Reliability and Validity of Hand Dynamometer Trunk Muscle Strength Measurements in Patients With AIS

June 29, 2026 updated by: Irem Kurt, Istanbul University - Cerrahpasa

Intra-rater and Inter-rater Reliability and Validity of Hand Dynamometer Trunk Flexor, Extensor and Lateral Flexor Muscle Strength Measurements in Patients With Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is a three-dimensional complex deformity of the spine characterized by lateral deviation of 10 degrees or more in the frontal plane, rotation in the transverse plane and hypokyphosis in the sagittal plane. It has been reported that in the presence of scoliosis, there is a change in muscle strength of people compared to their healthy peers due to the deterioration of their postural balance. There are many studies in the literature that evaluate the muscle strength of cases diagnosed with scoliosis with objective devices. Among these objective devices, reliability studies on hand dynamometry devices, which are easy to use, portable and cheaper than other devices, have been conducted for different populations. However, no reliability study of the handheld dynamometer device in patients with AIS has been found in the literature. Therefore, the aim of our study is to study the intra-rater and inter-rater reliability and validity of the trunk flexion, extension and lateral flexion muscle strengths of the hand dynamometer device in cases with AIS, which are known to have changes in muscle strength compared to their peers as a result of the change in spinal alignment. After obtaining the demographic information of the cases that meet the inclusion criteria within the scope of the study, the isometric muscle strength of the trunk flexor, extensor and right-left lateral flexor muscles will be evaluated by two different evaluators using a Lafayette hand dynamometer. To avoid systematic error, each participant will perform the isometric handheld dynamometer protocol in a random testing order. In order to determine interobserver reliability, on the first day of the test, the same hand dynamometer protocol will be applied to each participant by two different evaluators, after a 1-hour rest to prevent fatigue. To determine intraobserver reliability and compliance, participants will be re-evaluated by the same researchers at the same protocol, place and day period, 1 week apart to prevent learning effects. This study will reveal the intraobserver and interobserver reliability and validity of the handheld dynamometer device, which can be used in the evaluation of trunk muscle strength for clinicians working with AIS.

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

Adolescent Idiopathic Scoliosis (AIS) is a three-dimensional complex deformity of the spine characterized by lateral deviation of 10 degrees or more in the frontal plane, rotation in the transverse plane and hypokyphosis in the sagittal plane, and is an important public health problem with a global prevalence of 0.47-5.2%. Muscle strength is an important factor in maintaining postural balance in AIS, and it is observed that both clinicians and researchers evaluate the muscle strength of cases with AIS using different objective devices. Objective muscle strength assessment methods include electromyography, hand dynamometry and isokinetic dynamometry. Electromyography devices and isokinetic dynamometers are expensive and their use in the clinic is limited because they are not easily portable. Therefore, it has been shown to be a valid and reliable method to evaluate trunk muscle strength in different populations and pathologies such as healthy adults, healthy athletic individuals, chronic low back pain or hemiplegic patients; The handheld dynamometer device, which has the advantage of being cheaper and more portable than other devices, appears as a suitable option for clinicians to evaluate trunk isometric muscle strength. No reliability studies of hand dynamometer devices have been found in the AIS population. Therefore, our aim in the study is to study the intra-observer and inter-observer reliability and validity of the trunk flexion, extension and lateral flexion muscle strengths of the hand dynamometer device in patients with AIS, who are known to have changes in muscle strength compared to their peers as a result of the change in spinal alignment. This study will reveal the validity of the hand dynamometer device that can be used in the evaluation of trunk muscle strength for clinicians working with AIS.

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.
41

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

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

  • Child
  • Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Adolescent idiopathic scoliosis patients

Description

Inclusion Criteria:

  • Being between the ages of 10-18
  • Having been diagnosed with Adolescent Idiopathic Scoliosis by an orthopedic specialist
  • Ability to understand instructions
  • Volunteering to participate in the study

Exclusion Criteria:

  • History of traumatic trunk or pelvic injury
  • History of acute, subacute or chronic low back pain or neurological disease
  • Having had spinal surgery
  • Participating in heavy physical activity at least one day before the test days
  • Having experienced any acute situation that could affect muscle strength between the two tests (within 7 days)

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intra-rater and inter-rater validity and reliability
Intra-rater and inter-rater validity and reliability of trunk flexion, extension and right-left lateral flexion isometric muscle strength in cases with AIS will be performed with the Lafeyette hand dynamometer device ((Lafayette Manual Muscle Testing System, Lafayette Instrument Co, Lafayette, Indiana). To avoid systematic error, each participant will perform the isometric handheld dynamometer protocol in a random testing order. In order to determine inter-rater reliability, the same hand dynamometer protocol will be applied to each participant by two different assessors on the first day of the test. Participants will be given a 1-hour rest period between evaluators to prevent fatigue in the evaluations to be held on the same day. To determine inter-rater reliability and agreement, participants will be re-evaluated by the same researchers, at the same protocol, place and day, with a 1-week interval to prevent learning effects.

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
Isometric trunk flexor strength
Time Frame: Baseline (All rater), after 1 hour (Rater 1) and 1 week (Rater 1)
Isometric trunk flexor strength, two different test positions were adapted based on current literature. The first position will be measured on the back at 0 degrees of extension, with the knees straight. The dynamometer will be placed below the suprasternal notch of the sternum. Participants will be instructed to place their hand on the opposite acromion. To prevent pelvic rotation, participants will be fixed with the help of a belt from the anterior superior iliac spine and 10 cm above the lateral malleolus. The second position will be measured on the back in a 30 degree flexion position with the knees straight. The dynamometer will be placed below the suprasternal notch of the sternum. Participants will be instructed to place their hand on the opposite acromion. To prevent pelvic rotation, participants will be fixed with the help of a belt from the anterior superior iliac spine and 10 cm above the lateral malleolus.
Baseline (All rater), after 1 hour (Rater 1) and 1 week (Rater 1)
Isometric trunk extension strength
Time Frame: Baseline (All rater), after 1 hour (Rater 1) and 1 week (Rater 1)
Isometric trunk extension strength, two different test positions were adapted based on current literature. The first position will be measured face down in 0 degree extension position. The dynamometer will be placed at the height T4. Participants will be instructed to place their hands on their foreheads. Participants will be fixed with the help of a belt from the posterior superior iliac spine and 10 cm above the lateral malleolus to prevent pelvic rotation. The second position will be measured face down in a 30 degree flexion position. The dynamometer will be placed at the height T4. Participants will be instructed to place their hands on their foreheads. Participants will be fixed with the help of a belt from the posterior superior iliac spine and 10 cm above the lateral malleolus to prevent pelvic rotation.
Baseline (All rater), after 1 hour (Rater 1) and 1 week (Rater 1)
Isometric trunk lateral flexion strength
Time Frame: Baseline (All rater), after 1 hour (Rater 1) and 1 week (Rater 1)
Isometric trunk lateral flexion strength will be measured in the sitting position. Participants will sit on a chair with their feet not touching the ground and their hips in 90° flexion, and the participant will be fixed with the help of a strap. The dynamometer will be placed at shoulder level. Participants will be instructed to place their hand on the opposite acromion. Trials in which excessive motion (a detectable amount of movement or rotation in the transverse plane) occurs will be rejected and measured as.
Baseline (All rater), after 1 hour (Rater 1) and 1 week (Rater 1)

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.
Istanbul University - Cerrahpasa

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: İrem Kurt Ulusoy, Istanbul University - Cerrahpasa
  • Principal Investigator: Elcin Akyurek, Istanbul University - Cerrahpasa
  • Principal Investigator: İpek Yeldan, Istanbul University - Cerrahpasa
  • Principal Investigator: Ayse Zengin Alpozgen, Istanbul University - Cerrahpasa

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.
June 1, 2024

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.
February 10, 2026

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.
February 10, 2026

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).
May 12, 2024

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.
May 12, 2024

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.
May 16, 2024

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 1, 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.
June 29, 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.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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.
  • IUC5

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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