Smartphone Use and Hand Function in Young Adults

April 18, 2026 updated by: ESRA PEHLIVAN, Saglik Bilimleri Universitesi

The Relationship Between Daily Smartphone Use Duration and Dominant Hand Grip Strength, Thumb Strength, Wrist and Thumb Proprioception in Young Adults

This observational cross-sectional study aims to investigate the relationship between daily smartphone usage duration and hand function parameters in young adults. Specifically, the study will examine the association between smartphone screen time and dominant hand grip strength, thumb strength, and wrist and thumb proprioception. Healthy individuals aged 18-35 years will be included. All participants will undergo a single-session assessment including measurement of smartphone usage duration, hand grip strength, pinch strength, and joint position sense of the wrist and thumb. The findings are expected to provide insight into the potential effects of prolonged smartphone use on hand function and proprioceptive performance in young adults.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The widespread use of smartphones in daily life has increased significantly, particularly among young adults. While these devices provide convenience and accessibility, excessive smartphone use has been associated with various musculoskeletal and functional impairments, particularly in the upper extremity. Repetitive thumb movements, sustained grip positions, and prolonged device use may negatively affect muscle strength, joint proprioception, and overall hand function. Previous studies have reported that excessive smartphone use may lead to decreased grip strength, altered thumb mechanics, and impaired proprioception. However, there is limited research directly examining the relationship between objectively measured smartphone usage duration and detailed hand function parameters. This study is designed as a cross-sectional, observational, and analytical investigation. Healthy individuals aged 18-35 years will be recruited. Participants with a history of upper extremity injury, neurological disease, or musculoskeletal disorders affecting the hand and wrist will be excluded. All participants will be evaluated in a single session. Demographic data and clinical history will be recorded. Smartphone usage duration will be obtained from built-in device tracking systems (Screen Time for iOS and Digital Wellbeing for Android) based on the last 7 days of use.

Study Type

Observational

Enrollment (Estimated)

84

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 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

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Healthy Universitty Student

Description

Inclusion Criteria:

  • Healthy adults
  • Aged between 18 and 35 years
  • Voluntary participation in the study

Exclusion Criteria:

  • History of hand or wrist surgery
  • Fracture or serious injury in the hand/thumb within the last 6 months
  • Neurological disorders
  • Rheumatologic diseases
  • Cognitive impairment preventing understanding of instructions

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
Intervention / Treatment
Observational Group: Smartphone-Addicted Participants
Participants classified as having smartphone addiction according to the Smartphone Addiction Scale-Short Form will undergo a single-session assessment including daily smartphone screen time, dominant hand grip strength, thumb pinch strength, wrist joint position sense, and thumb joint position sense.
Other: Assessment Protocol
All participants will undergo a standardized assessment protocol including measurement of smartphone addiction level, daily smartphone screen time from the past 7 days, dominant hand grip strength, thumb pinch strength, wrist proprioception, and thumb proprioception in a single session
Observational Group: Non-Addicted Participants
Participants classified as not having smartphone addiction according to the Smartphone Addiction Scale-Short Form will undergo the same single-session assessment including daily smartphone screen time, dominant hand grip strength, thumb pinch strength, wrist joint position sense, and thumb joint position sense.
Other: Assessment Protocol
All participants will undergo a standardized assessment protocol including measurement of smartphone addiction level, daily smartphone screen time from the past 7 days, dominant hand grip strength, thumb pinch strength, wrist proprioception, and thumb proprioception in a single session

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Hand Grip Strength
Time Frame: Single assessment at baseline
Hand grip strength will be measured using a hydraulic hand dynamometer. The participant will be in a seated position with the elbow flexed at 90 degrees. Three measurements will be taken with a 10-second rest between each, and the average value will be recorded in kilograms (kg).
Single assessment at baseline
Thumb Pinch Strength
Time Frame: Single assessment at baseline
Thumb muscle strength will be measured using a pinchmeter. The participant will be seated with the elbow flexed at 90 degrees and the wrist in a neutral position. The average of three trials will be recorded in kilograms (kg).
Single assessment at baseline
Thumb Active Joint Position Sense (JPS)
Time Frame: Single assessment at baseline
Measured using a standard transparent plastic goniometer. The researcher will passively move the thumb to a 30-degree abduction target position. The participant will be asked to actively reproduce this angle. The absolute error between the target angle and the reproduced angle will be recorded in degrees.
Single assessment at baseline
Wrist Joint Position Sense (JPS)
Time Frame: Single assessment at baseline
Measured using a goniometer with the participant's eyes closed. The wrist will be passively moved to predetermined positions (30 degrees flexion, 30 degrees extension, 10 degrees radial deviation, and 15 degrees ulnar deviation). The participant will then actively reposition the wrist, and the absolute error will be calculated in degrees.
Single assessment at baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Smartphone Screen Time
Time Frame: Single assessment at baseline
Objective measurements of the participants' smartphone use over the last 7 days will be obtained. Data will be collected using built-in features such as "Screen Time" for iOS devices or "Digital Wellbeing" for Android devices.
Single assessment at baseline
Smartphone Addiction Scale-Short Form
Time Frame: Single assessment at baseline
The Smartphone Addiction Scale-Short Form (SAS-SF) was used to assess smartphone addiction. The scale comprises 10 items rated on a 6-point Likert scale (1 = strongly disagree to 6 = strongly agree), yielding a total score between 10 and 60. Higher scores reflect a higher risk or severity of smartphone addiction.
Single assessment at baseline

Collaborators and Investigators

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

Sponsor

Saglik Bilimleri Universitesi

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 (Estimated)

May 1, 2026

Primary Completion (Estimated)

May 1, 2027

Study Completion (Estimated)

May 1, 2027

Study Registration Dates

First Submitted

April 13, 2026

First Submitted That Met QC Criteria

April 13, 2026

First Posted (Actual)

April 20, 2026

Study Record Updates

Last Update Posted (Actual)

April 22, 2026

Last Update Submitted That Met QC Criteria

April 18, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Smartphone&Proprioception1

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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