Ergonomic Optimization of University Dormitory Furniture: A Digital Human Modeling Approach Using Jack Software

Abstract

University dormitories are vital spaces for students’ daily lives and informal learning, and require desks and chairs of utmost comfort. This study evaluates the desks and chairs at F University using Jack 8.01 software to optimize ergonomic design. By simulating three common sitting postures, this research identifies key issues, such as posture-related strain and limited reachability, particularly for female users. The optimized design introduces adjustable desk height (440~840 mm), chair height (250~520 mm), and tilt angle (0~60°), resulting in a 14.3% and 51.9% improvement in hip and knee joint comfort for the 5th percentile of female users, respectively, and effectively avoids the health risks caused by poor sitting posture. At the same time, based on the universal design concept, the design considerations for non-normative people are introduced. From the perspective of environmental sustainability, fewer wood-based panels used in the improved desk can reduce the greenhouse gas (GHG) footprint by approximately 135 kg CO₂ e. These enhancements highlight the critical role of digital human modeling (DHM) in developing ergonomic, “people-centered” furniture that promotes healthier and more effective learning environments, as well as the sustainable development of educational facilities. Future work will validate these findings in real-world settings and explore their applications across educational and professional spaces.

1. Introduction

University dormitories are not only essential for students’ daily lives but also for learning [1,2]. However, the desks and chairs commonly used in dormitories often lack ergonomic design, leading to discomfort, decreased learning efficiency, and long-term health risks [3]. As modern education increasingly emphasizes “people-centered” principles, optimizing dormitory furniture design has become an urgent requirement to enhance learning environments in universities.

In view of the design and research on university dormitory furniture, some scholars have concluded that the current desks in the dormitories of colleges and universities mostly follow the old style, the design is relatively single, and the structure of each part is fixed, which cannot meet the needs of some students for personalized adjustment [4]. Wang et al. pointed out that domestic university dormitory furniture lacks the design concept of keeping pace with the times; desktop computers are gradually being replaced by portable computers, and the space of desktop computer monitors and host locations placed in the past is gradually becoming outdated [5]. Yang’s team used a questionnaire survey to investigate the accommodation needs of college students in northern China and proposed an L-shaped desk design, which not only satisfies the personal privacy of basic behavioral activities but also increases the storage space [6]. It is not difficult to see that the importance of a dormitory as a learning space is gradually emerging, which has also led to the reassessment of the dormitory learning environment by scholars.

This paper examines desk and chair structures in college dormitories, which provide students with an intimate environment conducive to learning and communication [7]. Korean scholars have pointed out that desks should be adjusted accordingly to meet the needs of users [8]. Their design and user experience directly affect students’ learning efficiency and physical well-being [9,10]. Studies have shown that non-ergonomic school furniture is a major contributor to serious posture issues and musculoskeletal problems in adulthood [11]. Conversely, well-designed dormitory furniture can improve comfort, reduce posture-related strain, and minimize health risks associated with extended use [12,13]. For example, a bad sitting posture may be related to bad habits during growth and development [14]. Similarly, non-ergonomic desk designs increase the risk of musculoskeletal injuries during prolonged study periods [15,16]. These studies have pointed out the important influence of ergonomics on furniture, but most of the relevant evaluations mainly rely on the empirical value method and lack objectivity and accuracy in the data. Some scholars have evaluated the use of traditional experimental methods, which require physical scenes and equipment, and thus involve a significant expenditure of human, material, and financial resources [17,18].

In this paper, digital human modeling (DHM) technology is used to evaluate the comfort of dormitory tables and chairs by virtual simulation, which provides innovative solutions to solve these challenges [19]. By simulating the interaction between humans and furniture, DHM can achieve accurate and repeatable ergonomics evaluation, overcome the limitations of traditional subjective evaluation, and have strong flexibility and good economic benefits [20]. Many scholars have also conducted research in this field. For instance, Kumar R et al. used Jack software and kinect interface to prove the operator’s exposure to whole-body WMSDs when operating a manual mower [21]. Zhang Y et al. used Jack software to establish six digital human and welding torch models and evaluated and improved the standing posture of welders [22]. By analyzing two common push-pull tasks, Ji X et al. successfully evaluated the pose accuracy of whole-body dynamics simulation using Jack software [23]. As a widely used DHM tool, Jack software facilitates detailed ergonomic analyses of furniture without requiring physical participants, providing a scientifically grounded approach to design optimization [24]. Considering the importance of ergonomics in dormitory furniture, there is an urgent need to conduct studies that seek to quantify the comfort of desks in use.

Hence, the purpose of this study is twofold. Firstly, the DHM platform is used to quantify the user comfort of the dormitory desk in different usage scenarios to strengthen the existing research. Secondly, it aims to focus on the extension of learning methods and gender differences in furniture size so as to optimize the design of dormitory desks and chairs.

2. Materials and Methods

The field observation of students’ sitting posture in the dormitory environment found that their sitting posture was different from the correct learning sitting posture. Therefore, it is necessary to discuss this situation in the simulation. The ergonomics simulation process of the dormitory desk and chair based on Jack 8.01 software is shown in Figure 1.

In the data collection stage, this study took the desk and chair in the dormitory of F University as research objects, in which the relevant dimensions were recorded, and a 3D model was constructed, with details provided in Figure 2 and

Table 1. Main dimensions of the dormitory desk and chair.

Symbol	Description	Dimension/mm
H	Desktop height	770
H1	Total height of a desk	1723
H2	Seat height	430
H3	Table clearance height	630
W	Desktop width	1200
W1	Seat width	400
D	Desktop depth	580
D1	Seat depth	410

.

In order to verify the matching between the size of the table and chair and the actual user’s body shape, based on the measurement data of adult males and females aged 18~25 in the body size of Chinese adults in GB/T 10000-2023, the 5th, 50th, and 95th percentiles of human models for both males and females, which were created in Jack 8.01 software, were used to verify the universal applicability of the design [25]. Taking into account the universal design, the applicability of non-normative populations has increased, such as people with a height higher than a given age standard and patients with dwarfism. Males with a height of 200 cm (named NF) and females with a height of 120 cm (named NM) were created using Jack 8.01 software. The eight groups of virtual human models and related human body sizes are shown in Figure 3 and

Table 2. Body dimensions related to sitting posture for virtual human bodies.

Body Dimension	NM	M95th	M50th	M5th	F95th	F50th	F5th	NF
Stature/mm	2000	1837	1720	1616	1700	1599	1512	120
Body weight/kg	101	86	64	50	68	52	42	37
Sitting height/mm	1064	994	936	881	933	881	830	671
Sitting shoulder height/mm	729	668	614	567	621	574	531	425
Sitting knee height/mm	608	558	511	471	520	478	439	364
Sitting popliteal height/mm	508	461	422	385	427	389	357	315
Sitting hip-knee distance/mm	711	624	573	530	592	547	508	423

.

Then, according to different learning methods, the standard learning sitting posture is constructed, which is shown in Jack 8.01 software in Figure 4 [26,27,28,29]. In the actual environment, the sitting postures often used by students were recorded, with the main joint point changes marked in Figure 5, and these postures were then restored in the simulation environment to obtain Figure 6 [30,31,32].

In the stage of simulation environment construction and analysis, the static posture is divided into two groups for discussion. One group is to simulate the original table and chair structure under three actual sitting postures: upright, leaning forward, and leaning back sitting postures. The other group is to simulate the improved scheme structure under three standard learning postures: writing, using a computer, and reading. The main tools for evaluating sitting comfort include Comfort Assessment (CA): This module assesses joint comfort in various postures, determining whether each body part falls within a reasonable range. Ovako Working Posture Analysis (OWAS): Used to evaluate the posture load in each sitting position, categorizing load levels to inform ergonomic adjustments. Reach Zones (RZ): Analyzes hand reachability while using the desk and chair, assessing whether the current design meets operational convenience standards.

Based on the relevant functional size requirements of tables and chairs for educational institutions in the standard BS EN 1729-1:2015, the design scheme of desks and chairs in college dormitories is optimized [33]. Figure 7 illustrates the optimized design, and

Table 3. Comparison of dimensions between international standards and optimizations.

Main Dimension/mm	BS EN 1729-1:2015	Improved Scheme
Desktop width	600 (min)	1300
Desktop depth	500 (min)	600
Desktop height	460~820 (±20)	440~840
Seat width	240~400 (min)	420
Seat depth	300~460 (±15)	430
Seat height	260~510 (±10)	250~520

compares it with existing international standards. The desktop, which is divided into a fixed panel and an angle-adjustable (0~60°) active panel, features an electric adjustment controller for height operation, including a lifting adjustment key, a height display, and a three-speed height memory one-set reset function. At the same time, the smart sensor is equipped under the desktop to detect whether there are obstacles during the descent process [34]. Based on the universal design concept, the design takes into account the needs of a variety of people [35]. For left-handed users, the controller can also be selectively installed on the left side for ease of use. Under each function key, the braille symbol is marked to meet the needs of the visually impaired, and the groove of the activity panel and the bulge of the drawer also provide convenience for the use of the disabled upper limb. The adjustable components of the optimized table and chair are fine-tuned to accommodate the 5th, 50th, and 95th percentile male and female virtual human models and two sets of non-normative human models, as illustrated in

Table 4. Dimension adjustment for different virtual humans.

Main Dimension/mm	NM	M95th	M50th	M5th	F95th	F50th	F5th	NF
Desktop height	830	780	730	670	730	660	640	550
Chair height	510	450	440	390	440	390	360	320
Upper shelf height	1700	1540	1540	1400	1540	1400	1400	1100

.

Jack 8.01 software is used to verify the comfort of the schemes, judge whether it is within a reasonable range, and finally output the “people-centred” dormitory desk and chair ergonomics design.

3. Results

3.1. Simulation Results of the Original Scheme

3.1.1. Comfort Analysis

The CA tool was used to judge the comfort of a single joint in three sitting postures. According to the recommended values of the Porter (1998) database in the analysis tool, Porter is a parameter used to define the reasonable bending degree of the joint, and the yellow data value indicates that it is beyond the reasonable range [36]. The joint comfort data of the eight groups of virtual humans in three sitting postures are sorted out to obtain

Table 5. Comfort analysis of the original scheme.

Angle	Gender	Upright Sitting				Leaning Forward Sitting				Leaning Back Sitting
		5th	50th	95th	N	5th	50th	95th	N	5th	50th	95th	N
Head flexion	M	22.1	22.1	5.6	25.0	13.4	13.5	14.3	13.9	33.2	33.0	27.2	32.4
	F	2.9	21.6	22.3	21.6	0.7	15.8	13.9	13.5	17.1	32.0	34.8	32.0
Upper arm flexion right	M	30.6	30.6	44.6	27.5	36.7	36.7	37.9	33.9	38.0	32.3	38.3	33.9
	F	62.7	29.0	29.0	12.7	48.2	28.0	35.3	37.0	36.9	33.2	26.7	42.9
Upper arm flexion left	M	30.2	30.2	45.4	27.3	40.7	47.5	45.1	37.7	42.3	28.2	42.6	32.2
	F	50.3	34.8	35.5	18.0	36.4	45.4	40.9	49.8	37.5	31.7	26.3	40.0
Elbow included right	M	132.9	132.9	120.9	137.4	102.0	104.9	124.0	118.6	161.5	148.1	173.9	163.7
	F	128.0	130.3	131.5	124.8	97.9	91.9	112.9	105.4	161.1	148.9	144.4	177.2
Elbow included left	M	126.5	126.5	120.4	131.9	104.6	107.6	123.8	115.0	158.8	148.6	174.3	166.2
	F	89.4	138.7	143.6	130.6	69.9	91.9	114.9	112.8	160.9	156.1	155.3	177.2
Trunk thigh right	M	102.2	102.2	91.2	93.4	82.6	88.9	88.3	79.4	119.6	126.3	115.1	108.7
	F	88.7	110.3	106.0	119.3	83.4	91.9	93.8	95.6	123.5	125.0	122.5	127.3
Trunk thigh left	M	102.2	102.2	90.7	92.4	81.8	88.9	88.1	79.7	120.4	125.6	114.8	109.5
	F	88.2	110.3	106.0	119.3	82.9	95.6	94.1	95.9	120.4	125.9	123.6	126.2
Knee included right	M	109.6	109.6	109.0	89.9	103.9	109.6	106.4	99.3	102.9	112.2	102.4	93.6
	F	98.4	120.1	114.4	118.1	97.9	112.8	110.5	112.8	102.5	109.4	109.2	109.0
Knee included left	M	109.6	109.6	108.4	87.1	103.0	109.6	105.8	99.4	103.9	109.9	101.7	92.5
	F	97.3	120.1	114.4	118.1	96.8	112.5	110.3	112.5	98.6	110.5	110.6	106.9
Foot calf included right	M	97.6	97.6	90.5	85.4	96.5	97.6	99.9	96.4	92.0	93.0	88.9	92.0
	F	82.5	100.0	98.6	89.1	80.2	96.7	96.1	96.7	82.6	93.2	93.1	91.5
Foot calf included left	M	97.6	97.6	95.1	90.0	96.8	97.6	99.3	96.0	92.1	92.9	88.4	91.0
	F	86.8	100.0	98.6	89.1	84.5	94.4	93.9	94.4	86.7	93.4	93.3	91.2

Note: The yellow data bar indicates that the joint posture is beyond the comfort range.

. The data show that there are significant differences in comfort among various sitting postures, genders, and human body parts. For different sitting postures, except for women with a shorter height, the overall comfort of the rest of the people in the upright sitting posture is the highest, while the overall comfort of the leaning back sitting posture is the lowest, and there are different degrees of comfort problems in the eight groups of virtual people. Regarding gender differences, females’ overall sitting comfort is lower than that of males, especially for the 5th percentile of females and shorter females; the size of the table and chair set is not reasonable. For different body parts, the hip, knee, and elbow joints are prone to discomfort, which means that the heights of the table, chair, and back of the seat are not designed reasonably. The lack of support for the head in the leaning back sitting position easily leads to discomfort in the neck joint.

3.1.2. Posture Load Risk Assessment

The OWAS tool is used to evaluate the probability of damage or damage caused by a certain posture to the operator. The working posture’s urgency for improvement and its fatigue level are categorized into four grades, ranging from 1 to 4, and the degree of harm was deepened in turn. The analysis results reveal that the OWAS analysis results of women with a height of 120 cm in three sitting positions are all grade 2, which means that there may be some adverse effects on the human body that should be paid attention to in the near future. The OWAS analysis results of the upright sitting posture of the remaining seven groups of virtual humans are grade 1, indicating that the sitting posture is normal and does not need to be corrected, while for leaning forward and leaning back sitting postures, it is grade 2, and corresponding corrective measures should be taken to prevent potential health problems.

3.1.3. Reachability Verification

The RZ tool is used to describe the movement range of the left and right hands of the digital person sitting in front of the desk to verify the rationality of the desk frame design. The reachable areas of eight groups of virtual people in the upright sitting position are shown in Figure 8. It can be seen that the 5th percentile female and shorter females cannot touch the top of the shelf and need to get up to pick up items, while the width of the desktop and the height of the bookshelf are within the reasonable range of the other five virtual human operations.

3.2. Simulation Results of the Optimized Scheme

3.2.1. Comfort Analysis

The verification results of the single joint comfort of the improved scheme are shown in

Table 6. Comfort analysis of the optimized scheme.

Angle	Gender	Writing Sitting				Computer Sitting				Reading Sitting
		5th	50th	95th	N	5th	50th	95th	N	5th	50th	95th	N
Head flexion	M	21.9	21.7	5.6	14.7	21.4	19.7	3.2	19.6	19.1	5.9	5.6	8.1
	F	11.4	16.0	20.5	13.7	12.9	20.4	21.3	13.7	6.8	10.3	12.5	13.9
Upper arm flexion right	M	30.5	23.4	40.0	32.2	22.7	36.8	31.1	21.1	23.7	35.8	44.6	26.2
	F	37.1	28.8	29.2	20.5	39.1	28.5	22.1	25.3	50.0	31.0	43.5	28.4
Upper arm flexion left	M	34.2	27.6	40.9	33.7	31.5	37.7	42.2	22.9	35.0	40.2	45.4	24.8
	F	50.4	34.6	29.5	22.4	46.3	34.1	26.6	31.0	56.7	36.0	49.9	41.3
Elbow included right	M	131.1	111.2	114.2	112.9	113.9	136.2	116.7	92.5	100.2	97.4	120.9	87.1
	F	113.2	128.9	125.5	124.5	118.7	125.3	110.4	120.6	114.3	108.1	114.0	102.9
Elbow included left	M	132.2	108.9	113.7	109.8	118.3	127.8	134.5	90.7	107.5	101.4	120.4	89.9
	F	122.4	133.0	116.8	127.4	129.2	128.5	109.1	133.0	113.2	115.4	112.6	95.5
Trunk thigh right	M	96.6	98.7	91.4	102.2	97.3	101.5	90.5	107.8	95.2	98.7	91.2	107.8
	F	90.1	96.2	100.8	110.3	90.1	100.7	100.9	110.9	90.1	100.7	100.9	110.9
Trunk thigh left	M	96.5	98.7	90.9	102.3	96.0	101.5	90.6	107.8	93.9	98.7	90.7	107.8
	F	90.2	96.3	100.8	110.3	111.1	100.8	100.9	110.9	90.9	100.8	100.9	110.9
Knee included right	M	106.2	108.7	106.6	109.6	107.1	108.7	100.3	107.8	104.6	108.7	109.0	107.8
	F	108.9	102.6	102.8	110.0	110.0	107.8	102.8	101.7	111.1	107.8	102.8	101.7
Knee included left	M	106.2	108.7	105.4	109.6	105.1	108.7	101.1	107.8	102.7	108.7	108.4	107.8
	F	108.7	100.1	102.8	110.0	100.3	105.3	102.8	103.0	110.0	105.3	102.8	103.0
Foot calf included right	M	97.0	97.5	87.7	97.6	96.6	97.5	94.9	90.3	96.2	97.5	90.5	90.3
	F	104.5	96.8	92.1	89.9	109.6	97.5	92.1	80.9	109.6	97.5	92.1	80.9
Foot calf included left	M	97.0	97.4	92.0	97.6	95.1	97.4	95.5	90.3	94.8	97.4	95.1	90.3
	F	109.5	94.6	92.1	89.9	101.6	95.3	92.1	82.5	101.6	95.3	92.1	82.5

. The verification results show that the comfort values of each joint of the six groups of virtual humans after the optimization of the scheme are within a reasonable range. Especially after optimization and adaptive adjustment, the original scheme’s gender difference in comfort has been effectively addressed, resulting in the comfort of the hip and knee joints of the 5th percentile female in the writing posture being increased by up to 14.3% and 51.9%, respectively, compared with the original upright sitting posture.

3.2.2. Posture Load Risk Assessment

The OWAS analysis of eight groups of virtual humans under three working conditions was all grade 1, which belongs to the normal posture. The redesign of the table and chair effectively avoids the health risks caused by poor sitting postures, such as leaning forward and leaning backward, and provides corresponding comfortable sitting posture guidance for different learning activities.

3.2.3. Reachability Verification

Analysis of the reachable domain of the adjusted bookshelf is shown in Figure 9. It can be seen that the height of the bookshelf is within the controllable range of the 5th percentile females and shorter females after adaptive adjustment.

4. Discussion

4.1. Analysis of Gender Differences in Comfort

This study revealed that the original design was less suited for female users, particularly in terms of hip, knee, and elbow comfort. Some scholars have classified and analyzed the factors related to sitting comfort and discomfort and pointed out that gender will affect comfort or its proportion, which is consistent with the research results of gender differences in comfort in this paper [37]. The optimized design significantly reduced these gender disparities, enabling both male and female users to experience balanced comfort levels under the same furniture design, which is of great social significance for promoting gender equality.

4.2. Health and Educational Value

The study of Janabi-Sharifi et al. confirmed that unreasonable table and chair heights could directly affect people’s sitting posture and cause related musculoskeletal diseases [38]. The research on working posture analysis in this study further confirmed these results. Further, Waongenngarm et al. concluded in their study that the forward-tilting posture was the most uncomfortable sitting posture after sitting for a long time [39]. Students cannot maintain normal posture, and over time, this will cause damage to the lumbar muscles [40]. The evaluation results of the redesigned desks are consistent with previous research results.

4.3. Universal Design Concept

Adjustable desktops and movable bookshelves enable students to adapt to different learning tasks, thereby reducing the negative impact of long-term bad posture on health [41]. In addition, it incorporates design considerations for non-normative groups, follows the principles of equal use and flexible use, and considers users of different sizes to enable them to serve a wider population [42]. This improved furniture design is in line with the goals of modern educational institutions, which are to promote health equity, learning equity, and education equity.

4.4. Sustainable Design and Environmental Development

Using DHM technology, designers can optimize furniture to meet the needs of different users, thereby reducing frequent replacements due to inappropriate sizes and helping to reduce resource waste and environmental pollution. The main material of the desk is a wood-based panel, and the greenhouse gas (GHG) footprint for the production of 1 m³ of particleboard (PB) was evaluated within a cradle-to-gate system boundary, as illustrated in Figure 10. According to the research results of Wan-Li Lao, the GHG footprint of PB, excluding biogenic carbon storage, is 348 kg CO₂ e/m³ [43]. After the improvement, the desk’s use of wood-based panels was reduced by about 55.8%, which translates to a reduction of approximately 135 kg CO₂ e. It further illustrates the importance of school education facilities for the sustainable development of the proposed economy, society, and environment [44]. The design of adjustable school furniture not only meets the needs of functionality and comfort but also plays an important role in the sustainable development of the global environment, reflecting the commitment and practice of educational institutions to social responsibility.

4.5. Limitations and Future Research

The limitations of this study lie in the simplified assumptions of digital modeling, which may lead to deviations from actual use cases. Additionally, the Jack software parameters do not account for individual variations over prolonged use. Future research should conduct field tests in real-world settings, considering the dynamic learning behaviors of students, to further validate the optimized design. By leveraging intelligent technology, the active adaptation of desks and chairs to the human body can be enhanced, thereby ensuring their practicality in real environments.

5. Conclusions

After the ergonomics verification and optimization of the desks and chairs in the university dormitory, the following conclusions are drawn:

(1)

Traditional dormitory furniture design has the limitation of requiring users to adapt to preset features. The current dormitory furniture lacks adaptability, particularly impacting shorter female users in terms of comfort and reachability.

(2)

This study proposes an optimized design featuring adjustable desktop and chair heights that significantly improves comfort and balance for users of varying body types. The addition of a track-based adjustable bookshelf further meets individualized needs, especially enhancing accessibility for shorter users. For female users with a height of about 150 cm, the comfort of the hip and knee joints increased by 14.3% and 51.9%, respectively.

(3)

The optimized scheme increases the consideration of the use of diversified groups such as left-handed, blind, and upper-limb disabled people, provides students with a more inclusive and fair learning environment, and further promotes educational equity.

(4)

By enhancing the desk design, we achieved a roughly 55.8% reduction in artificial board usage versus the original model, which translates to a significant cut of about 135 kg CO₂ e in the GHG footprint. This improvement is crucial for advancing environmental sustainability.

In this study, DHM technology was used to evaluate the ergonomics of dormitory furniture, which provided reliable data support for research in this field and expanded scientific research methods. The insights gained are not only valuable for dormitory settings but also have broader implications for office and laboratory furniture design. In the environment of education modernization and home intelligence, tables and chairs can actively adapt to people’s behavior through the application of intelligent technology to provide people with more adaptive choice space. Future research should focus on assessing the real-world applicability of these ergonomic advancements to provide a blueprint for the design of furniture in diverse educational contexts.