Occupational health and safety management systems: a systemic approach / Sistemas de gerenciamento em saúde e segurança do trabalho: uma abordagem sistêmica

Abstract Risks are intrinsic to any human activity. Occupational Health and Safety Management Systems (OHSMSs) are mechanisms designed to mitigate risks, protect workers, and ensure productivity. This study aimed to support researchers' reflective analysis by examining scientific literature related to OHSMSs and identifying possibilities for future research with practical significance. Employing a qualitative approach, this systematic review was conducted using bibliographic procedures and action research. The intervention instrument ProKnow-C guided by a structured process from a constructivist perspective, was applied. A total of 3,130 studies were analyzed to select the bibliographic portfolio. The systemic analysis revealed that most articles neither demonstrate legitimacy nor consider companies' particularities. The paper advances theoretical knowledge of OHSMSs by assessing relevant studies in the field, identifying evolution patterns, and highlighting gaps. A research agenda is proposed to guide the development of future models. We conclude that the challenges of designing ad hoc OHSMSs and incorporating the decision-makers' knowledge throughout the process when addressed, have the potential to significantly contribute to the advancement of this field of knowledge.

Resumo Os riscos são intrínsecos a todas as atividades humanas. Os sistemas de avaliação de desempenho de saúde e segurança no trabalho (SADSSTs) são mecanismos projetados para lidar com riscos, proteger os trabalhadores e garantir produtividade. Este estudo objetivou apoiar a análise reflexiva dos pesquisadores com base na literatura científica relacionada aos SADSSTs, identificando possibilidades de pesquisas futuras de importância prática. Com abordagem qualitativa, esta revisão sistemática foi desenvolvida com a adoção de procedimentos bibliográficos e pesquisa-ação. Foi utilizado o instrumento de intervenção ProKnow-C, um processo estruturado orientado pela perspectiva construtivista. Um total de 3.130 estudos foi analisado para a seleção do portfólio bibliográfico. A análise sistêmica revelou que a maioria dos artigos não apresenta legitimidade, nem considera as particularidades das empresas. O artigo avança no conhecimento teórico dos SADSSTs avaliando os estudos relevantes na área e identificando padrões de evolução e lacunas. Propõe-se uma agenda de pesquisa para orientar o desenvolvimento de modelos futuros. Conclui-se que o desenvolvimento de um SADSST ad hoc, não genérico e concebido com o conhecimento do decisor em todo o processo, permanece sendo um desafio e tem potencial para contribuir para o avanço deste campo do conhecimento.

Quadriceps Muscle Morphology Is an Important Determinant of Maximal Isometric and Crank Torques of Cyclists.

The aim of this study was to determine if quadriceps morphology [muscle volume (MV); cross-sectional area (CSA)], vastus lateralis (VL) muscle architecture, and muscle quality [echo intensity (ECHO)] can explain differences in knee extensor maximal voluntary isometric contraction (MVIC), crank torque (CT) and time-to-exhaustion (TTE) in trained cyclists. Twenty male competitive cyclists performed a maximal incremental ramp to determine their maximal power output (POMAX). Muscle morphology (MV; CSA), muscle architecture of VL and muscle quality (ECHO) of both quadriceps muscles were assessed. Subsequently, cyclists performed three MVICs of both knee extensor muscles and finally performed a TTE test at POMAX with CT measurement during TTE. Stepwise multiple regression results revealed right quadriceps MV determined right MVIC (31%) and CT (33%). Left MV determined CT (24%); and left VL fascicle length (VL-FL) determined MVIC (64%). However, quadriceps morphological variables do not explain differences in TTE. No significant differences were observed between left and right quadriceps muscle morphology (p > 0.05). The findings emphasize that quadriceps MV is an important determinant of knee extensor MVIC and CT but does not explain differences in TTE at POMAX. Furthermore, quadriceps morphological variables were similar between the left and right quadriceps in competitive cyclists.

Effect of elastic resistance training on functional capacity in older adults: a systematic review with meta-analysis.

PURPOSE: This systematic review and meta-analysis investigated the effects of Elastic Resistance Training (ERT) on functional capacity (FC) in older adults. METHODS: The databases used were Embase, Virtual Health Library, PubMed, SciElo, Scopus, SPORTS Discus, and Web of Science. Eligibility criteria: aged ≥ 60 years; both sexes; intervention of at least 8 weeks; structured ERT; comparator group that performed other types of training or without any intervention; at least one functional test measurement. Functional tests were grouped according to their specificity for the sub-group meta-analyses. RESULTS: Twenty-six studies were considered eligible for qualitative synthesis, of which 16 were used for quantitative analysis. Favorable effects (p < .001) of ERT compared to the control group without intervention were observed in the 30-second sit to stand test, Timed Up and Go test, arm curl test, handgrip strength test, 6-minute walk test, lower and upper limb flexibility, and Short Physical Performance Battery (p = .007). Comparisons between ERT and other types of training were not performed because of the high heterogeneity of the studies. CONCLUSIONS: Our findings suggest that ERT is able to improve the FC of older adults when compared to older adults not involved in any type of training.

Usability and effects on gait of an optimized schoolchildren backpack.

BACKGROUND: Backpacks used by children is a global concern, because may cause musculoskeletal discomforts and pain. OBJECTIVE: The purpose of this study was to test the usability and effects on gait kinematics wearing the Trunkpack versus a traditional backpack and no backpack. METHODS: Twenty-four children (9 to 11 years old) from a public school participated in this study. The usability was evaluated after a five-week testing period using a questionnaire. Gait kinematics was evaluated (Vicon) when the children were wearing a standard backpack, an optimized backpack (Trunkpack), and no backpack. Both backpacks were loaded with 10% of body weight. RESULTS: Was observed more trunk, hip and knee flexion when the children carried a standard backpack in comparison using the Trunkpack and not carrying a backpack (p < 0.01). The Trunkpack and no backpack were similar. The Trunkpack was well accepted by the schoolchildren (81% positive responses), 79% liked the head opening, 88% liked the waist straps, and 83% liked the facility to put and take objects in and out of the Trunkpack. CONCLUSION: Trunkpack requires less postural adjustments during gait than a standard backpack. Gait kinematics with the Trunkpack was comparable to the gait without carrying a backpack.

Muscle Architecture and Maximal Strength between Male Practitioners of Functional Fitness Training and Strength Training.

Functional Fitness Training (FFT) is a very popular training method in recent years. However, the combination of aerobic and strength components of this training method raised the hypothesis of impaired strength and muscle structure when compared to Strength Training (ST). Thus, the study aimed to compare muscle architecture and strength between FFT and ST, and the relationship between muscle architecture and maximum strength performance. Males (28.46 ± 6.03 years), nonathletes, and practitioners for two years in FFT (n = 8) and ST (n = 8), in addition to males classified as physically active (n = 8) were recruited. Muscle architecture of the rectus femoris (RF) and vastus lateralis (VL) of the thigh were evaluated with the aid of B-mode ultrasound and maximum strength in the back squat through the one-repetition maximum test. For muscle architecture, the fascicle length (FL), pennation angle (PAn), and muscle thickness (MT) were evaluated, in addition to the cross-sectional area (CSA). The FL, PAn, MT, and CSA of the RF and VL did not differ between the FFT and ST groups. Similarly, maximum strength did not differ between the FFT (152 ± 23.68 kg) and ST (151.88 ± 14.77 kg) groups. A significant relationship was observed between the PAn of the RF and the maximum strength (r =0.862; p =0.006) of FFT practitioners. The muscle architecture, CSA, and muscle strength do not differ between FFT and ST male practitioners, and PAn of the RF correlates with the maximum force for FFT practitioners.

Muscle architecture of the vastus lateralis and rectus femoris in the production of knee extensor torque in physically inactive women

Abstract Aim: This study aimed to verify the data reliability of muscle architecture (MA) variables, and the relationship between MA and the isometric peak torque (PT) of the monoarticular and biarticular knee extensor (KE) muscle in physically inactive women. Methods: Ten physically inactive women (24.0 ± 1.64 years; 162.9 ± 5.34 cm; 63.5 ± 11.90 kg) participated in the study. An ultrasound device assessed the MA variables (muscle thickness, fascicle length, and pennation angle) of the Vastus Lateralis (VL) and Rectus Femoris (RF), and an isokinetic dynamometer assessed the PT. Pearson correlation evaluated the relationship between PT and MA variables, with a significance level of 5%. Additionally, the intraclass correlation coefficient, coefficient of variation, and standard error of measurement. Results: Excellent reliability between images was observed, and no significant relationships were observed between the PT and MA variables of the VL and RF. Conclusion: Isolated variables of the MA of a monoarticular or a biarticular muscle do not influence the production of the isometric PT of the KE.

Influence of Trunk Position during Three Lunge Exercises on Muscular Activation in Trained Women.

The present study aimed to compare the activation of the lower lumbar erector spinae, gluteus maximus, biceps femoris, and rectus femoris in two trunk positions (straight, and inclined) during three lunge exercises (static, step-forwarding, and walking) in trained young women in a randomized crossover design. Twelve women (24 ± 3 years) were selected and performed the lunge exercise with an overload of 30% of body weight in six conditions to analyze muscle activation via surface electromyography signals. Higher activation in the erector spinae (%MVIC) were observed (p < 0.05) when trunk position was inclined (straight = 20 ± 15, inclined = 40 ± 29) and during the walking lunge condition (static = 24 ± 16, forward = 26 ± 22, walking = 40 ± 33). Higher activation in the gluteus maximus was observed during step-forward and walking lunges conditions (static = 31 ± 12, forward = 54 ± 20, walking = 58 ± 30). All conditions displayed similar activations in the biceps femoris and rectus femoris (p > 0.05). Results indicate that positioning the trunk in a forward-inclined position induces greater lower lumbar erector spinae activation and dynamic lunge variations elicit greater muscular activation in the gluteus maximus than static lunges. Additionally, it seems that trunk and exercise variations do not influence the activation of tight muscles.

The effect of different work-rest schedules on ergonomic risk in poultry slaughterhouse workers.

BACKGROUND: Rest breaks are an organizational measure to reduce the high risk of upper limb work-related musculoskeletal disorders (UL-WMSDs) to which slaughterhouse workers are subject. OBJECTIVE: To analyze the effect of different work-rest schedules on ergonomic risk in poultry slaughterhouse workers. METHODS: A total of 36 repetitive tasks was selected in a Brazilian slaughterhouse. Using the Occupational Repetitive Action (OCRA) Checklist, the level of exposure of workers to risk factors of UL-WMSDs in two work-rest schedules was evaluated. In the real condition, 6 rest breaks of 10 minutes were performed, and in the simulated condition, 3 rest breaks of 20 minutes. RESULTS: The right side of the body presented a higher score on the OCRA Checklist (72%of the tasks) than the left side (p = 0.037) in the real condition. Additionally, the OCRA score (18.3±2.5) was significantly lower (p < 0.001) than the simulated condition (21.9±3.0). It was verified that the risk level in simulated condition remained the same in 13 (36%) tasks, while in 23 (64%) tasks there was an increase in the risk level. CONCLUSIONS: Work-rest schedule of 6 breaks of 10 minutes was better than 3 breaks of 20 minutes to reduce the risk of UL-WMSDs in poultry slaughterhouse workers.

Cutting force measurement: Hand tool instrumentation used in slaughterhouses - a systematic review.

Workers' intensive use of hand tool cutting in the meat packing industry is a risk factor for occupational health, mainly by mechanical compression of tissues in the upper limbs, which can cause Work-Related Musculoskeletal Disorders (WMSDs). This systematic review aimed to identify the characteristics and measured variables of instrumented knives and determine how they should be designed. The review process and article extractions occurred through an analysis of the (article) titles, keywords and abstracts, followed by reading the full texts by two reviewers independently. Searches were conducted in Medline, Web of Science, Science Direct, Scopus, Ebsco and Engineering Village for articles published in peer-reviewed journals from January 2000 to March 2019, in the English language. The result of (the) search included 1289 potentially eligible studies, with 894 duplicated/triplicated/quadruplicated articles that were excluded, resulting in 404 remaining articles of which 33 were considered eligible, with 36 additional articles, totaling 69 evaluated full texts. After the review, none of the 14 analyzed studies, were rated as having good methodological quality. In addition, four types of instrumented knives were used. Data acquisition was performed in both laboratory and meat processing plants. It is noteworthy that only one knife was submitted to a validation process and that the articles did not provide complete technical information about the knives. The result demonstrated that the cutting force varies within and between subjects, tasks, plants and blade finishings. All knives used some type of electrical connection via cable or wires. Of the articles found, none considered the influences that the workers are subject to when they do not use the same tool daily for data acquisition. Therefore, the development of different types of instrumented knives, with wireless data transmission and more rigorous studies are necessary to expand the knowledge of the cutting force and development of WMSD in slaughterhouse workers who perform meat cutting.

Acute effect of bodyweight-based strength training on blood pressure of hypertensive older adults: A randomized crossover clinical trial.

Background: Strength Training (ST) reduces the cardiovascular risk of hypertensive elderly people; however, there is a need for efficient and low-cost ST programs that aim to reduce blood pressure (BP) in elderly people with adherence and affectivity in this population. Objective: Evaluate the acute effect on BP and satisfaction with the practice of bodyweight-based strength training (BWST) in hypertensive older adults. Methods: Participants performed a BWST session and a control session (CS). The BWST consisted of six exercises, with three sets of 30 seconds. In the CS, no activity was performed. BP was measured before and at 0, 10, 20, and 30 minutes post-session. Participants' satisfaction was assessed. Results: Eleven older adults (65.8 ± 4.6 years; 7 men) participated in the study. There was an increase (p = .028) in systolic BP immediately after BWST, returning to baseline values in the intervals 10, 20, and 30 post-section. In the CS there was an increase (p = .009) 30 minutes post-session compared to 20 minutes. Between sessions, a lower systolic BP was found in BWST (-6.54 ± 3.31; p = .048) 30 minutes post-sessions. For satisfaction, 82% of participants were "totally satisfied" with BWST. Conclusion: The SBP is lower 30 minutes after BWST session than control session, and BWST promoted a pleasant affective response in hypertensive older adults.

A low-cost and efficient participatory ergonomic intervention to reduce the burden of work-related musculoskeletal disorders in an industrially developing country: an experience report.

Work-related musculoskeletal disorders (WMSDs) are the first cause of occupational illness in Brazil and the number of cases in the industrial sector has increased progressively in the last 6 years. In order to prevent WMSDs, workplace ergonomics interventions are frequently implemented worldwide. This article describes the implementation strategy of a participatory ergonomic intervention conducted in the quality control department of a medium-sized Brazilian garment company. The intervention was carried out based on the nine steps presented by Vink, Imada and Zinck, and workers' exposure to risk factors was investigated using the rapid upper limb assessment method. A low-tech and low-cost solution that successfully reduced workers' exposure to WMSD risk factors was proposed, prototyped, tested and, finally, introduced. Participatory ergonomic interventions can be a feasible and effective approach to reduce the exposure to work-related risk factors for WMSDs in industrially developing countries.

Exertion Perception When Performing Cutting Tasks in Poultry Slaughterhouses: Risk Assessment of Developing Musculoskeletal Disorders.

Brazil is the leader in poultry meat exports, in which most products are in the form of cuts. This study analyzed the exertion perception of poultry slaughterhouses workers when performing cutting tasks, as well as the influence of knife sharpness on the risk of developing musculoskeletal disorders by Occupational Repetitive Action (OCRA) method. Participants (n = 101) from three slaughterhouses were asked to rate their perceived exertion on the Borg scale during the cutting task when the knife was well and poorly sharpened. The OCRA results showed that the score for cutting with a dull knife was greater (43.57 ± 13.51) than with a sharp knife (23.79 ± 3.10) (p < 0.001). Consequently, there was a significant increase in the risk level of acquiring upper-limb work-related musculoskeletal disorders (UL-WMSD) by using a "poorly sharpened" knife (29%; p < 0.001; Borg scale 2-8). Thus, maintaining well-sharpened knives for optimal performance of the cutting task (fewer technical actions) is suggested, as well as including knife sharpening in the standard operating procedure to reduce musculoskeletal disorders.

Effects of Concurrent Training with Elastic Tubes in Hypertensive Patients: A Blind Controlled Randomized Clinical Trial.

BACKGROUND: Concurrent training (CT) has been recommended to minimize the deleterious effects of aging. However, few studies have investigated whether this type of training reduces blood pressure in the elderly. Therefore, our objective was to evaluate the effects of CT on the hemodynamic, cardiorespiratory, and muscle strength responses in medicated hypertensive patients. METHODS: Twenty-three hypertensives (62.65 ± 6.4 years) of both sexes were allocated to the concurrent training group (CTG) or control group (CG). The CTG performed aerobic training (70-85% of reserve heart rate) combined with resistance training with elastic tubes (2sets × 15 repetitions) for 8 weeks. Resting blood pressure (BP), peak oxygen consumption (VO2peak), and right knee and elbow flexion strength were evaluated. RESULTS: A reduction of 6.37% was observed in BP and increases of 16.68% in VO2peak and 16% in muscle strength for right elbow flexion in the CTG compared to CG (p < .05). Intragroup comparisons showed reduction of 5% for BP, and increases of 6.79% for VO2peak, 24.79% for elbow flexion, and 16.47% for knee flexion in the CTG (p < .05), without significant improvement in the CG. CONCLUSION: CT promoted a reduction in BP, and increased cardiorespiratory fitness and muscular strength of the upper limbs in the hypertensive older adults.

Human factors related to the use of a personal computer: A case study.

The aim of this study was to determine and compare the ergonomic requirements in the use of desktop computers and laptops. For comparison, postures in the sagittal and transversal planes involved while performing a typing and editing task on a desktop and laptop computers were verified. Thus, a case study was conducted with a Brazilian male of medium height, who works around 20 hours per week in a computer. Nine spherical markers of 2.5 cm in diameter were joined up with duct tape on the right side of the participant and the positions adopted by the subject were analyzed in the use of a desktop and a laptop computer, through direct observation and filming, using the videography technique. It is concluded that the use of desktop computers has lesser biomechanical demands since it showed angles closer to a neutral position and consequently having a lower risk of musculoskeletal complaints.

Development of a Mobile Phone App for Measuring Striking Response Time in Combat Sports: Cross-Sectional Validation Study.

BACKGROUND: TReaction is a mobile app developed to determine strike response time at low cost and with easy application in combat sports. However, the validity and accuracy of the response time obtained by the TReaction app has not yet been evaluated. OBJECTIVE: This study aimed to test the validity and reliability of the TReaction app in measuring motor response time in combat sports. METHODS: A total of two athletes performed 59 strikes to assess the response time upon visual stimulus using the TReaction app simultaneously with a high-speed camera. Accuracy of the measure was verified using a computer simulator programmed to discharge visual stimuli and obtain the response time. Pearson correlation, Student t test for dependent samples, and the Bland-Altman analysis were performed. Accuracy was verified using the intraclass correlation coefficient. Effect size (g) and the typical error of measurement (TEM) were calculated. The significance level was set at P<.05. RESULTS: No significant difference (P=.56) was found between both systems. The methods presented a very strong correlation (r=0.993). The magnitude of differences was trivial (g<0.25), and TEM was 1.4%. These findings indicate a high accuracy between the computer screen and the mobile app measures to determine the beginning of the task and the response time. CONCLUSIONS: Our findings suggest that the TReaction app is a valid tool to evaluate the response time in combat sports athletes.

Aquatic exercise and Far Infrared (FIR) modulates pain and blood cytokines in fibromyalgia patients: A double-blind, randomized, placebo-controlled pilot study.

Fibromyalgia (FM) has an inflammatory component, as elevated serum levels of inflammatory biomarkers are associated with its diagnosis. Treatments decreased pain, body temperature, improved quality of life and reduced serum levels of IL-6 in both groups; however, these beneficial effects were more pronounced in aquatic exercise (AE) + Far-Infrared (FIR) group. The findings of the present study suggest that the association of AE to FIR increases the benefits of aquatic exercise in patients with FM.

Association between perception of bodily discomfort and individual and work organisational factors in Brazilian slaughterhouse workers: a cross-sectional study.

OBJECTIVE: Brazil is the world's second largest poultry meat producer and leading exporter. Many poultry processing tasks are physically demanding and involve factors that increase the risk of developing a work-related musculoskeletal disorder (WMSD). However, little is known about the assessment of bodily discomfort in these workers. The aim of this study was to evaluate the association between perception of bodily discomfort and individual and work organisational factors in poultry slaughterhouse workers. DESIGN: Descriptive, cross-sectional study. SETTING: Three poultry slaughterhouses in the South of Brazil. PARTICIPANTS: This paper included 925 workers of 3 poultry slaughterhouses, 575 women and 350 men. The selection of the participants was random. MAIN OUTCOME MEASURE: Workers were asked about individual factors, work organiation, perception of bodily discomfort and cold, as well as ingestion of pain medication. Crude and adjusted ORs were estimated and 95% CIs were derived from binary logistic regression analysis for perception of bodily discomfort. RESULTS: There was a significant association (p<0.05) between perception of bodily discomfort and female gender (OR=1.77; 95% CI 1.30 to 2.41), performance of repetitive tasks (OR=1.81; 95% CI 1.12 to 2.91) and perception of cold (OR=2.05; 95% CI 1.44 to 2.91). CONCLUSIONS: The findings of this research demonstrated that the sector of occupational safety and health management in poultry slaughterhouses should monitor the symptoms of WMSD among their workers, especially female workers, workers who perform repetitive tasks, as well as those who perform tasks in cold environments because these groups are more likely to experience bodily discomfort.

Psychometric properties of a medium version of the Copenhagen Psychosocial Questionnaire (COPSOQ II) for southern Brazil.

BACKGROUND: The emerging frequency of Behavioural Mental Health Disorders among Brazilian workers and the recent legal demand for analysis of psychosocial risks in the workplace highlight the importance of standardizing measures to assess these risks as a way to allow identification and proper comparison among different populations. OBJECTIVE: To assess the psychometric properties of the COPSOQ II questionnaire medium version for southern Brazil, based on the Spanish medium-length version of COPSOQ-ISTAS21 II. METHODS: A sample of 426 workers from a university in southern Brazil answered the model under study online. Content validity and internal consistency were analyzed through Confirmatory Factor Analysis (AFC) and Exploratory Factor Analysis (AFE) and Cronbach's α coefficient. RESULTS: The study model presented a response rate of 48.46%. The analyses indicated the possibility of the instrument to present reliability and validity of content. From the AFE, the final model consisted of 13 dimensions and 70 items, and presented a Cronbach's alpha of 0.82, which is considered a good internal consistency. CONCLUSIONS: The results showed that the final model of this study presents acceptable levels of reliability and internal validity for the application in Brazil, along with the groups of workers that resemble the participants of the research, to assess psychosocial risks in the workplace.

Effect of job rotation on the risk of developing Ul-WMSDS in poultry slaughterhouse workers

This study analyzed the effect of job rotation on the risk of developing UL-WMSDs in a poultry slaughterhouse with 1,200 workers. Three organizational settings were evaluated (“without job rotation”, “with job rotation - tasks >1h” and “with job rotation - tasks <1h”) using the OCRA Checklist method and the fulfillment of requirements for the implementation of rotations established by the Brazilian Regulatory Standard NR-36. The OCRA score of the right upper limbs (16.5±5.7) were significantly higher (p<0.001) relative to the left upper limbs (15.0±5.6). The average scores on all three organizational conditions presented moderate risk. There was a significant difference between the scores of the conditions “without job rotation” and “with job rotation - tasks <1h” (p=0.011), as well as “without job rotation” and “with job rotation - tasks >1h” (p<0.001). Thus, the results of the risk using the OCRA Checklist method showed the inefficiency of the realization of rotations >1h and <1h compared to not carrying out job rotation for the reduction of the UL-WMSDs risk. In relation to NR-36 requirements, it was found that alternating sitting and standing posture, postural requirements reduction and monotony were met by most sectors. Finally, it was difficult implementing efficient rotations due to particularities of work in the slaughterhouses such as: tasks with similar musculoskeletal requirements, pace imposed by machines, inability to perform rotations between different sectors (health and occupational constraints), the predominance of tasks with moderate and high risks, hindering the distribution of risks between the tasks of the rotation.(AU)

Effect of job rotation on the risk of developing Ul-WMSDS in poultry slaughterhouse workers

This study analyzed the effect of job rotation on the risk of developing UL-WMSDs in a poultry slaughterhouse with 1,200 workers. Three organizational settings were evaluated (“without job rotation”, “with job rotation - tasks >1h” and “with job rotation - tasks 1h” (p1h and <1h compared to not carrying out job rotation for the reduction of the UL-WMSDs risk. In relation to NR-36 requirements, it was found that alternating sitting and standing posture, postural requirements reduction and monotony were met by most sectors. Finally, it was difficult implementing efficient rotations due to particularities of work in the slaughterhouses such as: tasks with similar musculoskeletal requirements, pace imposed by machines, inability to perform rotations between different sectors (health and occupational constraints), the predominance of tasks with moderate and high risks, hindering the distribution of risks between the tasks of the rotation.