Research

Energy balance

Uniaxial accelerometers fail to accurately distinguish energy expenditure during running speeds above 7.8 km/h because the vertical acceleration exceeds the sensor's threshold (1.94 g), leading to a plateau in activity levels despite increasing metabolic cost.

If you use a uniaxial waist accelerometer, be aware that it likely stops distinguishing between different running speeds once you exceed ~7.8 km/h (approx. 4.8 mph). The sensor saturates, so it will not accurately reflect the increased energy cost of vigorous running. It is more reliable for walking and moderate activities.

GoodRefutesHIGH confidence
The activity level was significantly different at 2.4 – 7.8 km/h, while it was not significantly different at > 7.8 km/h. ... the centre of gravity during running as measured by the accelerometry sensor readily exceeded the threshold of the present sensor (i.e. 1.94 g).
Hideaki Kumahara et al. · British Journal Of Nutrition · 2004

Why this rating

Controlled treadmill study with direct VO2 measurement (gold standard) for metabolic cost.

Source

The use of uniaxial accelerometry for the assessment of physical-activity-related energy expenditure: a validation study against whole-body indirect calorimetry

Hideaki Kumahara et al. · British Journal Of Nutrition · 2004

DOI 10.1079/bjn20031033

cross_sectional · n=89Cited 534×
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DOI resolved against Crossref · corpus check 2026-06-10

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