Accelerometer counts and raw acceleration output in relation to mechanical loading

• Published in: Journal of biomechanics Vol. 45; no. 3; pp. 448 - 454
• Main Authors: Rowlands, A.V, Stiles, V.H
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 02-02-2012; Elsevier; Elsevier Limited
• Subjects: Acceleration; Accelerometers; ActiGraph; Adult; Biological and medical sciences; Biomechanical Phenomena; Bone; Correlation; Counting; Force plates; Fundamental and applied biological sciences. Psychology; GENEA; Ground reaction force; Hip - physiology; Humans; Male; Monitoring, Ambulatory - instrumentation; Monitoring, Ambulatory - methods; Monitors; Motor Activity; Physical activity; Physical Medicine and Rehabilitation; Running; Running - physiology; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Walking; Walking - physiology; Bone; Physical activity; ActiGraph; GENEA; Ground reaction force; Human; Physical exercise; Osteoarticular system; Biomechanics; Locomotion; Walking; Mechanical stress; Accelerometer; Adult; Biomedical engineering
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2011.12.006

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.