Handgrip Strength, Trunk Muscle Endurance, and Functional Mobility in Adolescents With Mild Intellectual Disability

Relationship Between Handgrip Strength, Trunk Muscle Endurance, and Functional Mobility in Adolescents With Mild Intellectual Disability: A Cross-Sectional Comparison With Typically Developing Peers

This comparative, cross-sectional observational study examined handgrip strength, trunk muscle endurance, and functional mobility in adolescents aged 12-18 years with mild intellectual disability and compared their performance with typically developing peers. A total of 51 participants were evaluated during a single assessment session, including 24 adolescents with mild intellectual disability and 27 typically developing adolescents. Handgrip strength was measured using a digital hand dynamometer, trunk muscle endurance was assessed using the McGill trunk endurance test battery, and functional mobility was evaluated using the Timed Up and Go Test and the Timed Up and Down Stairs Test. The study also examined the relationships among handgrip strength, trunk muscle endurance, and functional mobility.

Study Overview

• Status: Completed
• Conditions: Intellectual Disability
• Intervention / Treatment: Other: Hand grip strength

Detailed Description

Study Design

This was a comparative, cross-sectional observational study. Participants were not assigned to any treatment, exercise program, or other intervention. All assessments were completed during a single study visit, and no 8-week intervention or follow-up assessment was conducted.

Participants

The study included 51 adolescents aged 12-18 years. The mild intellectual disability group consisted of 24 adolescents with a clinical diagnosis of mild intellectual disability according to DSM-5 criteria. The comparison group consisted of 27 typically developing adolescents without a diagnosis of intellectual disability, neurodevelopmental disorder, neurological disease, orthopedic condition, or serious systemic disease affecting assessment performance.

Assessments

Handgrip strength was measured separately for the right and left hands using a digital hand dynamometer. Three trials were performed for each hand, and the mean of the three trials was recorded in kilograms.

Trunk muscle endurance was assessed using the McGill trunk endurance test battery, including the trunk flexor endurance test, trunk extensor endurance test, right side bridge test, and left side bridge test. Performance duration was recorded in seconds.

Functional mobility was assessed using the Timed Up and Go Test and the Timed Up and Down Stairs Test. Completion times were recorded in seconds, with shorter times indicating better functional mobility.

Study Objective

The primary objective was to compare handgrip strength, trunk muscle endurance, and functional mobility between adolescents with mild intellectual disability and typically developing peers. The study also examined the relationships among these variables.

Registry Clarification

The initial registry version contained outcome-measure labels and assessment time points that did not correspond to the final assessment battery. After study completion, the record was updated to reflect the actual enrollment, the single-visit assessment schedule, and the outcome measures that were administered. Previous versions of the registry record remain accessible through the record history.

• Study Type: Observational
• Enrollment (Actual): 51

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Malatya
    • Malatya, Malatya, Turkey (Türkiye), 44280
      • Malatya Training and Research Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The study population consisted of adolescents aged 12-18 years recruited using a non-probability convenience sampling method. The mild intellectual disability group included adolescents with a clinical diagnosis of mild intellectual disability according to DSM-5 criteria. The comparison group included typically developing adolescents without intellectual disability or a neurological, neurodevelopmental, orthopedic, or serious systemic condition that could affect assessment performance. All participants included in the final analysis completed the assessments during a single study visit.

Description

Inclusion Criteria

• Adolescents aged 12-18 years.
• For the mild intellectual disability group: a clinical diagnosis of mild intellectual disability according to DSM-5 criteria.
• Ability to understand and follow simple verbal instructions.
• Ability to complete the assessment procedures safely.
• For the typically developing group: no diagnosis of intellectual disability, neurodevelopmental disorder, neurological disease, orthopedic condition, or serious systemic disease that could affect assessment performance.
• Written informed consent obtained from the participant's legal guardian.
• For participants with mild intellectual disability, verbal assent obtained using an age- and cognition-appropriate explanation.

Exclusion Criteria

• An orthopedic or neurological limitation preventing completion of the assessments.
• An additional medical or comorbid condition that could substantially affect assessment performance.
• Inability or unwillingness to complete the assessment session.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Mild Intellectual Disability Group; Adolescents aged 12-18 years with a clinical diagnosis of mild intellectual disability according to DSM-5 criteria, who were able to understand and follow simple verbal instructions and had no orthopedic or neurological limitation preventing completion of the assessments.
Typically Developing Group; Typically developing adolescents aged 12-18 years without a diagnosis of intellectual disability, neurodevelopmental disorder, neurological disease, orthopedic condition, or serious systemic disease that could affect completion of the assessments.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Hand Grip Strength in kilograms (kg)	Handgrip strength was measured separately for the right and left hands using a digital hand dynamometer. Three trials were performed for each hand in a standardized seated position, and the mean of the three trials was recorded in kilograms. Higher values indicated greater handgrip strength.	At the single study assessment visit (Day 0)
Trunk Muscle Endurance Assessed With the McGill Test Battery	Trunk muscle endurance was assessed in seconds using the McGill trunk endurance test battery, consisting of the trunk flexor endurance test, trunk extensor endurance test, right side bridge test, and left side bridge test. The duration for which each standardized test position was maintained was recorded in seconds. Longer durations indicated greater trunk muscle endurance.	At the single study assessment visit (Day 0)
Functional Mobility Assessed With the Timed Up and Go Test	Functional mobility was assessed using the Timed Up and Go Test. The time required to complete the standardized test was recorded in seconds. Shorter completion times indicated better functional mobility.	At the single study assessment visit (Day 0)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional Stair Mobility Assessed With the Timed Up and Down Stairs Test (TUDS)	Functional stair mobility was assessed using the Timed Up and Down Stairs Test (TUDS). The time required to ascend and descend the stairs according to the standardized test protocol was recorded in seconds. Shorter completion times indicated better functional stair mobility.	At the single study assessment visit (Day 0)

Collaborators and Investigators

• Sponsor: Inonu University

Publications and helpful links

Helpful Links

• Hand grip strength as a proposed new vital sign of health: a narrative review of evidences

Study record dates

Study Major Dates

• Study Start (Actual): April 15, 2025
• Primary Completion (Actual): May 19, 2025
• Study Completion (Actual): June 4, 2025

Study Registration Dates

• First Submitted: March 14, 2025
• First Submitted That Met QC Criteria: April 12, 2025
• First Posted (Actual): April 18, 2025

Study Record Updates

• Last Update Posted (Actual): August 4, 2026
• Last Update Submitted That Met QC Criteria: July 31, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Adolescents; Functional Mobility; Handgrip Strength; Trunk Muscle Endurance; Timed Up and Go Test; Mild Intellectual Disability; McGill Trunk Endurance Test; Timed Up and Down Stairs Test
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Neurobehavioral Manifestations; Neurodevelopmental Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Intellectual Disability
• Other Study ID Numbers: 2025/6862

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data are not planned to be shared publicly because the dataset contains sensitive information from adolescent participants, including individuals with intellectual disability.

Study Data/Documents

1. Clinical Study Report

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No