Month: August 2020

Repetitive movements. Pencil portraits.

Have you ever wondered how many similar movements need to be made to represent a portrait in a drawing? How many times do you need to slide the pencil in the same position and for how long? It is a task that involves repeated movements, the ergonomic risk for Repetitive Movements.

Pencil drawing. 2017.

These are those in which the same sequence of repeated movements takes place in more than 50% of the cycle or task that is carried out repeatedly. The number of actions carried out in each minute (speed), duration of the task, posture, intensity of force to be performed, the existence of pauses or recovery time and other additional factors such as the cold, the vibrations, the adequacy of Personal Protective Equipment to the dimensions of the individual, slip of what is held.

Perhaps it is easy to observe it in a repeated sequence of three movements, as it would be the three steps shown in the following drawing:

“One, two, three”. Ink drawing. May 2020.

Or trying to make an artwork with mud with no other tool but hands

Mud fingers towers

The drawing was carried out at ground level, with a spatula, given the need to adopt a forced dorsiflexion of the wrist, repeating the same sequence of movements and without rest intervals.

The movements that make up the cycles were performed quickly at a rate of 6 movements every 2 seconds.

The paper is wet, but following the same movements, to avoid monotony in the result of the work. Beyond a work where only lines in the same direction are visualized, it is necessary to value those others where the repetitiveness of movements is not intuited but are there, reason why recovery pauses and exercises as stretching ones, are necessary.

Pencil drawing. 2017.


Psychosocial risk is an ergonomic aggravator for the skeletal muscle system. The work shows how stress and exhaustion influence the outcome of a work. The week of March 9-15, 2020 was especially intense for me. The outbreak of cases of SARS-CoV-2 (Coronavirus or COVID-19) meant that during the 12th and 13th of March could not stop work activity, having started early morning with telephone calls, visits and managements until past the afternoon and beyond. Since then, the work has been intense until mid-May, affecting this situation on a psychological level.Stress has a physical effect on the tension in the muscles of the face, neck and back as a preparation for reacting to a stimulus that is dangerous and relaxes once it has passed. In the case of chronic muscles, it is constantly tense, which causes a decrease in blood flow to the muscles, thus reducing the supply of oxygen and nutrients, generating a greater accumulation of toxic waste and lactic acid. which entails a limitation of movement. Stress is involved in coordinating muscle groups while maintaining posture and balance during movement. This process involves headaches, chronic pain, contractures … so manual dexterity is also affected.

COVID-19. March 2020. Mixed media on paper.

Drawing holding 5 kg

Load handling is considered when handling a weight greater than 3 kg. According to the INSHT Technical Guide, it would be “any operation of transport or holding of a load by one or more workers, such as lifting, placing, pushing, pulling or moving, which due to its inadequate characteristics involves risks, in particularly dorsolumbar, for workers ”.

The weight that anyone should handle should be the equivalent of 10% of their weight. According to scientific studies, publications and recommendations at the level of reference entities, a person can handle 25 kg as the maximum load in ideal conditions, and up to 40 kg if trained (holding the load with both hands, in the height between hip and elbow, standing position with straight back, no turns, as close as possible to the body …), depending on the frequency and number of times it does so among other factors, as stated previously. In the case at hand and considering that my weight is 49 kg, the load held was a 5 Kg container of water in a totally unfavorable position given I did it at ground level.

Drawing holding 5 Kg