Early Dynamometry and Dynamometers

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 Dr. Arieh  N. Gilai. Head, Department of Clinical Neurophysiology, Alyn Children Rehabilitation Hospital, Jerusalem, Israel.

The Dynamometer is a medical instrument designed to measure accurately and quickly muscle group functions for use in a wide range of neuromuscular disciplines. Dynamometry is the precise quantitative measure of strength, endurance and anaerobic power by means of a dynamometer. These measurements are critical for identifying strength deficits, determining clinical progression of neuromuscular weakness as well as assessing the response to an intervention. The graphic record that may result from the use of a dynamometer is called a Dynagram. Dynamometers were invented in Europe during the second half of the 18th century.

Early Dynamometers were very simple mechanical devices that measure the muscle contractile force under isometric condition when the contracting muscle length is constant. These dynamometers were constructed with either in the form of a Steelyard arm balance or with a rigid metal spring. The Steelyard arm balance type shown in figure 1 worked by adjusting a sliding weight on the arm balance until the contracted muscle could just lift the weight. The spring type instruments shown in figure 2, worked by transferring the spring distortion to an amplifying lever connected to a force-indicating pointer. Both of these types could be arranged to measure force in a push or pull mode. In the push mode it is possible to measure handgrip strength of the forearm muscles and in the pull mode it is possible to measure the force exerted by muscles such as the Biceps, Deltoid, Back and various leg muscles.

 Modern dynamometers have an electronic sensor transducers (mostly strain gage) with digital display, and are able to measure muscle force or torque under isometric, isotonic (constant load like weight lifting) and isokinetic (constant rate of muscle shortening) condition, as well as muscular power and endurance. Muscle power is the ability to generate anaerobic force (strength) rapidly (work per unit of time). It is measured by electronic dynamometers capable of measuring forcedynamically while simultaneously measuring the velocity of the movement. In addition, modern dynamometers are capable of measuring muscular endurance, which is the ability to sustain the force generated by muscle groups.
Fig. 1. Graham-Desagulier Isometric Dynamometer. Invented in 1763 and worked by pulling the lever and adjusting a sliding weight on the arm balance until the contracted muscle could just lift the weight.
 Fig.2. Regnier Isometric Dynamometer. This is one of the first instruments invented to measure muscle force. Made in London in 1798 and signed by the French Civil Engineer Edme Regnier (1751-1823) who worked in 106 Houndsditch Street, London (near Liverpool street station). The instrument 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. Applying the force causes two dial hands to move up together, but one “freezes” at the maximum force achieved, while the other follows the grip or pull up or down to show the current force strength. Two scales are engraved on the brass dial plate: A). ‘Scale of Pressure’ divided into Stones and 'Hundredweight' (CWT), from 0 to 2 CWT or 16 Stones full scale (equal to 224 lb.). B). ‘Scale of Traction’ from 0 to 14 CWT or 112 Stones full scale (equal to 1568 lb.)
Four of Regnier’s dynamometers have been registered; (1) the first (see figure 3) is displayed in the Museum of the Physics Department in Urbino University in Italy and (2) a similar model is displayed in the Physics Laboratory of the Technical Institute of Tuscany, Florence, Italy. (3) The third is located in the Musée de l’Armée in Paris. (4) The fourth from the Gilai Collection (figure 2) was owned by  www.gilai.com. Other 19th century dynamometers similar in style to the one invented by Regnier, are: the Charriere Dynamometre (Figure 4), A French undefined instrument (Figure 5), and the George Tiemann’s Dynamometer (Figure 6 and Figure 7c), and an instrument made by the Marine Compass Company.
Reference: 1. Pearn J. (1978). Two early dynamometers. An historical account of the earliest measurements to study human muscular strength. J Neurol Sci. Jun; 37(1-2): 127-34. To see a copy of the complete article press here.
2. David Horne and Elizabeth Talbot (2002). The History of the Regnier Dynamometer. Iron Grip Magazine. Vol. 2, No. 3, July 2002. To see a copy of the complete article press here.
Fig. 3. Regnier's isometric Dynamometerinvented in 1798. This is the French version of the instrument which is similar to the English model described above and is displayed in the Museum of the Physics Laboratory at the University of Urbino, Italy. Accessories for operating the dynamometer in the pull mode include an iron rack, which is held down by foot pressure, double wooden handle with iron hook and two elliptic-shaped iron rings to be used as pull type for back muscles. (http://www.uniurb.it/PhysLab/strumenti/me1.html). 
Figure 4. Charriere Dynamometre. (From the David Horne collection*). This isPush-Pull type dynamometer similar to the one invented by Renier. Made in France by the prolific medical instrument maker Joseph-Frederic-Benoit Charriere (1803-1876). On the instrument are 2 different engraved scales: the first one is "force ord-re des reins“, the second "force ord-re des mains". On the left of the instrument there is an inscription: Echelle de Tirage. Also on the left (a little lower to the right) there is the inscription:

Echelle de Pression. On the upper right side of the instrument is engraved: Kilo's and a little stamp with the initials H.M. and the date 1877. (In my opinion this are the initials of a previous owner of the instrument and the date he purchased the instrument). In the middle of the instrument there is engraved: DYNAMOMETRE, pour les forces, Charriere. The large iron spring is approx. 9.5 inches wide (24 centimeters) and approx. 2.2 inches high (5,5 centimeters). Total height of the instrument measured from the base of the iron spring to the top of the brass part is 6.1 inches (15,5 centimeters).
* I would like to thank Mr. David Horne for providing the picture and description.
 Fig. 5. French Isometric Dynamometer. (From the Millington-Barnard Collection of Scientific Instruments. University of Mississippi Museum). The Dynamometer is a device used to measure force and mechanical power. The dynamometer invented by Edmund Regnier and described by him in 1798, appears to have been used for measuring force. The oval spring at the bottom could be compressed across its short dimension or elongated across its long dimension. The scale mechanism was connected to one side of the spring and the body of the device to the other side. This apparatus is shown in its original padded case, along with various attachments. It was probably purchased by Prof. F.A.P. Barnard for Mississippi in the second half of the 1950s from Lerebours et Secretan of Paris, and cost 250 francs, or about $50. Reference: Thomas Wright, "Dynamometer" in Robert Bud and Deborah Jean Warner, Instruments of Science, and Historical Encyclopedia (Garland Publishing, New York, 1998), pp 195-196
Fig. 6. Tiemann Dynamometer. (From the Bob Greenspan collection). This is a 19th century Push-Pull type dynamometer made of brass and steel by the American company of George Tiemann from New-York. This company has manufactured fine surgical instruments and other medical devices since 1826. Applying the force causes the two dial hands to move up together, but one “freezes” at the maximum force achieved, while the other follows the grip or pull up or down to show the current force strength. http://www.collectmedicalantiques.com 
Fig. 7. Late 19th Century Dynamometers. These are early types of push and pull isometric dynamometers described and used by Jay Seaver, Edward Hitchcock and Dudley Allen Sargent. Hitchcock worked in Amherst College and founded, in 1861, the science of anthropometry and Physical Education in the United States. Sargent worked at Harvard in 1880 and was considered an expert in anthropometry.
Measuring muscle strength with isometric dynamometers was used for many years in strongman championships. Two early examples using Regnier’s dynamometer are listed below. For a detailed list of several amateur and professional strongmen and wrestlers, see a Table in the article by David Horne and Elizabeth Talbot.  
Fig. 8. Pierre Bonnes. A 19th century strongman that participated in many contests. In 1903 he won the World Championships when the lifts contested included the right-hand press and the one-hand swing.  At one time Bonnes held the world record in the two-hand snatch at 253.5 pounds (Willoughby, The Super Athletes).  Interestingly, Willoughby also lists Pierre Bonnes among athletes with superior grips. Bonnes is listed as gripping 298 pounds on a Regnier dynamometer, which was the second highest recorded on the device.  (From an article by Tom Black in http://www.bigsteel.iwarp.com/Gallery/ Gallery7.html).

Fig. 9. Stanley Zbyszkowas born in April 1, 1881 as Stanislaus Cyganiewicz, Stanley Zbyszko was the name he later took for his wrestling career. Early photos of Zbyszko show an impressive development of the upper body with 20 inches neck circumference, 20½ inches biceps and 15 inches forearm that pointed to his tremendous physical power. Zbyszko had trained with weights and his grip strength was measured on a Regnier dynamometer to be 275 pounds. This was near the top of the range and nine pounds better than Charles Batta had done, and Batta was a famous strongman. (Fron an article by Graham Noble. InYo: Journal of Alternative Perspectives June2002).

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