An ergonomic intervention to reduce back strain among apple harvest workers in New York State

Effect of MSDs and scope of ergonomic interventions among rubber processing workers: a systematic review

BACKGROUND

The rubber processing workers experience various types of musculoskeletal disorders (MSDs) due to awkward postures, repetitive movements, and manual loads etc. Research on MSDs and ergonomic interventions in this area is limited. Therefore, the present systematic review aims to (i) identify various operations done by rubber processing workers and their associated MSDs, (ii) explore the ergonomic intervention and post-intervention study and its impact among the workers, (iii) identify the research gaps in MSDs and ergonomic interventions through bibliometric analysis.

METHODS

Comprehensive electronic searches were conducted in Web of Science, ScienceDirect and PubMed for the search term "Ergonomics" or "Musculoskeletal disorder" and "Rubber" for the article published before 2020. Eleven papers were identified for the review of MSDs and ergonomic interventions; data were extracted to summarize sample size, data collection methods, analyzing tools, various operations, MSDs, and ergonomic interventions.

RESULTS

The reviewed article is classified according to various operations such as rubber tapping, latex collection, rubber sheeting and sheet pressing. The review reveals that most of the workers experience lower back pain, which involved a traditional way of operating. Every author is trying to recommend some interventions, but post-intervention studies are limited.

CONCLUSIONS

Due to the limited post-intervention study, there is a scope of ergonomic interventions in every operation. So, the implementation of a proper ergonomic tool with adequate awareness improves the MSDs among the rubber processing workers. The review will help to identify the various intervention gaps in different operations associated with rubber farming.

Participatory Ergonomic Interventions for Improving Agricultural Work Environment: A Case Study in a Farming Organization of Korea

Farmers are often exposed to risk factors for musculoskeletal disorders through lifting, carrying heavy loads, and sustained or repeated full-body bending. Several relevant studies on ergonomic interventions have been conducted for specific agricultural tasks, such as harvesting and pruning, by experts without involving farmers. This study introduces ergonomic interventions to mitigate risk factors in a farming organization that cultivates peaches as the main crop based on ergonomic analysis of the entire peach farming cycle; subjective and objective evaluations of the proposed interventions are also performed. The ergonomic analysis and interventions were established based on consultations provided by an ergonomist, the government, and the organization members. Engineering controls were introduced for powered carts, sorters, and stools to reduce load carrying and awkward postures; moreover, thermal or cooling vests, winter shoes and gloves, and farmer hats were provided to alleviate cold or heat stresses. Administrative controls such as education/training and adjusting work–rest cycles were also recommended after considering the characteristics of the risk factors identified. The scores of the questionnaire survey from the organization members were high (>4.1 out of 5 for five questions), and postural loads for unstable postures by RULA were significantly reduced so as to avoid fast or immediate changes for the postures or working methods assessed. The study results are expected to help promote farmers’ health and enhance farming efficiency.

Ergonomic Task Analysis for Prioritization of Work-Related Musculoskeletal Disorders among Mango-Harvesting Farmers

This paper proposes a mixed ergonomic tool analysis algorithm to prioritize work-related musculoskeletal problems. This study is a cross-sectional study assessing the prevalence of work-related musculoskeletal disorders (WMSDs) with associated risk factors among 14 male mango-harvesting farmers (all right-handed) with the mean age of 52.28 ± 7.75 years. Four tasks following mango-harvesting processes were analyzed: (1) mango harvesting, (2) mango transporting, (3) mango size sorting, and (4) mango weighing and transporting to the truck. The perceived physical exertion while working on a mango-harvesting farm was based on the Borg CR-10 with a modified Standardized Nordic Questionnaire. Physical risk level due to awkward posture was evaluated by the Rapid Upper Limb Assessment (RULA), and risk due to whole-body posture in association with the level of WMSDs risk was evaluated by the Rapid Entire Body Assessment (REBA) score sheets. The subjective feelings of fatigue and posture analysis were normalized and combined using the theorem of power superposition to establish the fatigue effective index (FEI) for determining priorities to solve ergonomics-based task problems. This study indicated clearly that WMSDs are highly prevalent in mango-harvesting farmers, whereas the highest prevalence of WMSDs was reported in the right shoulder, right upper arm and lower back. The result provided the FEI of mango-harvesting farmers, ranked as follows: (1) size-sorting task, (2) weight-lifting task, (3) harvesting task, and (4) transporting task. The authors concluded that mango size sorting should be the first task to be improved to resolve the muscle fatigue problems among male mango-harvesting farmers.

Interventions for the prevention of musculoskeletal disorders in a seasonal work context: A scoping review

Seasonal work is characterized by difficult working conditions further influenced by organizational, physical, and time constraints which expose seasonal workers to high risks of MSDs. Our aim was to provide an overview of the recommendations and interventions carried out in a seasonal work context to prevent MSDs. To do this, we conducted a scoping review through a systematic electronic search of seven scientific databases and the websites of ergonomics and occupational health and safety organizations. After screening by independent reviewers according to specific criteria sets, we performed qualitative analyses on the 16 studies retained. Findings revealed six categories of transformation targets sought by the interventions/recommendations with the technical devices/physical work environment category being the most reported. We also found it was quite rare for studies to consider the seasonal work context in and of itself when developing and implementing interventions. Our review thus highlights the need to pay attention to intervention processes in order to better understand the influence of seasonality on the measures taken to prevent MSDs in working environments.

Occupational safety and health in traditional date palm works

OBJECTIVE

Date palm is mostly cultivated in Western Asia and North Africa and is the main wealth for the people of these regions. Traditional date palm crown access via manual climbing, as the main activity in date fruit production, suffers from occupational hazards. Mitigation of these problems through interventions or new designs initially needs to complete knowledge of safety and health aspects and relationships between them and characters of date palm climbers. This study provided detailed information about this concern.

METHODS

A questionnaire consisting of personal, operational, safety, satisfaction, financial and ergonomic demographics was used for data collection. 117 climbers participated in the study. Nonparametric correlations using Spearman's coefficient and logistic regressions investigated the linkage between characters obtained by the questionnaire.

RESULTS

The annual mortality rate of falls from height was calculated by 3.4 per one thousand men. Fall was a major challenge in traditional date palm crown access and its rate was highly greater in comparison with the estimation of International Labor Office (ILO) about fatal agricultural injuries. Safety and health condition was the main contributing factor in the status of date palm climbing and was significantly linked to job satisfaction. Safety risk-taking and non-awareness of technology had a significant linkage with together (r = - 0.195, p = 0.035). Safety risk-taking, also, had significant correlations with discomfort in back (r = - 0.201, p = 0.030). Regressions showed heavier climbers (> 75 kg) were expected about 4.3 (1/0.230) times than more lightweight ones to have an upper leg discomfort with high severity relative to low severity (p = 0.018).

CONCLUSION

Obesity, senescence, and awareness of technology as three personal characteristics of climbers need to be addressed. Future strategies are required to improve the safety condition of climbing and manage the workforces as well as governmental decision making to address the financial aspects of climbers for sustainable date production and reduction in reasons causing unemployment. Considering current status and modification of the present tool and equipment is recommended.

Comparisons of physical exposure between workers harvesting apples on mobile orchard platforms and ladders, part 1: Back and upper arm postures

This study compared farmworkers' exposure to non-neutral postures using a new mobile platform apple harvesting method and the traditional method using ladders. Twenty-four workers were recruited and assigned into three groups: ladder workers (n = 8) picking apples from full trees using a ladder, mobile platform workers (n = 8) picking apples from upper part of the trees while standing on a moving platform, and ground-based mobile platform workers (n = 8) picking apples from lower part of the trees which the mobile platform workers left out. Upper arm and back inclinations were continuously monitored during harvesting using tri-axial accelerometers over full work shifts (~8 h). Upper arm posture was characterized as the percentage of time that upper arm flexion and abduction exceeded 30°, 60°, and 90°. Back posture was characterized as the percentage of time that torso angles (sagittal flexion or lateral bending) exceeded 10°, 20°, and 30°. The 10th, 50th, and 90th postural percentiles were also calculated. The platform workers had lower exposures to upper arm flexion and abduction than the ground and ladder workers. There were no differences in torso angles between the ladder and mobile platform workers; however, the ground workers were exposed to more and greater percentages of time in torso flexions.

A feasibility study comparing objective and subjective field-based physical exposure measurements during apple harvesting with ladders and mobile platforms

Although mobile orchardplatforms have been developed to improve apple harvesting productivity in the US, the physical exposures of workers usingthe mobile platforms have not been well characterized, partlydue to the lack of assessment tools specific to the tree fruitorchard environment. The purpose of this study was to evaluate the feasibility and utility of different subjective and objective methods for characterizing apple harvesting workers' posture, armrepetition, heart rate, and perceived exertion during platform- and conventional ladder-based harvesting. During a regular full shiftwork (8 hours), the objective physical exposure measures (armelevation, torso inclination, and heart rate) of 6 platform, 6 ground, and 8 ladder workers were measured with tri-axial accelerometersand heart rate monitor; and subjective perceived exertion wascollected using standardized Borg RPE and CR-10 scales, translated into Spanish. The results showed that the arm elevation, torso forward bending, repetitiveness, heart rates, and perceived exertions were lower for the platform-based workers than forthe ladder-based workers. The subjective measures (Borg RPE and Borg CR-10) appeared to be similar and mirror the general trends of the objective heart rate and posture measures.These results indicate the potential benefit of these low-cost subjective measures when direct measurements are too costly,complicated, or not permitted. This study determined that field measurements of objective and subjective physical exposures were feasible for evaluating apple harvesting work. In summary, all themethods used appear to be feasible for field use in orchard-based environments..

Standing working posture and musculoskeletal pain among Citrus sinensis workers in a low-income country

Background. Work-related musculoskeletal pain (WRMP) among Citrus sinensis farm workers has barely been studied. Yet most work tasks in such farms are manually performed using awkward standing postures that can contribute to WRMP. Aim. This study assessed the standing working posture in relation to WRMP among C. sinensis workers. Methods. Ninety-two workers engaged in manual tasks participated in this cross-sectional study. Postures at the upper limbs were analysed using the rapid upper limb assessment (RULA) method. Data were analysed using SPSS version 20. Results. Analyses generally showed statistically significant associations (p < 0.05) between a body part RULA score and WRMP at the concerned body part. The upper arm score was >1 in 77.2% of the workers and caused upper arm pain in 66.3%; the association between the upper score and upper pain was statistically significant (χ ²= 20.57; p < 0.05). Similarly, significant associations were found between: (a) wrist score and wrist pain; (b) neck score and neck pain; (c) trunk score and back pain. Conclusions. C. sinensis workers use unsafe postures which contribute to WRMP at the upper arm, trunk, neck and wrists. Ergonomics measures are required to improve their working posture.

Agricultural stressors: identification, causes and perceived effects among Nigerian crop farmers

BACKGROUND

Many studies have focused on agricultural-related health hazards globally; however, little is known about agricultural stressors among crop farmers in the developing countries. This study identified agricultural stressors, their causes and ascribed effects among crop farmers in Nigeria.

METHODS

There were 70 crop farmers randomly selected in farming communities across Ekiti State, an agrarian State in South-Western, Nigeria. A structured questionnaire with interview was used for data collection. Data were analyzed using descriptive statistics.

RESULTS

Findings from the study showed that about 98% of the farmers were able to identify stressors that are occupational-related. About 80% of the respondents thought they had been mostly affected by agricultural stressors in a number of ways including inability to sleep regularly, relaxation problems, excessive tiredness, back problems, and intense headache. About 98% of these farmers are yet to develop structured means of coping with these stressors.

CONCLUSION

We concluded that agricultural stressors affect farmers' well-being. Efforts should be made at initiating a stress management campaign for Nigerian crop farmers. Government and development partners should assist farmers in their challenged areas, and there should be functional integration of mental health focused agricultural health in primary health care.

Building healthy construction workers: Their views on health, wellbeing and better workplace design

Construction is a heavy manual industry where working into later life can be a challenge. An interview study was conducted to explore workers' understanding of their health at work and ways of making their jobs easier, safer or more comfortable. Using purposive sampling, 80 trades' workers were selected from construction sites in the UK. The Nordic Musculoskeletal Questionnaire and Work Ability Index were used to explore aches and pains and reducing strain on the body. A high prevalence of symptoms was reported and ratings of work ability were high. Workers were aware of the physical demands of their work and had over 250 ideas around health and wellbeing e.g. rucksacks for tools, bespoke benches, adapting PPE, and higher cost solutions e.g. mechanical lifting aids. Engagement of the workforce should be encouraged and feed into change processes in the industry to enable all workers stay fit for work for longer.

Hired crop worker injuries on farms in the United States: A comparison of two survey periods from the National Agricultural Workers Survey

BACKGROUND

Hired crop workers in the United States are at high risk of occupational injury. Targeted surveillance is important for effective occupational safety efforts.

METHODS

The National Agricultural Workers Survey was utilized to collect injury data during the years 1999, 2002-2004 (period I) and 2008-2010 (period II).

RESULTS

The overall injury rate declined between the two periods from 4.3 to 2.9/100 per full-time week-based equivalents (FTEWB ). Injury rates remained high during both periods for those with greater than 20 years farm experience (3.6 and 3.8/100 FTEWB ) and pesticide handling work (4.9 and 5.0/100 FTEWB ). Overexertion, contact with objects and equipment, and falls from height were common during both periods. Older workers comprised a greater proportion of injury cases in period II.

CONCLUSION

Overexertion that leads to sprains/strains, dangerous ladder use, and pesticide use should be targeted as important risk exposures on the farm.

An integrated biomechanical modeling approach to the ergonomic evaluation of drywall installation

Three different methodologies: work sampling, computer simulation and biomechanical modeling, were integrated to study the physical demands of drywall installation. PATH (Posture, Activity, Tools, and Handling), a work-sampling based method, was used to quantify the percent of time that the drywall installers were conducting different activities with different body segment (trunk, arm, and leg) postures. Utilizing Monte-Carlo simulation to convert the categorical PATH data into continuous variables as inputs for the biomechanical models, the required muscle contraction forces and joint reaction forces at the low back (L4/L5) and shoulder (glenohumeral and sternoclavicular joints) were estimated for a typical eight-hour workday. To demonstrate the robustness of this modeling approach, a sensitivity analysis was conducted to examine the impact of some quantitative assumptions that have been made to facilitate the modeling approach. The results indicated that the modeling approach seemed to be the most sensitive to both the distribution of work cycles for a typical eight-hour workday and the distribution and values of Euler angles that are used to determine the "shoulder rhythm." Other assumptions including the distribution of trunk postures did not appear to have a significant impact on the model outputs. It was concluded that the integrated approach might provide an applicable examination of physical loads during the non-routine construction work, especially for those operations/tasks that have certain patterns/sequences for the workers to follow.

Health disparities of Latino immigrant workers in the United States

Purpose

– The purpose of this paper is to provide an overview of the literature pertaining to occupational health disparities experienced by Latino immigrant workers in the USA and to advance a general framework based on systems science to inform epidemiological and intervention research.

Design/methodology/approach

– Using papers and other sources from 2000 to the present, the authors examined the employment conditions and health outcomes of Latino immigrant workers and critically analyzed the pervasive evidence of health disparities, including causal mechanisms and associated intervention programs.

Findings

– The occupations, including the work environment and resultant living conditions, frequently performed by Latino immigrants in the USA represent a distinct trigger of increased injury risk and poor health outcomes. Extant intervention programs have had modest results at best and are in need of more comprehensive approaches to address the complex nature of health disparities.

Practical implications

– An integrated, systems-based framework concerning occupational health disparities among Latino immigrant workers allows for a holistic approach encompassing innovative methods and can inform high-leverage interventions including public policy.

Originality/value

– Reductionist approaches to health disparities have had significant limitations and miss the complete picture of the many influences. The framework the authors have provided elucidates a valuable method for reducing occupational health disparities among Latino immigrant workers as well as other populations.

Relationships between job organisational factors, biomechanical and psychosocial exposures

The relationships between work organisational, biomechanical and psychosocial factors were studied using cross-sectional data from a pooled dataset of 1834 participants. The work organisational factors included: job rotation, overtime work, having second jobs and work pace. Task and job level biomechanical variables were obtained through sub-task data collected in the field or analysed in the laboratory. Psychosocial variables were collected based on responses to 10 questions. The results showed that job rotations had significant effects on all biomechanical and most psychosocial measures. Those with job rotations generally had higher job biomechanical stressors, and lower job satisfaction. Overtime work was associated with higher job biomechanical stressors, and possibly self-reported physical exhaustion. Those having second jobs reported getting along with co-workers well. Work pace had significant influences on all biomechanical stressors, but its impact on job biomechanical stressors and psychosocial effects are complicated.

PRACTITIONER SUMMARY

The findings are based on a large number of subjects collected by three research teams in diverse US workplaces. Job rotation practices used in many workplaces may not be effective in reducing job biomechanical stressors for work-related musculoskeletal disorders. Overtime work is also associated with higher biomechanical stressors.

A field study of exposure to whole-body vibration due to agricultural machines in a full-time rice farmer over one year

OBJECTIVES

The aims of this study were to clarify in detail the levels of whole-body vibration (WBV) exposure from a variety of agricultural machines in a rice farmer over one year, and to evaluate the daily level of exposure compared with European and Japanese threshold limits.

METHODS

The subject was a full-time, male rice farmer. We measured vibration accelerations on the seat pan and at the seat base of four tractors with various implements attached, one rice-planting machine, two combine harvesters, produced by the same manufacturer, and one truck used for transportation of agricultural machines. The position and velocity of the machines were recorded in parallel with WBV measurements. In addition, during the year starting in April 2010, the subject completed a questionnaire regarding his work (date, place, content, hours worked, machines used). We calculated the daily exposure to WBV, A(8), on all the days on which the subject used the agricultural machines.

RESULTS

The WBV magnitude in farm fields was relatively high during tasks with high velocity and heavy mechanical load on the machine, and had no dominant axis. The subject worked for 159 days using the agricultural machines during the year, and the proportion of days on which A(8) values exceeded the thresholds was 90% for the Japan occupational exposure limit and 24% for the EU exposure action value.

CONCLUSIONS

Our findings emphasize the need for rice farmers to have health management strategies suited to the farming seasons and measures to reduce WBV exposure during each farm task.

Prevention of occupational Back Pain

This paper reviews scientific research on occupational back pain and focuses on prevention of this problem. It discusses some of the challenges of translating the evidence of this multi-factorial condition into policy. Medical science is currently unable to clearly distinguish between back pain caused by work and that possibly due to other causes but which affects the individual's capacity to work. Back pain affects the vast majority of people at some point in their lives and is very costly to both the health care system and the industry. Evidence suggests that heavy lifting, driving, and vibration of the whole body are linked to occupational back pain. Once the risk factors for occupational back pain are identified, an otherwise chronic and disabling condition can be prevented in the majority of patients. As explained in this article, three levels of prevention for occupational back pain have been reported as effective. Failure to implement preventive measures may lead to a high incidence of occupational back pain.

Evaluation of long- and short-handled hand hoes for land preparation, developed in a participatory manner among women vegetable farmers in The Gambia

OBJECTIVE

This study evaluated land preparation interventions (new short- and long-handled hoes), developed in a participatory manner with women vegetable farmers in West Africa, and identified indicators of long-term adoption of these interventions.

METHODS

Subjects (n = 48) engaged in timed trials, alternating between using an intervention tool and their traditional hand hoe to till specified plots of land. Heart rates were measured and subjects reported the relative ergonomic comfort and safeness of the tool after each trial. Follow-up interviews and focus groups were held one, two, and three months after the trials.

RESULTS

Compared to the traditional hoe, the new long-handled hoe required 22% less time (p = 0.01), while the new short hoe took 20% more time (p = 0.05) to till the standard plots in this study. Two months after the initial trials, 94% of subjects preferred the new hoes over the traditional hoe. Most subjects (75%) preferred the new short hoe over the new long hoe and thought it was faster (81%), despite measurements to the contrary.

CONCLUSIONS

While the new long-handled hoe performed better in the timed trials in this study, most subjects preferred the new short-handled hoe. Subjects should be sensitized on the benefits of the long-handled hoe.

Chronic back pain and associated work and non-work variables among farmworkers from Starr County, Texas

OBJECTIVES

This study estimated the prevalence of chronic back pain among migrant farmworker family members and identified associated work and non-work variables.

METHODS

Migrant farmworkers (n = 390 from 267 families) from Starr County, Texas were interviewed in their home once a year for 2 years. The original survey included items measuring demographics, smoking, sleep, farm work, and chronic back pain. For this cross-sectional analysis, multi-level logistic regression was used to identify associated work and other variables associated with chronic back pain while accounting for intraclass correlations due to repeated measures and multiple family members.

RESULTS

The prevalence of chronic back pain during the last migration season ranged from 9.5% among the youngest children to 33.3% among mothers. Variables significantly associated with chronic back pain were age (odds ratio [OR], 1.03, per year increase), depressive symptoms while migrating (OR, 8.72), fewer than 8 hours of sleep at home in Starr County (OR, 2.26), fairly bad/very bad quality of sleep while migrating (OR, 3.25), sorting crops at work (OR, 0.18), and working tree crops (OR, 11.72).

CONCLUSION

The role of work exposures, depressive symptoms, and sleep in chronic back pain among farmworkers warrants further examination. Refinements in outcome and exposure assessments are also needed given the lack of a standardized case definition and the variety of tasks and crops involved in farm work in the United States.

Orchard evaluation of ergonomically modified apple bucket

BACKGROUND

While preliminary laboratory tests indicate that a hip belt reduces the load on the back, neck and shoulders associated with musculoskeletal strain, an orchard trial is needed to more realistically assess both effectiveness and acceptability.

OBJECTIVE

to evaluate the hip belt's effectiveness in three areas: worker acceptance, worker productivity, and one-day muscle fatigue of the back and shoulder.

METHODS

Ninety-six New York apple harvest workers were randomly assigned to use the intervention hip belt or placebo belt for one week. In a second week all workers switched conditions. Subjects were interviewed at the end of each week to ascertain intervention acceptance. Employer records were reviewed to determine bushels picked per day. Subjects also underwent muscle fatigue testing at the beginning and again at the end of one workday during each week.

RESULTS

Ninety-one percent of the subjects favored the intervention hip belt. Use of the intervention did not appreciably slow picking speed (bushels per hour) as compared to placebo (8.8 bu/ hr vs. 8.89 bu/hr). Both were significantly faster than the regular equipment condition (8.13 bu/hr). No significant differences in one-day muscle fatigue were found with intervention use.

CONCLUSIONS

The belt was acceptable to the workers and did not hinder productivity. However, the anticipated ergonomic benefits were not demonstrable using one-day strength testing.

Musculoskeletal pain in women working in small-scale agriculture in South Africa

BACKGROUND

Musculoskeletal pain is associated with demographic, occupational and physical factors.

METHODS

Our study investigated the prevalence and factors associated with musculoskeletal pain in 911 women working in small-scale agriculture in rural northern KwaZulu-Natal, South Africa in 2006 using a questionnaire survey.

RESULTS

In total, 67% (n = 574) of women reported any chronic musculoskeletal pain. The 12-month prevalence of pain ranged from 63.9% to 73.3% and the prevalence of specific chronic pain lasting more than 3 months ranged from 42.8% to 48.3%. Older age, carrying heavy loads, working with hands above shoulder height, and frequently squatting and kneeling were associated with chronic musculoskeletal pain.

CONCLUSION

The prevalence of pain reported in our study, was similar to other developing countries, but considerably higher than in developed countries. Ergonomic interventions including improved and adapted work techniques and tools should be considered to reduce the prevalence of pain in our study population.

Electromyographic assessment of apple bucket intervention designed to reduce back strain

The authors previously developed an apple bucket that was modified by use of a hip belt to reduce muscle fatigue. The intervention of belt use was accepted by workers and shown not to interfere with productivity. However, use of this intervention did not appear to reduce muscle fatigue when measured by tests of voluntary muscle strength. The purpose of the present study was to evaluate the intervention's effect on muscle fatigue employing surface electromyographic (EMG) amplitude. Amplitude measurements on 15 muscles were taken from 10 laboratory volunteers who were carrying a full bucket of apples, once while wearing the intervention belt and once without the intervention. These measurements were taken for seven different postures (four angles of trunk flexion (0 degrees , 20 degrees , 45 degrees , 90 degrees ) and three raised-arm positions (both up, dominant up, non-dominant up)) common to apple harvest work. Participants were measured in these conditions both with the bucket carried in front and with the bucket carried to the side. Significant reductions in amplitude favouring the intervention were seen for 11 of the 15 muscles in models considering the four body flexion angles. Ten of these were of the middle and lower back. These control/intervention differences were seen with both bucket-carrying positions (front vs. side) and tended to increase with increasing flexion angle. In contrast, no significant intervention effects were observed in models considering treatment by arm-raised position. One significant main effect (upper trapezius, side bucket) showed an amplitude reduction in the treatment condition. Another main effect showing increased amplitude in the intervention condition use was observed in the dominant levator scapulae (side bucket). Thus, the use of the intervention belt reduces EMG amplitude among a number of mid- and lower-back muscles. This is suggestive of a protective effect against back strain.

Development and initial assessment of objective fatigue measures for apple harvest work

Previous research has shown that neck, back and shoulder musculoskeletal strain is a major occupational health problem affecting migrant orchard harvest workers. Researchers seek to measure the effect of an ergonomic modification to the apple picking bucket on muscle fatigue, however objective measures for use in the orchard are not yet available. The purpose of this study is to develop simple back, shoulder or arm strength measures, which detect statistically significant drops in strength over one workday. Candidate muscle strength measures were piloted in the laboratory, adapted for the orchard and evaluated (n=102). Data were analyzed for morning to afternoon fatigue, and for correlation between fatigue score and hours worked. In the laboratory, the timed arm hold (35.7% time reduction, 95% CI: 21.81-49.61), and the timed spinal extension (31.8% time reduction, 95% CI: 23.54-39.96) showed significant fatigue. In the orchard (n=102), only the timed arm hold showed significant (11.4%, p<.0001) fatigue. The potential effect of field conditions and subject motivation on these results needs further exploration.

Laboratory evaluation of belt usage with apple buckets

BACKGROUND

Migrant and seasonal orchard harvest workers experience musculoskeletal strain caused by carrying heavy loads and holding awkward postures. An ergonomic hip belt designed to redistribute weight from the upper back, neck, and shoulders to the hips was evaluated.

METHODS

A comparison of muscle exertion (using electromyography [EMG]) of four key back and shoulder muscles and shoulder surface pressure (using a surface pressure sensor [PS]) was made among 10 laboratory volunteers under intervention and control conditions, in two postures (standing erect [0 degrees ]) and flexed [45 degrees ]).

RESULTS

All but one measure showed a significant reduction in the flexed posture with the intervention. Two of eight measures showed a significant reduction in the erect posture. Correlations with shoulder discomfort were found for deep shoulder EMG (r=0.71, P=0.021) and shoulder surface pressure (r=0.58, P=0.082).

CONCLUSIONS

The hip belt intervention produces significant reductions in muscle activity while in a posture commonly assumed during orchard work.