Based on our research, stimulating muscle impulses and blood flow in limbs the main problem of disabled people. Exercise is necessary both for keeping muscles in the tone and as part of the rehabilitation course, during which a person can again move freely.

Millions of people worldwide suffer from weakness of lower limbs, or paraplegia, as we know it. Some are paraplegic from birth, but paraplegia takes a bigger toll on people who used to run and walk but then all of a sudden we're forced onto a wheelchair due to an unfortunate event like an accident or a stroke. Every passing day that they move around on wheels, they only wish for one thing and that is to be able to get back on their feet. When legs become immobile, the leg muscles waste away making it even more difficult for them to take control of their legs.

In most cases, those who are rehabilitating or recovering only go to physical therapy for an hour or two a few times a week, if they're lucky. This can often be expensive and time-consuming, and not all insurances cover the kind of care that a patient needs. This also means that when one can't be in physical therapy rehabilitating all day, muscles continue to atrophy and to be damaged.  (Source)

Evidence of Beneficial Effect of Physical Therapy After Lower-Extremity Trauma (Link)

Effectiveness of physical therapy treatment of clearly defined subacromial pain: a systematic review of randomised controlled trials (Link)