DATASET FOR STUDY: Test–Retest Reliability of Postural Sway Measures Using a Portable Low-Cost Force Plate

Objective: To investigate the test-retest reliability of center of pressure (CoP) parameters during bipedal and unipedal stance in healthy individuals using low-cost force plates system. Methods: A total of 27 healthy adults completed two laboratory sessions 7-10 days apart, performing three 30-second bipedal and three 30-second unipedal stance trials on each leg per session. Postural sway was recorded using a portable force plate while participants stood barefoot, maintained visual fixation, and held their hands on their hips. Results: Unipedal stance demonstrated consistently higher reliability (ICC > 0.85 for total CoP displacement displacement velocity) compared to bipedal stance, which showed poor reliability (low ICC) with exceptionally high within-subject variability (CV > 60% for ellipse area). Conclusion: Bipedal quiet standing is unsuitable for longitudinal balance assessment due to its low reliability. The unipedal stance, as a more challenging postural task, provides more reliable and robust measures of postural control, with total CoP displacement and sway velocity being the most stable indicator. Low-cost force plates showed as objective balance assessment tool through postural sway measurement accessible for wider clinical and research use.