Seat Cushion Research Articles

Evaluation of Child Anthropometries in Relation to Modern Vehicle Seat and Booster Dimensions.

This study compared modern vehicle and booster geometries with relevant child anthropometries. Vehicle geometries (seat length, seat pan height, shoulder belt outlet height, and roof height) were obtained for 275 center and outboard rear seating positions of US vehicles (MY 2009-2022). Measurements of 85 US boosters (pan height and pan length) and anthropometries of 80 US children between 4-14yo (seated height, thigh length, leg length, and seated shoulder height) were also collected. Comparisons were made between vehicles, boosters, and child anthropometries. Average vehicle seat lengths exceeded child thigh lengths (+9.5cm). Only 16.4% of seating positions had seat lengths less than the child thigh length mean+1SD. Even for children at least 145cm, only 18.8% had thigh lengths greater than the average vehicle seat length. Child thigh lengths were more comparable with average booster seat pan lengths for all multi-mode and high-back designs (-2.0cm) and low-back boosters (+3.1cm). The average observed booster pan height (9.9cm) would help most children achieve seated shoulder heights similar to the Hybrid III 5th percentile Female ATD. Compared to vehicle seats, booster geometries were more compatible with child thigh lengths and assist children in achieving seated shoulder heights more comparable to the vehicle restraint system. This emphasizes the continued need for shorter vehicle seat cushion lengths for these occupants and the need to educate caregivers and promote booster recommendations which highlight the importance of achieving proper belt fit and avoiding slouched postures, even for children greater than 8 years and/or 145cm.

Effectiveness of a dynamic seat cushion on recovery and recurrence of neck and low back pain in office workers: a secondary analysis of a randomized controlled trial

BackgroundNeck and low back pain are prevalent issues among office workers due to prolonged sitting, necessitating effective interventions. Dynamic seat cushion, designed to promote postural shifts, have emerged as promising solutions to address this concern. This study aims to evaluate the effectiveness of a dynamic seat cushion on recovery and recurrence of neck and/or low back pain in office workers.MethodsThis study used 6-month follow-up data of a randomized controlled trial, involving 66 office workers who reported neck and/or low back pain during the trial. At baseline, participants were cluster-randomized into an intervention group, which received a dynamic seat cushion designed to encourage postural shifts, or a control group, which received a placebo seat pad. Health outcomes included recovery duration and recurrence of pain. Analyses utilized log rank test and Cox proportional hazard models.ResultsThe recovery rate from neck and/or low back pain was 100% for the intervention group, and 86% for the control group. The median recovery duration of participants who reported pain during the 6-month period was 1 month in the intervention group and 3 months in the control group. The intervention group had a higher probability of recovery compared to the control group (HRadj 4.35, 95% CI 1.87–10.11; p < 0.01). The recurrence rate of neck and low back pain was 27% in the intervention group, which was 75% in the control group. The Hazard Ratio, after adjustment, for the intervention group compared to the control group was 0.50 (95% CI = 0.11–2.12).ConclusionsA dynamic seat cushion that encourages postural shifts shortened recovery duration of neck and low back pain among office workers. Due to small numbers, a potentially relevant reduction in the recurrence of neck and low back pain could not be statistically confirmed. A power analysis was not conducted for this secondary analysis, and future studies should be designed with adequate sample sizes to explore the recurrence of pain with greater statistical power.Trial registrationThis trial is retrospectively registered under the Thai Clinical Trials Registry: TCTR20230623002 (23/06/2023).

Development of Self-Help Lifting Pads for Elderly People with Difficulty in Sitting Up

As individuals age, physiological changes can make it increasingly difficult to sit up unassisted. This study aimed to develop ergonomic self-help lifting pads to aid elderly individuals. The first phase involved constructing the pads and a needs assessment with elderly participants and caregivers to survey the physical dimensions and requirements for the design. The second phase focused on cost, engineering, and usage efficiency. Cost efficiency was analyzed using descriptive statistics, engineering efficiency was assessed through testing seat cushion, force reduction, and electrical safety, and usage efficiency was evaluated with participants aged 40 to 50 years. Results from the first phase indicated that the pads should be at least 53.15 cm wide and 153 cm long, with a need for relaxation and affordability. In the second phase, prototype pads were developed according to these specifications. A cost analysis showed that while the manual pad was more expensive than comparable products, the other variants were more cost-effective. Engineering tests confirmed that the cushions met ASTM D3574 standards and that the electrical components conformed to IEC 60335 standards. Usage efficiency ratings were the highest for the massage system pad. Participant feedback indicated longer pads, more convenient controls, and increased cushion comfort, guiding the development of the second version.

Designing orthopaedic seat cushion made of rattan using quality function deployment approach

Using ergonomic orthopaedic chairs can address spinal issues, particularly HNP, due to their flexible and elastic properties. By achieving optimal ergonomic design, various positive aspects can be achieved, such as increasing work quality productivity and reducing the cost of injuries or accidents. This research demonstrates diverse product design approaches to enhance posture health ergonomics, address specific musculoskeletal disorder issues, and consider local needs and available materials. Rattan is a tropical vine widely used in the furniture industry and predominantly found in wooded areas such as Indonesia. This research combines market research, morphology, ergonomic study, concept selection, QFD, HoQ, stiffness test, and prototype review. The QFD method was chosen in this study due to its excellence in connecting consumer desires with the product development process. Data of respondents consist of 51 % of respondents were male, 49 % were female, 88 % were aged between 18 and 34 years old, and 10 % were aged between 35 and 54 years old. The approach of 6 stages of product design as the primary framework for developing our product such as: planning, concept development (concept screening, product morphology, concept selection), system-level design, detailed design, testing, refinement and launching. Based on the calculations using the HOQ, it is identified that the primary focus in designing the rattan-based orthopaedic seating, lies in the orthopaedic design that provides maximum comfort for the spine. The comparison results indicate that the stiffness level of rattan weaving is nearly like latex, with a similarity percentage of 89 %. Data analysis using the QFD method indicates that the primary priority aspect is the orthopaedic design, followed by the selection of quality materials, cost-effectiveness, versatility, and appealing design aspects. Rattan's superior air circulation provides comfort by preventing excessive heat accumulation, excellence in strength and durability, ensuring ease of lightweight modelling, and providing more sustainable material.

Development of low-cost pressure mapping device to evaluate force distribution for seat cushion modification

This study aimed to determine the reliability and concurrent validity of a low-cost pressure mapping system (Smart mat) and reference standard pressure mapping (MatScan). Thirty healthy volunteers aged 29.57 ± 4.50 years who could sit still for at least one minute and had a hip width of less than 40 cm (36 ± 2.05 cm) were recruited. The participants sat on the Smart mat system and MatScan for 60 s per trial for 3 trials. The reliability of Smart mat using intraclass correlation coefficients (ICC) showed an excellent ICC of normalised total force (nTF) and normalised ischial width (nIW) in sitting (0.93, 0.98). The validity was assessed using Spearman correlation coefficients, which showed that nTF in sitting had a significantly strong correlation (r = 0.70**) and nIW in sitting had a significantly moderate correlation (r = 0.67**). This study’s satisfactory results indicated that a low-cost pressure mapping system could be used for assessing forced distribution and ischial width during sitting.

Static Factors in Sitting Comfort: Seat Foam Properties, Temperature, and Contact Pressure

The seat characteristics have high relevance in overall comfort on any transportation means. In particular, the foam’s mechanical properties, interface pressure, and contact temperature play an important role in low- or no-vibration situations regarding static comfort. The present work presents the complete protocol for a static evaluation of different foams and seat covers to assess railway seats. Based on the evaluation of the foam’s mechanical properties and interface pressure profiles, it was concluded that higher-density foam (80 kg/m3) is the most favorable. Regarding the foam cover, a thermographic assessment demonstrated that the fabric cover that induces lower temperatures at passenger interface contact promotes higher comfort levels. It should be highlighted that experiments were conducted on real train seat cushions and environments using a thermographic camera and pressure map sensor.

The effectiveness of a dynamic seat cushion in preventing neck and low-back pain among high-risk office workers: a 6-month cluster-randomized controlled trial.

This study evaluated the effectiveness of the promotion of postural shift intervention using a dynamic seat cushion on the 6-month incidence of neck and low-back pain among high-risk office workers. In a cluster-randomized controlled trial (RCT), 133 office workers were randomly assigned, at cluster level, to intervention (N=67) and control (N=66) groups. The intervention group received a dynamic seat cushion to encourage postural shifts during sitting, while the control group received a placebo seat pad. Primary outcomes were 6-month incidence of neck and low-back pain. Secondary outcomes included sitting discomfort, pain intensity, disability, and trunk muscle performance. Analyses utilized Cox proportional hazard models. During the 6-month period, 15% of participants in the intervention group developed neck pain and 10% developed low-back pain. For the control group, this was 65% and 59%, respectively. Hazard rate (HR) ratios, after adjusting for biopsychosocial factors, indicated a protective effect of the intervention for neck pain [HRadj 0.19, 95% confidence interval (CI) 0.09-0.39, P<0.001] and low-back pain (HRadj 0.16, 95% CI 0.07-0.35, P<0.001). The intervention group demonstrated a significant reduction in sitting discomfort and improvement in trunk muscle performance compared to the control group (P<0.05). However, the intervention did not reduce pain and disability in individuals experiencing pain compared to the control group. The dynamic seat cushion effectively reduced the incidence of neck and low-back pain by promoting postural shifts. These findings suggest that the key factor in reducing the risk of developing neck and low-back pain is the facilitation of postural shifts during sitting, which can potentially be achieved with other dynamic interventions designed to reduce prolonged and static sitting among office workers.

Postural shifts and body perceived discomfort during 1-hour sitting when leaning and sitting on an air-filled seat cushion among healthy office workers

This study compared the number of postural shifts and perceived discomfort while leaning and sitting on an air-filled seat cushion for 1 hour. Sixty office workers typed a standard text while leaning on a cushion placed behind the low back, sitting on a cushion placed under the buttocks, and sitting without a cushion (a control condition). The number of postural shifts was collected using a seat pressure mat device. Low back discomfort was assessed using the Borg CR-10 scale. Leaning on a seat cushion (22 shifts/h) led to a significantly higher number of postural shifts than sitting on a seat cushion (18 shifts/h) and the control condition (20 shifts/h). Leaning or sitting on a seat cushion significantly decreased low back discomfort compared to the control condition (p < 0.05). Leaning on a seat cushion placed behind the low back may be an effective means of preventing low back pain among office workers.

Rancang Ulang Meja dan Kursi untuk Kelas 1 di SMK Negeri 3 Medan dengan Menggunakan Metode RULA dan Pahl &amp; Beitz

SMKN 3 students use tables and chairs for approximately six hours a day during the teaching and learning process. If the sitting posture of this student is not correct, such as leaning forward or a footrest that is too high, of course it can cause pain in the waist and pain in the knees. This study aims to make tables and chairs that are comfortable for use by students of SMKN 3 MEDAN and to find out the design for ergonomic tables and chairs so that when using tables and chairs students do not feel pain in the waist or other complaints. This study resulted in a new table and chair design. Based on the calculation results, the results of the new chair dimensions were as follows: table height 71.15 cm, table length 58 cm, table width cm, seat cushion width 32 cm, seat cushion length 43 cm, height seat cushion 40 cm, backrest height 54 cm. The dimensions of the bag are 10 cm for width, 40 cm for height, 30 cm for length. Therefore the tables and chairs that have been redesigned are in accordance with the anthropometry of students at SMKN 3 MEDAN

Smart seat cushion feasibility pilot study: automated interface pressure modulation of individuals with spinal cord Injury

This study investigates the functionality and feasibility of a novel smart seat cushion system designed for wheelchair users with spinal cord injuries. The cushion, equipped with air cells that serve as both sensors and actuators, was tested on 24 participants for its real-time pressure mapping, automated pressure redistribution, and pressure offloading functions. A commercial pressure mat was concurrently used to validate the cushion’s pressure modulation functions. Additionally, the perceived comfort of the cushion was evaluated using General Discomfort Assessment (GDA) and Discomfort Intensity (DIS) scores, which provided insights into participants’ overall comfort and discomfort levels. Real-time pressure profiles generated by the cushion resembled commercial pressure mat readings. During tests with individuals with spinal cord injury, the cushion was able to dynamically generate and display the real-time pressure profile of a seated individual with strong precision (correlation to commercial pressure mat: r ranging from 0.76 to 0.88), providing effective input into pressure modulation functions. Pressure redistribution algorithms eliminated peak pressure and reduced the overall pressure at the interface. Pressure offloading algorithms automatically identified the regions with the highest interface pressure and subsequently relieved the pressure from those areas. User feedback showed that the cushion was comfortable after redistribution and offloading. This work demonstrated the feasibility of an advanced smart seat cushion system for wheelchair users with spinal cord injuries. The cushion was capable of redistributing pressure evenly across the seating surface, ensuring user’s comfort. Additionally, it identifies and eliminates high-pressure points, further improving comfort and reducing the risk of pressure injuries.

Measurement uncertainty of vertical combustion test of civil aircraft interior materials

The civil cabin interior materials vertical combustion test is the necessary test to verify the flame retardancy ability of the floor coverings, textiles, seat cushions and cushions. It is an inspection step required for cabin interior materials before installation, which is of great significance for the safe flight of civil aircraft. During the experiment process, variable factors such as personnel and equipment are highly likely to impact the test results. To ensure the reliability of test results, it is necessary to summarize and evaluate the factors that may affect the results of the test process. Thus, in this paper, the test method, measurement model, and sources of measurement uncertainty have been analysed, and the calculation case of experimental measurement uncertainty has been introduced.

The Development of a High-Static Low-Dynamic Cushion for a Seat Containing Large Amounts of Friction

Exposure to whole-body vibration (WBV) has been shown to result in lower-back pain, sciatica, and other forms of discomfort for operators of heavy equipment. While WBV is defined to be between 0.5 and 80 Hz, humans are most sensitive to vertical vibrations between 5 and 10 Hz. To reduce WBV exposure, a novel seat cushion is proposed that optimally tunes a High-Static Low-Dynamic (HSLD) stiffness isolator. Experimental and numerical results indicate that the cushion can drastically increase the size of the attenuation region compared to a stock foam cushion. When placed on top of a universal tractor seat, the cushion is capable of mitigating vibrations at frequencies higher than 1.1 Hz. For comparison, the universal tractor seat with a stock foam cushion isolates vibrations between 3.4 and 4.1 Hz, as well as frequencies larger than 4.8 Hz. Friction within the universal seat is accurately modeled using the Force Balance Friction Model (FBFM), and an analysis is conducted to show why friction hinders overall seat performance. Finally, the cushion is shown to be robust against changes in mass, assuming accurate tuning of the preload is possible.

Improving wheelchair user sitting posture to alleviate lumbar fatigue: a study utilizing sEMG and pressure sensors.

The wheelchair is a widely used rehabilitation device, which is indispensable for people with limited mobility. In the process of using a wheelchair, they often face the situation of sitting for a long time, which is easy to cause fatigue of the waist muscles of the user. Therefore, this paper hopes to provide more scientific guidance and suggestions for the daily use of wheelchairs by studying the relationship between the development of muscle fatigue and sitting posture. First, we collected surface Electromyography (sEMG) of human vertical spine muscle and analyzed it in the frequency domain. The obtained Mean Power Frequency (MPF) was used as the dependent variable. Then, the pose information of the human body, including the percentage of pressure points, span, and center of mass as independent variables, was collected by the array of thin film pressure sensors, and analyzed by a multivariate nonlinear regression model. When the centroid row coordinate of the cushion pressure point is about 16(range, 7.7-16.9), the cushion pressure area percentage is about 80%(range, 70.8%-89.7%), and the cushion pressure span range is about 27(range, 25-31), the backrest pressure point centroid row coordinate is about 15(range, 9.1-18.2), the backrest pressure area percentage is about 35%(range, 11.8%-38.7%), and the backrest pressure span range is about 16(range, 9-22). At this time, the MPF value of the subjects decreased by a small percentage, and the fatigue development of the muscles was slower. In addition, the pressure area percentage at the seat cushion is a more sensitive independent variable, too large or too small pressure area percentage will easily cause lumbar muscle fatigue. The results show that people should sit in the middle and back of the seat cushion when riding the wheelchair, so that the Angle of the hip joint can be in a natural state, and the thigh should fully contact the seat cushion to avoid the weight of the body concentrated on the buttocks; The back should be fully in contact with the back of the wheelchair to reduce the burden on the waist, and the spine posture can be adjusted appropriately according to personal habits, but it is necessary to avoid maintaining a chest sitting position for a long time, which will cause the lumbar spine to be in an unnatural physiological Angle and easily lead to fatigue of the waist muscles.

Study on the effect of human sympathetic nerve cold stimulation to relieve driving fatigue based on order recurrence plot

Driving fatigue is very likely to cause traffic accidents, seriously threatening the lives and properties of drivers. Therefore, accurate detection and effective mitigation of driving fatigue are crucial for ensuring the personal safety of drivers. This study proposes a method to relieve driving fatigue by properly reducing the temperature to stimulate the human sympathetic nerve. The method uses the intelligent cooling and blowing device on the car seat cushion to achieve cold stimulation of the sympathetic nerve of the driver by reducing the temperature of the driver’s hip, back and neck, so as to increase the excitement of the sympathetic nerve, keep the driver alert and achieve the purpose of fighting driving fatigue. In view of the fact that the traditional fatigue detection method is easily affected by environmental factors and individual differences, this study uses the order recurrence plot (ORP) method to detect driving fatigue based on electroencephalogram (EEG) signals. The results show that ORP textures drawn by EEG signals of the two driving conditions (normal driving condition and sensory cold stimulation driving condition) are significantly different, and the quantization parameters determinism (DET) and average diagonal line length (DLL) values are significantly different. Cold stimulation of the subjects’ hips, back and neck to alleviate driving fatigue was the best when the temperature was 21 °C. In addition, compared with the traditional methods of fatigue relief, the sensory cold stimulation method proposed in this study does not easily to produce tolerance and has no damage to the body.

Preparation and Characterization of Chloroprene Latexes Modified with Vinyl-POSS.

Water-based chloroprene latex is a solvent-free, environmentally friendly adhesive. Currently, its market demand is growing rapidly. However, there are problems such as a lack of heat resistance and poor mechanical properties, which limit its application. The introduction of vinyl-POSS (OVS) into the resin structure can effectively improve the thermal stability of chloroprene adhesives. In this paper, modified waterborne chloroprene latex was prepared by copolymerization of methyl methacrylate and OVS with chloroprene latex. The results showed that vinyl-POSS was successfully grafted onto the main chain of the waterborne chloroprene latex, and the modified waterborne chloroprene latex had good storage stability. With the increase in vinyl-POSS, the tensile strength of the chloroprene latex firstly increased and then decreased, the tensile property (peel strength of 20.2 kgf) was maintained well at a high temperature (100 °C), and the thermal stability of the chloroprene latex was improved. When the addition amount was 4%, the comprehensive mechanical properties were their best. This study provides a new idea for the construction of a new and efficient waterborne chloroprene latex system and provides more fields for the practical application of waterborne chloroprene latex. This newly developed vinyl-POSS modified chloroprene latex has great application potential for use in home furniture, bags, and seat cushions.

Pelvis and thoracolumbar spine response in simulated under-body blast impacts and protective seat cushion design.

Purpose: The aim of this study is to investigate the dynamic and biomechanical response of the pelvis and thoracolumbar spine in simulated under-body blast (UBB) impacts and design of protective seat cushion for thoracolumbar spine injuries. Methods: A whole-body FE (finite element) human body model in the anthropometry of Chinese 50th% adult male (named as C-HBM) was validated against existing PHMS (Postmortem Human Subjects) test data and employed to understand the dynamic and biomechanical response of the pelvis and thoracolumbar spine from FE simulations of UBB impacts. Then, the protective capability of different seat cushion designs for UBB pelvis and thoracolumbar injury risk was compared based on the predictions of the C-HBM. Results: The predicted spinal accelerations from the C-HUM are almost within the PHMS corridors. UBB impact combined with the effects from physiological curve of the human thoracolumbar spine and torso inertia leads to thoracolumbar spine anterior bending and axial compression, which results in stress concentration in the segments of T4-T8, T12-L1 and L4-L5. Foam seat cushion can effectively reduce the risk of thoracolumbar spine injury of armored vehicle occupants in UBB impacts, and the DO3 foam has better protective performance than ordinary foam, the 60 mm thick DO3 foam could reduce pelvic acceleration peak and DRIz value by 52.8% and 17.2%, respectively. Conclusions: UBB spinal injury risk is sensitive to the input load level, but reducing the pelvic acceleration peak only is not enough for protection of spinal UBB injury risk, control of torso inertia effect would be much helpful.

Comparative occipital pressure mapping in the operating room.

Hospital-acquired occipital pressure injuries are a preventable cause of morbidity and mortality in the perioperative setting. To find the occipital cushion/pillow with the lowest measured peak pressures and the highest measured surface area using pressure mapping technology. A quality improvement project involving 3 operating room staff volunteers was conducted using pressure mapping. Five different pillows were tested based on what the study location commonly used and had available. The pillows included: standard pillow with pillowcase, non-powered fluidized positioner, medium-sized (17 × 17 × 1.5 inches) static seat cushion placed under the shoulders and head, pediatric-sized (13 × 13 × 2 inches) static air cushion placed under the head, and foam donut. The non-powered fluidized positioner had the highest average pressure and peak pressure for all 3 volunteers. The medium static air seat cushion had the lowest average and peak pressures for 2 out of 3 volunteers. None of the head cushions consistently demonstrated a larger surface area of pressure distribution. The medium-sized static air seat cushion, placed under the shoulders and head, demonstrated the most favorable pressure redistribution properties. The non-powered fluidized positioner demonstrated the least favorable pressure redistribution properties.

Ergonomic Evaluation of Speed Boat Passenger Seats in Derawan Island Using Anthropometric Data

This research aims to evaluate the ergonomics of passenger seating in speed boats used as a means of transportation in the Derawan Islands, Berau Regency, East Kalimantan. This evaluation was carried out by considering anthropometric data from the Indonesian people. Anthropometric data is used to design seats that suit the size and needs of passengers to increase passenger safety and comfort during travel. The research method involved collecting anthropometric data from Indonesian people of various ages and genders. This data is used as a basis for designing seating that suits variations in human body size. Ergonomic evaluation is carried out by considering parameters such as seat width, seat back, seat cushion width, seat height, and the distance between two seats. This research indicates that existing seating designs must meet the optimal criteria for passenger ergonomic needs. Therefore, recommendations for improving seating design are prepared based on the results of the ergonomic evaluation. This design improvement aims to increase passenger safety and comfort and reduce the risk of injury. This research contributes to developing more ergonomic seating designs for sea transportation, especially using speed boats in the Derawan Islands area. The results of the ergonomic evaluation and recommendations for improvements can be used by related parties to improve service quality and passenger safety in the Derawan Islands.

Pemanfaatan Sampah Plastik Menjadi Bantal Kursi Untuk Mengurangi Pencemaran Lingkungan

This research aims to address the environmental pollution issue caused by plastic waste in Bantan Timur Village, Medan Tembung Subdistrict, by transforming plastic waste into a valuable product, namely seat cushions. The problem of waste has become a global challenge, especially with the increasing population and activities. The rise in waste leads to negative impacts on the environment, such as disease outbreaks, floods, and a decline in aesthetic value. In this context, this article proposes a solution through the Research and Development (R&amp;D) research method to produce seat cushions from plastic waste. Plastic waste is processed through steps of washing, drying, cutting, and packaging. The product is expected to raise awareness about proper waste management, reduce environmental pollution, and have a positive economic impact. Making seat cushions from plastic waste serves as a practical example of sustainable waste management, involving ecological and social aspects. The results are anticipated to inspire similar efforts in other regions, creating creative and sustainable solutions to address environmental pollution issues.

Trend analysis of rear child occupants’ injury influenced by protection system parameters

As road traffic accidents are the leading cause of child injuries and deaths, the most common frontal impact is offset impact. Taking into consideration the lack of research on rear seat child occupants’ safety in road accidents, this study focuses on 10-year-old child occupants seated in the rear and establishes an analytical model of child injury during frontal offset impact, which is validated using test data from a real car impact of the same model. The study then examines the effects of restraint system parameters, including seat belt force-limited level, seat belt anchorage position, and seat cushion stiffness, on head, neck, and chest-abdomen injury response in the rear seat child occupants. The study found that reducing the seat belt force-limited level appropriately resulted in a significant decrease in the child occupant’s head resultant acceleration by 39.9% and the upper neck force by 53.2%. Meanwhile, increasing the seat cushion stiffness was found to reduce the child occupant’s head resultant acceleration by 18.8%, the upper neck force by 31%, and the abdominal pressure by 34.4%. This study provides a reference for the protection of rear seat child occupants.