Forward head posture is a common postural abnormality characterized by anterior positioning of the head in the sagittal plane. This posture may increase biomechanical stress on the cervical spine and may be associated with compensatory changes in spinal and lumbopelvic alignment.

This observational study will investigate the relationship between forward head posture and sagittal lumbopelvic alignment among male smartphone users aged 18 to 35 years. Craniovertebral angle will be measured using the APECS mobile application, and sagittal lumbopelvic alignment parameters will be measured using the Spine3D LiDAR system.

Forward head posture is considered one of the commonly occurring musculoskeletal postural abnormalities. It is characterized by an anterior position of the head relative to the body's line of gravity in the sagittal plane. This altered posture may increase mechanical load on cervical joints, ligaments, and surrounding soft tissues.

Sagittal spinal and lumbopelvic alignment are important components of global postural balance. Changes in one spinal region may influence adjacent regions through compensatory mechanisms that help maintain horizontal gaze and keep the body's center of gravity within the base of support.

Smartphone use is commonly associated with prolonged neck flexion and altered head posture. Therefore, this study aims to investigate the relationship between craniovertebral angle, as an indicator of forward head posture, and sagittal lumbopelvic alignment parameters among smartphone users.

A total of 85 male participants with forward head posture will be recruited from outpatient clinics and students of the Faculty of Physical Therapy, Sphinx University. Forward head posture will be assessed using craniovertebral angle measured by the APECS mobile application. Sagittal lumbopelvic alignment will be assessed using the Spine3D LiDAR system by Sensor Medica, including lordotic angle, lumbar arrow, and trunk inclination.

Inclusion Criteria:

• Male participants aged 18 to 35 years.
• Craniovertebral angle equal to or less than 50 degrees, measured photographically using the APECS mobile application.
• Body mass index from 18.5 to 24.9 kg/m².
• Smartphone use of at least 4 hours per day for at least 6 months.
• Asymptomatic participants without diagnosed musculoskeletal or neurological conditions.
• Medically stable participants.
• Participants willing to provide informed consent.

Exclusion Criteria:

• History of trauma.
• Major psychological problems.
• Previous surgery involving the spine, abdomen, or shoulders.
• Spinal deformity.
• Lower limb deformity.
• Low back pain.
• Current or chronic pain in the neck, back, or pelvis.
• Obesity.
• Concomitant systemic diseases, including systemic lupus erythematosus, diabetes mellitus, sickle cell anemia, multiple sclerosis, fibromyalgia, or cancer.
• Pregnancy.
• Degenerative or radicular cervical spine disorders, including cervical spondylosis, cervical degenerative disc disease, cervical radiculopathy, or cervical spinal stenosis.
• Degenerative or radicular lumbar spine disorders, including herniated disc or lumbar spinal stenosis.
• Participation in regular postural correction therapy or specific spine-focused exercise programs within the previous 6 months.

Male smartphone users aged 18 to 35 years with forward head posture, recruited from outpatient clinics and students of the Faculty of Physical Therapy, Sphinx University. Eligible participants use smartphones for at least 4 hours per day for at least 6 months and have craniovertebral angle equal to or less than 50 degrees. Participants are medically stable and free from diagnosed musculoskeletal or neurological conditions.