![](bg4.png)
Table 2: Peak acceleration, angular velocity and vertical angle during falls and ADLs.
Trials Acceleration (g)
Angular velocity (°/s) Angle (°)
Pitch Roll Sagittal Lateral
Falls
Backward
4.1 ± 0.6 300.3 ± 59.7 45.7 ± 14.2 94.2 ± 4.7 4.7 ± 3.2
Forward
4.5 ± 0.5 220.6 ± 41.6 75.9 ± 17.2 89.6 ± 9.2 8.4 ± 4.6
Side
4.4 ± 0.6 121.2 ± 13.7 419.4 ± 61.3 6.69 ± 2.7 75.95 ± 12.4
ADLs
Sit-Stand
1.4 ± 0.2 110 ± 23.1 8.9 ± 7.6 31.1 ± 6.1 2.6 ± 1.3
Stand-Sit
2.2 ± 0.3 392.3 ± 61.3 11.2 ± 6.1 11.63 ± 3.1 1.12 ± 2.7
Sit-Lying
1.1 ± 0.1 80.7 ± 31.7 15.3 ± 3.8 90.3 ± 8.3 4.3 ± 2.8
Walking
2.1 ± 0.2 50.1 ± 10.9 59.3 ± 14.9 1.4 ± 6.2 2.1 ± 3.1
Jump
7.5 ± 1.1 421.2 ± 149.1 102.3 ± 62.1 27.3 ± 2.1 3.6 ± 3.8
Running
4.2 ± 0.9 132.8 ± 45.7 98.2 ± 34.9 11.5 ± 9.7 2.6 ± 4.1
(1997) found that the maximum lean angle where
subjects could recover balance with a single forward
step averaged 32.5° for young men and 23.9° for
older men. Therefore, it can be noted that our
threshold 30° of sensor angle is very well within the
limits of balance recovery during the fall process.
For lying activities in ADLs, there was a small
variation in acceleration and no wrong recognition
was found even though the angle changed to 90°.
It should be pointed out that all activities tested
in this study was performed by healthy volunteers
aged below 30, since the experimental procedure
was not understandably suited for elderly subjects
who are at greater risk of suffering injury. The
movement of younger subjects is bound to differ
from that of the elderly population, who may have as
lower reaction time and lesser ability to rescue the
body from falling. In addition, our algorithm were
tested against a small range of fall types and ADLs.
Therefore, further tests are needed for other types of
falls such as tripping and slipping.
Nevertheless, our pre-impact fall detection
algorithm can be implemented in a wearable fall
injury minimization system to track a user’s body
movement and notify the fall impact reduction
device.
ACKNOWLEDGEMENTS
This study was supported by the National Research
Foundation of Korea (NRF) funded by the Ministry
of Education (2013H1B8A2032194).
REFERENCES
Annekenny, R. and O’Shea, D., 2002. Falls and syncope in
elderly patients. Clinics in Geriatric Medicine 18(2),
xiii–xiv.
Bourke, A. K., O’Donovan, K. J., O´ Laighin, G., 2008.
The identification of vertical velocity profiles using an
inertial sensor to investigate pre-impact detection of
falls. Medical Engineering & Physics 30(7), 937–946.
Davidson, M. E., 2004. System for protection from falls.
United States Patent Office Document,
US2004/0003455.
Gross, Y. T., Shimamoto, Y., Rose, C. L., Frank, B., 1990.
Why do they fall? Monitoring risk factors in nursing
homes. Journal of Gerontology and Nursing 16(6), 20–
25.
Hayes, W. C., Myers, E. R., Robinovitch, S. N., Van Den
Kroonenberg, A., Courtney, A. C., Kenny, R. A.,
O’Shea, D., 2002. Falls and syncope in elderly
patients. Clinics in Geriatric Medicine 18(2), xiii–xiv.
Lockhart, T. E., 2006. Fall-sensing systems, hip protector
systems, and other protective systems. United States
Patent Office Document, US2006/0049950A1.
Nevitt, M.C., Cummings, S. R., Hudes, E. S., 1991. Risk
factors for injurious falls: a prospective study. Journal
of Gerontology 46, M164–M170.
Nyan, M. N., Tay, F. E., Tan, A. W., Seah, K. H., 2006.
Distinguishing fall activities from normal activities by
angular rate characteristics and high-speed camera
characterization. Medical Engineering & Physics 28
(8), 842–849.
Peczalski, K., Wojciechowski, D., Sionek, P., Dunajski,
Z., Palko, T., 2006. Impedance cardiography vs clamp
pletysmography of Penaz in diagnostic of patients with
vasovagal syncope. Journal of Biomechanics 39(1),
S453.
Smeesters, C., Hayes, W. C., McMahon, T. A., 2001.
Disturbance type and gait speed affect fall direction
and impactlocation. Journal of Biomechanics 34(3),
309–317.
Thelen, D. G., Wojcik, L. A., Schultz, A. B., Ashton-
Miller, J. A., Alexander, N. B., 1997. Age differences
in using a rapid step to regain balance during a forward
all. Journals of Gerontology SeriesA: Biological
Sciences and Medical Sciences 52A(1), M8–M13.
Ulert, I. A., 2002. Hip protector. United States Patent
BIODEVICES2014-InternationalConferenceonBiomedicalElectronicsandDevices
210