REPORT RE THE KNEELSIT BALANCE CHAIR
The Kneelsit chair is similar in concept to the Balans Kneeling chair. However, all of the
problems of the Balans chair, which brought this innovative form of seating into disrepute and caused such
poor reviews in the literature, have been overcome in the Kneelsit Balance chair.
The problems of the Balans kneeling chair were:-
1) Lack of back support required the erector spinae to work constantly to maintain the lordosis.
If one has a chronic low back condition, the back musclature is already weakened. If the chair requires
the back muscles to constantly contract, they will quickly tire in the person with back problems,
leaving the seated person in a slumped position, which immediately increases the pressure on the disc.
2) Pressure on the shins was quite intolerable in many instances.
3) Ingress and egress from the chair was quite difficult.(Cram & Vinitzky, Drury & Francher, Lander et al,
The Kneelsit chair overcomes all these problems whilst maintaining the benefits of a forward
a.) The lumbar support is adjustable from the seated position to support the back through all the available
ranges of forward tilt of the seat pan.
The lumbar rest also allows the sitter to recline in a supported position. Thus the erector spinae are relaxed
while the lumbar spine lordosis is maintained at all times , not only by the lumbar rest but by the forward
inclination of the seat, which allows for a greater degree of extension of the hip joints.
Background to the forward-sloping seat:-
Keegan showed (1953), when discussing the disadvantages of the cubist or 90º hip/trunk position in
sitting, that this position is achieved by 60º of hip flexion and 30º of lumbar flexion & pelvic rotation.
As a result lumbar lordosis is reduced and the disc pressure increased.
Mandal (1976) was the first to write of the benefits of tilting the seat pan forward, thereby reducing
hip flexion and making it easier to maintain lumbar lordosis without active muscle contraction.However
Mandal's suggestion the seat should be inclined forward to 15º met with severe criticism because of the
weight forced onto the feet, the feeling the chair was ejecting the sitter, and the problems of the clothes
rucking (Drury ∓ Francher, Graf et al). It is now universally accepted a forward tilt seat promotes
better posture not only by opening out the hip/trunk angle but by altering the centre of gravity
The forward tilt seat is particularly beneficial to those involved in intensive keyboarding or
a.) The Kneelsit chair's adjustable forward tilt seat allows just such an open position of the hip/trunk
but there is no sensation of increased weight on the shins no feeling of ejection from the chair,
and no sensation of the clothes rucking.
b.) The seat and shin pad of the Kneelsit chair are adjustable to individual lengths of thigh and shin and
move to a variety of tilts via the unique axle system. The shin rest is suitably deep and wide to distribute
pressure evenly and there is no sensation of undue pressure over the tibiae.
c.) The shin rest drops away to a vertical postion when weight is taken off it to allow ease of ingress
d.) The unique axle system of the chair allows movement from a reclined position to a forward position
without the necessity of adjusting levers. This makes the chair ideal for people working in a keyboard
intensive task or a communication/ meeting situation. This ease of movement allows the sitter to change
positions frequently, and also allows, if not encourages, movement of the spine from the lordosed to
flexed position, thus improving nutrition to the discs. (Mackenzie)
The Kneelsit Balance Chair combines the best features of seating to ensure an excellent posture no matter
what the task.
Cram J.R., Vinitzky I., Effects of chair design and back muscle fatigue. J. Occ.Rehab. 5 (2) 1995
Drury C., Francher M., Evaluation of a forward sloping chair. Applied Ergonomics 16. 1. 41-47 1985
Lander C., Korbonn G., De Good D., Rowlingson J. The Balans chair and its semi kneeling position;
an ergonomic comparison with the conventional sitting position. Spine Vol 12 No. 3 1987
Pheasant S. Ergonomics, work and health. Aspen Publications USA 1991
KeeganJ. Alterations of the lumbar curve related to posture and seating.
J.B.J.S. Vol. 35A No. 3 July 1953
Mandal A.C. Work chair with a tilting seat. Ergonomics Vol. 19 No. 2 1976
Graf M., Guggenbuhl U., Krueger H. Investigation on the effects of seat shape and slope on posture,
comfort and back muscle activity. Int. J. Ind. Erg. Vol. 2, 91-103, 1993
Stewart P., McQuilton G. Straddle seating for a cerebral palsy child Physiotherapy.
Vol. 73 No. 4 1987
Mackenzie R. Treat your own back. Spinal Publication NZ Itd. 1985,