Validation of smoothness evaluation during standing and sitting motions using an accelerometer.
Takeshi Shimamura, Hiroshi Katoh
PMID 33814712WHAT IT FOUND
An accelerometer measured standing and sitting motions in 17 healthy men.
Root mean square (RMS) scores consistently rose under unstable conditions, suggesting it detects wobble. Entropy scores were inconsistent, and the two indices did not correlate when instability was introduced.
Key findings
01RMS values were significantly higher under unstable conditions across all directions tested.
02Entropy values were significantly higher under unstable conditions in the vertical, longitudinal, and triaxial directions, but not in the lateral direction.
03RMS and entropy were significantly negatively correlated under normal conditions, but this correlation was not significant under unstable conditions.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study included only 17 healthy young men, so the findings do not represent older adults, women, or patients with movement disorders. The unstable condition was artificially created using an air cushion in healthy participants, which may not mimic the natural instability seen in clinical populations. The study did not compare these accelerometer measures against standard clinical assessments of balance or fall risk.
Declared interests
None declared.
The easy way to misread this
Do not assume that RMS or entropy are validated diagnostic tools for patients with balance disorders. The study tested healthy young men under artificial instability, so these indices have not been shown to distinguish between healthy and impaired movement patterns in a clinical population.