Stride variability measures derived from wrist- and hip-worn accelerometers.
Jacek K Urbanek, Jaroslaw Harezlak, Nancy W Glynn and 3 others
PMID 27936440WHAT IT FOUND
Wrist-worn accelerometers can track walking rhythm and activity levels as well as hip-worn devices in healthy older adults.
However, they cannot reliably measure stride-to-stride variability. Use wrist data for general activity counts, but do not expect it to detect subtle inconsistencies in walking.
Key findings
01Cadence measured from the wrist was highly correlated with cadence measured from the hip, suggesting wrist devices can accurately track walking rate.
02The measure of stride-to-stride phase deviation, which looks at timing consistency, was not associated with physical function tests when derived from either hip or wrist sensors.
03Amplitude deviation, a measure of stride intensity variability, was associated with chair stand speed and gait speed across all sensor locations, including both wrists.
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 involved only 46 healthy older adults with no history of gait-affecting conditions, so results may not apply to patients with neurological or musculoskeletal impairments. Data was collected during a controlled 400-meter walk in a lab setting, which does not reflect the complexity of free-living walking where arm swing may be interrupted by carrying objects or using a phone. The study did not validate these measures against gold-standard optical motion capture, relying instead on correlations between different sensor locations and physical function tests. The analysis focused on a single 20-meter lap, which may not capture fatigue-related changes in gait variability over longer periods.
Declared interests
The authors declared no financial or non-financial conflicts of interest.
The easy way to misread this
Do not assume that because wrist devices accurately count steps, they can also assess gait quality or stability. This study found that wrist-derived measures of stride timing variability (Phase Deviation) were not related to physical function, meaning a patient's step count might look normal while their gait consistency is compromised.