Children are experiencing an increase in sedentary lifestyle as a result of the rising utilization of technology, i.e. smartphones. With the prolonged use of smartphones, increased concerns have been raised regarding constant neck flexion, neck movements limitation, and decreases in pulmonary function due to potential changes in spinal posture. Therefore, the purpose of this research thesis was to evaluate changes in craniovertebral angles (CVA), cervical range of motion (ROM), and pulmonary function among boys and girls 8 to 13 years of age who use smartphones. A cross-sectional study was conducted on a sample of 50 participants (24 boys and 26 girls) with mean age 10.5±1.6 years and mean body mass index (BMI) 18.6±3.0 kg/m2. Participants were assigned to 2 groups based on their scores on the Smartphone Addiction Scale Short Version for Adolescents (SAS-SV): addicted group (score > 32, n=32) and non-addicted group (score ≤ to 32, n=18). The CVA was measured to evaluate the changes in the cervical spine. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC), and peak expiratory flow (PEF) were measured to evaluate pulmonary function. Maximal voluntary ventilation (MVV), maximum inspiratory pressures (MIP), and maximum expiratory pressures (MEP) were measured to assess respiratory muscles’ strength. A significant difference in CVA measures was found between both groups; girls (p=0.02) and boys (p=0.03). Cervical ROM in extension was limited in addicted boys (p=0.04). Also, in addicted boys, FVC and FEV1 were significantly lower (p=0.04 and p=0.05 respectively). FEV6% showed a significant lower value in addicted boys, compared to non-addicted boys (p=0.02). while addicted girls had significantly lower values in MIP when compared to non-addicted girls (p=0.05). We conclude that frequent use of smartphones could negatively affect cervical posture, as well as respiratory biomechanics among boys and girls. Pulmonary dysfunction has found to be associated with FHP as a result of constant neck flexion while viewing the phone. Therefore, education on proper posture while using the smartphone and education on the effects of prolonged usage of smartphones are necessary to preserve craniocervical function.

LLU Discipline

Physical Therapy


Physical Therapy


School of Allied Health Professions

First Advisor

Gurinder Bains

Second Advisor

Abdullah Alismail

Third Advisor

Noha S. Daher

Fourth Advisor

Rhonda Nelson

Degree Name

Doctor of Science (DSc)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Posture - Physiology; Muscles - Physiology; Pulmonary function tests; Respiratory Function Tests

Subject - Local

Smartphone addiction; Smartphone frequent use; Forward head posture; Respiratory muscle weakness; Respiratory muscle strength



Page Count

87 p.

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives