Post 537 by Gautam Shah
Postures are some of the body-positions we use to conduct tasks. These positions or postural arrangements may need additional supports, reach tools and transfer utilities. Such postural arrangements are fairly persistent, but could be transient. All body postures have few things in common, such as: the manner of gaining and exiting out of a posture, achieving a stable or consistent position, confirming and exploiting the gravity for stability and transit to another posture and accommodation of minor shifts to relieve fluid pressures and muscle fatigue. Postures, along with the supports, reach tools, and transfer utilities, projects a behavioural attitude. When a person realizes this, the posture is modified.
A posture as a body arrangement is a utility, with or without concurrent facilities. It increases the efficiency of work, rest, expression and communication. Postural arrangements develop due to many reasons such as the traditions of tasks handling by the society reflecting the local materials, processes, technological developments, customs and manner of accompanying interpersonal interactions. Some postural positions are affected by the body physique or stature, age related disabilities, training, anthropometric variations and climate. Postural positions are adopted from one task situation to another, due to the habit and predictable results. Postures differ according to age profiles, gender of the person, experience and incentives.
The prime influencing factor for postures is the gravity. Gravity affects the posture in static, mobile, and during transition from one posture to another. The body is rarely in a static condition, some degree of dynamism occurs due to body sway, respiration, restlessness, repositioning to adjust body fluids, metabolic activity and perspiration evaporation. Nominally in a static position with head held ‘high’, the centre of gravity lies near the sacral segment (pelvic bone). Its location can vary according to body stature, age, and sex. It may shift upward, downward, or sideways with new position of the body and limbs. The line of gravity is directed downward, and if falls within the base or ‘footprint’, the person is stable, or else needs an additional support for stability. Body-fat, clothing, footwear, hand held or shoulder carried baggage and walking with someone are some of the factors that shift the position of centre and line of gravity. Such constant shifts affect the personal gait, bearing, metabolism, respiration and muscular-skeletal system.
Centre of gravity and line of gravity have some correlation. A lower centre of gravity creates a shorter line of gravity leading to stability. A very low centre of gravity with a very wide body base, such as in case of supine body, very stretched out body (as on beach sands), or sitting in very low -deep seat makes it difficult to shift the body to any other posture. The reclining body has reduced energy usage, circulatory stresses are better managed.
Visitors room, casual meeting cubicles, personal secretaries, peons, snack-bar attendants, who need to shift the body-positions frequently are provided with a straight back and slightly taller then normal height sitting arrangements. Elders, who have difficulty in shifting the body posture without a support, need a flatter, levelled and taller seat with full depth and slightly taller then normal hand rests. The same is partly relevant for seats on Metro and city bus systems. Seats are curved in width and depth directions. The width curve restricts sideways shifts, making the posture more fixed, whereas depth curve makes getting out difficult. Bucket seats as in airlines and cars have bends in both the directions, to restrict passenger movement and fully support the body against sway in case of accident. The body contoured forms of seat elements are rendered useless, when the seat, back or hand rests are adjustable like through tilting, compressive cushioning or seat height adjustments.
Direction of weave for seat furnishing fabrics are more accommodative (stretchable) in weft direction and are oriented width wise. To overcome this directional accommodation of fabrics for space-ship seats bi-directional, formed through knit-weaving. The fabric fibres are so formed-spun that cushions are not required to adjust the fluid circulatory issues.
A proper posture, whether standing, sitting, crouching, squatting, kneeling, crawling, lying or sleeping, allows tummy to nominally remain withdrawn, even during inhalation. This can be done through training and exercise, but also by planning for posture in-out procedures. A bed that allows one to turn sideways to rise-up; a chair slightly wider and strong enough to lean on one of its sides to get out of it; a dining or worktable that discourage bend-forward sitting; paths or stairs of consistent passageways (visual, sensorial qualities and functionality, like colour, texture, gradient and side supports) where one need not be bothered about inconsistencies; are some examples that help provide ‘a tucked-in tummy’ posturing. A correct posture encourages good metabolic activity, which in turn determine the quality of health and performance. Both of these govern the stress the body takes.