Grip Strength Test

The Grip Strength Test and pinch grip test are used to assess function of the hand, using a dynamometer grip strength.

A loss of hand grip strength or pinch is a measurable factor used in the determination of permanent disability by compensation boards in some states.

How is the grip strength measurement?

A number of protocols using a sealed hydraulic dynamometer, such as the Jamar dynamometer grip strength, have been shown to be accurate, reliable, and valid in measuring grip strength. These dynamometers register force in pounds per square inch, or kilopound per square centimeter, and have adjustable handles to accommodate any sized hand, or any hand that may have a limitation of finger joint motion.

See Also: Hand Anatomy

Studies have demonstrated that the second handle setting of the Jamar grip test allows for the maximum grip strength from the patient.

The widest grip uses mostly the profundus muscles. At the narrowest grip, the profundus and superficialis muscle excursion are fully used, preventing much in the way of their contribution to the over all grip strength.

Unfortunately, these grip tests are not purely objective, as they rely on the sincerity of effort from the patient. Thus a number of tests have been introduced in an attempt to aid in the detection of insincerity of effort.

See Also: Hand Muscular Strength Test

What are the Grip Strength Tests?

The five position grip strength test:

This test uses the Jamar dynamometer and uses the five handle settings to measure grip strength at the five different grip widths. In normal and motivated patients, maximum grip strength occurs at the second or third grip width. The maximum grip strength, recorded at the first or fifth width setting, is supposed to be indicative of an insincerity of effort, although the reliability of the five-position grip strength test has been questioned.

The rapid exchange grip test, rapid simultaneous grip strength tests:

The first test was developed by Lister. Both of these tests use the Jamar dynamometer and compare the maximum grip strength during a five-position static grip strength test, with the maximum grip strength recorded when gripping the dynamometer repeatedly at a fast rate (80 times per minute).

In normal and motivated patients the static measure of grip strength of grip strength should be approximately 15 percent greater than the dynamic measure, while in patients demonstrating insincerity of effort, the dynamic measure is equal to or greater than the initial static measure.

The rapid exchange and the rapid simultaneous grip strength tests are time consuming and frequently performed erroneously in the clinical setting

The rapid repeat test:

The patient is seated with their arm by their side, the elbow in 90 degrees of flexion, and the forearm and wrist in neutral. The dynamometer, set at the second handle setting, is supported by the clinician and the patient alternately grips with both right and left hands on ten occasions, or until the patient has to stop due to fatigue or discomfort. This test has been found to be an unreliable discriminator of true and faked hand weakness.

It is probably wise to combine the results of different grip strength tests before making any decisions

Grip Dynamometer

Use of a grip dynamometer provides a quantitative assessment of grip strength. The patient holds the grip dynamometer with the elbow flexed to 90° and the radioulnar joint in its neutral position.

The dynamometer is set at one of five specified settings (1, 1.5, 2, 2.5, and 3 inches). The patient squeezes the dynamometer’s handle with maximum force at every setting, with adequate recovery time allowed between bouts. The values are recorded, and the test is repeated on the opposite hand.

More than 10% bilateral strength deficit compared with the opposite hand. Because of the wide range of variation in grip strength, the outcome of each of these tests is most meaningful when compared with a baseline measure. This test can be repeated three times at any one setting and the results averaged.

References

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2. Thorngren KG, Werner CO. Normal grip strength. Acta Orthop Scand. 1979 Jun;50(3):255-9. doi: 10.3109/17453677908989765. PMID: 474096.
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9. Lister G: The hand: Diagnosis and Indications, 2nd ed. New York: Churchill Livingstone, 1984.
10. Joughin K, Gulati P, Mackinnon SE, et al: An evaluation of rapid exchange and simultaneous grip tests. J Hand Surg Am 18A:245–252, 1993.
11. Hildreth DH, Breidenbach WC, Lister GD, et al: Detection of submaximal effort by use of the rapid exchange grip. J Hand Surg Am 14A:742– 745, 1989.
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13. Gunther, CM, et al: Grip strength in healthy Caucasian adults: reference values. J Hand Surg Am, 33:558, 2008.