Validity and reliability of wearable inertial sensors in healthy adult walking: a systematic review and meta-analysis.
Dylan Kobsar, Jesse M Charlton, Calvin T F Tse and 5 others
PMID 32393301WHAT IT FOUND
Wearable sensors accurately measure basic walking timing and length.
However, they are unreliable for assessing step-to-step variability or symmetry. Clinicians should trust the average numbers but avoid making decisions based on how consistent a patient's gait pattern is using these devices.
Key findings
01Mean spatiotemporal parameters like step time and stride length showed excellent to good validity and reliability.
02Variability and symmetry metrics showed poor to moderate validity, meaning the sensors do not consistently match gold-standard measurements for these specific outcomes.
03The lack of high-quality evidence in the field is largely due to underpowered studies and inconsistent reporting, rather than flaws in the sensor technology itself.
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 review focused only on healthy adults, so findings may not apply to clinical populations with pathological gait patterns. Most included studies were rated as low or moderate quality, with 95% failing to justify their sample size. The review excluded measures like gait speed and cadence because they are derived from other metrics, limiting the scope of direct validation. Inability to pool data for kinematic outcomes (joint angles) means evidence for those specific measures remains qualitative and less certain.
Declared interests
The paper is supported by non-U.S. government funding. The authors declared no competing interests.
The easy way to misread this
Do not assume that because a wearable sensor is accurate for measuring average step length, it is equally accurate for measuring gait variability. The study found that variability and symmetry metrics have poor validity, so clinical judgments about a patient's gait consistency based on these devices may be incorrect.