Accuracy of a piezoelectric pedometer in persons with and without Down syndrome.
Piezoelectric pedometers give accurate step counts for adults with Down syndrome at normal or brisk walking speeds but miss steps when pace is slow.
01Research in Context
What this study did
The team asked adults with Down syndrome to walk on a treadmill at three speeds.
A piezoelectric pedometer sat on their hip and counted every step.
The same test was run with neurotypical adults so the two groups could be compared.
What they found
At normal or brisk speeds the pedometer was almost perfect for both groups.
When speed dropped below one meter per second the device missed steps.
Adults with Down syndrome and neurotypical adults showed the same error pattern.
How this fits with other research
Ferguson et al. (2020) built on this result. They showed you can turn the same hip step counts into calorie estimates for adults with Down syndrome.
Hilgenkamp et al. (2012) adds confidence. They found four days of pedometer wear gives a stable weekly step count in adults with intellectual disability.
Forseth et al. (2022) sounds a warning. They saw that standard accelerometer cut-points misclassify activity in teens with Down syndrome, so adult step counts may also need custom rules.
Why it matters
You can trust a cheap piezoelectric pedometer for adults with Down syndrome who walk at everyday speeds.
Skip the device if the person shuffles or walks slowly; it will under-count.
Use four days of data, check speed first, and pair the count with the F et al. equation to estimate calories during your next fitness plan.
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02At a glance
03Original abstract
BACKGROUND: Piezoelectric pedometers with a tri-axial accelerometer mechanism may effectively monitor physical activity in persons with Down syndrome (DS), but their accuracy has not been determined in this population. AIM: To examine the accuracy of a pedometer with a tri-axial accelerometer mechanism in measuring steps at different walking speeds in persons with and without DS. METHODS: Eighteen persons with DS (8 women; age 25±7y) and 22 persons without DS (9 women; 26±5y) participated in this study. Participants completed six over-ground walking trials at the preferred speed and at 0.5, 0.75, 1.0, 1.25, and 1.5ms-1, each lasting 6min. The steps taken were measured with hand-tally and with the Walk4Life MVPa piezoelectric pedometer. Pedometer accuracy was assessed with absolute percent error and Bland-Altman plots. RESULTS: Absolute percent error did not differ between persons with and without DS across speeds. Error decreased with increased speed (p<0.001), but leveled off at ≥1.0ms-1. Pedometers underestimated steps at 0.5 and 0.75ms-1, but were highly accurate at the preferred walking speed and at speeds ≥1.0ms-1. CONCLUSIONS: A piezoelectric pedometer with a tri-axial accelerometer mechanism measures steps with high accuracy at the preferred walking speed and at speeds ≥1.0ms-1 in persons with and without DS. Accuracy, however, is compromised at slower speeds. Across speeds, pedometer error is similar between persons with and without DS.
Research in developmental disabilities, 2016 · doi:10.1016/j.ridd.2016.08.003