Analysis of Worker Posture on the Crosscut Machine Using the RULA Method in the Raw Material Division at CV. Valasindo Sentra Usaha ^†

Abstract

CV. Valasindo Sentra Usaha (VSU) is a garden furniture manufacturing company with a raw material division that has the highest number of workers and machines. The crosscut machine operators in this division reported pain in the arms, shoulders, waist, and back based on observations using the Nordic Body Map questionnaire. This study aims to analyze the ergonomics of the crosscut machine operators’ body posture using the Rapid Upper Limb Assessment (RULA) method. The analysis results showed that posture 1 had a RULA score of 6, posture 2 scored 5, and posture 3 scored 6, indicating a high ergonomic risk. Proposed improvements, such as redesigning the work desk, ergonomic chairs, and footrests, successfully reduced the RULA score to 3, showing significant improvement in the operators’ body posture.

1. Introduction

Furniture refers to essential elements in interior design. Furniture serves as a connection between architecture and the occupants of a space. It provides a transition and functionality in terms of form and size between interior spaces and the people who inhabit them. Furniture makes a room more comfortable and functional for various activities carried out by its occupants [1]. The furniture industry is one of the industries with the potential for export to other countries [2]. Without furniture, a room is just an empty space with very little usefulness for its occupants. Therefore, furniture makes a room significantly more functional according to its intended purpose.

One of the industries operating in the furniture and woodworking sector is CV. VSU. CV. VSU was established in 1999, rooted in the trust of the government, business partners, and the community, supported by market opportunities and high demand for furniture abroad. The company covers an area of approximately 12,000 square meters and is located at Jalan Solo Purwodadi, Karanganyar Regency, Central Java. The company’s primary focus is on producing garden furniture. CV. VSU is an extension of a previous furniture company, CV. Roda Jati, located in the same subdistrict in Karanganyar Regency. The company was established in response to abundant market opportunities, particularly from Europe, America, Australia, and Asia. The company employs around 165 workers and has already marketed and exported its products internationally. CV. VSU produces furniture such as tables and chairs made from teak wood.

The management of CV. VSU continuously strives to create a good working system for its employees. A work system design fundamentally begins with an ergonomic analysis. Ergonomics is the science that studies the relationship between humans and their work environment, considering aspects of psychology, physiology, anatomy, management, engineering, and design [3]. Ergonomics is defined as the science that analyzes various aspects and characteristics of humans in the work environment, studies the relationship between humans, machines, and the environment, and is followed by facilities that facilitate, maintain health, and ensure work safety [4]. The work postures or positions commonly adopted by workers include sitting, standing, bending, squatting, walking, and others. These work positions are determined by the conditions within the existing work system [5].

One of the most critical divisions in the production system at CV. VSU is the raw material division. In this division, there are at least four types of machines, including two band saw machines, three metal band saw machines, three rip saw machines, and four cross-cut machines, with each machine operated by one worker. The raw material division is the first step in the furniture production process at CV. VSU. In this division, the main material, large teak wood, is split and then cut into specific shapes and sizes according to needs. Workers often complain of injuries to certain parts of their bodies due to non-ergonomic working postures, which is a problem in the raw material division of CV. VSU.

In response to this issue, the research will focus on evaluating the existing work system in the raw material division of CV. VSU through an ergonomic approach to assess the non-ergonomic working postures using the RULA (Rapid Upper Limb Assessment) approach and the Nordic Body Map questionnaire. RULA is a research approach that can be applied to investigate disorders in the upper body parts of workers [6]. The RULA method measures the risk of Musculoskeletal Disorders (MSDs) complaints related to upper body parts based on the assessment of posture, force, and movement during activities [7]. On the other hand, the Nordic Body Map is a questionnaire tool often used to identify discomfort or pain in workers’ bodies [8]. The Nordic Body Map (NBM) aims to identify problems and complaints experienced by workers related to the current production process [9].

Observations were conducted on 12 workers in the raw material division, each operating a machine, including two band saw machines, three metal band saw machines, three rip saw machines, and four cross-cut machines, making a total of 12 machines with four different types of machines (see

Table 1. Recapitulation of NBM Questionnaire for Workers in the Raw Material Division.

No.	Machine	Average Score
1.	Band Saw	39.00
2.	Metal Band Saw	33.33
3.	Rip Saw	43.33
4.	Crosscut	44.75
Total		160.42

). After observing the working postures of the 12 workers in the raw material division, the next step was to distribute the NBM questionnaire to the 12 respective workers. The results of the NBM questionnaire recap are as follows.

From the recapitulation table of the NBM questionnaire for workers in the Raw Material Division above (see

Table 2. Recapitution of NBM Questionnaire for Cross-cut Machine Operators.

No.	Complaint Location	Total Score	Percentage
0	Upper Neck	4	2.23
1	Lower Neck	5	2.79
2	Left Shoulder	12	6.70
3	Right Shoulder	12	6.70
4	Left Upper Arm	14	7.82
5	Back	8	4.47
6	Right Upper Arm	14	7.82
7	Waist	12	6.70
8	Lower Waist	11	6.15
9	Buttocks	7	3.91
10	Left Elbow	4	2.23
11	Right Elbow	4	2.23
12	Left Forearm	4	2.23
13	Right Forearm	4	2.23
14	Left Wrist	4	2.23
15	Right Wrist	4	2.23
16	Left Hand	4	2.23
17	Right Hand	4	2.23
18	Left Thigh	4	2.23
19	Right Thigh	4	2.23
20	Left Knee	4	2.23
21	Right Knee	4	2.23
22	Left Calf	8	4.47
23	Right Calf	8	4.47
24	Left Ankle	4	2.23
25	Right Ankle	4	2.23
26	Left Sole	4	2.23
27	Right Sole	4	2.23
Total		179	100

), it can be seen that the machine with the highest average score is the cross-cut machine. The following are the detailed NBM questionnaire results for the cross-cut machine operators.

From the results of the NBM score calculation table (see Table 2), it can be observed that the complaint locations with the highest to lowest percentages are the left upper arm and right upper arm, each with a percentage of 7.82%, followed by the left shoulder and right shoulder, each with a percentage of 6.70%, the waist with a percentage of 6.70%, the lower waist with a percentage of 6.15%, the back with a percentage of 4.47%, the left and right calves, each with a percentage of 4.47%, and the buttocks with a percentage of 3.91%. Workers did not report any pain in other parts of the body. In response to these findings, the research will focus on evaluating the working postures of workers operating the cross-cut machine. The study will also assess the work equipment used by the operators of the cross-cut machine.

2. Methods

The research procedure is a systematic series of steps undertaken to achieve the research objectives. The implementation of the research procedure includes several stages, which are as follows:

2.1. Preliminary Study

The preliminary study is the initial step in starting research. At this stage, the researcher will directly observe the research object, specifically the posture of workers operating the cross-cut machine in the raw material division at CV. VSU.

2.2. Literartur Review

The literature review is conducted to gather relevant information or references related to the research topic, which then serves as the basis for problem-solving. The sources of data in the literature review come from journals, books, and previous research reports.

2.3. Problem Identification

The problem identification process involves direct observation and interviews with relevant parties to understand the workers’ postures while performing their tasks and to obtain information about any complaints the workers may have.

2.4. Problem Formulation

Problem formulation is a critical stage in identifying the key points of the issue under investigation. It is derived from the results of the problem identification conducted earlier.

2.5. Research Objectives

The research objectives are the specific goals that the research aims to achieve in addressing the problem formulation. The objectives of this study are to identify the posture of workers operating the cross-cut machine in the raw material division at CV. VSU, evaluate the ergonomics level of the workers’ posture at the cross-cut machine, and provide recommendations for improving the workers’ posture at the cross-cut machine.

2.6. Data Collection

The data collection process used in this research involves direct observation through interviews and the distribution of the NBM questionnaire to workers operating the cross-cut machine in the raw material division. Additionally, data collection is carried out by documenting the workers’ posture through photos and videos while they are using the cross-cut machine in the raw material division.

2.7. Data Processing

Data processing using the RULA method is conducted by observing and capturing images or videos of the workers’ posture while they are working. Rapid Upper Limb Assessment (RULA) is a research approach used to evaluate upper body musculoskeletal disorders. This approach was introduced by Lynn McAtamney and Nigel Corlett in 1993 and provides calculations on the level of musculoskeletal load in work activities that pose a risk to body parts from the waist to the neck or upper limbs [6]. Several variables evaluated in the RULA approach include static work posture, workload intensity, duration of work, and muscle energy utilization [10].

The RULA approach uses posture images and three scoring tables to assess risk aspects. The risk aspects analyzed include external loads, such as movement frequency, static muscle work, required force, and the alignment of work posture with the supporting environmental conditions. These conditions refer to the work environment that allows workers to work comfortably, safely, and in relation to work facilities [11].

The captured images or videos of the workers are then analyzed. The body parts analyzed using the RULA approach include the angles formed by the upper arm and forearm, considering whether the forearm movement crosses the midline of the worker’s body or is outside of it; the angles formed by the wrist and wrist movements; the angle formed by wrist rotation; the angle formed by neck position and considering rotational and lateral neck movements; the angle formed by torso position and considering lateral and rotational body movements; the position of the workers’ feet, and whether the body is well supported by both feet; and the assessment of the load level and muscle utilization in body Group A and Group B. The results of the analysis are then calculated using the RULA worksheet. Once the data is processed using the RULA worksheet (see Figure 1), the final risk level score of the workers is obtained.

2.8. Data Analysis

The analysis and discussion of data derived from processing NBM and RULA data on work posture is a crucial stage of data analysis. This stage can serve as a reference for proposing improvements based on the risk level and worker activities in the raw material division of CV. VSU.

2.9. Improvement Proposals

Improvement proposals are provided for the cross-cut machine workstation, which was found to have a high-risk level during the study. The proposed improvements are expected to assist workers in improving their posture while performing their tasks. These suggestions are also intended to help the company’s management in implementing a work system that is ergonomic and comfortable for the workers.

2.10. Conclusion and Recommendations

Based on the data evaluation, conclusions can be drawn, summarizing the data analysis and discussion outcomes. The recommendations provided are intended to guide the company’s management in promoting a work system and proper body posture that is safe for workers, aiming to reduce the risk of MSDs.

3. Results and Discussion

The following section presents the results and discussion regarding the work posture of workers operating the cross-cut machine in the raw material division of CV. VSU.

3.1. Identification of Cross Cut Machine Operator Work Activities

During the operation of the cross-cut machine, the worker assumes three main postures. The first posture occurs when the worker positions the wood according to the required size. The second posture occurs when the worker pulls the saw to cut the wood, and the third posture occurs when the worker drops the wood down to be collected by another worker. The worker responsible for collecting the wood also has the task of supplying wood to be cut and placing it on the cross-cut machine table, so the operator does not need to retrieve wood from the storage area.

3.2. Data Processing Using the RULA Method

The following section details the data processing of cross-cut machine operation activities using the RULA method. In this stage, the worker’s posture is analyzed to determine the angles formed by the worker’s body while performing their tasks. Below are the analyzed postures, revealing the angles formed. A sample was taken from one worker to represent the other three workers. This approach was taken because the proposed improvements will be applied to all cross-cut machine operators, with the goal of improving the posture of all workers to be more ergonomic.

Figure 2 shows how the workers’ posture is formed when positioning wood according to size. The RULA score is then calculated based on the angle formed from the worker’s posture. The results of the RULA score calculation for the following posture are presented in

Table 3. Rula Score Calculation for Posture When Positioning Wood According to Size.

RULA Score Calculation for Posture When Positioning Wood to Size
Upper Arm Score	3	Neck Score	2
Lower Arm Score	2	Trunk Score	3
Wrist Twist Score	1	Legs Score	1
Wrist Score	3
Posture A Score	4	Posture B Score	4
Muscle Use Score	0	Muscle Use Score	0
Force/Load Score	1	Force/Load Score	1
Wrist & Arm Score	5	Neck, Trunk, & Legs Score	5
RULA Score = 6 (Further Investigation, Changes Required Immediately)

below.

From the table of RULA Score Calculation for Posture When Positioning Wood to Size above (see Table 3), it can be seen that the score obtained when the worker performs the task of positioning wood to the correct size is 6, which indicates the need for further investigation and immediate changes.

Figure 3 shows how the workers’ posture is formed when pulling the saw during wood cutting activities. The RULA score is then calculated based on the angle formed from the worker’s posture. The results of the RULA score calculation for the following posture can be found in

Table 4. Rula Score Calculation for Posture Formed When Pulling the Saw.

RULA Score Calculation for Posture When Positioning Wood to Size
Upper Arm Score	3	Neck Score	3
Lower Arm Score	1	Trunk Score	3
Wrist Twist Score	1	Legs Score	1
Wrist Score	2
Posture A Score	3	Posture B Score	4
Muscle Use Score	0	Muscle Use Score	0
Force/Load Score	1	Force/Load Score	1
Wrist & Arm Score	4	Neck, Trunk, & Legs Score	5
RULA Score = 5 (Further Investigation, Changes Required Immediately)

below.

From the table of RULA Score Calculation for Posture When Pulling the Saw above (see Table 4), it can be seen that the score obtained when the worker performs the task of pulling the saw is 5, which indicates the need for further investigation and immediate changes.

Figure 4 shows how the workers’ posture is formed when dropping wood that has been cut. The angles formed by the worker’s body were analyzed and then calculated to obtain the RULA score. The results of this analysis are shown in

Table 5. Rula Score Calculation for Posture When Dropping Cut Wood.

RULA Score Calculation for Posture When Positioning Wood to Size
Upper Arm Score	3	Neck Score	3
Lower Arm Score	3	Trunk Score	2
Wrist Twist Score	2	Legs Score	1
Wrist Score	4
Posture A Score	5	Posture B Score	3
Muscle Use Score	0	Muscle Use Score	0
Force/Load Score	1	Force/Load Score	1
Wrist & Arm Score	6	Neck, Trunk, & Legs Score	4
RULA Score = 6 (Further Investigation, Changes Required Immediately)

below.

From the table of RULA Score Calculation for Posture When Dropping Cut Wood above (see Table 5), it can be seen that the score obtained when the worker performs the task of dropping cut wood for another worker to collect is 6, indicating the need for further investigation and immediate changes. After performing the RULA calculations on the three worker postures, the following conclusions were obtained:

From the table above (see

Table 6. Recapitulation of RULA Scores.

Posture	Table C Score
Positioning wood according to size	6
Pulling the saw	5
Dropping cut wood	6

and

Table 7. RULA Score Assessment Based on Table C.

RULA Score	Action
1–2	Acceptable Posture
3–4	Further Investigation, Changes May Be Required
5–6	Further Investigation, Changes Required Immediately
7	Investigate and Implement Changes

), it can be concluded that the posture for positioning wood according to size has a RULA score of 6, indicating the need for further investigation and immediate changes. The posture for pulling the saw has a RULA score of 5, also requiring further investigation and immediate changes. Similarly, the posture for dropping cut wood has a RULA score of 6, requiring further investigation and immediate changes.

3.3. Improvement Suggestions

Based on the RULA calculation results, it is concluded that the risk of worker activities when using the cross-cut machine is very high, necessitating investigation and implementation of changes. Factors contributing to the high scores include the worker’s posture, which shows large angles at the neck position, large angles in unsupported upper arms, and a hunched back posture. The proposed improvements are designed according to the workers’ anthropometry to reduce the risk of muscle injury while performing tasks [12]. The proposed improvements include changes to the workbench dimensions and the design of a new, more comfortable chair for the workers. The proposed design improvements are also adjusted using anthropometric data to ensure they are suitable for the workers’ bodies and comfortable for extended use [13]. Anthropometric data will be used to determine the appropriate dimensions and design for the improvements intended for the workers using the product [14].

3.3.1. Improvements to the Cross-Cut Machine Workbench

The workbench for the cross-cut machine has a height of 83 cm, a width of 70 cm, and a length of 110 cm. The issue with the cross-cut machine workbench is that it is too wide, despite the fact that the machine is only used to cut wood with a width of no more than 30 cm. The excessive width of the workbench causes the worker’s sitting position to be far from the place where the wood is placed and far from the machine’s handle. As a result, when the worker needs to place the wood or move the machine, they have to lean forward to reach it.

Based on this issue, the proposed improvement to the cross-cut machine workbench is to modify or change the width of the workbench. The current width of 70 cm will be reduced to 45 cm. This dimension has been adjusted to the anthropometric data for Indonesian males aged 18 years and above, with the 50th percentile being used, where the forearm length is 45 cm. The 50th percentile is used to ensure that the size is suitable for all workers (see

Table 8. Anthropometric Data for the Table.

Description	Measurement	Percentile	Tolerance
Forearm Length	45 cm	50th	+2 cm

Source: Indonesian Anthropometric.

). Reducing the width of the workbench is intended to make it easier for workers, so they do not have to lean forward when placing wood or moving the saw. The following is the proposed design improvement for the workbench.

The proposed improvement to the cross-cut table has dimensions of 83 cm in height, 45 cm in width, and 110 cm in length (see Figure 5). The change in table width is intended to prevent workers from having to bend forward excessively while using the machine. This improvement suggestion is based on the following anthropometric data.

3.3.2. Improvement of the Worker’s Chair at the Cross-Cut Machine

In addition to issues with the table, there are also problems with the chair used at the cross-cut machine workstation. The current chair does not comply with ergonomic principles and lacks a backrest and cushioning on the seat, making it uncomfortable for workers to sit for extended periods. The current chair has dimensions of 45 cm in length, 42 cm in width, and 62 cm in height.

Based on these issues, the proposed improvement is to design a new ergonomic chair that is comfortable for workers to sit in for long periods. Below is the design of the proposed chair (see Figure 6).

The proposed improvement for the chair design for the cross-cut machine operator uses teak wood as the primary material. This choice is based on field conditions where there is a significant amount of leftover teak wood that is not being utilized. The chair’s backrest design features an open structure, allowing for air circulation, which helps keep the worker’s back cool and prevents overheating and sweating. The chair is also equipped with a cushion for seating comfort, enabling workers to sit comfortably for extended periods. The design of this chair is simple yet functional, which makes it easy to manufacture and quick to produce, ensuring it can be used without disrupting production. The proposed chair design has dimensions of 118 cm in height, 43 cm in width, and 40 cm in length. This improvement suggestion is based on the following anthropometric data.

The selection of the 50th percentile for sitting shoulder height is intended to create a backrest that does not need to be too high to support the worker’s back, thus saving on raw materials. The 5th percentile for popliteal length is chosen to ensure that workers with shorter popliteal lengths can still use the chair comfortably, while the 95th percentile for hip width ensures that the seat width can accommodate all workers (see

Table 9. Anthropometric Data for the Table.

Description	Measurement	Percentile	Tolerance
Sitting Shoulder Height	52.09 cm	5th	-
Popliteal Length	30.51 cm	5th	5.49 cm
Popliteal Height	37.2 cm	5th	2.8 cm
Hip Width	43.85 cm	95th	-
Upper Arm Length	42.15 cm	95th	-

Source: Indonesian Anthropometric.

).

3.3.3. Addition of Footrests

An additional suggestion to enhance the ergonomic comfort for the cross-cut machine operator is the inclusion of footrests. This recommendation is made because, during work, the worker’s feet are currently resting on the chair, leading to an uncomfortable foot position. Below is the design proposal for the additional footrest improvement.

The footrest design features an adjustable platform that can be customized for height and angle according to the worker’s leg length and preferred incline. The footrest is made from teak wood for both the support structure and the footrest platform, with metal rods serving as the support for the platform and a knob for locking the height adjustment in place (see Figure 7). The proposed footrest design has dimensions of 40 cm in height, 43 cm in width, and 30 cm in length. These dimensions are based on the following anthropometric data.

The 95th percentile for hip width is used to ensure that the footrest can be comfortably used by workers with varying body widths. The 95th percentile for foot length is chosen to ensure that the footrest platform can comfortably support the feet of workers with different foot lengths (see

Table 10. Footrest Anthropometric Data.

Description	Measurement	Percentile	Tolerance
Hip Width	43.85 cm	95th	-
Foot Length	29.03 cm	95th	0.7 cm

Source: Indonesian Anthropometric.

).

3.4. Improvement Results

After the design for the proposed improvements was created, the next step was to perform a simulation of the proposed improvements and analyze the results.

3.4.1. Simulation

The proposed improvements were analyzed using simulations with the assistance of Catia software Version 5.0. This simulation was conducted to determine the effectiveness of the proposed design. The simulation was performed for the three work postures, and an analysis was conducted for each posture. Figure 8 shows is the simulation that was performed for the three work postures using Catia software.

3.4.2. Analysis of Simulation Results

After conducting the simulations, the next step is to analyze the results of each work posture simulation. The analysis will be performed using the RULA method to determine the scores generated after improvements were made to the cross-cut machine workstation. Figure 9, Figure 10 and Figure 11 shows is the analysis of each work posture using the RULA method.

Figure 9 shows the improved work posture formed when workers positioning wood according to size (see Figure 2). After analyzing the improved work posture and obtaining data on the angles formed by each part of the worker’s body, the next step is to calculate the RULA score based on the angles formed. Below is the RULA score calculation for the improved work posture.

From the RULA score calculation table for the Positioning Wood Posture above (see

Table 11. RULA Score for the Positioning Wood Posture.

RULA Score Calculation for Posture When Positioning Wood to Size
Upper Arm Score	2	Neck Score	2
Lower Arm Score	2	Trunk Score	1
Wrist Twist Score	1	Legs Score	1
Wrist Score	1
Posture A Score	3	Posture B Score	2
Muscle Use Score	0	Muscle Use Score	0
Force/Load Score	1	Force/Load Score	1
Wrist & Arm Score	4	Neck, Trunk, & Legs Score	3
RULA Score = 3 (Further Investigation, Changes May Be Required)

), it can be seen that the score resulting from the simulation when the worker performs the task of positioning the wood is 3, indicating that further investigation may be required, and changes might be necessary.

Figure 10 shows the improved work posture formed when workers pulling the saw during the wood cutting activities (see Figure 3). After analyzing the work posture and obtaining data on the angles formed by each part of the worker’s body, the next step is to calculate the RULA score based on the angles formed. Below is the RULA score calculation for the improved work posture.

From the RULA score calculation table for the Saw-Pulling Posture above (see

Table 12. RULA Score for the Saw-Pulling Posture.

RULA Score Calculation for Posture When Positioning Wood to Size
Upper Arm Score	2	Neck Score	2
Lower Arm Score	1	Trunk Score	1
Wrist Twist Score	1	Legs Score	1
Wrist Score	1
Posture A Score	2	Posture B Score	2
Muscle Use Score	0	Muscle Use Score	0
Force/Load Score	1	Force/Load Score	1
Wrist & Arm Score	3	Neck, Trunk, & Legs Score	3
RULA Score = 3 (Further Investigation, Changes May Be Required)

), it can be seen that the score resulting from the simulation when the worker performs the task of pulling the saw is 4, indicating that further investigation may be required, and changes might be necessary.

Figure 11 shows the improved work posture formed when workers dropping wood that has been cut (see Figure 4). After analyzing the work posture and obtaining data on the angles formed by each part of the worker’s body, the next step is to calculate the RULA score based on these angles. Below is the RULA score calculation for the improved work posture.

From the RULA score calculation table for the Wood-Dropping Posture above (see

Table 13. RULA Score for the Wood-Dropping Posture.

RULA Score Calculation for Posture When Positioning Wood to Size
Upper Arm Score	2	Neck Score	2
Lower Arm Score	3	Trunk Score	1
Wrist Twist Score	1	Legs Score	1
Wrist Score	1
Posture A Score	3	Posture B Score	2
Muscle Use Score	0	Muscle Use Score	0
Force/Load Score	1	Force/Load Score	1
Wrist & Arm Score	4	Neck, Trunk, & Legs Score	3
RULA Score = 3 (Further Investigation, Changes May Be Required)

), it can be seen that the score resulting from the simulation when the worker performs the task of dropping the cut wood is 3, indicating that further investigation may be required, and changes might be necessary.

The results and comparisons of the scores between the pre- and post-improvement simulations of the worker’s posture can be summarized as follows (see

Table 14. Recapitulation of RULA Scores After Improvement.

Posture	RULA Score
Posture of positioning the wood	3
Posture of pulling the saw	3
Posture of dropping the cut wood	3

).

Based on the tables above (see

Table 15. Comparison of RULA Scores.

Posture	RULA Score
	Before Improvement	After Improvement
Posture of positioning the wood	6	3
Posture of pulling the saw	5	3
Posture of dropping the cut wood	6	3

), it can be concluded that the posture of positioning the wood initially had a RULA score of 6, which was reduced to 3 after the improvement. The posture of pulling the saw initially had a RULA score of 5, which was reduced to 3 after the improvement. Similarly, the posture of dropping the cut wood initially had a RULA score of 6, which was reduced to 3 after the improvement.

4. Conclusions

After further research into workers’ complaints of pain, it was found that this discomfort stemmed from the operator’s work posture, which was not yet ergonomic. This finding aligns with the study by [15], which states that the causes of musculoskeletal complaints include excessive muscle stretching, unnatural work positions, repetitive activities, and excessive load.

Data processing and analysis using the RULA method showed that the work posture of the cross-cut machine operator in the raw material division of CV. VSU received RULA scores of 6 for positioning the wood, 5 for pulling the saw, and 6 for dropping the cut wood. These postures were not yet ergonomic and required immediate improvement. This is consistent with the study by [16], which concluded that a RULA score of 6 indicates a medium risk level that requires further investigation and prompt changes.

To reduce workers’ complaints, immediate improvements are necessary. This is supported by [17], who stated that proposed improvements are expected to reduce workers’ complaints. The proposed improvements include changing the width of the cross-cut machine workbench to prevent workers from bending over while positioning the wood and operating the machine. Another suggested improvement is to redesign the worker’s chair, which is currently inadequate and not ergonomic. The proposed chair design considers ergonomic principles and is based on human anthropometric data. An additional suggestion is to provide a footrest with adjustable height to allow workers to position their feet comfortably during work.

An ergonomic workstation design is crucial in maintaining workers’ posture and preventing injury risks, as emphasized by [18], who stated that an ergonomic chair design is essential for avoiding muscle injury risks during work. After simulating the proposed improvements, the next step was to analyze the work posture using the RULA method. The analysis revealed that the RULA score for the first work posture decreased from 6 to 3, the score for the second posture decreased from 5 to 4, and the score for the third posture decreased from 6 to 3 after the improvements.

Based on this analysis, the proposed improvements were deemed effective in significantly reducing the RULA scores, thereby decreasing the risk of muscle injury for cross-cut machine operators in the raw material division of CV. VSU. This is consistent with the study by [19], which found that using an ergonomic chair designed according to the RULA risk scale can reduce the risk of MSDs.