Gymnasticon is a machine that modern stationary bikes are based on. It was an early exercise device invented by the Francis Lowndes back in 1796. He invented a machine to exercise joints of the whole body. Gymnasticon invention was a contribution to orthopedics and it led to massive development of physical therapy in the 1800s.
Gymnasticon had flywheels in junction with wooden wheels which were connected together. This complete mechanism together represented a resistance mechanism.
Francis Lowndes described this exercise machine as “Machine which will give and apply motion and exercise, voluntary or involuntary, to the limbs, joints, and muscles of the human body“.