Thought Bytes...
June 2002

Ergonomics for Crafters and Sewers

There are 3 key issues in ergonomics for sewers and crafters:

1. Good lighting is essential to good posture
2. Different task complexities require different working heights
3. We were not designed to sit

Illumination of the task is essential. Sewers and crafters tend to work under poor lighting conditions (i.e. basements, dining rooms, etc.). A friend once asked me why she kept having the take-up bar of the sewing machine hit her in the forehead. It was simply because she was using the light from the machine ONLY to see by. In an effort to see better, she kept moving her head closer and closer to the work. An incandescent or fluorescent goose neck lamp, in addition to the machine light, is a good start. I often recommend using a Tru-Color Ott light for maximal colour rendition. This is absolutely necessary when working with matched threads and fabrics. To avoid eye strain, you should always illuminate the task not the eye. The bulb should never be directly visible to the eye. In the end, the eyes control the rest of the body. If the tasks are not sufficiently illuminated, posture will be compromised so that the task can be seen.

I recently downloaded an ergonomic guide for industrial sewers from an American government health and safety site. On the cover, in the picture reflecting positive ergonomic changes, they had placed the task lamp behind the sewing machine - casting the needle into shadow and making the bulb visible to the eye. This would be like reading a book with the light shining on the back / spine of the book. It would actually be harder to read than if there had been no light intervention. Light should shine over the shoulder, projecting onto the task where the hands are located and where the eyes are looking to.

Activities that require constant visual reference are called fine motor tasks. These should be done with the forearms supported on the table surface, with the elbow about 6" away from the side of the body. From a relaxed, arm at the side of the body position, with the elbow flexed to 90 degrees, this would place the table height at approximately 1.5-2" above the underside of the elbow. Examples of fine motor tasks include hand stitching and quilting, model making, using sharp tools like exacto knives, and machine piecing (when the skill level is low). If this task is done at too low a hand position, the arms will seek that level of support requiring the upper body to hunch over.

Medium motor tasks do not require as frequent visual reference, but the task still needs to be in view. Much like keyboard height for those who can touch type, the working surface / finger height should be approximately 1" below the flexed elbow. Examples of medium motor tasks include knitting (with moderate skill level), machine quilting (meandering and overall designs) and general assembly tasks. If this task is done at too high a position, the shoulders will elevate and the worker will slide forward on the chair in an effort to raise the body.

Heavy tasks are those that require some use of the body weight and are often done standing. These activities are done with the hand between groin and waist so that the upper body can lean into the work. Examples include wood working and heavier tool use (saws, etc.), rotary cutting, quilt basting, etc. If these tasks are done at too high a height, the worker will attempt to generate force by using more muscle activation.

Lastly, because the human body was designed for motion (hunting and gathering, etc.) when we sit all day at the computer, and then go home and sit doing hobbies, there is a tremendous strain to the discs, ligaments and muscles of the back. For that reason it is important to invest in a chair with a good lumbar and upper back support and that is easily height adjustable. Sewers and crafters tend to sit at the front edge of the chair because they get up and move around a lot (back and forth to the ironing board) or in an effort to have their feet reach the floor or foot pedal when working at the sewing table or a work bench. The buttocks should be pushed firmly to the back of the chair. >From that position, if the feet don't touch the floor, foot support will be needed appropriate to the distance of the heel to the floor.

As an ergonomist, my goal is to help people (ultimately) retire in comfort. We all want to go home at the end of the day and enjoy our lives, hobbies and families. If we can do this in relative comfort, then I have succeeded.

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