Are you Sitting Comfortably?
Achieving a good sitting position is the result of a number of interrelated factors involving the support surface, the chair, supporting the body.
The head positioned centrally to a straight spine and shoulders facilitates interaction with people and surroundings.
Supported arms help maintain trunk and shoulder position and provide arm support for activities.
If the back and neck are in line with the pelvis this maintains a central position and ensures support for the head.
Supported and well-positioned pelvis will maintain a functional head position and avoid twisting and rotating which can cause the spine to flex and bend.
Straight, vertical pelvis assists with even weight distribution across the seat’s surface whilst maintaining the spine’s “midline”, symmetrical position ensuring that internal organs and blood supply function effectively, improving breathing and digestion.
Ramped seat angle helps to keep the pelvis upright and prevents sliding forward or “shearing” which puts stress on the skin and the muscle tissue.
Supporting the feet helps to distribute the weight of the legs onto the floor and by keeping the knees at the correct height so thighs are level, reduces pressure on the underside of the thighs allowing full circulation to lower legs and feet.
Important Elements of Good Seating
For those who have limited ability to make small changes in movement, it is important to consider “dynamic” seating. Dynamic seating has a range of adjustments to tailor the chair to the user’s physical requirements to prevent the user becoming “fixed” in the same shape as the chair they are using. It enables posture and body weight to be adjusted throughout the day to prevent pressure build up in isolated areas.
Tilt in Space
Tilt in Space enables the occupant to be tilted forwards or backwards in a chair whilst maintaining the position of the knees and hips. A resting position can be achieved whilst maintaining their posture and pelvic position. By keeping the angle between the chair seat and back at around 110°, the occupant will not slide forwards into an uncomfortable, slumped position. Tilting the body has the effect of distributing weight over a larger contact surface providing a simple and effective way to combat the build up of pressure.
Elevating Footrest or Legrest
Lymphatic and blood circulation can be reduced through age or illness. Circulation to the legs is affected by the ability of the heart and arterial system to pump blood around the legs. Lifting and straightening the knees has the effect of allowing the blood to circulate more easily, reducing the effort required by the heart and arterial systems. Raising the legs is also used to help alleviate leg oedema, a build up of fluid in the legs.
Back Angle Recline
Traditionally, the independent back recline has facilitated resting or napping and is ideal for those who are able to maintain their position independently. However, for those less physically able to sustain pelvic stability, a back angle recline in conjunction with a steeply ramped or angled seat enables the benefit of a resting position or an upright position for meal times to be realized by this user group too.
Age and disability can lead to problems getting up from furniture due to reduced muscular strength and impaired functioning of the joints. Raise facilities within furniture gently lift individuals to a standing position without significant pressure placed upon limbs and joints whilst stability and positioning is maintained by ensuring the feet remain close to the floor.
Skin and muscle tissue are constantly subjected to pressure caused by body weight or friction. The effects of these pressures will vary between individuals according to health, weight and ability to correct and change posture. Distributing body weight over a larger surface area will help reduce pressure but in acute cases the introduction of special pressure relief cushions can improve relief and help prevent the development of pressure sores.
The contact surface between user and chair has great significance. Body temperature, perspiration and tactile response are dependent on the finish and quality of the material used to upholster the chair. The practicalities of keeping a chair clean must be considered along with its appearance. Durability and wear are also important elements in choosing the right material for a chair.