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. Author manuscript; available in PMC: 2018 Dec 7.
Published in final edited form as: Hum Mov Sci. 2017 May 9;54:154–171. doi: 10.1016/j.humov.2017.04.005

Table 3:

Sensitivity of ground reaction forces to component stiffness and speed.

Ground Reaction Force Outcomes - Dimensionless Redimensionalized Increment Effects
Quantity Mean ± SD
(NS 1.1)		 Slope vs. KFore
P-val 		Coef. KFore*v
P 		Slope vs. KHind
P 		Coef. KHind*v
P 		Slope* vs. Speed v
P 		Mean ± SD
(NS 1.1)		 Slope vs. KFore
(units) 		Coef. KF*v
(units) 		Slope vs. KHind
(units) 		Coef. KH*v
(units) 		Slope* vs. Speed v
(units) 		FID
+15 N/mm
(units) 		HID
+15 N/mm
(units) 		VID
+0.2 m/s
(units)
Prosth. Side 1.13±0.08 3.3E−3 −7.1E−3 3.4E−3 −1.2E−2 0.47 932±63
(N) 		3.2
(N per N/mm) 		−2.2
(N per N/mm per m/s) 		3.2
(N per N/mm) 		−3.9
(N per N/mm per m/s) 		126
(N per m/s) 		11
(N) 		−15
(N) 		−2.1
(N)
Fz Peak 1
0.12 0.24 0.03 0.004 0.16
Prosth. Side 1.07±0.06 2.2E−4 −8.4E−4 1.5E−3 −2.9E−3 0.20 883±49
(N) 		0.21
(N per N/mm) 		−0.26
(N per N/mm per m/s) 		1.4
(N per N/mm) 		−0.90
(N per N/mm per m/s) 		54
(N per m/s) m/s) 		−1.2
(N) 		6.0
(N) 		5.5
(N)
Fz Peak 2
0.86 0.81 0.07 0.18 0.29
Intact Side 1.13±0.05 −1.9E−3 9.5E−3 4.8E−4 −1.7E−3 0.14 931±39
(N) 		−1.8
(N per N/mm) 		3.0
(N per N/mm per m/s) 		0.46
(N per N/mm) 		−0.52
(N per N/mm per m/s) 		38
(N per m/s) m/s) 		22
(N) 		−1.7
(N) 		18
(N)
Fz Peak 1
0.29 0.06 0.70 0.62 0.62
Intact Side 0.986±0.026 4.4E−4 −1.0E−3 1.0E−3 −2.2E−3 0.47 812±21
(N) 		0.42
(N per N/mm) 		−0.32
(N per N/mm per m/s) 		0.94
(N per N/mm) 		−0.68
(N per N/mm per m/s) 		127
(N per m/s) m/s) 		0.93
(N) 		2.9
(N) 		21
(N)
Fz Peak 2
0.78 0.82 0.43 0.52 0.06
Prosth. Side 2.96±0.54 - - −2.1E−2 0.13 3.6 7860±1440
(N/s) 		- - −64
(N/s per N/mm) 		134
(N/s per N/mm per m/s) 		3110
(N/s per m/s) 		- 1254
(N/s) 		1828
(N/s)
Fz Loading Rate
- - 0.13 <0.001 0.07
Prosth. Side −3.39±0.42 3.9E−3 3.7E−3 - - −9.7 −8980±1100
(N/s) 		12
(N/s per N/mm) 		3.7
(N/s per N/mm per m/s) 		- - −8400
(N/s per m/s) 		240
(N/s) 		- −1645
(N/s)
Fz Unloading Rate
0.72 0.90 - - <0.001
Prosth Side −0.115±0.033 −9.7E−4 7.1E−4 −1.3E−3 3.8E−3 −0.20 −94.6±27.5
(N) 		−0.92
(N per N/mm) 		0.22
(N per N/mm per m/s) 		−1.3
(N per N/mm) 		1.2
(N per N/mm per m/s) 		−53
(N per m/s) m/s) 		−10
(N) 		0.61
(N) 		−4.3
(N)
Fy Peak Decel.
0.09 0.66 0.005 0.004 0.03
Prosth Side 0.155±0.021 4.8E−4 −2.9E−3 4.0E−4 −8.2E−4 0.46 128±18
(N) 		0.45
(N per N/mm) 		−0.89
(N per N/mm per m/s) 		0.38
(N per N/mm) 		−0.25
(N per N/mm per m/s) 		125
(N per m/s) m/s) 		−7.9
(N) 		1.5
(N) 		20
(N)
Fy Peak Accel.
0.40 0.07 0.34 0.48 <0.001
Intact Side −0.161±0.039 1.3E−3 −3.7E−3 −2.7E−4 6.0E−4 −0.39 −133±32
(N) 		1.2
(N per N/mm) 		−1.2
(N per N/mm per m/s) 		−0.25
(N per N/mm) 		0.19
(N per N/mm per m/s) 		−106
(N per m/s) m/s) 		−0.73
(N) 		−0.70
(N) 		−25
(N)
Fy Peak Decel.
0.04 0.04 0.58 0.64 <0.001
Intact Side 0.159±0.034 5.3E−4 −8.6E−4 3.4E−4 −8.8E−4 0.55 131±28
(N) 		0.50
(N per N/mm) 		−0.27
(N per N/mm per m/s) 		0.32
(N per N/mm) 		−0.27
(N per N/mm per m/s) 		150
(N per m/s) m/s) 		3.1
(N) 		0.24
(N) 		27
(N)
Fy Peak Accel.
0.33 0.57 0.42 0.44 <0.001

P-values and Slopes vs. Speed are estimated conservatively. P-values are the greater of the P-values of the Speed coefficient in mixed linear regressions with KForefoot or KHindfoot. Slope values are the lesser of the two Speed coefficients.

-

Indicates statistical test not performed.

NS 1.1: Result for Nominal Stiffness condition at 1.1 m·s−1.