Ballistocardiograph or BCG detects and measures recoil of the human body due to the momentum of the blood that the heart is currently pumping.
Ballistocardiography is a technique for producing a graphical representation of repetitive motions of the human body arising from the sudden ejection of blood into the great vessels of each heart beat.[1] To be more specific a BCG measures the impact of blood colliding with aortic arch, which causes the body to have an upward thrust, then the downward thrust of the blood descending.
One Example of the use of a BCG is a ballistocardiographic scale, which measures the recoil of the persons body who is on the scale. A BCG scale is able to show a persons heart rate as well as their weight.
The term ballistocardiograph originated from the Roman ballista, which is derived from the Greek word ballein (to throw), a machine for launching missiles, plus the Greek word for heart and writing.