Johann Christoph Friedrich GutsMuths (1759-1839) was a German teacher and educator, and is especially known for his role in the development of physical education. GutsMuths introduced systematic physical exercise into the school curriculum, and he developed the basic principles of artistic gymnastics. He is thought of as the 'grandfather of gymnastics'.
His book 'Gymnastik für die Jugend' was published in 1800 and was in the English-speaking world a standard reference for physical education. The image above shows some devices that could be found in the book.
The German physician Christoph Wilhelm Hufeland (1762-1836) published the book 'Gemeinnützige Aufsätze zur Beförderung der Gesundheit, des Wohlseyns und vernünftiger medizinischer Aufklärung' about the significance of the different types of physical exercise for human health and life expectancy.
German physician Bernhard Christoph Faust (1755-1842) his 'Gesundheitskatechismus', which contained clear behavioral rules on how to live healthily
The Gymnasticon was invented by the English physician Francis Lowndes (1751-1818). The original function of the device was to exercise the joints, but the device can be considered as the forerunner of the ergometer. The Gymnasticon depended on of a set of flywheels that connected the wooden treadles for the feet to cranks for the hands, which could drive each other or operate independently. The resistance could be increased through springs. The Gymnasticon emerged from the newly developed science of orthopedics, originated by the French physician Nicolas Andry (1658-1742) in 1741. It was an early example of a series of new technologies in gymnastics that would lead to the development of physical therapy in the nineteenth century. Lowndes had previously established himself as an authority on medical electricity. His book 'Observations on Medical Electricity', published in 1787, contained descriptions of a number of cases 'in which electricity has either cured the disease, or given great relief'.
The Regnier Isometric Dynamometer was manufactured in 1798 in London after drawings by the French Civil Engineer and gunmaker Edme Regnier (1751-1823). The device was used for assessing human muscle force and determining clinical progression of neuromuscular weakness. With this dynamometer two types of forces were measured: Pressure force by gripping and squeezing the double steel bow, and Traction force by pulling a single bow.
In 1798 Professor Franz Nachtegall (177-1847) was the first to set up a gymnastics club in Denmark. In 1804 he organized gymnastics in the army and with the support of King Friedrich VII (1808-1863) he initiated also school gymnastics for boys in his country in 1814 and 24 years later for girls. In 1839 he founded a state teachers' college school for the training of gymnastics teachers. One of the first pupils of Nachtegall was the Swede Pehr Henrik Ling (1776-1839), who remained in Copenhagen until 1804, but then returned to his home state where he became the founder of Swedish gymnastics.