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Active sitting occurs when seating allows or encourages the seated occupant to move. Also referred to as dynamic sitting, the concept is that flexibility and movement while sitting can be beneficial to the human body and make some seated tasks easier to perform. One of the earliest forms of active sitting is the common rocking chair which allows forward and backward swaying motion. In the field of ergonomics, the concept of active sitting is gaining recognition, particularly among people whose work involves prolonged sitting. In the field of pediatric and adult rehabilitation, active or dynamic sitting is of growing interest to individuals who use wheelchairs and adaptive seating, such as children and adults with cerebral palsy and spinal cord injury. ==Active vs. Static Sitting== Active or dynamic sitting is the opposite of static sitting. Static sitting occurs when seating is rigid, and results in sustained mechanical tissue loading. The bodily strain occurring with traditional rigid seating is widely thought to contribute to negative health effects. The human body is not well adapted for long hours spent sitting in a restrictive or constrained posture. In static sitting, the abdominal muscles may instinctively relax and even atrophy over prolonged periods of lessened physical activity. Furthermore, the prolonged postural loading of the spine while sitting, without natural movement and mobilization of the spinal joints, can reduce joint lubrication and increase stiffness, which can be detrimental to back health. Circulation, particularly of the legs, can be adversely affected as well. In fact, back pain and circulation discomfort are part of a growing avalanche of complaints which can be attributed in part to extensive static sitting. Additionally, sustained postures at a computer can place the upper back and neck muscles into positions of strain that, when combined with stress factors, contribute to muscle tension and resulting pain. The field of ergonomics recognizes that only in recent history is a large proportion of the human population sitting for long periods with little movement. The rising number of office jobs, as well as driving, contributes to the increased amount of static sitting that occurs. Furthermore, many wheelchair users are positioned in wheelchairs or other adaptive seating devices that result in a static body posture. Because of the reduced postural stability of these individuals, prolonged sitting may cause them to adopt a flexed spinal posture and posteriorly tilted pelvis. Because these individuals may be unable to physically reposition without considerable assistance, their bodies can be subject to considerable positional strain and immobility, with detrimental physical repercussions. Adverse health effects include the formation of pressure ulcers, low back pain, and lumbar immobility and joint stiffness.〔 Children and adults in wheelchairs or seating devices that are rigid and/or semi-reclined can require significant physical effort to change their body posture on their own. Additionally, positioning accessories may be restrictive in an effort to counteract low tone, to restrain involuntary spastic movement, or to optimize body symmetry. Unfortunately, such positioning effectively prevents development of active postural movement control. Since the spinal motion of these individuals is constrained between their secured pelvis and the backrest of the wheelchair or chair, their potential to acquire an improved ability for active postural repositioning is negligible. Their movement can be limited to that of the upper extremities only. Thus, for wheelchair users, this static body posture may not only lead to physical strain, discomfort, and health issues, but can also interfere with performance of functional movement tasks. The majority of chairs, stools, wheelchairs, and adaptive seating commercially available today still tends to be static, that is, they limit or restrict active postural movement. However, new options for seating are emerging. These innovative products are at the forefront of a new wave of office furniture and adaptive seating device options. These products typically allow some freedom of movement that encourages the human occupant to assume a more dynamic posture. These products may allow the seat and/or backrest to tilt in such a way that it follows and conforms to the movements and physical shape of the seated occupant. In this way, the seating enables dynamic sitting, which enhances functional movement and prevents the physical discomfort and potential bodily damage due to prolonged static sitting. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Active sitting」の詳細全文を読む スポンサード リンク
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