Elsevier

Journal of Biomechanics

Volume 45, Issue 3, 2 February 2012, Pages 448-454
Journal of Biomechanics

Accelerometer counts and raw acceleration output in relation to mechanical loading

https://doi.org/10.1016/j.jbiomech.2011.12.006Get rights and content
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open access

Abstract

The purpose of this study was to assess the relationship of accelerometer output, in counts (ActiGraph GT1M) and as raw accelerations (ActiGraph GT3X+ and GENEA), with ground reaction force (GRF) in adults. Ten participants (age: 29.4±8.2 yr, mass: 74.3±9.8 kg, height: 1.76±0.09 m) performed eight trials each of: slow walking, brisk walking, slow running, faster running and box drops. GRF data were collected for one step per trial (walking and running) using a force plate. Low jumps and higher jumps (one per second) were performed for 20 s each on the force plate. For box drops, participants dropped from a 35 cm box onto the force plate. Throughout, three accelerometers were worn at the hip: GT1M, GT3X+ and GENEA. A further GT3X+ and GENEA were worn on the left and right wrist, respectively. GT1M counts correlated with peak impact force (r=0.85, p<0.05), average resultant force (r=0.73, p<0.05) and peak loading rate (r=0.76, p<0.05). Accelerations from the GT3X+ and GENEA correlated with average resultant force and peak loading rate irrespective of whether monitors were worn at the hip or wrist (r>0.82, p<0.05, r>0.63 p<0.05, respectively). In conclusion, accelerometer count and raw acceleration output correlate positively with GRF and thus may be appropriate for the quantification of activity beneficial to bone. Wrist-worn monitors show a similar relationship with GRF as hip-worn monitors, suggesting that wrist-worn monitors may be a viable option for future studies looking at bone health.

Keywords

ActiGraph
GENEA
Ground reaction force
Physical activity
Bone

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