Therefore, when the term “children” is used in the context of agricultural labor, the implication is that the parents oversee the welfare and legal circumstances related to this working yet “dependent” population. “Youths” and “adolescents” are usually used interchangeably, and according to the World Health Organization , refer to the period of transition from childhood to adulthood, commonly between the ages of 10 and 19 . Hence, in this paper, as in most of the related literature, the terms children, youths and adolescents will be used interchangeably, and will refer to the age range of 10–17, unless otherwise specified; whereas, the term “adult” will refer to the age of 18 and above. Regardless of the hazardous nature of farm-related activities, in agriculture, age does not limit participation and children may do the work of an adult . Youths 13 to 15 years old are usually expected to do pretty much what adults can do . Additionally, the youth-involved farm-related activities are highly correspondent to geographical regions and commodity types . The same study indicates that, in the U.S., Midwestern youths are primarily assigned to animal care and farm maintenance jobs , compared to Western youths, whose tasks are mainly crop management . Every year in the U.S., approximately 126,000 hired youth farm workers aged 14–17 years of age are employed in crop agriculture . These hired youth farm workers, especially the ones who work on non-family owned farms, commercial plant racks are generally involved in harvesting/picking tasks . Studies have documented harvesting tasks as being associated with potential LBD risk factors and back pain reports . In addition, All read and colleagues have investigated the magnitude of LBD risk that youth are exposed to while performing tasks that are routinely performed by Midwestern farm youths.

They have quantitatively measured the trunk kinematics of these youth workers as well as workplace factors while the workers are performing 41 manual materials handling tasks and found that the associated LBD risks of some tasks were comparable to that of industrial jobs with high LBD risks. Out of the 41 evaluated tasks, seven tasks are placed in the high LBD risk category, corresponding to the LBD risks found in industrial jobs, and 24 tasks are placed in the middle risk category. Work-related injuries among youth workers in agricultural settings are a serious problem. The estimates of annual farm-related non-fatal injuries range from 1,700 to 1,800 per hundred thousand child farm residents . Youths holding farm jobs simultaneously with non-farm jobs have a significantly higher proportion of injuries, of which sprain and strain are some of the most common types . In addition, muscle aches and strains of the back, shoulder, and other joints, are described as everyday occurrences among youths working on farms . A study focusing on youth workers in Wisconsin fresh markets also revealed that over half of the youth workers reported experiencing low back discomfort, while 25% reported disabling discomfort . Intervention studies with the specific aim of reducing LBD risk factors associated with tasks performed by working farm youths have been somehow limited in the literature, with few notable exceptions . Hence, the purpose of this study is to introduce and evaluate two interventions for bucket handling on farms. The two interventions and their development are firstly presented, followed by two evaluation phases; “Phase 1” is an intervention evaluation with adult volunteers, and “Phase 2” consisted of a confirmatory evaluation with youth volunteers from a local high school. The evaluation approach focused on the effectiveness of these two interventions in reducing LBD risk during the lifting, carrying, and dumping of water buckets.

Subjective responses were also obtained during the two testing phases. The job of handling water/feed buckets entails three main tasks: 1) lifting the bucket, 2) carrying the bucket to the destination and 3) dumping the content of the bucket at the destination . This job is commonly performed by youths on farms , where they transport water or feed from a source, such as water pump or a barn, to animal feeding containers. The objective of this phase of the study was to develop tools that are expected to reduce LBD related risk factors foryouths performing manual handling of water/feed buckets. The design approach was to develop two tools; one to simultaneously address the carrying and dumping tasks, and another to address the lifting task. In setting the tools design criteria, the research team relied on existing agricultural, bio-mechanical and ergonomic literature and guidelines, and consulted with colleagues and designers who are themselves farmers and grew up and worked on farms during their youth, and were familiar with the requirements and conditions surrounding bucket handling on farms. Kepner-Tregoe decision analysis was performed to select the design of the major components for each task: the lifting aid, the carrying device, and the dumping mechanism . Constraints and criteria used in the analysis are described. Based on the brainstormed design ideas, prototypes were built for testing purposes. Prototype testing results were then applied in the KT analysis for design comparisons and selection. The analysis results are presented in the following section for each of the three tasks. Carrying—A wheeled design was chosen for the carrying method. The main decision was the number of wheels employed in the design. The type and size of the wheels were determined based on other criteria and are discussed below. Three options– two-wheel, three-wheel, and four-wheel– were evaluated and compared using the KT analysis.

Two-wheel design- In order to use a two-wheel design, the user has to bear partial weight of the handled object . This design approach is used extensively on farms. Three-wheel design- A three wheel design can support the full weight of object handled. Also, it allows the user to control the cart by maneuvering the pushing handles . However, during field testing, this prototype design tended to commonly tip over on dirt roads. Four-wheel design- This design can also support the full weight of the handled object. Additional handles are required at the rear side of the cart, since the rear wheels prevent the user from reaching the handles in the front . In addition, the design exhibited greater stability on dirt roads than the three-wheel design. The results of the KT Analysis are shown in Table 1. A four-wheel design met all the design constraints and was pursued for in the final design. Dumping—Three dumping mechanisms were analyzed and compared using KT analysis. Table 2 summarized the analysis results. Type A- While the bucket is hanging in a frame that has a pivot point fixed to the carrier, users can dump by tilting the frame. The activation force is greatly reduced because of the difference in the acting moment arms . The moment arm for the activation force is adjusted to be three times the moment arm associated with bucket weight , ebb and flow tray with MA1 equals to approximately the radius of a five-gallon bucket . Type B- An air cylinder aided tilting mechanism that utilizes an air actuator to reduce the force required for the dumping process. An electric-powered compressor is required as the source of compressed air. Type C- Rails on both sides of the bucket with wheels mounted on its sides were considered. Dumping is completed by sliding the bucket down along the rails. Comparing the three mechanism types, Type A was selected as the option fulfilling all the desired design constraints and most of the design criteria . Lifting—The basic design for the lifting aid, a rod with a handle on one side and a hook at the other, allows the users to reach the handle of the bucket without bending down. However, the selection decision depended on the lifting mechanism, for which three types of mechanisms were compared . Table 3 shows the KT analysis results for this comparison.

Based on these results, the two-handed operation was selected over the other two mechanisms. Design Specifications and Modifications—Based on all the KT analyses presented above for each task, a carrier with four wheels was deemed best for the carrying task; a tilting mechanism which users operate at the same position as they push the cart was best for the dumping task; and a two-handed tool was best for the lifting task. For carrying and dumping tasks, an intervention, namely Ergonomic Bucket Carrier , was developed. For the lifting tasks, another intervention, called Easy Lift , was constructed. The dimensions of the prototypes of the EBC and EL were based on the anthropometric data of youths between ages 12.5 and 17.5 and environmental factors associated with dumping/carrying/lifting of water/feed buckets . The dimensions of several parts of the EBC, including the height of the pushing handle and the height of the bucket stand, were made adjustable to match the users’ anthropometrics and needs. Ergo Bucket Carrier —The final design of the EBC is shown in Figures 6 and 7. To use the device, the user first loads the bucket to the EBC, pushes the device to the destination, and then activates the dumping device by pushing a handle . The wheels were selected based on commercial availability, outdoor road conditions, and price. Pneumatic wheels that are less than 15 inches in diameter were selected to meet outdoor road conditions and to provide close contact with the destined container. The wheels selected for the front-end were fixed, pneumatic wheels with a 14 inch diameter; whereas, for the rear-end they were swivel, pneumatic wheels with a 10 inch diameter. Minor changes were made to the original designs to improve usability and performance. For example, the position of the handle for activating the dumping mechanism was changed from vertical to horizontal so that the users could activate the dumping mechanism at the same position as they were in to push the EBC, which would facilitate the efficiency of the process . The length of the handle remained unchanged and so did the moment arms and related forces. In addition, the positions of the cart handles were altered with an outward angle so that users’ wrists could remain in neutral position . Easy Lift —The final design of the EL is shown in Figure 8. A power grip design is used on the grip handle. The power grip was an angled handle that kept the users’ wrist in a neutral position so that the user can utilize her/his maximum power grip’s strength . The spinal loads associated with the use of EL are also expected to be less compared to manual lifting of the bucket due to the anticipated reduction in forward flexion and spinal moment arms . During lifting and carrying, the user hooks the EL’s U-shaped hook to the bucket’s handle to lift and carry the bucket . For dumping, the user sets the bucket on the floor, rotates the EL to hook a long screw to the bottom of the bucket, and uses the bucket’s handle and EL to lift and dump the bucket into the container .The results of this study showed that the developed interventions could be effective in reducing the overall LBD risk for the bucket handling job; however, the tools were different in their effectiveness in risk reduction among the three tasks. The overall LBD risk for the Manual job was reduced from 58% to around 52% for the EBC and 50% for the EL. This seemingly modest reduction is due to the fact that the overall LBD risk for the “job” is based on the maximum risk factors values observed among all three sub tasks. An approach that incorporates the advantages of each of the two introduced interventions would yield more substantial reduction in the overall LBD risk. Therefore, it is recommended that for lifting the bucket , the EL should be used; whereas, the EBC should be used during the carrying and dumping tasks. This combined approach is expected to provide maximum reduction in the overall LBD risk, since it capitalizes on the strength of each tool in reducing the risk factors within the sub tasks . This approach is expected to be especially effective if the job requires the bucket to be carried over long distances .