Browse > Article
http://dx.doi.org/10.9718/JBER.2009.30.6.516

Determination of filtering condition and threshold for detection of Gait-Cycles under Various Gait Speeds and Walkway Slopes  

Kwon, Yu-Ri (School of Biomedical Engineering, Konkuk University)
Kim, Ji-Won (School of Biomedical Engineering, Konkuk University)
Lee, Jae-Ho (School of Biomedical Engineering, Konkuk University)
Tack, Gye-Rae (School of Biomedical Engineering, Konkuk University)
Eom, Gwang-Moon (School of Biomedical Engineering, Konkuk University)
Publication Information
Journal of Biomedical Engineering Research / v.30, no.6, 2009 , pp. 516-520 More about this Journal
Abstract
The purpose of this study is to determine optimal filtering condition and threshold for the detection of gait-cycles for various walkway slopes as well as gait velocities. Ten young healthy subjects with accelerometer system on thigh and ankle walked on a treadmill at 9 conditions (three speeds and three slopes) for 5 minutes. Two direction signals, i.e. anterior-posterior (AP) and superior-inferior (SI) directions, of each sensor (four sensor orientations) were used to detect specific events of gait cycle. Variation of the threshold (from -1G to 1G) and lowpass cutoff frequency (fc) were applied to the event detection and their performance was evaluated according to the error index (EI), which was defined as the combination of the accuracy and false positive rate. Optimal fc and threshold were determined for each slope in terms of the EI. The optimal fc, threshold and their corresponding EI depended much on the walkway slope so that their coefficients of variation (CV) ranged 19~120%. When all data for 3 slopes were used in the identification of optimal conditions for each sensor, the best error indices for all sensor orientations were comparable ranging 1.43~1.76%, but the optimal fc and threshold depended much on the sensor position. The result indicates that the gait-cycle detection robust to walkway slope is possible by threshold method with well-defined filtering condition and threshold.
Keywords
gait cycle; accelerometer; pedometer; walkway slope; speed;
Citations & Related Records
연도 인용수 순위
  • Reference
1 G.J. Welk, J.A. Differding, R.W. Thompson, S.N. Blair, J. Dziura, and P. Hart, "The utility of the Digi-walker step counter to assess daily physical activity patterns," Med Sci Sports Exerc, vol. 32, no. 9, pp.S481-488, 2000   DOI
2 T. Mitsui, K. Shimaoka, S. Tsuzuku, T. Kajioka, and H. Sakakibara, "Pedometer-determined physical activity and indicators of health in Japanese adults," J Physiol Anthropol, vol. 27, no. 4, pp.179-184, 2008   DOI   ScienceOn
3 S.D. Han, Human engineering, Seoul, Korea, Hakmunsa, 1983
4 G.C. Le Masurier, S.M. Lee, and C. Tudor-Locke, "Motion sensor accuracy under controlled and free-living conditions," Med Sci Sports Exerc, vol. 36, no. 5, pp.905-910, 2004
5 B. Auvinet, G. Berrut, C. Touzard, L. Moutel, N. Collet, D. Chaleil, and E. Barrey, "Reference data for normal subjects obtained with an accelerometric device," Gait Posture, vol. 16, no. 2, pp.124-134, 2002   DOI   ScienceOn
6 G.C. Le Masurier, and C. Tudor-Locke, "Comparison of pedometer and accelerometer accuracy under controlled conditions," Med Sci Sports Exerc, vol. 35, no. 5, pp.867-871, 2003   DOI   ScienceOn
7 M. Silva, E.F. Shepherd, W.O. Jackson, F.J. Dorey, and T.P. Schmalzried, "Average patient walking activity approaches 2 million cycles per year: pedometers under-record walking activity," J Arthroplasty, vol. 17, no.6, pp.693-697, 2002   DOI   ScienceOn
8 C. Tudor-Locke, S.B. Sisson, S.M. Lee, C.L. Craig, R.C. Plotnikoff, and A. Bauman, "Evaluation of quality of commercial pedometers," Can J Public Health, vol. 97 Suppl 1, no., pp.S10-15, S10-16, 2006
9 M.W. Beets, M.M. Patton, and S. Edwards, "The accuracy of pedometer steps and time during walking in children," Med Sci Sports Exerc, vol. 37, no. 3, pp.513-520, 2005   DOI   ScienceOn
10 E.V. Cyarto, A.M. Myers, and C. Tudor-Locke, "Pedometer accuracy in nursing home and community-dwelling older adults," Med Sci Sports Exerc, vol. 36, no. 2, pp.205-209, 2004   DOI   ScienceOn
11 S. Nakae, Y. Oshima, and K. Ishii, "Accuracy of spring-levered and piezo-electric pedometers in primary school Japanese children," J Physiol Anthropol, vol. 27, no. 5, pp.233-239, 2008   DOI   ScienceOn
12 N. Leenders, W.M. Sherman, and H.N. Nagaraja, "Comparisons of four methods of estimating physical activity in adult women," Med Sci Sports Exerc, vol. 32, no. 7, pp.1320-1326, 2000   DOI   ScienceOn
13 P.L. Schneider, S.E. Crouter, O. Lukajic, and D.R. Bassett, Jr., "Accuracy and reliability of 10 pedometers for measuring steps over a 400-m walk," Med Sci Sports Exerc, vol. 35, no. 10, pp.1779-1784, 2003   DOI   ScienceOn
14 S. Horvath, D.G. Taylor, J.P. Marsh, and D.J. Kriellaars, "The effect of pedometer position and normal gait asymmetry on step count accuracy," Appl Physiol Nutr Metab, vol. 32, no., pp.409-415, 2007   DOI   ScienceOn
15 C. Tudor-Locke, B.E. Ainsworth, R.W. Thompson, and C.E. Matthews, "Comparison of pedometer and accelerometer measures of free-living physical activity," Med Sci Sports Exerc, vol. 34, no. 12, pp.2045-2051, 2002   DOI   ScienceOn
16 C.Y. Chung, M.S. Park, I.H. Choi, T.J. Cho, W.J. Yoo, and J. Y. Kim, "Three dimensional gait analysis in normal Korean," Korean Orthop. Assoc., vol. 40, no. 1, pp.83-88, 2005   DOI
17 S.E. Crouter, P.L. Schneider, M. Karabulut, and D.R. Bassett, Jr., "Validity of 10 electronic pedometers for measuring steps, distance, and energy cost," Med Sci Sports Exerc, vol. 35, no. 8, pp.1455-1460, 2003   DOI   ScienceOn