How to Choose the Correct Hand Dynamometers for Your Practice

Learn how popular hydraulic hand dynamometers compare to digital and Bluetooth counterparts and assess which one is best for your clients

Hand dynamometers are bread-and-butter tools for physical therapists, occupational therapists, sports medicine practitioners, and more. Used to measure hand grip strength and the isometric strength of other upper body muscle groups, these handy tools are frequently employed to track rehabilitative progress after injury or surgery.

Beyond their usefulness in evaluative applications, hand dynamometers are used as a predictive tool. Numerous studies have shown that hand grip strength is correlated with longevity and overall health, and can even help predict the risk of cardiovascular disease. Because these small, portable devices can reveal so much about a person’s health and strength, they are a staple in physical therapy clinics and doctors’ offices.

But with a great variety of applications also comes great variety of product types. Navigating the crowded market to select the perfect hand dynamometer for your needs can be overwhelming – whether you’re looking to invest in your first hand dynamometer or are in the market to replace or upgrade an old one. Below, we’ll break down the different types of hand dynamometers and compare some of the most popular models.

Types of Hand Dynamometers

Hand dynamometers fall into three primary categories: hydraulic, pneumatic and mechanical (aka Smedley). Hydraulic and pneumatic devices do not use moving parts – as their names imply, hydraulic types use liquid and pneumatic types use air to measure strength and force. Mechanical devices do use moving parts. Within each category, there are analog, digital and, sometimes, Bluetooth options.

In this comparison, we will focus on the most commonly used type of hand dynamometer: hydraulic, and its digital and Bluetooth counterparts.

Comparing Hydraulic, Digital & Bluetooth Hand Dynamometers

	Jamar Hydraulic Hand Dynamometer	Jamar Plus Hand Dynamometer	KINVENT K-Grip Hand Dynamometer
Maximum Grip Force Measured	90 kgs	90 kgs	90 kgs
Number of Grip Positions	5, from 1.375” to 3.375”	5, from 1.375” to 3.375”	Multiple, sizing may be modified with soft TPE detachable grip covers
Reading	Peak-hold needle	LCD display	Transmitted via Bluetooth to KINVENT Physio App
Maximum Number of Trials Before Resetting	One	Five	Unlimited
Accuracy	Highly accurate, when calibrated, and read and interpreted properly	Highly accurate, when calibrated	Highly accurate: within 0.2% of reading
Ease of Use	Fairly easy, but calculations must be done manually, and consistent maintenance is required	Easy, calculations are completed automatically	Extremely easy, biofeedback is sent to the app and analyzed in real time
Weight	1.5 kg	1.8 kg	0.2 kg
Power Source	Hydraulic fluid	2 AAA batteries	Rechargeable battery
Average Lifespan	10 to 15 years; up to 40 years if impeccably maintained	5 years	New entrant to the market; data not available at this time
Base Price	$270.53	$427.87	$490.00
Calibration Cost	Generally, under $150	Generally, under $150	Generally, under $150
Calibration Frequency	Once per 12 months of use, and when dropped or subjected to other severe movement	Once per 12 months of use, and when dropped or subjected to other severe movement	Once per 12 months of use; calibration not required when dropped, etc.
Additional Costs	N/A	N/A	KINVENT Physio App subscription: annual plans start at $350
Replacement Parts Available?	Varies; if oil leaks, the entire device must be replaced	No	Yes
Approximate Total Cost Range (Based on 10 Years of Use)	~$2,500 to $3,000*	~$3,000 to $3,500*	~$5,000 to $6,000***

*Range includes one device and the approximate cost of two to three annual calibrations
**Range includes the approximate cost of two to three annual calibrations and assumes a new device will need to be purchased at the 5-year mark
***Range includes one device, the approximate cost of one annual calibration, and varies based on selected app subscription

A Deeper Dive

Jamar Hydraulic Hand Dynamometer

Frequently cited as the “gold standard” tool for measuring grip strength, the Jamar Hydraulic Hand Dynamometer has excellent test-retest reliability. The Jamar dynamometer was developed by a physical therapist, engineer and machinist at the bequest of an orthopedic surgeon in the 1950s and its design has changed very little since then. It is a fixture in doctors’ offices, has been relied upon to conduct countless clinical studies and is the tool recommended by the American Society of Hand Therapists (ASHT) to measure grip strength.

But, despite its stellar reputation and ability to generate highly reliable data, users must frequently check all parts (including posts, hydraulics, handle and peak-hold needle) to ensure the accuracy of readings. Further, the analog nature of the device makes it somewhat outdated compared to its more technologically enabled peers. The time it takes to set up and reset tests and collect and analyze data is inefficient and pulls focus from patients.  

Pros:

• Tried-and-tested model, trusted by industry experts, including ASHT
• Lowest initial cost, compared to digital and Bluetooth (though the total lifespan cost may exceed the total cost of digital and Bluetooth dynamometers, depending on how frequently the device must be calibrated)

Cons:

• Hydraulic fluid may leak and, if it does, repair is impossible
• Can be temperamental and may require more frequent recalibration
• Due to the device’s weight, testing and measurement may be difficult or skewed for elderly patients
• Manual calculations are prone to error and time-consuming, so less time may be spent focusing on patients
• It takes time to set up the device and reset it after each test

Buy this if: you are looking for an accurate and reliable hand dynamometer without any bells and whistles – and are willing to put in extra legwork when it comes to reading and calculating results.

Jamar Plus Hand Dynamometer

The Jamar Plus Hand Dynamometer is a more sophisticated version of its hydraulic counterpart. Like the hydraulic model, Jamar’s digital dynamometer is highly regarded by physicians and industry leaders. In many ways, the Jamar Plus delivers all the benefits of Jamar’s hydraulic dynamometer – while solving many of the original device’s pitfalls.  

Unlike the hydraulic model, the digital model uses precision electronic load cells – and not hydraulics —to measure strength, which eliminates the possibility of oil leakage. The digital device is easy to use: the type of test, number of trials, and test reset can all be controlled with a click of the button. Grip force measurements and calculations (including average, standard deviation and coefficient of variation) are calculated and displayed on the LCD display automatically, thus reducing the possibility of user error and saving time.

Pros:

• Same, stellar industry-leading reputation as the hydraulic Jamar
• More efficient than the hydraulic Jamar
• Readings and analysis less prone to user error than the hydraulic Jamar

Cons:

• Like the hydraulic Jamar dynamometer, the device’s heavy weight may prohibit testing or generate invalid data for elderly patients
• Replacement parts are not available
• Relatively short lifespan (generally around 5 years)

Buy this if: you want the reliability of Jamar’s hydraulic hand dynamometer but with the added convenience and time-savings benefits of a digital device.

KINVENT K-Grip Hand Dynamometer

While KINVENT's K-Grip Hand Dynamometer is a newer entrant to the hand dynamometer market, it is a strong competitor to Jamar’s hydraulic and digital dynamometers. And, though the K-Grip may not yet be as widely used as Jamar dynamometers, it has proven to be as reliable as its more well-known predecessors: a recent study confirmed the K-Grip “can be used as an alternative to the Jamar Plus Dynamometer.”

The most technologically sophisticated of the three devices, the K-Grip transmits data to the KINVENT Physio App via Bluetooth in real time – which makes testing and reporting easier, faster and more foolproof. The streamlined, efficient process allows physicians to spend more time focused on rehabilitating patients and devising care plans that drive improved health outcomes.

Pros:

• The speed with which numbers are generated and automatically analyzed make KINVENT testing the most efficient of the three options
• Data and analyses are stored in the app, and may be easily shared with other members of a patient’s care team
• The light weight of the device means patients of all ages and strength levels will be able to use and generate accurate data with the device
• The device generally does not need to be calibrated as frequently as hydraulic and digital dynamometers, and is far less sensitive to being dropped or strenuously handled
• Replacement parts are available, and repairs may be made easily

Cons:

• The most expensive of the three options

Buy this if: you want a cutting-edge, top-of-the-line hand dynamometer that’s hyper efficient and easy to use – and plan on investing in other Bluetooth biofeedback devices that connect to the KINVENT Physio App.

Still Not Sure Which Hand Dynamometer Is Right for You?

Depending on your practice, your patients, and your budget, any of the hand dynamometers highlighted above may be suitable for your unique needs. If you still aren’t sure which device is right for you – or just want to talk through your options – contact JLW Instruments to speak to a hand dynamometer expert. We stock and calibrate a wide variety of hand dynamometers (including the Jamar Hydraulic, Jamar Plus and KINVENT K-GRIP) and can assist in selecting the device that will best serve you and your patients.