Without more context from the asker, it's difficult to give a conclusive answer. Judging by websites with information on 'zelfrijders' (ignoring sites about farm machinery), the term seems to refer to the common wheelchair as used daily by many 'alternatively perambulating individuals' around the world. The other broad category of wheelchair is the 'powered wheelchair', which - as the name suggests - is not propelled by elbow grease, but by an electric motor.

-> "TYPES OF MANUAL WHEELCHAIRS

Because the wheelchair market is changing so rapidly, there is no universally accepted terminology to describe the various kinds of manual wheelchairs. However, manual wheelchairs sold today generally can be placed in one or more of the following categories..."
http://www.abledata.com/text2/manwhch.htm