Modern students are increasingly exposed to prolonged sedentary behaviour through smartphone usage, classroom lectures, online learning, assignments, and extended screen-based studying. Although sitting is often considered a passive activity, biomechanics research demonstrates that prolonged sitting imposes continuous static loading on the vertebral column, intervertebral discs, thoracolumbar fascia, and postural musculature, potentially leading to postural dysfunction, spinal instability, neuromuscular fatigue, and chronic musculoskeletal disorders.
The spine is biomechanically designed for dynamic and repetitive movements. At the start of the act of sitting, the spine is stabilised using muscles such as multifidus, erector spinae, transversus abdominis, deep neck flexors, and gluteal stabilisers. However, with prolonged static sitting postures, the endurance capacity of the muscles, circulation, and oxygenation is decreased, causing more mechanical load on passive tissue like ligaments, joints, thoracolumbar fascia, and intervertebral discs. This mechanism was termed as 'viscoelastic creep' by Wong et al. (2019), whereby prolonged lumbar flexion induces changes in passive tissues of the spine and leads to increased intradiscal pressure, resulting in forward head position, thoracic kyphosis, rounded shoulder, and lumbar flexion posture.
As noted by Koswara et al. (2024), the proportion of students suffering from low back pain (LBP) is 40.1%, whereas 72.1% spend more than 7 hours sitting per day, and 33.3% have poor sitting posture. The correlation was established between sitting time, posture, and LBP prevalence (RR = 1.69, p = 0.041; RR = 1.69, p = 0.009), and the risk of LBP among those with poor posture was 2.438 times higher. Likewise, in another study conducted by Dang et al. (2024), including 2,082 participants, it was found that prolonged sitting without engaging in any leisure-time physical activity led to a significant increase in neck musculoskeletal discomfort (PR = 1.46; 95% CI = 1.18–1.80) and shoulder dysfunction (PR = 1.30; 95% CI = 1.03–1.64). Mechanically, cervical flexion causes increased compression and shearing stress on the cervical vertebrae, facet joints, and surrounding muscles and leads to "text neck syndrome," cervicogenic headaches, upper trapezius hypertonicity, and reduced cervical mobility. According to Alaca et al. (2025), sitting time, improper posture, lack of exercise, and prolonged sitting behaviour were directly related to low back pain and postures
Prolonged sitting negatively affects thoracic mobility, hip biomechanics, and respiratory efficiency. Heneghan et al. (2018) demonstrated significantly reduced thoracic spine mobility in prolonged sitters compared with physically active individuals (p < 0.001). Continuous hip flexion promotes adaptive shortening of the iliopsoas, rectus femoris, and tensor fascia latae while inhibiting gluteal activation, producing lower crossed syndrome, altered lumbopelvic rhythm, impaired kinetic chain efficiency, and compensatory lumbar loading. These biomechanical alterations may negatively affect mobility, sprint mechanics, athletic performance, and injury resistance.
Common warning signs associated with sitting for long periods include neck stiffness, lower back pain, shoulder stiffness, hip stiffness, headache, paraesthesia, thoracic lumbar region pain, difficulty concentrating, and postural fatigue. This shows that the body is being subjected to more mechanical strain, neuromuscular fatigue, and postural instability.
The body’s biomechanical reaction to extended periods of sitting varies depending on age and sex. Women are likely to have high joint flexibility and instability of the pelvis, while men will show stiffened spine and lack of spinal flexibility. Children and adolescents are prone to developing poor postural habits, lumbar instability and forward head posture owing to their excessive time spent on screens.
The digital mode of learning has made significant increases in daily sitting duration due to class work, digital learning, use of screens, and hours studying. Reduced physical activity and variations in movement cause continuous mechanical stress on the spine tissues, leading to postural problems, spinal instability, and other musculoskeletal conditions.
As a result, being aware of posture, making appropriate ergonomic corrections, taking regular exercise breaks, mobility exercises, and remaining active are key aspects of spine maintenance. To the students studying B.Sc. Sports and Exercise Science at REVA University, biomechanics and movement science offer a lot of insights about injury, treatment, posture, and performance in an ever more sedentary world.
Author
Manikandan. K
Assistant Professor, Department of Sports & Exercise Science, REVA University.
