# A Review on Ergonomics in Agriculture. Part I: Manual Operations
## 1 Introduction
Even during agricultural activities that do not entail heavy lifting, repetitive or sustained actions involving stooping posture can increase the risk of low back pain [16]. Apart from low back pain, knee and hip osteoarthritis (OA) are very prevalent among rural workers [17]. OA takes place when the articular cartilage, which protects the ends of the bones, starts wearing down. Furthermore, OA constitutes the most common type of arthritis and its prevalence increases with age. The constantly increasing age of the agricultural workforce justifies the international concern about the rising incidence of OA in this field. Additional risk factors are obesity, female gender, and low educational level [18]. Repetitive bending of the knee, which is very common in rural activities, contributes to the aggravation and acceleration of knee OA [19]. Given the huge number of agricultural workers globally, ergonomic technologies have been developed, implemented, and evaluated as a means to attenuate the MSDs. These interventions intend to assist the agricultural workforce via optimizing the worker-workplace interface, improving the tools, as well as investigating ways to prevent workers from extravagant forces, repetitive motions, and awkward postures. Throughout systematic ergonomic efforts it has been observed that even small changes translate to large differences in reported pain [20]. A characteristic successful example was the use of tubs of smaller size regarding the harvesting of grapes. Another, also successful, simple ergonomic intervention was the reducing of the space between rungs in orchard ladders [20]. Moreover, [PERSON] and [PERSON] [21] showed that introducing a long-handled hoe for weeding substantially reduced the flexion of the trunk and, at the same time, this approach proved to be more productive when compared with other weeding techniques. The use of extended-handle carriers was also tested for potted plants, a method that substantially diminished the stoop and squat with the intention of moving or lifting them [22]. Additionally, the incorporation of pneumatically-powered cutters during manual cutting demonstrated that even workers with partial disability, owing to the overuse of shears, could return to their occupational tasks [21]. Finally, the list of small successful interventions includesalso frequent breaks that enable temporary relief, for example, during persistent labor in a stooped posture [23]. In a nutshell, ergonomics in agriculture is a versatile and interdisciplinary topic that involves the identification of the risk factors pertaining to MSDs; the determination of the root causes; as well as the development, implementation, and evaluation of ergonomic interventions. The present review study aims at summarizing the recent scientific articles dealing with all the above-mentioned aspects. The 27 selected articles presented in this review were published in peer-reviewed journals during the last decade, namely, between 2010 and 2019, in an effort to guarantee the reliability and up-to-date progress in this field. The methodology, exclusive criteria, along with the search engines that were used are presented in the \"Methods\" section. Subsequently, the \"Results\" section follows, which is divided into three main subsections. In the first subsection, a preliminary data visualization analysis is presented for the identification of the relevant research organizations and trends in this field, whereas the second one briefly describes the selected articles. As agricultural manual operations involve a variety of activities, each of them is investigated in a different subsection for the sake of better analysis of the results. The third subsection deals with the identification of the main risk factors for the development of MSDs based on our literature survey. Finally, the \"Discussion\" section follows, where concluding remarks are drawn, along with strengths and limitations of the present study, as well as future policy directions.