Smartphones have become an indispensable part of daily life, and their increasing use has raised concerns about various health effects, including musculoskeletal symptoms. Repetitive movements of the thumb and hand muscles can lead to issues such as tendinosis, myofascial pain syndrome, and a decrease in pinch strength. Studies have shown that musculoskeletal symptoms related to smartphone use are common among young adults and university students. Additionally, an increase in device size may place greater strain on the wrist and finger muscles. Repetitive movements can cause stiffness changes in the thumb muscles, and the relationship between these changes and pinch strength is considered an important research topic. In this study, we aimed to investigate the effects of smartphone addiction on pinch strength, muscle stiffness, hand/wrist pain, and function in young adults.
Willing to participate in the study
Have been using a smartphone for more than one year
Aged between 18 and 25 years
Send 25 or more text messages or emails per day
Having radiating/radicular pain in the upper extremity
Having neck pain
Congenital deformities in the upper extremity and neck
A history of diagnosed neurological, rheumatic, musculoskeletal, or cardiovascular diseases
University student from Istanbul Kent University and Istanbul Gelisim University.
Case-control
Cross-sectional
No intervention.
Other interventionParticipants allocated to the groups were assessed only once. No intervention was applied, and they were not followed up.
Muscle Stiffness
Muscle stiffness (Abductor Pollicis Brevis, Abductor Pollicis Longus and Extensor Pollicis Brevis) was measured using the MyotonPRO (Myoton SA, Tallinn, Estonia) device. A brief mechanical impulse was applied to the muscle and then quickly released. Stiffness (N/m) is a parameter related to the capacity to withstand an external force. The reliability of the device has been proven in healthy individuals. The measurement site was marked on the skin with a pen. In all applications, the MyotonPRO probe was placed perpendicular to the skin, and in multi-scan mode, three measurements were recorded with 10 pulses at 1-second intervals. The average of the three measurements was used for analysis.
Pinch Strength
Lateral and palmar pinch strength were measured in kilograms using a Jamar hydraulic pinch gauge (ICC: 0.94-0.99). The measurements were performed in the standard position recommended by the American Society of Hand Therapists: seated, with the shoulder in adduction and neutral, elbow in 90 degrees of flexion, forearm in mid-rotation and supported, and wrist in neutral. Three consecutive measurements, each lasting five seconds, were taken, with one-minute rest intervals between each measurement to prevent muscle fatigue. The average of the three trials was used for analysis.
Smartphone Addiction Scale-Short Version (SAS-SV)
The SAS-SV is a 10-item scale developed by Kwon and colleagues to measure the risk of smartphone addiction in adolescents. It is evaluated using a six-point Likert scale. The scale items are scored from 1 to 6. The scale scores range from 10 to 60, with higher scores indicating an increased risk of addiction. The scale is unidimensional and does not have subscales. In the Korean sample, the cutoff score is 31 for males and 33 for females.
Patient-Rated Wrist/Hand Evaluation Questionnaire (PRWHE)
This form consists of two subscales: a pain subscale with five items, a specific function subscale with six items, and a daily function subscale with four items. Each item is scored on a scale from 0 to 10. In this scale, pain and function problems are weighted equally, and the total score is measured out of 100 points.
Finkelstein Test
The Finkelstein test, one of the most commonly preferred clinical examination tests for diagnosing De Quervain's disease, was used. Participants were asked to make a fist with their thumb inside, and the researcher passively deviated the fist ulnarly. The presence of tenderness and pain at the radial styloid indicated a positive test.
Smartphone Surface Area
The dimensions of the smartphones used by the participants were measured by the researchers. Using a measuring tape, the width and length of the smartphone were recorded in centimeters. The value used for statistical analysis was determined as the surface area of the smartphone (width × length).
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Istanbul Gelisim University
Lead sponsor
Istanbul University - Cerrahpasa
Collaborator
Istanbul Kent University
Collaborator
