Assessment of Muscular Activity and Postural Load During Coffee Harvesting Activities – A Case Study

Abstract

Objective: The goal of this case study was to analyze and evaluate the posture, force and repetitive movement risks associated with manual coffee harvesting activities. Materials and Methods: A self-discomfort report was administered to 28 participants, of whom 4 volunteered for an evaluation of postural load on muscular activity using electromyography and electrogoniometry. Eight upper limb muscles and the kinematics of the wrist and upper arm of the dominant arm were assessed. Results: The results of the self-discomfort report showed a greater demand, from the harvester’s perception, in areas such as the back, lower back, knees and feet during a period of one week of work. The outcomes of the muscular activity assessment showed that the extensor carpi ulnaris (ECR) was the muscle with the highest demand during the assessment. The dynamic activity of the muscle exceeded 20% of the maximum voluntary contraction (MVC), which classifies coffee harvesting as a threatening activity. The postural load on the body segments revealed that wrist deviation was critical due to an abnormal range of the wrists during the activity. Conclusions: It is necessary to improve the working conditions of the coffee harvesters.

Musculoskeletal Symptoms and Assessment of Ergonomic Risk Factors on a Coffee Farm

“…In a study carried out with workers who harvested coffee manually, although it was found that they mainly manifested musculoskeletal discomfort in the lower extremities, when evaluating the intensity of muscle contraction by means of surface electromyography and the measurement of joint angles, it was found that this activity requires considerable physical effort at the level of the upper limbs [42]. A study in Colombian coffee plantations showed that the muscle with the greatest demand was the extensor carpi ulnaris muscle, which is located at the level of the upper extremities; the dynamic activity of this muscle exceeded 20% of the maximum voluntary contraction, making coffee harvesting a threatening activity for the generation of musculoskeletal injuries [43].…”

“…The identification of ergonomic risks to which workers are exposed is the first step to improve working conditions, achieving a balance between decent work and economic growth (SDG8). Previous studies in coffee farms show that workers are exposed to biomechanical risk factors and present musculoskeletal discomfort [36,[42][43][44][45][46][47][48], thus, the need arises to carry out a specific evaluation that considers these risk factors. That is why the objective of this research is to identify musculoskeletal symptoms and evaluate ergonomic risk factors in three occupations of a certified coffee farm in Honduras.…”