Strength

Grip Strength (Jamar Dynamometer)

Maximal isometric grip force of the hand and forearm. Widely used as an index of upper extremity function and overall strength status.

Administration

Standardized position (American Society of Hand Therapists): seated, shoulder adducted and neutrally rotated, elbow flexed to 90 degrees, forearm neutral, wrist between 0 and 30 degrees of extension.
Jamar dynamometer set to the second handle position unless hand size dictates otherwise; record which position was used.
Three trials per hand; record the mean of the three trials.
Allow rest between trials and alternate hands to reduce fatigue effect.

Normative data

Adult grip strength means, ages 20 to 39verify before clinical use

Age group	Male right	Male left	Female right	Female left
20-24	121	104	70	61
25-29	121	110	74	64
30-34	122	110	79	68
35-39	120	113	74	66

Mean values in pounds (lb). Verify against the published table before clinical use; full norms cover ages 20 to 75+ with standard deviations.

Source: Mathiowetz et al., 1985

Interpretation

Compare the mean of three trials to the age- and sex-matched norm. A between-hand difference of roughly 10 percent favoring the dominant hand is a commonly used rule of thumb, though published data show wide individual variation.

References

Mathiowetz V, Kashman N, Volland G, Weber K, Dowe M, Rogers S. Grip and pinch strength: normative data for adults. Arch Phys Med Rehabil. 1985;66(2):69-74. PubMed