Effect of change in worktop height on postural deviation during standing cutting task

Introduction

Work-related musculoskeletal disorders (WMSD) are a major health problem (Nazari et al., 2012; Widanarko et al., 2014, Tabrizi et al., 2025, Akinwande 2026, Condie et al., 2026) having negative impacts on production and revenues of both individuals (Pradhan and Khan 2024, Badea et al., 2025, Choobineh et al., 2026 ) and countries globally (Coury et al., 2000, Buckle and Devereux, 2002 Holt 2025, Tolera et al., 2025). WMSDs have been reported among virtually all occupational groups including students (Alghadier et al., 2026, Daltaban et. al., 2026), dental hygienists (Alotaibi et al., 2026), office workers (Mohammadian et al., 2025, Karim et al., 2026, Mirnajafi Zadeh et al., 2026) sewing machine operators (Bulduk et al., 2017, Brohi et al., 2022, Su al., 2023), computer operators (Prasetya et al., 2024, Demissie et al., 2025) custom tailors (Ahmad et al., 2025, Adeleye and Akanbi 2026), health workers (Gao et al. 2025, Bonin et al., 2026) butchers (Sompan and Keeratisiroj 2025, Jahangiri et al., 2026), fishermen and crab fishers (Sorensen et al., 2025, Adithiyalakshmi and PL 2026) and kitchen workers (Yates and Brown 2025, Göz and Göz 2025) among others.

All these studies go further to show that in performing either simple or complex tasks (occupational, domestic or social), work-surface height is an essential in all the tasks engaged in by all human beings - workers, children, adults and elderly. Examples of such tasks include writing, typing, drawing, eating, screen watching, painting; surgical operation on patients, patient transfer from bed to chair; meat cutting, fabric cutting, dough rolling, screwing, welding, sewing, and so on. Performance of these tasks as usually done with just about any available work-surface/table heights, leads to WMSD that affect several body parts—the neck, upper limbs, trunk and calf, and so on (Gorce and Jacquier-Bret 2025, Liu et al., 2025).

Obviously then, prevention of these WMSD would be expected to have salutary impact on enhancement of productivity during execution of these tasks, as well as promotion of health and safety at work (Alhashim et. al., 2025, Shakerian and Salehi 2026). Herein is one reason for researching the subject of worktop/table (WT) height and its impact on occupational health

WT-height tasks are usually repetitive engagements involving the coordination of the use of both hands at tasks, visual control of the respective task, and forward inclined posture of both head and trunk. Users have to adapt their posture to the WT-heights, if the latter is not well fitted to the human subjects, leading to awkwardness of body postures if the WT-height is too high or too low. This awkward posture is the basis of many cases of WMSD, particularly in the back, neck and upper limbs (Sealetsa and Thatcher, 2011, Anculia et al., 2025, Ramadan et al., 2026,).

WT-height is a basic, essential feature of most domestic, occupational and social activities. This height is a function of the sitting or standing posture required to perform a task. Almost all human activities involve the use of WT whose height ranges from floor height such as rod-working trade (Salas et al, 2016) to above shoulder height (Kadir et al., 2025, Pentenga et al., 2025, Martinez et al., 2025, Jin et al., 2025). Work surface, intermittently used as work top could be a table, counter or desk but this study will stick to worktop/table (WT). WT usage is neither age- nor gender-bound but covers different facets of life (from toddler to old age) and the height differs accordingly. Several scientific studies on WT revealing inappropriate usage that led to WMSD have had to make appropriate recommendation for improvement. For instance, butchers and custom tailors work on tables that are either too high or too low (Magnusson & Örtengren 1987, Ghasemi et al. 2020, Adeleye and Akanbi 2015); also, there is usually a mismatch of students and their desks leading to postural overload and adolescent low back pain (Milanese and Grimmer 2004, Batistão 2010, Yanto et al., 2017). Students performed significantly better when seated in furniture that suited their body sizes (Smith-Zuzovsky and Exner 2004, Wingrat and Exner 2005, Castellucci et al., 2016, Parvez et al., 2018, Abdul Latip et al., 2025, Wang et al., 2025). Inappropriate sorting table heights in crab fishers lead to low back loads/pain (Salehi et al., 2025). For the enhancement of task-performance, and avoidance of excessive bending and stress on the upper limb region, an adjustable work surface height of 700 - 900 mm was recommended for the elderly (Bonenberg et al., 2019; Kirvesoja et al, 2000; ¨Ozalp, 2020). The annual prevalence of WMSDs among computer users varied from 33.8 to 95.3 % (Demissie et al., 2025a, Demissie et al., 2025b).

Studies showed that garment workers (sewing, ironing, packing workers) and custom tailors have high prevalence of WMSD (Sealetsa and Thatcher 2011, Adeleye and Akanbi 2015, Javed et al., 2025, Bizuneh et al., 2026) attributable to poor working postures as determined by their worktop height during cutting, sewing and ironing tasks. Butchers have high prevalence of hands, shoulders, low back and neck WMSD which has been attributed to inappropriate working postures among other factors (Salehi et al., 2025). Commercial fishermen, Dungeness crab fishers and harvesters suffer from WMSD of the lower back, shoulders and knees attributable to inappropriate sorting-table work surface heights (Nørgaard Remmen et al., 2021; Kim and Kincl, 2022, Kim et al., 2023, Salehi et al., 2025)

Several other studies examined the effects of work-height on physical workload (Gupta 2024, Petju et. al., 2026.) and biomechanical loads on the low back and shoulders (De Bock et al., 2022, Choi et. al., 2024). Work top height has extensively been studied by researchers (Pekkarinen and Anttonen 1988, Magnusson and Örtengren 1987, Berquer et al., 2002, Manasnayakorn et al., 2009, Lee et al., 2025). Some identified four critical anthropometric measures for working surface height are stature, floor-to-elbow height (standing), floor-to-elbow height (seated), and seat-to-elbow height (Ward & Kirk, 1970, Ackermann et al., 2025, Silva et al., 2025, Kan-Dapaah et al., 2025). Additionally, literature emphasized that specific tasks and functions performed on work surfaces could vary and require varying work heights (e.g., sink for cleaning tasks, stovetop for cooking tasks, and counter for food preparation tasks) (Ward & Kirk, 1970; Yang & Yu, 1990; Ward, 1971; Sandhu et al., 2008; Patil & Rajhans, 2018). Therefore, adjustability of the counter height, if possible, was frequently proposed as an important design consideration in contemporary kitchens (Hoag & van Dyke, 1975; Bonenberg et al., 2019; Pheasant & Haslegrave, 2006). Moreover, studies conducted in Asia reported kneading and rolling dough as an important task to be considered in worktop height designing (Kishtwaria et al., 2007; Sandhu et al., 2007).

In both seated and standing worker, the basic biomechanics of the Body load and Work-table height are found in the neck, upper limbs, trunk, legs and butts. In their study, Magnusson and Ortengren (1987) found out that working at a table that is too low requires a forward bent posture, meaning increased load on the back; when the arms are kept in front of the body the load increases even more (Nachemson, 1966; Andersson et al, 1977; Rahman et al., 2025). Crab sorting on low surface-height forces severe trunk flexion and increases biomechanical load in the low back thereby elevating the risk of low back injuries (Salehi et al., 2025). When the work is performed at a table that is too high, a compensatory raising of the shoulders and an abduction of the arms are demanded. Such arm positions very quickly lead to fatigue in the shoulder muscles even when the load is only the weight of the arm (Hagberg, 1981, Tobias et al., 2025). The reason why fatigue develops rapidly when the arms are abducted over 30 ° is that larger torque is required and that the shortening of the active muscles decreases their capacity to develop force (Chaffin, 1973, Zimmermann et al., 2025). Working with the neck bent forward may cause large load on the neck (Hagberg, 1981).

The WMSD of Butchers are localised in the low back, shoulders, neck, hand, wrist, and elbow and is attributable to inappropriate working postures among other factors. (Magnusson et al, 1987, Nordander et al., 2009). Most times, meat cutting or trimming is done on the table of varying heights which could be too low or too high for the workers (Magnusson & Örtengren 1987, ) This incongruency between anthropometry and table height was also found in custom tailors (Adeleye and Akanbi 2015) Students (Yanto et al., 2017). Working posture, muscles activity, standing duration and holding time are some of the known risk factors associated with standing jobs and could be the basis for developing the prolonged standing strain index (Halim and Rahman, 2012). Metal stamping workers, electronics parts assembly operators, automotive industry welders, and lathe operators require working in a standing posture, a risk factor WMSD (Halim and Rahman, 2012, Anderson et al., 2018).

Workers who perform their work standing continuously load their back during standing for about 78% of their working time. This prolonged loading of the musculo skeletal system can be modified by provision of adjustable worktop height because change in work-surface height significantly affects the shoulder and low back (Pekkarinen and Anttonen 1988, Adeleye et al., 2020). For workers whose work must be performed standing, 78% of their working time involves standing postures (Pekkarinen and Anttonen, 1988). Standing for prolonged periods has been associated with health concerns such as low back pain (LBP) and leg discomfort (Tissot et al., 2009; Ryan, 1989; McCulloch, 2002; Waters and Dick, 2015). When tasks are carried out in standing positions, the back (spinal column) is continuously loaded in a peculiar way. Although the musculoskeletal system (MSS) is continuously loaded whether in standing or sitting position but the nature of tasks to be done and how it is to be done further determines the additional loading of the MSS (Zhao et al., 2026). The type and perceived demands of standing work tasks can affect postural movement (Glinka et al., 2018). Risk factors associated with standing jobs, such as working posture, muscles activity, standing duration, holding time, whole-body vibration, and in-door air quality, were the basis for developing the prolonged standing strain index (PSSI). Prolonged standing can contribute to discomfort and muscle fatigue particularly in the back and legs (Halim, and Rahman 2012). This study was therefore designed to quantify an objective biomechanical metric (joint angles) in the neck, shoulder, elbow, wrist and trunk during table-top tasks at different work-surface heights.

Methodology

Twenty-four (24) healthy volunteers with mean age 25.58 (±3.57) yrs, height 66.09 (± 3.54) inches and weight 29.24 (± 6.80) Kg participated in the study. The inclusion criteria were right-handedness, normal or corrected-to-normal vision, and no musculoskeletal problems in the last one year of the study. The study protocols were approved by the Virginia Tech IRB, and informed consent procedures were completed by each before any data collection. Each participant performed his/her experiment independently. The first session of the study involved detailed explanation of the experimental procedure given to the participant followed by familiarization with materials and equipment to be used. Next came the participant’s paperwork where the participant read through and signed the consent form if comfortable with the contents otherwise, opted out of the experiment. This was followed by biodata collection which were dully recorded on each participant’s data form. A Standiometer and a weighing scale were used for collecting the height and weight data. Next is Xsens suit wearing where the MVN Xsens system connected to a computer was used for the data collection of the anatomical region angular deviation from the neutral. Once fully kitted as shown below, the participant moved to the work-station to carry out the experimental tasks.

Each participant carried out 24 tasks involved cutting of same pattern on two different kinds of fabric using 4 different designs of manual scissors on 3 different table heights. This experimental design gave a 2x4x3 task orders. To avoid the pitfall of standard repeated measures designs, counterbalancing was used since all participants were exposed to the same experimental conditions. A complete balanced Latin matrix square was used to randomly assign task-order to the 24 subjects in order to evenly distribute the tasks without any bias. The upper body posture was monitored using the passive Xsens motion capture system. A computer system was set up with the MVN software for data collection from the Xsens system. Xsens system, (two inertial measurement units IMUs: Xsens technologies B.V., Enschede, the Netherlands) was worn by participants on the upper body to monitor the angular deviation of some anatomical regions from their normal posture. These regions are stated in table 1 of the results and discussion.

Prior to cutting, the participant stood still in front of the workstation without any motion other than breathing for the Xsens system calibration. The N-pose was chosen; once prompted by the computer system that the calibration was good or acceptable, the procedure continues but if the report was poor, then the sensors of the Xsens system were re-adjusted and the calibration repeated until a good result was achieved. Calibration was repeated at the beginning of every session. Each cutting session involved 4-different cutting tasks and there were 6 sessions in the experiment separated by 5- minutes break each. Each cutting task involved cutting of the traced template pattern and was immediately followed by questionnaire filling for each task by the participant. Still pictures of participants at the work-stations are equally part of the data acquisition and the experiment ended with the removal of the Xsens system followed by other protocols.

The simulated fabric-cutting tasks involved a uniformly drawn pattern of C and S joined by a straight line drawn on all the experimental fabric pieces. Participants were instructed to cut the drawn pattern on the fabric pieces (10" x 30" each) which had been prepared in advance. The tasks were completed in 24 conditions of three independent variables: four right-handed scissor designs (SD 1-4), three workstation heights (WH), and two fabric types (FT). The vertical distance between the top of the work surface and the ground (workstation height - WH) was set at three levels WH Low (33"), WH Mid (36"), and WH High (39"). Fabric types (FT) were the softer (FT Soft) and the harder (FT Hard). Participants’ training and testing sessions were completed in standing posture, but sitting was available during the rest periods. During the experimental tasks, participants adhered strictly to the given instructions such as unidirectional right hand cutting only, non-lifting of the fabric piece off the table and starting scissors usage from the unlocked position.

All the digital information from the camera and computer were transferred to the external drive safety and further analysis. As part of the precautions taken during the experiment, the researcher ensured that there was no group contact nor group training of participants so as to avoid bias, not more than 2 participants were taken per day, and each had a separate experimental time without contact with the second person. Each participant’s data were correctly labelled as they got saved into the computer, each task was correctly input into the system as it was performed by the participant and the table height was changed intermittently as required by each task to 33, 36 or 39 inches. The Xsens data recorded in sinusoidal waves and translated into numeric values by the MVN software were first entered into a Matlab software where the descriptive statistics were found for each task of every participant. These results were then transferred into excel sheets for further analysis.

Results And Discussion

Fig 1 shows two participants of different anthropometry (A - short; B - tall) cutting fabric at the different table heights WH₁ (33"), WH₂ (36"), and WH₃ (39"). The participants adapted themselves to the low WH₁ by engaging over 45⁰ trunk bending angle which included neck flexion. While WH₂ looks perfect for the shorter participant A, WH₃ seems best for the taller participant B where both participants are at near neutral work posture.

Improper table height as shown in fig 1 led to the awkward posture of the neck, trunk and upper extremities of the participants in agreement with Rahman et. al., (2025). However, appropriate table height for every individual is a function of his/her anthropometric features. Trunk and neck flexion from neutral position elevated lower spinal loading as indicated at WH₁ station; at WH₂ station, participants tended to more neutral alignments which reduced the biomechanical strain of their upper body but increased the neck flexion. WH₃ showed increase in shoulder elevation and arm abduction, especially in participant A. The arm elevation and abduction as well as lateral neck flexion were more pronounced in the participant A because she is shorter. Hence the table height 39" was above elbow height for participant A while it was below elbow height for participant B. This shows that the upper body kinematics which involved movements of the neck, trunk, shoulder, elbow, wrist, and forearm was controlled by both the table height and the participants’ anthropometry during task performance in agreement with Tobias et al., (2025). The participants’ average age, height and weight were (25.58 ± 3.57)yrs, (66.09 ± 3.54) cm, and (29.24 ± 6.80) kg respectively.

Variation of duration with worktop height

Figure 1 shows the variation of duration with worktop height. The average task duration decreased slightly as worktop height increased from WH1 (94.24 s) to WH2 (90.96 s) and WH3 (89.65 s). Although the reduction appears small, the repeated-measures ANOVA (Table 1) indicates that worktop height significantly affected task completion time (p = 0.004). This suggests that participants performed the cutting task more efficiently at higher worktop heights. At the lower worktop (WH1), greater trunk and neck flexion were required, increasing postural demands and potentially slowing task execution. The reduced duration observed at WH2 and WH3 may therefore be attributed to improved visibility of the cutting line at lower trunk flexion angle. Reduction in discomfort reduces task performance duration in agreement with Bhasker et al., (2025).

Variation of Shoulder Movement with Worktop Height

The shoulder flexion/extension angle (UA1) increased markedly from 16.34^o at WH1 to 39.62^o at WH3, while shoulder abduction/adduction (UA2) decreased from 39.62 at WH1 to 32.12^o at WH2 and slightly increased to 33.90^o at WH3. This pattern indicates that increasing worktop height progressively elevated the upper arm in front of the body, thereby increasing shoulder flexion. At low worktop heights, participants compensated lowering their shoulders and leaning forward. As the table height became higher, shoulder elevation increased to maintain hand contact with the cutting surface. Excessive should flexion at WH3 may increase static muscular loading of the deltoid and trapezius muscles, contributing to shoulder fatigue during prolonged work. Conversely, the reduction in shoulder abduction suggests that higher worktops brought the arms closer to the body, thereby reducing lateral shoulder displacement.

Variation of Elbow Movement with Worktop Height

Figure 3 shows that elbow flexion/extension (LA1) decreased substantially from 101.09^o at WH1 to 78.66^o at WH2 and 80.84^o at WH3. Similarly, elbow abduction/adduction (LA2) moved progressively toward the neutral position as worktop height increased. These findings suggest that lower worktops required participants to bend their elbows more while performing the cutting task. Increased elbow flexion is expected when workers lean toward a low work surface. As the worktop height is increased, the forearm became more extended and elbow posture approached a neutral configuration. The reduction in elbow abduction/adduction also indicates improved upper-limb alignment at higher worktop heights. Therefore, WH2 and WH3 appear more favourable than WH1 with respect to elbow posture.

Wrist Movement

Figure 4a shows that the wrist rotation in flexion/extension (WI) remained relatively stable across all worktop heights, varying only between approximately 4.6^o and 5.8^o. Wrist radial/ulnar deviation (W2), however increased from -0.89^o at WH1 to 7.89^o at WH3. The minimal variation in W1 confirms that worktop height had little influence on wrist flexion and extension. This agrees with the ANOVA results in Table 1, which showed no significant effect of worktop height on W1. In contrast, the increase in radial/ulnar deviations suggests that participants gradually altered wrist orientation as table height increased. Nevertheless, the magnitude of change remained relatively small compared with changes observed in other regions. Meanwhile, Figure 4b indicates that wrist pronation/supination (WT1) changed only slightly from -3.80^o at WH1 to 0.35^o at WH3. This limited variation indicates that forearm rotational movements were largely determined by the cutting technique and scissor operation rather than worktop height. The relatively constant wrist posture across all workstations suggests that participants maintained a consistent hand orientation regardless of the vertical position of the cutting surface.

Variation of Neck Movement with Worktop Height

Figure 5 shows that neck lateral bending (N1) decreased from 14.72^o at WH1 to 8.7^o at WH3. Neck abduction/adduction (N2) and neck axial rotation (N3) also showed decreasing trends with increasing worktop height. The results indicate that low worktop heights imposed greater neck postural demands. Participants were required to bend and rotate the neck to maintain visual contact with the cutting pattern while simultaneously compensating for the lower work surface. Increasing the worktop height reduced these deviations and brought the neck closer to a neutral posture. Since excessive neck flexion and lateral bending are known risk factors for neck discomfort and work-related musculoskeletal disorders, the observed reduction at WH2 and WH3 suggests improved ergonomic conditions.

Variation of Trunk Movement with Worktop Height

Figure 6 indicates that trunk lateral bending (T1) increased substantially from 11.08^o at WH1 to 19.29^o at WH3. Trunk abduction/adduction (T2) also increased, while trunk axial rotation (T3) showed a gradual decrease with increasing worktop height. The increase in trunk lateral bending at higher worktop heights indicates that participants compensated for the elevated work surface by shifting their torso sideways. This finding contrasts with the neck results, where posture improved as worktop height increased. The decrease in trunk rotation suggests that higher worktops reduced the need for rotational adjustments during cutting. Generally, the trunk exhibited the greatest sensitivity to worktop height, indicating that inappropriate worktop design may substantially alter whole-body posture. Excessive trunk bending at WH3 may increase loading of the lumbar and thoracic spine during prolonged task performance.

Repeated-measures ANOVA Results

Table 1 shows the repeated-measures ANOVA statistics which demonstrate that worktop height significantly affected task duration and almost all measured joint movements. Significant effects were observed for shoulder movements (UA1, UA2), elbow movements (LA1, LA2). Wrist radial/ulnar deviation (W2), wrist pronation/supination (WT1), neck movements (N1, N2, N3) and trunk movements (T1, T2, T3), all with p-values less than 0.05.

Among all variables, trunk lateral bending (T1) exhibited the highest F-value (413.261), indicating that trunk posture was the most strongly influenced by the changes in worktop height. Shoulder flexion (UA1) and elbow abduction/adduction (LA2) also showed very large F-values, demonstrating substantial postural adaptation of the upper extremities. The only variable not significantly affected by worktop height was wrist flexion/extension (W1) (p = 0.224), indicating that wrist posture remained relatively constant across all workstation heights.

Legend: Angles in degrees

UA1Shoulder flexion/extension angle UA2 Shoulder abduction/adduction angle

LA1Elbow flexion/extension angle LA2 Elbow abduction/adduction angle

W1Wrist flexion/extension W2 Wrist radial/ulnar deviation

WT1pronation/supination of the wrist N1 Neck lateral bending

N2Neck abduction/adduction N3 Neck axial rotation

T1Trunk lateral bending T2 Trunk abduction/adduction

T3Trunk axial rotation

Summary Statistics

The descriptive statistics in Table 2 reveal a clear pattern of postural adaptation with increasing worktop height. Shoulder flexion increased, elbow flexion decreased, neck deviations generally reduced, and trunk lateral bending increased as the worktop became higher. Taken together, the data suggest that WH1 promoted excessive neck and elbow flexion, whereas WH3 increased shoulder elevation and trunk bending. WH2 generally produced intermediate values for most variables and therefore appears to represent the best compromise between the adverse postural effects observed at the lower and higher workstation heights. From an ergonomic perspective, the medium worktop height (36 inches) may provide the most balanced posture during standing fabric-cutting tasks.

Conclusion

This study supports the findings of previous studies that work surface height plays a major role in coordination movements of the shoulder, neck, vertebrae column and the upper limbs in agreement with Goncaves et al., 2019. The results indicated that as table height increased from low WH₁ to high WH₃ almost all the certain joint angles measured underwent significant changes. The neck lateral bending (N1) angle was significantly greater at higher table heights WH₂ and WH_3. The neck axial rotation (N3) angle at WH₂ (5.86° ± 3.92) is significantly greater than that at WH₃ (4.13° ± 5.43), with a p < 0.10 between WH₂ and WH_3. The shoulder flexion/extension angle (UA1) showed significant differences of increasing shoulder flexion as table height increased. The elbow flexion/extension angle (LA1) showed a significant decrease as table height increased. No significant differences were found across table heights for wrist flexion/extension (W1), wrist radial/ulnar deviation (W2), and pronation/supination (WT1). However, trunk lateral bending (T1) significantly increased with the table height.

While all the other angular body parts considered show a significant change with work surface height, the wrist kinematics were relatively unaffected by table height. Trunk and neck flexion from neutral position elevated lower spinal loading at WH₁. A more neutral alignments that reduced biomechanical strain of the upper body was observed at WH₂ with increased the neck flexion while WH₃ showed increase in shoulder elevation and arm abduction. None of the table height resulted in a posture without load on both back and shoulders at the same time. However, the table height below the elbow height of each participant resulted in low Ioadings on both the low back and the shoulder. An adjustable cutting table is therefore recommended to accommodate various users’ height.