Modern armies need to move troop’s long distances at very short notice, by land, sea or air. As most people who have travelled long distances will testify, fatigue at the end of the journey is not uncommon. Troops that are seated comfortably are much less likely to suffer seating pain and will be able to perform more efficiently. They will be more alert, suffer less fatigue and ready to go into action much quicker. How are these improvements made? By sitting the troops on a seat that:-
* Reduces pressure and increases venous blood flow in the legs.
* Automatically adjusts seating posture to a more relaxed position.
* Improves physiological conditions associated with circulation.
Two UK companies, ACS International Ltd and Seating Design and Development Ltd (SDD), are in the forefront of developing seats which make all this possible.
The ‘MouleTec’? seat concept was invented by the late Terry Moule, who had been involved with vehicle seating for over twenty years utilising his 40 years’ experience as a qualified Osteopath and Naturopath specialising in back and posture problems. Terry had worked closely with SAAB on seat design and cabin ergonomics. Other consultancy had included work for Rolls Royce, Ford, Vauxhall (including a 2 year “campaign for comfort”) plus design, consultancy and ergonomic advice for a number of other automotive manufacturers. He also wrote for “What Car?” for 4 years on Seating & General Comfort.
How does the seat achieve this?
We sit on the ischial tuberosities (the bony prominences at the buttocks), where many nerves, arteries, veins pass and where the muscles at the rear of the thigh originate. They assist in movements of the hip and knee joints.
The action of sitting, causes increased pressure on these and the thighs leading to reduced venous blood flow (blood returning to the heart from the legs), and reduced sensation in the lower limbs.
ACS International Ltd has helped develop the ‘MouleTec’? concept for military use utilising both the multi-density foam cushion and hard moulded polycarbonate variants.
In the case of the soft padded cushions the densities of the foam will be varied to spread the load on the thighs and buttocks, to reduce pressure as desired. Although the hard mouldings are made from a fairly rigid polycarbonate material the moulded shape still gives “unconscious positional control” when people of varying, size, height and weight (5th to 95th%ile) are needed to sit on the seat for long periods of time.
The diagram on the left is a pressure map of a person sitting on a standard seat and the one on the right of a MouleTec seat. The outline is of the persons thighs. The bright red areas are the highest pressure graduating to blue as the lowest.
Preliminary medical and ergonomic testing and evaluation has been conducted at Loughborough University where improvements to the venous blood flow from the legs are noticeably improved. Therefore personnel sitting for long periods of time will generally feel less tired and stiff. It is also anticipated physiological conditions associated with circulation, such as DVT (Deep Vein Thrombosis) may be alleviated.
To substantiate these claims testing has been carried out by Prof. Andrew Bradbury 1, in the autumn and winter of 2004 / 2005. He used 10 subjects sitting for 7 hours in standard economy class aircraft seats. This was then repeated with the same subjects in MouleTec seats. On both occasions the effect on the venous blood flow volume2 from the lower leg was measured. Bradbury concluded3, “……When compared to a standard seat, use of the ‘MouleTec’? seat was associated with:
* A reduction in subject reported lower limb venous symptoms
* Better preservation of lower limb venous function on objective testing
Specifically, when compared to a standard seat, use of the MouleTec seat for 3 and 6 hours was associated with increased:
* Ejection volume (EV) as measured by photoplethysmography (PPG)