Human with physical disability or mental illness often need wheelchair for executing everyday activities. Prolonged sitting in wheel chair can cause physical injuries such as spinal degeneration, Low back pain, obesity, pressure ulcers and other bio-mechanical health issues. Modern wheel chairs are equipped with assistive seating system with the intent of providing comfort and correct sitting posture to the human. This generally prevents injuries to the person sitting for extended duration on a wheel chair. Due to multiple human and ergonomic parameters such as body weight, height, age, duration of sitting etc. it becomes difficult to accurately predict the effectiveness of seating system in providing comfort to the person using wheel chair. This book is aimed at preliminary investigation of Human body and its Biomechanics when seated in wheel chair for prolonged durations and to particularly apply this analysis to individuals with physical disabilities using computer codes written in MATLAB