In this three step guide, we share all you need to know about grip strength and hand dynamometers.Read on for answers to questions such as – what is a dynamometer? How does a dynamometer work? And what is a hand dynamometer used for?Grip strength is rapidly emerging as an indispensable biomarker of health, with thousands of studies highlighting its relevance across various clinical specialties.
It holds tremendous value for healthcare providers and is being integrated into leading clinical practices internationally. However, there is a barrier to easy adoption: a gap between scientific knowledge and practical application.
Literature supports the unquestionable importance of grip strength, but there is a lack of clarity on how to effectively incorporate it into clinical workflows.
This document provides guidance for unlocking the power of grip strength measurements as part of standard care.
We’ve distilled the most respected research on hand dynamometry to provide clear, actionable steps to choose the best dynamometer and integrate grip strength measurements into everyday practice.
First of all, what is a hand dynamometer? And what is a dynamometer designed to do?
A dynamometer is used to measure grip strength. A clinician will use a hand dynamometer to measure how hard a person can squeeze to evaluate muscle strength, monitor changes over time, and assess the risk of conditions like frailty, sarcopenia (muscle loss associated with age), or other health concerns. [1]
There are a few key concepts in handheld dynamometry that are important to understand. These concepts will help you choose an appropriate hand dynamometer for clinical use, as well as apply research findings to your patient population.
The below concepts are aligned with research by Elaine Ewing Fess, a leading voice in defining the components of a clinically appropriate hand dynamometer and published in the Journal of Hand Therapy. [2]
Measurement reliability refers to the consistency or stability of hand dynamometer readings over time without random or systematic errors.
If a measurement is reliable, it will produce the same results under consistent conditions. Reliability and validity are quantified with an Intraclass Correlation Coefficient (ICC) score between 0 and 1.
There are a few requirements that must be met to demonstrate the reliability of handheld dynamometry in a specific device:
Accuracy:
Interrater Reliability:
Test-Retest Reliability:
The clinical hand dynamometer market features a wide variety of devices, and most do not provide measurement reliability.
The three primary categories of hand dynamometers are hydraulic, pneumatic, and mechanical devices, with Bluetooth and digital hand dynamometer versions also gaining popularity.
Jamar hand dynamometers (Jamar and Jamar PLUS+) are the most widely used handheld dynamometers on the market, up until this point considered the gold standard due to reliability and familiarity.
The Jamar / Jamar PLUS+ and GripAble hand dynamometers stand out for their rigorous scientific validation, thorough testing and extensive peer-reviewed research.
As a result, we believe these are the only devices with sufficient evidence to be consistently recommended for clinical best practice, setting them apart in terms of accuracy, reliability, and clinical relevance.
In the following section, we explore the similarities and differences between GripAble and Jamar, and lay out how they compare against each other in the clinical and operational characteristics previously described.
*For this comparison, we assume that the Jamar and Jamar PLUS+ devices are equivalent. Research papers suggest that there is some variability between the Jamar and Jamar PLUS+ [9-13] however, Jamar itself has not published its own comparison study. Despite using different sensing mechanisms, the Jamar and Jamar PLUS+ have the same shape and size. Furthermore, Jamar continues to support the use of their normative data with the Jamar PLUS+.
**There have been revised hand dynamometer norms published since then, but they have not been widely adopted and are not distributed in the Jamar User Guide. [8]
***Some older studies use the Pearson Coefficient Measure. A strong correlation of r > 0.99 demonstrates excellent agreement across measurements, to simplify reporting without separate values for left and right sides. The Pearson correlation coefficient measures the strength of a linear relationship between two variables (quantified as a score between -1 and 1), while the ICC is a measure of agreement for continuous outcomes.
Even the most clinically appropriate dynamometer that meets Fess’s criteria may not align with the fast-paced, data driven demands of modern healthcare systems.
Research with clinicians across various specialties has identified several key challenges in operationalizing grip strength as a benchmark in clinical settings.
The following outlines the main challenges clinicians face when using grip strength as a biomarker in practice, along with solutions provided by GripAble and the Able Assess Platform.
Leading hand dynamometers on the market require periodic returns to the manufacturer for recalibration. For example, Jamar recommends recalibration every 12 months, which incurs significant costs and necessitates the device’s absence from the clinic for weeks.
The GripAble and Able Assess Solution: The GripAble sensor design ensures reliable long-term performance while minimizing the need for frequent recalibration [4].
Rigorously bench-tested, the GripAble sensor has demonstrated its ability to maintain accuracy and calibration even after multiple drops. Additionally, it includes an in-app function that allows clinicians to quickly reset (tare) the sensor to zero for immediate adjustments when needed.
Standard protocol for measuring grip strength requires clinicians to take three measurements on each hand and calculate the average. Manually recording these measurements and comparing them to normative tables or previous results can be time-consuming.
The GripAble and Able Assess Solution: The Able Assess platform streamlines the assessment process by automatically performing calculations. It provides percentile ranks stratified by age and biological sex, along with mid-range averages for similar individuals.
The app allows for a single grip strength test, saving time while maintaining good to excellent test-retest reliability (ICC = 0.91, 95% CI 0.83-0.95 for one trial; ICC = 0.97, 95% CI 0.94-0.98 for three trials) [7]. Additionally, the platform integrates with health records for immediate documentation and efficient outcome comparisons over time.
Published research has utilized various hand dynamometers. Findings from studies using one dynamometer may not be applicable to clinical practice with another, complicating the understanding of relevant results.
The GripAble and Able Assess Solution: A comparative study between GripAble and the Jamar PLUS+ (the most widely used hand dynamometer [3]) now enables findings from studies conducted with Jamar or Jamar PLUS+ to be relevant for populations using the GripAble sensor.
Additionally, a normative data set has been published, enabling the application of percentiles from other publications directly to this data set.
Quick reference sheets for various populations and conditions where grip strength is significant have also been published [link], converting findings into equivalent GripAble measurements.
Note: Conversion of study findings from Jamar to equivalencies with the GripAble sensor are made possible through a comparison study performed with many subjects [3]. While it is appropriate to convert grip strength values that have been calculated at the population-level e.g. risk-based cut offs, these equivalencies should not be used on an individual basis e.g. interchangeable device use for a single individual.
In order to understand the best ways to apply grip strength research to a patient population, it is helpful to understand cut-off points and quantiles.
Cut-off points are single measurements that help determine if a patient is in the “red zone,” indicating high risk. These are especially useful for quick assessments during routine visits or when the patient presents with other conditions. See various resources as grip strength as a biomarker.
Note: Conversion of study findings from Jamar to equivalencies with the GripAble sensor is made possible through a comparison study done with many subjects [3]. While this is appropriate to do at a population level, these equivalencies should not be used on an individual-to-individual basis.
Quantiles show an individual’s grip strength relative to peers, using age and sex-specific benchmarks from normative data to provide a percentile ranking. For instance, being in the 1st quantile (0-25th percentile) indicates lower grip strength than 75% of similar peers.
Clinicians should monitor quantiles to assess patient health over time, particularly noting significant drops into lower quantiles that persist for days or weeks. Such declines warrant further investigation, considering the patient’s comorbidities and risk profile.
Thank you for reading our comprehensive hand dynamometer guide – we hope you found it useful and informative.
For further reading, dive into our extensive collection of studies on using a hand dynamometer, grip strength and more here including:
Get in touch via email to hello@able-care.co or visit our website at www.able-care.co
[1] Shechtman, O. & Sindhu, B. S. American Society of Hand Therapists TM Grip Strength Key Recommendations for Outcome Evaluation of Grip Strength. [Link]
[2] Fess, E. E. . Guidelines for evaluating assessment instruments. Journal of Hand Therapy : Official Journal of the American Society of Hand Therapists, 8(2), 144–148.(1995). [Link]
[3] Mutalib, S. A., Mace, M., Seager, C., Burdet, E., Mathiowetz, V., & Goldsmith, N. Modernising grip dynamometry: Inter Instrument reliability between GripAble and Jamar. BMC Musculoskeletal Disorders, 23(1), 80. (2022). [Link]
[4] Mace, M., Mutalib, S. A., Ogrinc, M., Goldsmith, N., & Burdet, E. . GripAble: An accurate, sensitive and robust digital device for measuring grip strength. Journal of Rehabilitation and Assistive Technologies Engineering, 9(1), 20556683221078456.(2022). [Link]
[5] Mathiowetz, V., Weber, K., Volland, G., & Kashman, N. . Reliability and validity of grip and pinch strength evaluations. The Journal of Hand Surgery, 9(2), 222–226. (1984). [Link]
[6] Mutalib, S. A., Sharma, D., Pike, S., Gwynne, L., Hyde, S., Morehouse, J., Davey, H., Edwards, L., Douglass-Kirk, P., Burdet, E., Goldsmith, N., & Mace, M.. GripAble: Interrater reliability and normative grip strength of UK population. Journal of Hand Therapy. (2024). [Link]
[7] McGee, C.W., Test-Retest Reliability and Precision of GripAble, A Multi-Purpose Exergaming. (2025). [Link]
[8]Jamar_Plus_Hand_Dynamometer_Instruction_Manual_012221. (n.d.). [Link]
[9] Cooper, R., Lessof, C., Wong, A., & Hardy, R. . The impact of variation in the device used to measure grip strength on the identification of low muscle strength: Findings from a randomised cross-over study. Journal of Frailty, Sarcopenia and Falls, 06(04), 225–230. (2021). [Link]
[10] Du, W., Cornett, K. M. D., Donlevy, G. A., Burns, J., & McKay, M. J. Variability between Different Hand-Held Dynamometers for Measuring Muscle Strength. Sensors, 24(6). (2024). [Link]
[11] King, T. I.. Inter-Instrument reliability of the Jamar electronic dynamometer and pinch gauge compared with the Jamar hydraulic dynamometer and B&L Engineering mechanical pinch gauge. The American Journal of Occupational Therapy : Official Publication of the American Occupational Therapy Association, 67(4), 480–483. (2013). [Link]
[12] Lessof, C., Cooper, R., Wong, A., Bendayan, R., Caleyachetty, R., Cheshire, H., Cosco, T., Elhakeem, A., Hansell, A. L., Kaushal, A., Kuh, D., Martin, D., Minelli, C., Muthuri, S., Popham, M., Shaheen, S. O., Sturgis, P., & Hardy, R. Comparison of devices used to measure blood pressure, grip strength and lung function: A randomised cross-over study. PLoS ONE, 18(12 December).(2023). [Link]
[13] Savas, S., Kilavuz, A., Kayhan Koçak, F. Ö., & Cavdar, S. Comparison of Grip Strength Measurements by Widely Used Three Dynamometers in Outpatients Aged 60 Years and Over. Journal of Clinical Medicine, 12(13).(2023). [Link]
Able Care has signed the American Physical Therapy Association Digital Transparency pledge, illustrating our commitment to the fact that digital "physical therapy" services are only performed or directed by licensed physical therapists in accordance with all regulations and APTA’s Standards of Practice for Physical Therapy.
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