Limitations in the field of vision of young operators of utility all-terrain vehicles.

PROBLEM: All-Terrain Vehicles (ATVs) cause a distressing number of fatalities and injuries among farm youth in the United States. The number of severe injuries caused by ATV crashes on farms, which stood at 25 children in 2019, is expected to rise due to increased ATV sales during the COVID-19 pandemic. Existing research into children's injuries has explored physical capabilities like anthropometry, strength, and visual acuity. Yet, studies assessing youths' physical ability to operate ATVs remain limited. This study tests the hypothesis that diminished vision field in young ATV operators raises crash risks. METHODS: This study used SAMMIECAD digital human modeling system to simulate and compare the field of vision of youth and adult ATV operators. The simulations incorporated 3-D mockups of ATVs, humans, sprayer tanks, windshields, and obstacles. Ten utility ATVs and children of both genders across nine ages (8-16) and three height percentiles (5th, 50th, 95th) were evaluated. RESULTS: Simulations showed that young ATV operators generally have a more restricted field of vision than adults, particularly those aged 6-11 years. DISCUSSION: Visual limitations hinder riders' ability to see ATV controls, potentially leading to vehicle control loss. Moreover, they impair environmental perception during riding, compromising youths' ATV operation abilities and increasing crash risks. PRACTICAL APPLICATIONS: These findings offer crucial data in support of modifying ATV safety guidelines. Additionally, they can guide youth occupational health professionals in preventing ATV-related incidents in agricultural settings.

Ability of youth operators to reach agricultural all-terrain vehicles controls.

PROBLEM: Utility All-Terrain Vehicles (ATVs) are one major cause of youth injuries and fatalities on farms. Utility ATVs have heavy weights and fast speeds that require complex maneuvering. Youth's physical capabilities may not be sufficient to perform those complex maneuvers correctly. Therefore, it is hypothesized that most youth engage in ATV-related incidents because they ride vehicles unfit for them. There is a need to assess ATV-youth fit based on youth anthropometry. METHOD: This study focused on evaluating potential inconsistencies between the operational requirements of utility ATVs and the anthropometric measures of youth through virtual simulations. Virtual simulations were performed to assess 11 youth-ATV fit guidelines proposed by several ATV safety advocacy organizations (National 4-H council, CPSC, IPCH, and FReSH). In total, 17 utility ATVs along with male-and-female-youth of nine ages (8 to 16 years old) and three height percentiles (5th, 50th, and 95th) were evaluated. RESULTS: The results demonstrated a physical mismatch between ATVs' operational requirements and youth's anthropometry. For example, male-youth aged 16 of the 95th height percentile failed to pass at least 1 out of the 11 fit guidelines for 35 % of all vehicles evaluated. The results were even more concerning for females. Female youth 10 years old and younger (from all height percentiles) failed to pass at least one fit guideline for all ATVs evaluated. DISCUSSION: Youth are not recommended to ride utility ATVs. PRACTICAL APPLICATIONS: This study provides quantitative and systematic evidence to modify current ATV safety guidelines. Furthermore, youth occupational health professionals could use the present findings to prevent ATV-related incidents in agricultural settings.

Development and Evaluation of Ergonomic Interventions for Bucket Handling on Farms.

OBJECTIVE: The aim of this study was to introduce and evaluate two interventions, Ergo Bucket Carrier (EBC) and Easy Lift (EL), for youths (and adults) to handle water/feed buckets on farms. BACKGROUND: The physical activities of both adult and youth farm workers contribute to the development of low-back disorders (LBDs). Many of the activities youths perform on farms are associated with increased LBD risk, particularly, the handling of water and feed buckets. METHOD: Seventeen adult and youth participants (10 males and seven females) participated in this study. To assess the risk of LBDs, the participants were instrumented with a three-dimensional spinal electrogonio-meter while lifting, carrying, and dumping water buckets using the traditional method and the two interventions. RESULTS: For both the adult and youth groups, the results showed that the two interventions significantly decrease the magnitudes of LBD risk in many of the tasks evaluated. Overall, the use of the EBC resulted in a 41% reduction in the level of LBD risk for the carrying task and a reduction of 69% for the dumping task. Using the EL, on the other hand, is especially effective for lifting tasks (55% reduction in LBD risk). Results of the subjective response were consistent with the objective evaluations. CONCLUSION: This study demonstrated the potential for ergonomic interventions in reducing LBD risk during the common farming task of bucket handling. APPLICATION: Potential application of this study includes the introduction of the EBC and EL in family farms to reduce the LBD risk among youth and adult farmers.

Effect of a personal weight transfer device on muscle activities and joint flexions in the stooped posture.

Repetitive work in the stooped posture is a known risk factor for developing low back disorders (LBDs); regardless, the stooped posture is widespread throughout the world in the agriculture, construction, and mining industries. An on-body weight transfer device was tested as a possible intervention for reducing the risk of developing LBDs. Eighteen subjects (11 male and 7 female), with no history of LBDs, performed stooped posture tasks in the laboratory. Surface electromyograms of the erector spinae, rectus abdominis, biceps femoris, and tibialis anterior muscles were recorded. Bodily joint flexions were measured with a combination of inclinometers and electrogoniometers. When wearing the device in the stooped posture, biceps femoris activity and lumbar flexion were significantly reduced. Subjects who did not experience flexion-relaxation had a significant reduction in lumbar erector spinae activity. By reducing back muscle activity, and by limiting lumbar flexion, the device could reduce the risk of developing LBDs for those who work while adopting the stooped posture. The device may also be beneficial for those with existing LBDs. Follow up field studies are needed to confirm the long-term potential benefits of such an intervention approach.

Subject-specific, whole-body models of the stooped posture with a personal weight transfer device.

A prior laboratory study found that when wearing a weight transfer device in the stooped posture, trunk flexions were reduced, and subjects who did not experience flexion-relaxation of the erector spinae had reduced back muscle activity. Whole-body musculoskeletal models, which included individual passive torso stiffness and anthropometry, were implemented to predict loads in the passive tissues of the back and the leg joints. Results predicted that when wearing the device in the stooped posture, compression and shear forces at the L5-S1 level were reduced by 13% and 12% respectively. Internal loads in the leg joints were reduced between 10% and 31%. Much of the reduction in joint loads may be a result of the device's ability to limit torso flexion during stoop, rather than a transferring of load. While these results show possible benefit in the short-term, further study is needed on the long-term effects to determine if the device is an effective intervention for those who use the stooped posture routinely.

Noninvasive high resolution mechanical strain maps of the spine intervertebral disc using nonrigid registration of magnetic resonance images.

High resolution strain measurements are of particular interest in load bearing tissues such as the intervertebral disc (IVD), permitting characterization of biomechanical conditions which could lead to injury and degenerative outcomes. Magnetic resonance (MR) imaging produces excellent image contrast in cartilaginous tissues, allowing for image-based strain determination. Nonrigid registration (NRR) of MR images has previously demonstrated sub-voxel registration accuracy although its accuracy and precision in determining strain has not been evaluated. Accuracy and precision of NRR-derived strain measurements were evaluated using computer generated deformations applied to both computer generated images and MR images. Two different measures of registration similarity--the cost function which drives the registration algorithm--were compared: Mutual Information (MI) and Least Squares (LS). Strain error was evaluated with respect to signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and strain heterogeneity. Additionally, the creep strain response from an in vitro loaded porcine IVD is shown and comparisons between similarity measures are presented. MI showed a decrease in strain precision with increasing CNR and decreasing SNR while LS was insensitive to both. Both similarity measures showed a decrease in strain precision with increasing strain heterogeneity. When computer generated heterogeneous strains were applied to MR images of the IVD, LS showed substantially lower strain error in comparison to MI. Results suggest that LS-driven NRR provides a more accurate image-based method for mapping large and heterogeneous strain fields and this method can be applied to studies of the IVD and, potentially, other soft tissues which present sufficient image texture.

Migrant women farm workers in the occupational health literature.

Little attention has been given to the vulnerable populations of migrant women agricultural workers. A systemic review in PubMed was carried out (1990-2008) using terms related to migrant agricultural workers, with specific focus on women. Case studies from Lebanon and California are presented to highlight key physical, psychosocial, and cultural risk factors among these working populations. The review revealed a host of potential problems that span from pesticide exposure and musculoskeletal disorders to socio-cultural barriers. Comprehensive exposure-outcome and intervention studies focusing specifically on migrant women in agriculture are lacking. In depth studies focusing on the work environment of migrant women workers in the agricultural sector are needed. Personal and environmental factors that influence health should be considered in any effective intervention aiming to influence policy making and have a positive impact on these vulnerable working populations.

Evaluation of a personal device in reducing the risk of low back disorders during stooped work.

Adoption of the stooped posture in the workplace is widespread throughout the world in agriculture, construction, and mining. This type of posture has been established as a risk factor for developing low back disorders (LBDs). The purpose of this study is to evaluate a personal weight transfer device as a possible intervention to reduce the load on the lumbar spine, thereby reducing the risk of developing LBDs. Eighteen healthy subjects performed stooped posture tasks in a laboratory study designed to simulate harvesting of low-growing crops. Results showed that when wearing the device in the static stooped posture, biceps femoris activity was reduced by 17%, lumbar flexion was reduced by 12%, ankle plantar-flexion increased by 5%, and the lumbar erector spinae of those subjects who did not experience flexion-relaxation of the erector spinae was reduced by 26%. Hip and knee flexion were not significantly altered. Therefore, the device may be beneficial for those with existing LBDs, and who use the stooped posture routinely.

Spinal disc hydration status during simulated stooped posture.

Stooped work has been shown to be associated with the development of low back disorders, particularly those that affect the spinal intervertebral discs. Although several studies have been conducted to evaluate the effects of physical factors on disc health, little research has focused on the effect of prolonged stooped work on disc hydration- a critical component of disc health. The purpose of this study is to explore the connection between stooped work and low back pain through controlled mechanical loading and quantitative analysis of disc hydration during in vitro simulated stooped and erect loading conditions of porcine discs. The results showed that stooped postures exhibit significantly decreased overall water content relative to erect postures. Since as disc hydration forms the foundation for overall disc health and proper function, these results have implications for the injury mechanisms associated with stooped work.

Musculoskeletal disorders in labor-intensive agriculture.

This paper gives an overview of the extent of musculoskeletal disorders (MSDs) in agriculture, and a historical perspective on how ergonomics has been used to reduce the health effects of labor-intensive agriculture. A summary of exposure to MSD physical risk factors within various classes of crops, along with various administrative and engineering controls for abating MSDs in agriculture is given. These controls range from programmed rest breaks to mechanized or partially-mechanized operations. Worker-based approaches such as prone carts and platforms, and load transfer devices hold promise in combating the prevalent stooped work in agriculture. Including the worker as an integral contributor to all aspects of developing and implementing an intervention, and considering the psychosocial and socio-cultural aspects of the work environment are crucial elements of effective interventions for reducing MSDs. Despite the advent progress in new technologies in agricultural practices, reliance on labor, especially in fresh market fruits and vegetables, will always be a major cornerstone of agriculture for at least the foreseen future. It is encouraging to see the increased interest among health and safety professionals, epidemiologists, engineers, social scientists, and ergonomists throughout the world who are committed to the plight of reducing MSDs and other health problems among agricultural workers.

Full-time homemakers: workers who cannot "go home and relax".

This paper examined how musculoskeletal disorders (MSDs) of female homemakers were studied in the literature. It also presented preliminary findings from field observations of housework and fulltime homemakers in urban settings. PubMed, Ergonomics Abstracts, Sociofile, and PsycINFO databases were used in the literature search. The review focused on comparing demands of housework and paid work. Also, exposure factors found in studies of various occupations were compared with the results of field observations of housework in 4 homes in Beirut, Lebanon. Few studies systematically examined associations between MSDs and risk factors in housework. Some well-known risk factors for MSDs were identified in the Beirut homes; however, other unique factors were noted. Housework activities expose homemakers to known risk factors for MSDs, which calls for further studies to identify appropriate intervention and prevention strategies.

In vitro measurements of porcine anterior column units under free swelling.

The objectives of this study are to present a 2-D optical method for measuring gross kinematics of porcine anterior column units (ACUs) exposed to swelling with no applied load, provide a detailed error analysis of the 2-D optical measurement technique, and present a 2-D radiographic technique for measuring the distribution of x-ray intensity through an axial slice of the disc. The 2-D optical technique was sufficient for detecting the flexion-extension behavior of the ACUs tested. The error analysis concluded that the use of a second camera to quantify out of plane movement of the specimen would greatly improve the accuracy of the measurement of angle. The 2-D radiographic technique provided limited information on changes in intradiscal material. It was also limited in its accuracy and dependability (i.e., only 5 out of 13 specimens provided radiographs suitable for this analysis). The results of this study indicate that a relationship might exist between the flexion-extension behavior observed from swelling and intradiscal shifts of matter. Further work is needed to confirm this relationship.