Assessing the Feasibility of a Novel Dynamometry Protocol for Measuring Finger Extensor Strength

July 27, 2026 updated by: Boston University Charles River Campus

This study aims to evaluate the feasibility and reliability of a novel method for assessing finger extension strength using an adapted dynamometer, addressing the limitation of current hand grasp assessment protocols that focus only on finger flexor muscles. The study will recruit able-bodied adult participants, and a force gauge will be used to obtain precise measures of the strength of their extensor digitorum muscles.

Participants will be seated with their upper extremity supported on an adjustable table and have a force gauge, connected to a custom-made support positioned around their proximal phalanx. The support will be connected to a force gauge, which will measure participants' extensor muscles strength in Newtons (N). To assess the feasibility and reliability of this new setup, three measurements will be collected for each hand, with a one-minute interval between each measurement and a 5-minute break between evaluators, with the order randomized to reduce bias.

The study will recruit participants from BU's Sargent College of Health and Rehabilitation Sciences and will be conducted by independent evaluators trained in muscle assessment and clinical evaluation of the hand and upper extremities. The total participation time should not exceed 30 minutes per participant.

The primary hypothesis is that this novel and accessible device can provide accurate and reliable measurements of participants' finger extensor muscles' strength. Results from this study could have important implications for hand rehabilitation and therapy, particularly for individuals with hand dysfunction due to musculoskeletal disorders or injuries.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

The purpose of this observational study is to measure the strength of independent finger extension for the four middle digits (II-V). Independent extension involves actively extending one finger while keeping the other fingers fully flexed, while dependent extension involves actively extending all the fingers, including the index finger. The study protocol is based on a previous study (Matter-Parrat et al., 2017), where researchers used a similar device to compare dependent and independent finger extension. However, in contrast to the previous study, this study aims to measure extension forces for all fingers, not just the index finger.

To achieve this, the tests will be performed three times, on both hands, by three examiners and compared to determine the intra-examiner reproducibility and the inter-examiner reproducibility. The investigators will measure all fingers on participants' dominant hand first, following by their non-dominant hand. This sequence will be repeated three times for each evaluator. A five-minute interval will be stablished between each evaluator, as well as 1-minute break between each attempt, to minimize the risk of muscle fatigue.

During the test procedures, the participants' upper extremity will be positioned over a height-adjustable table, which will be placed on the side of the participant. This will allow for optimal support and stability during the measurement of finger extension strength. The height of the table will be adjusted to ensure that the participant's shoulder is in abduction, and their elbows are at a 90-degree angle of flexion. The forearms will be placed in a pronated position, while the wrists and metacarpophalangeal joints will be maintained in a neutral position to prevent any unwanted movement during the test. The participants will be seated comfortably with their back supported by a chair with no armrests to avoid any interference with the test procedures. In case active extension of the wrist is observed by an elevation of the metacarpal heads from the stand, the test will be repeated to obtain isolated extension of the fingers.

To measure participants' finger extension strength, a 3D printed support was specifically designed and printed in PLA (Polylactic Acid) on an ENDER 3 printer. Additionally, PLA is a suitable material that can be easily disinfected with 70% ethanol, maintaining hygiene standards between participants. We will print several scaled models of the support, ensuring the support can be tailored to best fit participants' hands. We will select the support whose size comfortably accommodate the dorsum of the participant's proximal phalanx, providing a secure and ergonomic fit. Once the support is connected to the force gauge's M6 Metric attachments, participants will be asked to extend each finger independently as forcefully as possible while keeping the other fingers in full flexion.

Data will be obtained by recording the peak value using the Baoshishan 500N force gauge, a commercially available device used to measure the strength of extensor digitorum muscles. The device, manufactured by Baoshishan Instrument Co., Ltd, China, has a measuring range of 0-500N (0-112.4 lbf) and an accuracy of ±0.5% of full scale. It features a resolution of 0.1N (0.0225 lbf) and a sampling frequency of 2000Hz. The gauge has a large, easy-to-read LCD display that shows force values in Newtons (N) or pounds (lbf). The device is compact and lightweight, measuring 170 x 86 x 38 mm and weighing 0.5 kg. Safety precautions will be followed to ensure participant well-being, including proper handling of the device, avoiding damage to internal components, and keeping it away from water and other liquids. The rechargeable battery will be charged according to the manufacturer's instructions, and the device will be stored in a dry, cool place when not in use.

All data analysis procedures will be performed using SPSS version 27.0 (IBM Corp., Armonk, NY, USA). Continuous data will be presented as mean ± standard deviation, and categorical data will be presented as numbers and percentages. The normality of the distribution will be assessed using the Shapiro-Wilk test and graphically. For all statistical analyses, a significance level of 0.05 will be considered, and confidence intervals will be reported where appropriate.

To assess the reproducibility of the measurements, the intra-class correlation coefficient (ICC) will be calculated. The confidence interval for the ICC will be determined using the bootstrap method with 10,000 replicates. An F-test will be performed to determine if the ICC significantly differs from zero, indicating nil reproducibility. Good intra-examiner and inter-examiner reproducibility will be defined as ICC values above 0.90 and 0.75, respectively.

Mixed linear regression models will be used to compare extension strength between the dominant and non-dominant hands, incorporating a 'subject' random effect to account for within-subject correlation. This analysis will allow us to examine potential differences in finger extension strength between the hands while considering individual variation.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
50

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Massachusetts
      • Boston, Massachusetts, United States, 02215
        • Boston University - Department of Occupational Therapy

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

This study will invite a convenience sample of 50 English-speaking adults with no existing medical condition affecting the motor performance of their upper extremities, such as fractures, joint stiffness, neurological, rheumatological, or musculoskeletal conditions

Description

Inclusion Criteria:

English-speaking adults No diagnosis or history of conditions affecting their upper extremities mobility.

Exclusion Criteria:

Current or past history of neurologic, rheumatologic, or orthopedic disorders impacting physical performance; A current disorder affecting cognition; Visual, tactile, or perceptual deficits that could prevent full participation in the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Finger extensor - muscle force
Time Frame: 1 hour
Muscle force generated by participant's extensor digitorum muscles (both hands), measured in Newtons.
1 hour

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Boston University Charles River Campus

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Pedro Almeida, PhD, Boston University - Department of Occupational Therapy

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 1, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 30, 2023

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2023

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 10, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 27, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 28, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 28, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2023

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 7053E

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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