Evidence map›Paper›PMID 42061870›Full record

ArticleJMIR human factors2026

Grip Strength Estimation Using Input Data From a Commodity Smartphone: Model Development and Validation Study.

Komei Tajima, Kaori Ikematsu, Toshiya Isomoto, Kunihiro Kato, Yuta Sugiura

Abstract readValidation Study
In one paragraph

Article in JMIR human factors, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

What it found

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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0 citing papers in PubMed.

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4 · The record

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PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Komei TajimaDepartment of Information and Computer Science, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, Yokohama, Japan.ORCID 0009-0008-0258-3883
Kaori IkematsuLY Corporation, Tokyo, Japan.ORCID 0000-0002-7017-6744
Toshiya IsomotoLY Corporation, Tokyo, Japan.ORCID 0000-0003-3054-313X
Kunihiro KatoJapan Women's University, Tokyo, Japan.ORCID 0000-0002-0117-8981
Yuta SugiuraDepartment of Information and Computer Science, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, Yokohama, Japan.ORCID 0000-0003-3735-4809

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundGrip strength is a crucial indicator of muscle deterioration, recovery, sarcopenia, and neurological disorders. However, conventional measurement requires a dedicated dynamometer, which limits accessibility and requires specific movements.

objectiveThis study aimed to propose and validate a method for estimating grip strength using standard smartphone operations, thereby eliminating the need for specialized equipment.

methodsData were collected from 21 young adults in the main experiment, who performed standard smartphone tasks (tapping, flicking, and dragging) after measuring their grip strength with a dynamometer. A predictive regression model was developed using touch and inertial sensor data. The model was first evaluated using a random split of the entire dataset (random split evaluation). To further assess practical feasibility and generalizability, we conducted leave-one-user-out validation and a few-day calibration validation; the latter simulated a calibration scenario by incorporating 1 to 4 days of user-specific data into the training set.

resultsThe regression analysis using a random split of the dataset demonstrated high accuracy, with a mean absolute error of 2.62 (SD 0.18) kg, a mean absolute percentage error (MAPE) of 8.91% (SD 0.57%), and a coefficient of determination of 0.802 (SD 0.036). In the validation of practical scenarios, the leave-one-user-out validation resulted in a MAPE of 15.08% (SD 5.40%). However, the personalized few-day calibration model showed significant improvements as calibration days increased, with the MAPE decreasing to 13.96% (SD 5.57%) after 1 day and reaching 11.64% (SD 5.80%) after 4 days. Furthermore, the National Aeronautics and Space Administration Task Load Index assessment indicated a low overall subjective workload (mean 3.04, SD 2.23 on a scale of 10), confirming the method's suitability for daily use without a significant burden on users.

conclusionsThe proposed method demonstrates that smartphones can serve as a viable, pervasive tool for daily grip strength monitoring, offering a convenient alternative to traditional dynamometers.

Indexed as

Hand StrengthSmartphoneAdultFemaleHumansMaleReproducibility of ResultsYoung Adultgrip strengthhuman computer interactionmachine learningmobile healthsmartphone

Identifiers

PMID42061870
PMCPMC13153751

What Socratic holds

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LicenceCC BY
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.