Table 2.

Gait features contained in feature set 2 used in the single- and multiple-time fall prediction model.

Gait feature name	Direction
Stride time	–
Walking speed	–
Walking distance	–
Mean step length	–
Stride time variability	–
Stride length variability	–
Stride speed variability	–
Stride frequency	–
Stride frequency variability	–
Acceleration standard deviation	AP, ML, V, Vector magnitude
Stride regularity (Moe-Nilssen and Helbostad, 2004)	AP, ML, V, Vector magnitude
Harmonic ratio (Yack and Berger, 1993; Doi et al., 2013)	AP, ML, V
Index of harmonicity (Lamoth et al., 2002)	AP, ML, V
Spectral range (Weiss et al., 2013)	AP, ML, V
Spectral dominant frequency (Weiss et al., 2013)	AP, ML, V
Spectral slope (Weiss et al., 2013)	AP, ML, V
Spectral width (Weiss et al., 2013)	AP, ML, V
Spectral amplitude (Weiss et al., 2013)	AP, ML, V
Low frequency percentage (Rispens et al., 2015)	AP, ML, V, Vector magnitude
Lyapunov exponent R (Rosenstein et al., 1993)	AP, ML, V, Vector magnitude
Lyapunov exponent W (Wolf et al., 1985)	AP, ML, V, Vector magnitude
Lyap. exponent per stride R (Rosenstein et al., 1993)	AP, ML, V, Vector magnitude
Lyap. exponent per stride W (Wolf et al., 1985)	AP, ML, V, Vector magnitude