Measurement of Osteogenic Exercise – How to Interpret Accelerometric Data?

Department of Medical Technology, Institute of Biomedicine, University of Oulu Oulu, Finland.
Frontiers in Physiology (Impact Factor: 3.53). 10/2011; 2:73. DOI: 10.3389/fphys.2011.00073
Source: PubMed


Bone tissue adapts to its mechanical loading environment. We review here the accelerometric measurements with special emphasis on osteogenic exercise. The accelerometric method offers a unique opportunity to assess the intensity of mechanical loadings. We present methods to interpret accelerometric data, reducing it to the daily distributions of magnitude, slope, area, and energy of signal. These features represent the intensity level of physical activities, and were associated with the changes in bone density, bone geometry, physical performance, and metabolism in healthy premenopausal women. Bone adaptations presented a dose- and intensity dependent relationship with impact loading. Changes in hip were threshold dependent, indicating the importance of high-impacts exceeding acceleration of 4 g or slope of 100 g/s as an osteogenic stimulus. The number of impacts needed was 60/day. We also present the daily impact score to describe the osteogenic potential of daily mechanical loading with a single score. The methodology presented here can be used to study musculoskeletal adaptation to exercise in other target groups as well.

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Available from: Timo Jämsä
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    • "However, newer accelerometers directly provide acceleration gravitational units (m/s 2 ), which may provide a relevant index of mechanical intensity. An additional accelerometer parameter, jerk or change in acceleration (g/s), has recently been shown to improve the prediction of physical activity dose as related to bone outcomes (Jämsä et al., 2011). Because bone can adapt to short bouts of mechanical loading if the load is of high intensity (Turner et al., 1994), the time-stamped feature of accelerometers is important. "
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