Effects of smartphone use in various floor sitting positions on spinal and pelvic alignment and gluteal pressure in healthy adults.
Ying Liu, Yi-Heng Zhang, Hyoung-Won Lim
PMID 40511313WHAT IT FOUND
Side sitting on the floor while using a smartphone caused the most uneven pressure on the buttocks and the largest pelvic tilt.
Long sitting was the most symmetrical posture, but all three positions led to increased trunk flexion over 30 minutes.
Key findings
01Side sitting resulted in significantly higher gluteal pressure asymmetry than cross-legged or long sitting at all time points during 30 minutes of smartphone use.
02Trunk flexion angle decreased significantly in cross-legged and side sitting positions, indicating the trunk collapsed forward, while long sitting showed minimal change.
03Pelvic obliquity increased in cross-legged and side sitting positions but remained stable in long sitting.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
The study measured healthy adults with no pain, so the results may not apply to patients with existing musculoskeletal conditions or pain. The study only assessed 30 minutes of sitting, which may not reflect the effects of longer periods of daily smartphone use. The study did not measure pain or discomfort, only biomechanical changes, so it does not confirm that these postures caused symptoms. The groups were small (10 per position), which limits the generalizability of the findings.
Declared interests
The author declares no conflicts of interest and the research received no external funding.
The easy way to misread this
Do not assume these postural changes cause pain or injury. The study measured healthy adults without pain and did not assess symptoms, so the findings describe biomechanical shifts rather than clinical harm.