Ergonomics -- designing the work space to fit the body to reduce discomfort, fatigue, muscle tension and strain and eliminate or minimize intermittent and chronic pain and permanent disability. Proper design of the work space allows the body to work in either seated or standing neutral body positioning. Neutral body positioning creates the least amount of excess muscle tension and strain on body parts. The goal of ergonomics is to eliminate or minimize body parts held in awkward and unusual postures for extended periods (static loading), and reduce repetitive motion strain on joints and muscles. This results in reduction musculoskeletal disorder and resultant disfunction.
Seated neutral body position -- Feet flat on floor under knees, knees parallel with floor at same height as hips, head straight and over shoulders, back straight and not slouched, head straight and not tilted up, down, or sideways. The elbows should be kept low and close to the body whenever possible. While seated, the wrists and elbows should be at the same height or parallel with the floor. Wrists can be slightly above the elbows when your hands are on the sewing machine.
Standing neutral body position -- Feet flat on the floor or one leg propped up is ok, back straight, shoulders back, head straight and over shoulders. Head and eyes should not be tilted up, down, or to the side for long periods.
Determine seated neutral body positioning first -- The first things to look at are your chair parameters. Always start with your chair first and make sure it is adjusted correctly for you. Then consider adjustments to sewing table, cutting table, big board table, and ironing board table heights if needed.
Chair adjustments -- Correct chair adjustments strive to maintain neutral body positioning while seated for as much of the work time as possible. Review and adopt the following chair parameters to achieve neutral seated body positioning;
Seat height -- The correct seat height results when feet are flat on the floor, knees & hips are at the same height and parallel with floor. Adjust seat height to achieve this.
Seat pan tilt -- adjust to middle or slightly forward
Seat pan size -- correct seat pan size allows 1 inch extra on sides and back
Seat pan distance -- (depth of the seat pan in relation to your hips and knees), seat pan should be not too far forward or backward and approximately 1-4" behind the knees.
Seat back height and lumbar support -- (adjust seat back height to support the lower lumbar region of the back. The swale or bulge in the chair back should contact the lower lumbar area. If the swale does not contact the lower lumbar region of the back, use a lower back support cushion or pillow to support the lumbar region. If a seat back cushion is added, a strap on the cushion will hold it in place.
While seated, sit all the way back in the chair so that good lumbar support is maintained. Sit up straight whenever possible with chin straight and head aligned over spine or slightly tilted down.
Swivel chair feature minimizes bending and twisting of the spine.
Chair arm rests are not generally provided for a sewing chair as they take up work space.
The following section lists several on-line resources for chair lumbar cushions or make your own and add a strap so that it stays put.
Lower back or (lumbar chair cushion resource); www.sitincomfort.com, about $20 plus tax, also, www.rehaboutlet.com. Look for a small one with an adjustable chair strap to keep it in place on the chair back, or make your own and add a strap.
Sewing surface and sewing table heights -- There are actually two sewing surface heights to consider at a sewing table. The first is sewing surface height which is the bed of the machine and where the needle and throat plate are. To determine sewing surface height once proper chair seat height is determined; sit straightly with elbows comfortably at sides and forearms parallel with the floor. Have someone measure from the floor to the bottom of your elbow while seated. This measurement is called seated elbow height. This is the recommended height of the sewing surface or bed of the sewing machine. If possible, adjusted the sewing surface height or the bed of the machine to your seated elbow height. This height allows sewing with elbows low and close to the body, head over spine, and shoulders back.
Sewing table height -- is the height of your sewing table surface which could be a cabinet with an adjustable recessed opening for your machine to set in, or it could be a dining room table or other non-adjustable table surface. Sewing machine cabinets typically have two machine table height adjustments either with the machine on top of the main surface or with the machine bed recessed into the cabinet opening. If possible adjust the sewing surface height or bed of the sewing machine to your seated elbow height in the recessed opening if your cabinet has one. If you cannot lower the machine bed in a recess opening to seated elbow height, you'll have to raise your chair height so that your elbows while seated are even with the sewing surface height or machine bed height. If the sewing table height cannot be changed, adjust the chair seat height to keep forearms parallel with the floor. If seat height is raised, provide a surface so that the non-pedal foot can rest flat on it and thighs remain parallel to the floor. Sit with knees directly in front of hips, feet in front of knees, with foot pedal directly under the foot.
Position your chair far enough under the machine so that you minimize leaning forward. A convenient and very helpful ergonomic tool available today is a tilt table. A tilt table sits under the machine and the back two leg heights are adjustable. It allows the front edge of the machine to tilt slightly downward, minimizing forward lean allowing you to sit up straight. This minimizes back strain from leaning forward and allows for much better and easier viewing of the sewing surface area. The tilt table can even be placed in the recessed opening of a sewing cabinet and for some models an acrylic table can be added to slightly modify your sewing surface with a forward tilt.
A tilt table is wonderful ergonomic tool and is highly recommended to incorporate into your sewing work station.
Creeping or movement of the sewing machine foot pedal can be minimized by adding a rubber mat or double-sided tape underneath or on the bottom of the foot pedal.
Cutting table, ironing board, and big board work surface heights -- Back muscle tension, soreness, stiffness, and pain can result from prolonged periods of leaning, bending, and stooping at the cutting table, big board table, and during ironing if your work surface heights are not adjusted properly for you. The correct height for those work surfaces should be set at hip height. To determine hip height stand straight and raise one knee bending your leg at the hip. Place you finger tips at the bend in your hip and have someone measure from the floor to your finger tips. This measurement is hip height. Adjust your cutting table, big board, and ironing board surface heights to the hip height measurement. An average cutting table height is 36" and typically does not take hip height into consideration. Cutting table or big board work surface heights can be raised to the correct height by placing bricks, blocks of wood, or food cans under the table legs or big board surface. Bed risers can be placed under table legs and are also available from linen stores such as Linen's and Things, or Bed Bath and Beyond, and in the Vermont Country Store catalog. Ironing board heights are usually easily adjustable. If not consider a replacement.
Other sewing ergonomic Issues
When machine stitching -- pinch gripping and awkward or unusual head, arm, neck, and trunk postures may be required particularly if chair and table heights have not been adjusted properly. Prior to machine stitching;
Check chair seat height and make sure it is properly adjusted. Adjust if needed.
Check chair seat back height for proper lower lumbar support. Adjust if needed.
For better task viewing, to reduce neck strain, and to allow for better sitting posture, use a tilt table under the machine.
Sit close to the machine so leaning forward is not needed.
Locate frequently used items close to minimize bending and reaching. Avoid side reaches and bending and twisting while seated. Swivel chairs reduce bending and twisting.
Provide good general overhead lighting.
Provide and adjust task lighting for easy viewing and minimum shadows.
For machine quilting and piecing and for fabric gripping and manipulation wear quilting gloves or rubber finger cots. This also helps keep elbows close to the body.
Whenever possible keep elbows low and close to the body.
Avoid resting arms on sharp edges. When possible sharp edges of work surfaces should be padded or rounded.
Break frequently. Get up and stretch upper and lower body parts.
For fine work -- examples include; visually checking work, frog stitch (rippit), hand hemming, hand and ribbon embroidery, crochet, knitting, hand applique, and hand sewing. Pinch gripping with either or both hands may be required to hold small scissors, ripper, needle(s), thread, ribbon, yarn and fabric while doing hand work. Repetitive muscle movements and prolonged static postures may be required for muscles in the fingers, hands, wrists, and forearms. Finger, hand, wrist, and arm muscle tension, numbness, strain, and pain can result after prolonged work or the next morning upon awakening. Neck and shoulder muscle tension, strain, and pain can result if holding head down for too long and particularly if poor lighting is used as well as eye strain.
For fine work tasks if feasible raise work surface 2-4" above seated elbow height.
Tilt the work surface front edge lower if possible.
Prior to starting work locate items used with easy arm's reach.
Use good task lighting and adjust for best viewing and minimum shadows. The older we get the more light is needed. Use magnification if needed.
Invest in tools designed to promote neutral joint postures and minimize contact stresses such as ergo grip scissors or electric scissors and snips.
Make sure chair seat height and seat back are adjusted properly.
Use a timer in another room set at 20-30 minutes to force break times.
Use rubber needle grippers for hand sewing & hand embroidery.
Use Thread Heaven to reduce thread tension & required pull strength and grip force.
Use thimbles when hand sewing with needles.
Take frequent breaks and do affected body area stretching and strengthening exercises frequently.
RELAX and ENJOY THE PROCESS!
Magnification Supply sources; www.independentliving.com -- a good assortment of many magnifier styles, and www.FirstStreetOnline.com as well.
Scissor work -- Much repetitive movement involved! Scissor work can require repetitive small finger, hand, wrist, arm, and shoulder muscle movements and prolonged and unusual postures. This can result in muscle tension, strain, numbness, and pain to affected body parts after prolonged use. Scissor or rotary cutter work at the cutting table may require bending over the table to reach full fabric length.
Ensure cutting table work surface height is set to hip height to reduce bending, leaning, and reaching.
Invest in tools designed to promote neutral joint postures and minimize contact stresses such as ergo grip scissor, electric scissors and snips.
Keep scissors and snips oiled, cleaned, and sharpened.
Use largest scissor that can accomplish the task.
Use rotary cutter when feasible over the hand scissor.
Take frequent breaks or switch to a less manual task often.
Take extra care, time, and use caution when using rotary cutters. Very sharp and dangerous! Avoid dropping or carrying rotary cutters without securing the blade. Do not permit rotary cutter use by children unless supervised. Use blade guards and secure rotary cutter blades when not in use and between uses.
Good ergo scissors; Fiskars bent/cushioned handles, use snips versus tiny scissors, or small scissors with larger ergo grip handles (Fiskars), may be others. Snips are better than small scissors because they spread the cutting force required out over a larger portion of the hand or over more muscles than just the fingers.
Electric scissors; Black & Decker Power Scissors-Ni-Cad rechargeable battery, cordless, good ergo design, available at either at WalMart or Amazon.com. also Dritz Electric Scissors, others are available
Material handling -- Moving fabric bins, sewing room furniture or stash or bulk fabric to different locations can result in awkward postures and potential arm, back and shoulder injuries. Twisting while lifting or lowering can cause back injuries.
Use proper lifting techniques, keep load close to body. Lift with knees bent, not with back alone. Do not twist while lifting. Use bins with good handles. For heavy objects, use two people. Store heavy containers at waist height or lower. Avoid overhead lifting particularly with heavy objects. Request assistance for heavy items whenever possible.
This article was submitted by Susan Wilkerson.