A Novel IMU-Based System for Work-Related Musculoskeletal Disorders Risk Assessment.

This study introduces a novel wearable Inertial Measurement Unit (IMU)-based system for an objective and comprehensive assessment of Work-Related Musculoskeletal Disorders (WMSDs), thus enhancing workplace safety. The system integrates wearable technology with a user-friendly interface, providing magnetometer-free orientation estimation, joint angle measurements, and WMSDs risk evaluation. Tested in a cable manufacturing facility, the system was evaluated with ten female employees. The evaluation involved work cycle identification, inter-subject comparisons, and benchmarking against standard WMSD risk assessments like RULA, REBA, Strain Index, and Rodgers Muscle Fatigue Analysis. The evaluation demonstrated uniform joint patterns across participants (ICC=0.72±0.23) and revealed a higher occurrence of postures warranting further investigation, which is not easily detected by traditional methods such as RULA. The experimental results showed that the proposed system's risk assessments closely aligned with the established methods and enabled detailed and targeted risk assessments, pinpointing specific bodily areas for immediate ergonomic interventions. This approach not only enhances the detection of ergonomic risks but also supports the development of personalized intervention strategies, addressing common workplace issues such as tendinitis, low back pain, and carpal tunnel syndrome. The outcomes highlight the system's sensitivity and specificity in identifying ergonomic hazards. Future efforts should focus on broader validation and exploring the relative influence of various WMSDs risk factors to refine risk assessment and intervention strategies for improved applicability in occupational health.

Quantitative Assessment of Surgical Ergonomics in Otolaryngology.

OBJECTIVES: Objective evaluation of the ergonomic risk of common otolaryngology procedures and assessment of work-related musculoskeletal pain and injury. STUDY DESIGN: Cross-sectional intraoperative assessment and survey. SETTING: Department of Otolaryngology at a tertiary children's hospital. SUBJECTS AND METHODS: Sixteen otolaryngology attendings, fellows, and residents participated in a blinded study. Intraoperative ergonomics was assessed for tonsillectomies, adenoidectomies, and tympanostomy tube insertions using the Rapid Upper Limb Assessment (RULA). Follow-up surveys were sent to all participating surgeons to determine the prevalence of musculoskeletal pain and formal ergonomic training. RESULTS: Zero percent (N = 0/275) of intraoperative observations were found to have a negligible level of ergonomic risk, with 47% low risk, 37% high risk, and 16% very high risk. Tympanostomy tube insertions conferred less risk than tonsillectomy and adenoidectomy, while the use of headlamp or loupes conferred increased risk. Eighty percent of respondents reported having musculoskeletal pain and 40% reported experiencing pain while operating within the past year. The most common area of pain was the cervical spine. No surgeons reported formal ergonomic training. CONCLUSIONS: Our study demonstrates an unacceptable level of ergonomic risk for common procedures in otolaryngology. Furthermore, most participants reported experiencing musculoskeletal pain despite the duration of examined procedures being relatively short. The high prevalence of work-related musculoskeletal pain and the lack of ergonomic training in our cohort highlight the need for increased awareness of ergonomics as well as the development of formal ergonomic curricula.

An empirical comparison of OWAS, RULA and REBA based on self-reported discomfort.

This study aimed to compare three observational techniques, the Ovako working posture analysis system (OWAS), rapid upper limb assessment (RULA) and rapid entire body assessment (REBA), based on whole-body discomfort. Fifteen college students participated in the experiment measuring discomfort. Hand height, hand distance and external load were used as independent variables. The results showed that while just the two independent variables of hand height and distance significantly affected the OWAS action category, all three independent variables including external load were significant for the discomfort, RULA grand and REBA scores. The grand score was more linearly correlated to discomfort, compared to the OWAS action category and REBA score. RULA generally assessed postural loads for the postures tested more highly than OWAS and REBA. Based on these findings, it was concluded that, of the three methods, RULA may be the best for estimating postural stress under the conditions of this study.

The Effect of Pulmonary Function on the Incidence of Vocal Fatigue Among Teachers.

INTRODUCTION: Females face a significantly higher risk of presenting with voice problems than males. This discrepancy has been associated with a number of differences in respiratory behavior and the physiology of the laryngeal and endocrine systems. METHODS: In conjunction with established spirometry measures, the Vocal Fatigue Index (VFI) was used to determine (1) if there is a relationship between base pulmonary function and vocal fatigue among teachers; and (2) if that relationship is different in females from males. One hundred and twenty-two elementary and middle school teachers (96 females and 26 males) from the Jordan School District in Northern Utah participated in the study. RESULTS: VFI factors were predictors of the outcomes of several raw spirometry measures for female participants, but the same predictive relationship was not found for male participants. Additionally, there appeared to be no relationship between VFI and spirometry measures in females when using normalized, rather than raw, spirometry metrics. CONCLUSIONS: The results suggest that the pulmonary physiology that would result in reduced raw pulmonary function, in combination with other differences associated with gender, may lead to a greater incidence of vocal fatigue among female teachers than their male counterparts.

Health risk assessment on musculoskeletal disorders among potato-chip processing workers.

Musculoskeletal disorders (MSDs) are the most common complaint among industrial workers. The potato-chip processing industry involves workers in repetitive activities leading to MSDs. This cross-sectional descriptive study aimed to assess MSDs health risk among potato-chip processing workers. It was conducted among 107 randomly sampled workers from a distribution like other groups exposed to similar ergonomics factors. A MSDs health-risk assessment produced a matrix of combined results based on a self-report questionnaire (5 levels) and an ergonomics risk assessment using RULA (4 levels). The self-reported MSDs questionnaire showed that workers had moderate to very high discomfort levels, i.e., 11.21% trunk, 9.35% lower limbs, 8.41% upper limbs and 4.66% for the neck. Ergonomic risks were found to be at a very high level, 77.57%, and high risk level, 19.63%. The combined matrix assessments showed that most workers were at moderate to very high MSDs risk, i.e., 43.92% trunk, 36.45% upper limbs, 32.71% lower limbs and 20.56% for the neck. This health risk matrix found a higher proportion of workers presenting with MSDs health risk compared with the musculoskeletal disorders self-assessment alone. Therefore, the MSDs risk matrix assessment could be useful for surveillance screening prior to implementing a risk-reduction program. Further, using ergonomics training programs and improving work stations for high-risk groups are also recommended based on the ergonomic and health risk assessments in this study.

Determinants of international variation in the prevalence of disabling wrist and hand pain.

BACKGROUND: Previous research has indicated that wide international variation in the prevalence of disabling low back pain among working populations is largely driven by factors predisposing to musculoskeletal pain more generally. This paper explores whether the same applies to disabling wrist/hand pain (WHP). METHODS: Using data from the Cultural and Psychosocial Influences on Disability (CUPID) study, we focused on workers from 45 occupational groups (office workers, nurses and other workers) in 18 countries. Among 11,740 participants who completed a baseline questionnaire about musculoskeletal pain and potential risk factors, 9082 (77%) answered a further questionnaire after a mean interval of 14 months, including 1373 (15%) who reported disabling WHP in the month before follow-up. Poisson regression was used to assess associations of this outcome with baseline risk factors, including the number of anatomical sites other than wrist/hand that had been painful in the 12 months before baseline (taken as an index of general propensity to pain). RESULTS: After allowance for other risk factors, the strongest associations were with general pain propensity (prevalence rate ratio for an index ≥6 vs. 0: 3.6, 95% confidence interval 2.9-4.4), and risk rose progressively as the index increased. The population attributable fraction for a pain propensity index > 0 was 49.4%. The prevalence of disabling WHP by occupational group ranged from 0.3 to 36.2%, and correlated strongly with mean pain propensity index (correlation coefficient 0.86). CONCLUSION: Strategies to prevent disability from WHP among working populations should explore ways of reducing general propensity to pain, as well as improving the ergonomics of occupational tasks.

Assessment of pulmonary function among cleaners in governmental hospitals in Addis Ababa, Ethiopia; comparative cross-sectional study.

OBJECTIVE: Work-related disorders are the major causes of different diseases in working populations. Respiratory disorders are among the most common occupational diseases. The alterations of the pulmonary function of professional cleaners in hospitals have not been addressed previously in Ethiopia. The aim of this study was to assess the pulmonary functions of cleaners working in the hospital setting in Addis Ababa, Ethiopia. A comparative cross-sectional study design was employed. The study was composed of 70 cleaners and 70 control subjects. Spirometer was used to measure pulmonary function. The data were coded, entered and analyzed using SPSS version 20. RESULTS: The mean and standard deviation of both actual value and percent predicted for forced vital capacity, forced expiratory volume in 1 s, percent ratio of forced vital capacity and forced expiratory volume in 1 s, peak expiratory flow rate and forced expiratory flow between 25 and 75% of cleaners were found to be significantly lower than the control group. Among cleaners 24.3% (n = 17) and controls 8.6% (n = 6) had shown obstructive lung disease, and among cleaners 22.9% (n = 16) and controls 4.3% (n = 3) had shown restrictive pattern.

Worker heat stress prevention and work metabolism estimation: comparing two assessment methods of the heart rate thermal component.

The heart rate thermal component ( ΔHRT ) can increase with body heat accumulation and lead to work metabolism (WM) overestimation. We used two methods (VOGT and KAMP) to assess ΔHRT of 35 forest workers throughout their work shifts, then compared ΔHRT at work and at rest using limits of agreement (LoA). Next, for a subsample of 20 forest workers, we produced corrected WM estimates from ΔHRT and compared them to measured WM. Although both methods produced significantly different ΔHRT time-related profiles, they yielded comparable average thermal cardiac reactivity (VOGT: 24.8 bpm °C-1; KAMP: 24.5 bpm °C-1), average ΔHRT (LoA: 0.7 ± 11.2 bpm) and average WM estimates (LoA: 0.2 ± 3.4 ml O2 kg-1min-1 for VOGT, and 0.0 ± 5.4 ml O2 kg-1min-1 for KAMP). Both methods are suitable to assess heat stress through ΔHRT and improve WM estimation. Practitioner summary: We compared two methods for assessing the heart rate thermal component ( ΔHRT ), which is needed to produce a corrected HR profile for estimating work metabolism (WM). Both methods yielded similar ΔHRT estimates that allowed accurate estimations of heat stress and WM at the group level, but they were imprecise at the individual level. Abbreviations: AIC: akaike information criterion; bpm: beats per minute; CI: confidence intervals; CV: coefficient of variation in %; CV drift: cardiovascular drift; ΔHRT: the heart rate thermal component in bpm; ΔHRT: the heart rate thermal component in bpm; ΔΔHRT: variation in the heart rate thermal component in bpm; ΔTC: variation in core body temperature in °C; HR: heart rate in bpm; HRmax: maximal heart rate in bpm; Icl: cloting insulation in clo; KAMP: Kampmann et al. (2001) method to determe ΔHRT; LoA: Limits of Agreement; PMV-PPD: the Predicted Mean Vote and Predicted Percentage Dissatisfied; PHS: Predicted Heat Strain model; RCM: random coefficients model; SD: standard deviation; TC: core body temperature in °C; TCR: thermal cardiac reactivity in bpm °C-1; τΔHRT: rate of change in the heart rate thermal component in bpm min-1; τTC: rate of change in core body temperature in °C min-1; tα,n-1: Student's t statistic with level of confidence alpha and n-1 degrees of freedom; TWL: Thermal Work Limit model; V̇O2 : oxygen consumption in ml O2 kg-1 min-1; V̇O2 max: maximal oxygen consumption in ml O2 kg-1 min-1; VOGT: Vogt et al. (1973) method to determine ΔHRT; WBGT: Wet-Bulb Globe Temperature in °C; WM: work metabolism.

Assessment of manual dysfunction in occupationally active women with carpal tunnel syndrome.

OBJECTIVES: The aim of this study is to evaluate 2-point discrimination sense (2PD), strength and kinesthetic differentiation of strength (KDS), range of motion (ROM) and kinesthetic differentiation of movement (KDM) dysfunctions in occupationally active women with mild and moderate forms of carpal tunnel syndrome (CTS) compared to a healthy group. MATERIAL AND METHODS: The 2PD sense, muscle strength and KDS, as well as the ROM and KDM of the radiocarpal articulation were assessed. RESULTS: The results of the 2PD sense assessment showed significantly higher values in all the examined fingers in the CTS women group compared to healthy women (p < 0.01). There was a significant difference in the percentage value of error in the strength and KDS of pincer and cylindrical grips (p < 0.01) in the CTS women group compared to healthy women. There was no difference in the ROM of flexion and extension between studied groups (p > 0.05). There was a significant difference in the percentage value of error in the KDM of flexion and extension movement of the radiocarpal articulation (p < 0.01) between the studied groups. CONCLUSIONS: There are significant differences in the 2PD sense, KDS and KDM in occupationally active women with mild and moderate forms of CTS compared to healthy women. There are no significant differences in ROM in professionally active women with mild and moderate forms of CTS compared to healthy women. Int J Occup Med Environ Health. 2019;32(2):185-96.

Relation Between Musculoskeletal Pain and Voice Self-Assessment in Tele-Operators.

OBJECTIVES: To investigate musculoskeletal pain, vocal fatigue, and voice-related quality of life of tele-operators and compare these aspects with nonvoice-related professionals; and verify if there is a relationship between musculoskeletal pain and vocal fatigue and voice-related quality of life (V-RQOL) of tele-operators and nonvoice-related professionals. METHODS: Thirty-five tele-operators (SG) and 35 nonvoice-related professionals with no vocal complaints (control group) participated in the study. All of them answered investigating questionnaires of musculoskeletal pain, vocal fatigue index, and V-RQOL. The data were statistically analyzed in aim to compare the groups and the association between variables. RESULTS: Women from SG presented higher pain frequency in their upper back than women from control group (P = 0.039). Different correlations were observed between musculoskeletal pain and vocal fatigue, just as between musculoskeletal pain and V-RQOLindex, for men and women in both groups. However, men presented a higher number or correlations between the protocols than women from both groups. CONCLUSION: Female tele-operators presented higher pain frequency on their upper back when compared to nonvoice-related professional women. Musculoskeletal pain has a negative impact on voice-related quality of life and on the increase of vocal fatigue during oral communication, regardless of the professional use of the voice.

Assessment of Respiratory Symptoms and Pulmonary Function Status among Workers of Flour Mills in Addis Ababa, Ethiopia: Comparative Cross-Sectional Study.

BACKGROUND: Flour dust in the respiratory tract affects lung function. Flour dust is a heterogeneous organic substance which can have a tendency to cause respiratory ailments. There is growing consensus on the deleterious effects of flour dust on respiratory symptoms and lung performance of flour mill workers. METHODS: The study design was comparative cross-sectional. A total of 54 flour mill workers who work for more than eight-hour shift per day and 54 control subjects matched for sex, age, weight, height, and area of residence were enrolled. Anthropometric measurement was done. Lung function was measured by using a digital portable spirometer (Spiro Pro) based on the ATS guidelines. FVC, FEV1, FEV1/FVC, PEFR, and FEF25%  -75% were measured. Productive cough, dry cough, wheeze, and breathlessness were evaluated using BMRC questionnaire guidelines, administered through face-to-face interview. RESULT: This study showed statistically significant reduction in the mean values of pulmonary function tests in flour mill workers as compared to their matched controls. Reduction of pulmonary function indices in study subjects was significant for FVC (4.25±0.93 vs. 5.30±0.71, p<0.001), FEV1 (3.46±0.86 vs. 4.50±0.72, p<0.001), PEFR (5.43±2.43 vs. 7.87±2.53, p<0.001), and FEF25%  -75%, (3.87±1.61 vs. 4.60±1.60, p<0.05), but not significant for FEV1/FVC (81.93±12.74 vs. 83.40±12.50, p>0.05). Flour mill workers developed 27.7% of restrictive type and 11.1% of obstructive type of lung disorders. Percentage prevalence of respiratory symptoms was evaluated as dry cough (27.7% vs. 9.3%), productive cough (11.1% vs. 5.6%), wheeze (14.8% vs. 3.8%), and breathlessness (16.6% vs.7.4%) in flour mill workers and controls, respectively. CONCLUSION: Based on the results of the present study, occupational exposure to flour dust could cause respiratory dysfunction, thereby reducing lung efficiency.

An Upper Extremity Risk Assessment Tool Based on Material Fatigue Failure Theory: The Distal Upper Extremity Tool (DUET).

OBJECTIVE: Musculoskeletal tissues repeatedly loaded in vitro fail in accordance with material fatigue failure theory, and there is evidence to suggest that the same process occurs in vivo. The current paper presents a new upper extremity risk assessment tool, the Distal Upper Extremity Tool (DUET), predicated on material fatigue failure theory. METHODS: DUET requires an estimate of force exertion level and the number of repetitions performed to derive estimates of damage and probabilities of experiencing a distal upper extremity outcome. Damage accrued over multiple tasks may be summed to estimate the cumulative damage (CD) accrued over a workday. Validation of this tool was performed using five distal upper extremity (DUE) outcomes (involving medical visits and pain) from an existing epidemiological database involving data from six automotive manufacturing plants. Logistic regression was used to assess the association of the log of the DUET CD measure to DUE outcomes. RESULTS: Results demonstrated that the log of the DUET CD measure was highly associated with all five DUE outcomes in both crude analyses and those adjusted for site, age, gender, and body mass index ( p < .01). A model relating the continuous DUET log CD score to the probability of the DUE outcome Injury + Pain Last Year was developed, which demonstrated a significant dose-response relationship. CONCLUSIONS: Results suggest that fatigue failure-based risk assessment techniques are highly associated with DUE outcomes and provide support for the notion that an underlying fatigue failure process may be involved in the development of upper extremity musculoskeletal disorders.

Improving work for the body - a participatory ergonomic intervention aiming at reducing physical exertion and musculoskeletal pain among childcare workers (the TOY-project): study protocol for a wait-list cluster-randomized controlled trial.

BACKGROUND: The prevalence of musculoskeletal pain (MSP) is persistently high throughout the world. Work-related factors such as high physical workload (lifting, bending and twisting of the back) are considered to be among the main causes of MSP. Work in childcare includes the need to lift, carry, and support children in a range of activities, requiring several demanding postures and movements, such as bending forward and twisting of the back and sitting on the floor. Participatory ergonomics may represent a solution for decreasing the physical workload to reduce MSP. We present the protocol of a study aiming to evaluate the effect and process of a participatory ergonomics intervention designed to reduce physical exertion during work and MSP (including MSP interfering with work) among childcare workers. METHODS/DESIGN: This study will use a two-arm cluster-randomized design employing a wait-list control, with childcare institutions forming the clusters. Three workshops will be conducted during the 4-month intervention period. Participants will identify risk factors for strenuous work and MSP, develop solutions for reducing the identified risk factors, and implement them in their team. An ergonomic consultant will guide the process. The data collection will consist of questionnaires and objective measures of heart rate and physical activity, observations of physical workload, and information on sickness absence based on company records. Primary outcomes are physical exertion during work and MSP (including pain-related work interference) measured at 4 months. Secondary outcomes measured at 4 months are sickness absence due to MSP; objectively measured occupational physical activity and heart rate; and self-reported self-efficacy, employee involvement, and need for recovery. Alongside the trial, a process evaluation and an economic evaluation will be conducted. DISCUSSION: The study will evaluate the effect and process of a participatory ergonomics intervention to reduce physical exertion at work and MSP among childcare workers. By performing a cluster-randomized controlled trial with an effect evaluation based on both objective and self-reported measures with the addition of a process evaluation and economic evaluation, this study will contribute to the evidence for prevention of MSP among a less studied occupational group. Results are expected in 2018-2019. TRIAL REGISTRATION: ISRCTN, ISRCTN10928313 . Registered on 11 January 2017.

Equivalence Testing as a Tool for Fatigue Risk Management in Aviation.

BACKGROUND: Many civilian aviation regulators favor evidence-based strategies that go beyond hours-of-service approaches for managing fatigue risk. Several countries now allow operations to be flown outside of flight and duty hour limitations, provided airlines demonstrate an alternative method of compliance that yields safety levels "at least equivalent to" the prescriptive regulations. Here we discuss equivalence testing in occupational fatigue risk management. We present suggested ratios/margins of practical equivalence when comparing operations inside and outside of prescriptive regulations for two common aviation safety performance indicators: total in-flight sleep duration and psychomotor vigilance task reaction speed. Suggested levels of practical equivalence, based on expertise coupled with evidence from field and laboratory studies, are ≤ 30 min in-flight sleep and ± 15% of reference response speed. METHODS: Equivalence testing is illustrated in analyses of a within-subjects field study during an out-and-back long-range trip. During both sectors of their trip, 41 pilots were monitored via actigraphy, sleep diary, and top of descent psychomotor vigilance task. Pilots were assigned to take rest breaks in a standard lie-flat bunk on one sector and in a bunk tapered 9 from hip to foot on the other sector. RESULTS: Total in-flight sleep duration (134 ± 53 vs. 135 ± 55 min) and mean reaction speed at top of descent (3.94 ± 0.58 vs. 3.77 ± 0.58) were equivalent after rest in the full vs. tapered bunk. DISCUSSION: Equivalence testing is a complimentary statistical approach to difference testing when comparing levels of fatigue and performance in occupational settings and can be applied in transportation policy decision making.Wu LJ, Gander PH, van den Berg M, Signal TL. Equivalence testing as a tool for fatigue risk management in aviation. Aerosp Med Hum Perform. 2018; 89(4):383-388.

Assessment of gesture behavior and knowledge on low back pain among nurses.

BACKGROUND: Low back pain is particularly problematic among nursing professionals. Education is part of the rehabilitation process for low back pain and has been heavily studied. In parallel, gestural behaviors play an important role during the evaluation of the low back pain, especially while performing the activities of daily living. The aim of the present study was to evaluate gesture behavior and knowledge on LBP among nurses with and without LBP and correlate these factors with pain, physical functioning and quality of life. METHODS: An observational, controlled, cross-sectional study was carried out in 120 female nurses: 60 with LBP and 60 without LBP. The two groups were matched for age. The measures used for the evaluation were the Gesture Behavior Test, LBP Knowledge Questionnaire, Numerical Pain Scale for LBP, Roland Morris Disability Questionnaire and the Short Form-36 (SF-36) to assess quality of life. RESULTS: Mean age in both groups was 31 years. In the group with LBP, the mean Numerical Pain Scale score was 5.6 cm and the mean score on the Roland Morris questionnaire was 2.7. No statistically differences between groups were found regarding the scores of the LBP Knowledge Questionnaire or Gesture Behavior Test (p = 0.531 and p = 0.292, respectively). Statistically lower scores were found in the group with LBP for the following SF-36 domains: physical functioning (p <  0.001), physical role (p = 0.015), pain (p = 0.001), general health perceptions (p = 0.015), vitality (p <  0.001) and mental health (p = 0.001). CONCLUSIONS: No differences were found when comparing nurses with or without LBP regarding gesture behavior or knowledge on LBP. Nurses with LBP showed a decrease in some domains of quality of life.

Voice Use Among Music Theory Teachers: A Voice Dosimetry and Self-Assessment Study.

OBJECTIVES: This study aimed (1) to investigate music theory teachers' professional and extra-professional vocal loading and background noise exposure, (2) to determine the correlation between vocal loading and background noise, and (3) to determine the correlation between vocal loading and self-evaluation data. METHODS: Using voice dosimetry, 13 music theory teachers were monitored for one workweek. The parameters analyzed were voice sound pressure level (SPL), fundamental frequency (F0), phonation time, vocal loading index (VLI), and noise SPL. Spearman correlation was used to correlate vocal loading parameters (voice SPL, F0, and phonation time) and noise SPL. Each day, the subjects self-assessed their voice using visual analog scales. VLI and self-evaluation data were correlated using Spearman correlation. RESULTS: Vocal loading parameters and noise SPL were significantly higher in the professional than in the extra-professional environment. Voice SPL, phonation time, and female subjects' F0 correlated positively with noise SPL. VLI correlated with self-assessed voice quality, vocal fatigue, and amount of singing and speaking voice produced. CONCLUSIONS: Teaching music theory is a profession with high vocal demands. More background noise is associated with increased vocal loading and may indirectly increase the risk for voice disorders. Correlations between VLI and self-assessments suggest that these teachers are well aware of their vocal demands and feel their effect on voice quality and vocal fatigue. Visual analog scales seem to represent a useful tool for subjective vocal loading assessment and associated symptoms in these professional voice users.

Assessment of shoulder and low back muscle activity of male kitchen workers using surface electromyography.

OBJECTIVES: This study aims to assess muscle fatigue for kitchen workers during various tasks in a kitchen. MATERIAL AND METHODS: This study consists of 2 phases: a) surface electromyography (EMG) to determine muscle fatigue of trapezius and erector spinae muscles bilaterally for 12 healthy male volunteers during 30 min of Indian flatbread (chapati) preparation, b) self-administered questionnaire study after 30 min preparation to determine the impact on performance. RESULTS: Surface EMG results show that the right trapezius muscle had significantly higher fatigue during kneading, rolling and roasting tasks. Similarly, right erector spinae muscle showed significantly higher fatigue during rolling and roasting tasks. CONCLUSIONS: Both phases of the study conclude that, even though the dynamic postural adjustment may reduce fatigue during the work schedule; the combination of risk factors like the repetitive task, forceful exertion and prolonged standing during working results in a high risk of developing muscle fatigue. Int J Occup Med Environ Health 2018;31(1):81-90.

Valoración mediante espirometría de mineros del carbón de Paipa, Colombia / Spirometry in a population of coal miners in Paipa, Colombia

RESUMEN Introducción: Las enfermedades respiratorias derivadas de la exposición a material en partículas, como sucede en la minería del carbón, continúa siendo un reto investigativo en el país y un problema de salud pública. La espirometría es una prueba de la función respiratoria, fundamental para el diagnóstico y la vigilancia de este tipo de enfermedades pulmonares crónicas. Objetivo. Determinar los valores de la espirometría en la población minera de carbón del municipio de Paipa, y su asociación con la edad y el tiempo de exposición laboral. Materiales y métodos. Se hizo un estudio descriptivo de corte transversal. Se diligenció el cuestionario de enfermedad respiratoria ocupacional de la American Thoracic Society (ATS), se registraron las mediciones de la espirometría y se interpretaron siguiendo las recomendaciones internacionales. Resultados. La muestra incluyó 226 trabajadores de minas de carbón de Paipa; en 12,3 % (n=28) de ellos se registraron alteraciones leves, de tipo obstructivo o restrictivo. En 35 % (n=80) hubo disminución de la relación entre la capacidad vital forzada y el volumen espirado en el primer segundo (CVF/VEF1 ). Se encontró una asociación estadísticamente significativa entre el rango de edad (p=0,002) y los años de trabajo minero (p=0,34), además de trastornos restrictivos y obstructivos. Asimismo, hubo una asociación estadísticamente significativa entre el rango de edad (p<0,01) y los años de trabajo minero (p<0,01), de diferente seriedad en el patrón de las mediciones de la espirometría. Conclusiones. La espirometría es una prueba útil para detectar la presencia de trastornos respiratorios en la población minera del carbón. La enfermedad respiratoria en estos mineros estuvo significativamente asociada con el tiempo de exposición.

ABSTRACT Introduction: Respiratory diseases resulting from exposure to particulate matter such as in coal mining remains a research challenge in this country and a public health issue. Spirometry is a basic test of fundamental respiratory function for the diagnosis and monitoring of these types of chronic lung diseases. Objective: To determine spirometric values in the coal mining municipality of Paipa and their association with age and occupational exposure times. Materials and methods: We conducted a descriptive cross-sectional study. The occupational respiratory disease questionnaire of the American Thoracic Society (ATS) was completed while spirometric measurements were performed and interpreted in accordance with international recommendations for conducting the test. Results: The sample consisted of 226 coal mining workers of the municipality of Paipa. Twenty-eight subjects (12.3%) of the sample showed patterns of obstructive and restrictive respiratory disease with mild degrees of severity. Eighty subjects (35%) showed a decrease in the forced vital capacity ratio/expiratory volume in one second (FVC/FEV1 ). A statistically significant association between age range (p=0.002) and years of mining work (p=0.34) with the development of restrictive and obstructive disorders was found. Also, there was a statistically significant association between age range (p<0.01) and years of mining work (p<0.01) with various degrees of severity of the spirometric pattern. Conclusions: Spirometry is a useful test for detecting the presence of respiratory disorders in the population of coal miners. The time of exposure was significantly associated with the respiratory disease exhibited by these miners.

[The comparative assessment of the vocal function in the professional voice users and non-occupational voice users in the late adulthood]. / Sravnitel'naia otsenka golosovoi funktsii u professionalov golosa pozhilogo vozrasta i lits negolosovykh professii.

The objective of the present study was to evaluate the clinical and functional condition of the voice apparatus in the elderly patients and to elaborate recommendations for the prevention of disturbances of the vocal function in the professional voice users. This comprehensive study involved 95 patients including the active professional voice users (n=48) and 45 non-occupational voice users at the age from 61 to 82 years with the employment history varying from 32 to 51 years. The study was designed to obtain the voice characteristics by means of the subjective auditory assessment, microlaryngoscopy, video laryngostroboscopy, determination of maximum phonation time (MPT), and computer-assisted acoustic analysis of the voice with the use of the MDVP Kay Pentaxy system. The level of anxiety of the patients was estimated based on the results of the HADS questionnaire study. It is concluded that the majority of the disturbances of the vocal function in the professional voice users have the functional nature. It is concluded that the method of neuro-muscular electrophonopedic stimulation (NMEPS) of laryngeal muscles is the method of choice for the diagnostics of the vocal function of the voice users in the late adulthood. It is recommended that the professional vocal load for such subjects should not exceed 12-14 hours per week. Rational psychotherapy must constitute an important component of the system of measures intended to support the working capacity of the voice users belonging to this age group.