Two early dynamometers. An historical account of the earliest measurements to study human muscular strength

An account of two of the earliest dynamometers is presented, together with results of the first experiments attained with them. The Graham--Desaguliers dynamometer was developed in London in 1763 to measure human muscular force, in such a way that synergistic muscles could not impart a false mechanical advantage to the test. The Regnier dynamometer was invented in Paris in 1798 to measure the traction properties of artillery-horses, but was desinged as an all-purpose instrument to measure specific human muscle groups as well. Dynamometers were developed to record human strength along a continuum, to remove the need for a dead-weight or biological standard, and to measure many different groups of muscles, not just those of lifting or pushing. The foundations of modern clinical dynamometry are described.