Manual Wheelchairs - World Health Organization

2.4.3 Pushing efficiency
desIgn and productIon I 53
Pushing efficiency is related to the amount of energy required for the user to push the wheelchair
over a given distance. Lighter wheelchairs are normally easier to push, but there are many factors
and wheelchair features that affect how difficult or easy it is to push one’s wheelchair. Ways of
improving the pushing efficiency and their associated advantages and disadvantages are shown
in Table 2.9.
Table 2.9. Aim: to improve pushing efficiency
Advantages Disadvantages
By moving the rear wheels forward in relation to the user
See Table 2.7 for related effects.
By optimizing seat width and putting the push rims in line with shoulders
n User will not have to reach out for hand rims.
By putting camber in the rear wheels
n Brings the top of the hand rims closer to the body and
more in line with the user’s natural push stroke.
See also Table 2.5 for related effects.
With an aligned wheelchair; wheelchair is in good condition and working order
Note: A wheelchair with a broken or misaligned component (e.g. untrue wheels, distorted frame, broken bearings
causing friction, unparallel wheels or poorly inflated pneumatic tyres) resists the user’s forward motion, thereby wasting
much of the user’s pushing energy.
For use on smooth ground, use harder tyres
n Harder tyres (which deform less) have lower rolling
resistance on smooth ground than softer tyres, all other
factors being equal.
n Solid tyres can never fail the user by being punctured.
n Harder/solid tyres provide little shock absorption.
n Solid tyres are difficult to repair or replace (unless a
supply of replacement parts is available).
For use on imperfect surfaces (such as outdoors), use tyres that return energy and “spring back”
(such as pneumatic tyres)
n Tyres that return energy have lower rolling resistance
than those that dissipate energy (i.e. they deform
but return to shape slowly, such as solid foam tyres or
inserts).
n Pneumatic bicycle tyres are relatively easy to repair with
the right facilities.
n Spikes or knobs, such as those on mountain bike tyres,
cause additional flexing of the tyre and thus higher
rolling resistance.
n Pneumatic bicycle tyres can be punctured.
For use on imperfect surfaces, use larger-diameter wheels that have lower rolling resistance
than smaller wheels of similar construction
2