Table 3.

Significant inertial-sensor-based variables (p < 0.05) with associated sensor location

Category	Variable	Sensor location
Position and Angle Variables	AP peak to peak amplitude	LB [52]
	ML peak to peak amplitude	LB [52]
	V peak to peak amplitude	LB [52]
	AP and ML postural sway length during stance	LB [43,51]
	Trunk tilt	St [44]
Angular Velocity Variables	Min, mean, max AP	Sha [50]
	Min, mean, max ML	Sha [50]
	Min, mean, max V	Sha [50]
	AP peak to peak amplitude	LB [52]
	ML peak to peak amplitude	Sha [50]
	V peak to peak amplitude	LB [52]
	Postural sway velocity during stance	LB [43,51]
	Mean squared modulus ratio for postural sway	LB [46-48]
	AP RMS during stance	LB [51]
	ML RMS during stance	LB [51]
	V RMS during stance	LB [51]
	3D RMS during stance	LB [51]
	ML variability	UB [73]
Linear Acceleration Variables	Median AP	LB [74]
	SD of AP	He [18], LB [74], Hi [18]
	Peak AP	UB [75]
	Peak V	UB [75]
	AP peak to peak amplitude	LB [52]
	ML peak to peak amplitude	LB [49,52,60]
	V peak to peak amplitude	LB [52]
	AP RMS	He [55], LB [55]
	ML RMS	He [55], LB [55]
	V RMS	He [55], LB [55,71]
	AP RMS during stance	LB [51]
	ML RMS during stance	LB [51]
	V RMS during stance	LB [51]
	2D RMS (ML and AP) during stance	LB [43]
	3D RMS	LB [1,57]
	3D RMS during stance	LB [51]
	Jerk	St [42]
	Sit to stand AP range	LB [74]
	Stand to sit AP range	LB [74]
	Sit to stand Jerk	LB [74]
	Dissimilarity of AST subcomponents	LB [57,67]
	Dissimilarity of STS subcomponents	LB [67,68,70]
Spatial Variables	Number of steps	LB [60], Sha [50]
	Step length	He [64], LB [60,64,72]
Temporal Variables	Gait Speed	He [55,64], LB [40,44,55,64,72,74]
	Cadence	He [64], LB [39,58,64], Kn [41], Sha [50], An [41]
	Step duration	LB [74], Sha [50]
	Step duration variability	He [55], LB [55]
	Stride time	Fo [71]
	SD of stride time	Fo [71]
	% GC double support	Sha [50]
	TUG time	LB [66,74], Sha [50]
	TUG subcomponent time	LB [57,66], Sha [50]
	TUG: number of gait cycles	Sha [50]
	STS time	LB [66]
	STS subcomponent times	LB [57], Th [42]
	SD of STS subcomponent times	LB [66]
	Normalized SD of STS subcomponent times	LB [58,66]
	Sit/stand transition duration	St [17,45]
	Sit/stand SD of transition duration	St [17]
	AST time	LB [66]
	AST subcomponent times	LB [57,58,68,70]
	SD of AST subcomponent times	LB [66]
	Normalized SD of AST subcomponent times	LB [67,68,70]
Energy Variables	Kinetic Energy	LB [49]
	Local wavelet energy	St [45]
	Summed magnitude area of acceleration	LB [57,58,67]
	25% quartile frequency	He [18], Hi [18]
	50% quartile frequency	He [18], Hi [18]
	75% quartile frequency	He [18], Hi [18]
	Sway frequency during stance	LB [51]
	Number of FFT peaks	LB [61,62]
	Dominant FFT peak parameters	LB [59,61,62]
	1st FFT peak parameters	Sho [41], El [41], Wr [41], Kn [41], An [41]
	Ratio of magnitude of even harmonics to odd harmonics	He [55,64], UB [44,75], LB [44,50,52,53,59,72]
	Area under 1st 6 harmonics divided by remaining area	LB [57,58]
	Ratio of 1st 4 harmonics to magnitude of 1st 6 harmonics	LB [57,58]
	ML spectral edge frequency	St [42]
	Entropy of power spectrum	LB [53]
	Correlation between left and right arm signals	Sho [41], El [41], Wr [41]
	Maximum V acceleration Lyapunov Exponent	Hi [56], Kn [56], An [56]
	Maximum AV Lyapunov Exponent	UB [73], Hi [56], Kn [56], An [56]
	Autocorrelation coefficients of acceleration signal	LB [39,65]
	Trunk level forces	St [45]
	Continuous wavelet transform	LB [63]
	Discrete wavelet transform	St [45], LB [63]
	Detrended fluctuation fractal scaling index of acceleration derived stride time	Fo [69]
	Fractal dimension of acceleration versus AV	St [45]
	Number of abnormal sit/stand transitions	St [17]

An, ankle, AP, anteroposterior, AST, Alternating Step Test, AV, angular velocity, COP, center of pressure, CoV, coefficient of variation, El, elbow, FFT, Fast Fourier Transform, Fo, foot, He, head, Hi, hip, GC, gait cycle, Kn, knee, LB, lower back, ML, mediolateral, RMS, Root Mean Square, SD, standard deviation, Sha, shank, Sho, shoulder, St, sternum, STS, sit-to-stand transitions, Th, thigh, TUG, Timed Up and Go, UB, upper back, V, vertical, Wr, wrist.