Grip Strength Measurement with Jamar Dynamometer

Chances are if you have ever been to see a physical or occupational therapist for your upper half, you have seen or used the Jamar Hand Dynamometer. The Jamar Hand Dynamometer is a widely recognized tool in clinical and rehabilitation settings, used to measure grip strength accurately and reliably. This blog post explores what the Jamar Hand Dynamometer is, why it is used, and the normal grip strength ranges for men and women from ages 15 to 75.

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What is the Jamar Hand Dynamometer?

The Jamar Hand Dynamometer is a handheld device designed to measure isometric grip strength. This is why when you squeeze it, it literally feels like you aren’t doing a gosh darn thing (but I promise you are!). It has an adjustable handle that allows for multiple grip positions, accommodating different hand sizes and testing hand strength in more of an intrinsic or extrinsic position. The device provides a digital or analog reading of grip force, usually measured in kilograms (kg) or pounds (lbs).

Features

1. Adjustable Handle: Allows for five different grip positions to assess hand strength at various levels of finger flexion. Position 2 is the standard testing position.
2. Hydraulic Mechanism: Ensures accurate readings by measuring the pressure applied to the handle.
3. Ergonomic Design: Comfortable for patients of all ages, ensuring consistent testing results.
4. Easy To Read Results: There is a red 2nd hand that moves when you squeeze it and will stop where your limit for gripping is, making it easy to read the results.

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Why is the Jamar Hand Dynamometer Used?

The dynamometer is a critical tool for assessing hand function/strength and diagnosing various conditions. It provides objective data that can guide treatment decisions and track progress over time. Grip strength allows us to open doors, open jars, lift and carry laundry baskets, play pickleball, tennis, baseball, football, hockey, and rock climb. We need grip in order to function. Being able to accurately assess grip strength is detrimental in hand therapy.

Common Applications

1. Sports Performance:
   • Used to measure hand strength for sports like rock climbing, tennis, or baseball.
2. Rehabilitation and Recovery:
   • Evaluates recovery after hand, wrist, or forearm injuries such as fractures, tendon injuries, or nerve damage.
   • Monitors progress in conditions like carpal tunnel syndrome, arthritis, or stroke.
3. Pre-Employment Screening:
   • Measures baseline grip strength to determine a worker’s physical capability for jobs requiring manual labor.
4. Medical Diagnosis:
   • Help to detects neuromuscular dysfunctions, such as peripheral neuropathy or muscular dystrophy.
5. Research and Population Studies:
   • Collects data for studies related to aging, health status, and physical performance.

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Normal Grip Strength Ranges

Grip strength varies significantly based on age, sex, and hand dominance. The following table presents the grip strength ranges for the right and left hands in pounds.

Age Group	Men (Right Hand)	Men (Left Hand)	Women (Right Hand)	Women (Left Hand)
15–19	103–126	95–116	64–77	58–69
20–24	101–123	93–113	62–75	56–67
25–29	99–121	91–111	60–73	54–65
30–34	97–119	89–109	57–71	52–63
35–39	93–115	85–104	55–69	50–61
40–44	90–111	82–100	53–66	48–58
45–49	86–106	78–96	51–64	46–56
50–54	82–101	74–91	46–59	41–51
55–59	77–97	70–87	44–57	39–49
60–64	73–91	66–82	42–55	37–46
65–69	66–84	60–76	37–50	32–41
70–74	59–77	53–69	33–46	28–37
75+	53–70	47–61	31–43	26–34

These ranges included in this post are for the population typically seen in outpatient hand therapy settings. Please note: there are ranges for younger than 15 and older than 75 years of age.

In order for an individual to be able to complete basic ADLs, or Activities of Daily Living, one needs AT LEAST 20 lbs of grip strength. Now, we are talking getting dressed, bathing/showering, laundry, doing dishes, meal prep, etc. Some individuals are going to want/need more to do leisure activities or work-related activities. This is where the history gathered during the subjective portion of the eval is critical!

Interpreting the Values

Below Normal: Suggests potential health issues, such as muscle weakness, nerve damage, or systemic illness. The ranges listed above are based on data from the American Society of Hand Therapists and other research studies.

Above Normal: Indicates stronger hand function, often seen in athletes or manual laborers.

Within Normal Range: Reflects sufficient grip strength for daily tasks and functional independence.

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How to Use the Jamar Hand Dynamometer

Using the Jamar Hand Dynamometer involves a standardized process to
ensure accurate and reliable results.

Step-by-Step Procedure

1. Adjust the Handle: Set the handle to the desired position based on the patient’s hand size. The 2nd position is most commonly used for standard testing.
2. Position the Patient:
   • The patient should be seated with the elbow at a 90-degree angle and the forearm in a neutral position.
   • The wrist should be in a neutral position (not flexed or extended).
3. Instruct the Patient: Ask the patient to squeeze the dynamometer as hard as possible for 3–5 seconds. I always remind patients to not push through pain over 4-5/10, or pain that is sharp.
4. Record the Measurement: Note the reading on the dial or digital display.
5. Repeat the Test: Perform the test three times on each hand, with a brief rest between trials. Record the highest or average value.

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Factors Affecting Grip Strength

Several factors can influence grip strength measurements:

• Age and Gender: Men typically have higher grip strength than women, and strength decreases with age.
• Dominant Hand: The dominant hand usually exhibits 5–10% greater strength than the non-dominant hand. Side note: I haven’t seen any research studies on this, but in individuals who are left handed and older than 40-50 years, I have typically seen their Right hand stronger than there left, but in left-handed individuals younger than 40 (more 25 and younger) I have typically seen their Left hand stronger. Interesting observation!
• Health Conditions: Conditions like arthritis, neuropathy, or muscle atrophy can reduce grip strength.
• Effort and Fatigue: Inconsistent effort or muscle fatigue can lead to variable results.

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Conclusion

The Jamar Hand Dynamometer is an invaluable tool for assessing grip strength and providing objective data in clinical, occupational, and research settings. Understanding the normal ranges for grip strength can help identify potential health issues and monitor recovery. Whether evaluating injury recovery, athletic performance, or overall health, the Jamar Hand Dynamometer remains a cornerstone of functional hand assessment.

By following standardized procedures and interpreting the results within the context of individual patient factors, clinicians can make informed decisions that enhance patient care and outcomes.

Here is a link to the Jamar Dynamometer manual. It’s always a good idea to understand the devices you are using in clinic!

While it is not the Jamar Dynamometer (typically can only buy from medical supply websites/stores), if you are looking to check your grip strength at home, check this device out!

Looking to increase your hand strength? Check out my Amazon List Specific To Hand Strength!

Did you learn anything new from this post? Let me know in the comments!

Thanks for learning with me!
-Logan

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