. \"Anthropometry\" was the most important factor influencing comfort, meaning that the legroom and seat width are inadequate for the size of different parts of the human body [66]. The seat and inclination need attention in relation to anthropometrics [67]. Simulation of passengers' perceived comfort at different launch angles is one of the approaches. The results of such analysis could be explained by embedding a discomfort triggered adjustment (DTA) process in existing comfort models to address the cycle of discomfort development, the trigger, and the friction between movement desire and the practical constraints until the joy of comfort [68]. Some studies have found that staggered seats were significantly better in terms of comfort and privacy based on short-term evaluations [69; 70]. In summary, research on aircraft seats is mainly carried out by means of experimental simulations, which are costly, and the object of their study is mainly the comfort of the seats. In conclusion, the above research clearly indicates that there is a lack of research performed on the biomechanics of furniture design, with the main focus being on comfort, human health, and ergonomics for seating furniture. When designing special furniture, reducing upper limb injuries, and ensuring applicability are the primary design considerations.