Table 2.

Load and prosthesis impedance parameters moderately affected subjects’ joint work. The first 4 columns summarize joint work normalized to body mass (W/kg) and averaged across subjects for each testing condition (mean ± s.d.). The last 3 columns summarize the factor effects of carrying load and altering the prosthesis impedance control parameters (i.e. p-value from ANOVA, 50 denominator degrees of freedom). Statistically significant changes are in bold font. Conditions without the same superscript letter (a–c) are significantly different at the 0.05 level with Tukey’s multiple comparisons adjustment.

	No Load		Load		Load Main Effect	Impedance Main Effect	Interaction Effect
	Impedance for no load	Impedance for load	Impedance for no load	Impedance for load
Intact Ankle
(positive)	0.25 ± 0.07a	0.23 ± 0.08a	0.24 ± 0.08ab	0.22 ± 0.09b	0.015	0.198	0.119
(negative)	−0.17 ± 0.05ab	−0.19 ± 0.03b	−0.16 ± 0.04a	−0.18 ± 0.04ab	0.123	0.030	0.922
Intact Knee
(positive)	0.10 ± 0.07a	0.09 ± 0.06a	0.10 ± 0.06a	0.09 ± 0.06a	0.150	0.041	0.748
(negative)	−0.05 ± 0.02a	−0.06 ± 0.02ab	−0.07 ± 0.02b	−0.07 ± 0.02b	<0.001	0.294	0.772
Intact-side Hip
(positive)	0.15 ± 0.03a	0.16 ± 0.03a	0.17 ± 0.05a	0.15 ± 0.04a	0.721	0.387	0.105
(negative)	−0.02 ± 0.01ab	−0.02 ± 0.01a	−0.03 ± 0.02c	−0.03 ± 0.02bc	<0.001	0.148	0.428
Prosthetic-side Hip
(positive)	0.14 ± 0.08ab	0.12 ± 0.07ab	0.14 ± 0.09a	0.12 ± 0.07b	0.612	0.008	0.349
(negative)	−0.06 ± 0.02a	−0.06 ± 0.01a	−0.07 ± 0.03a	−0.07 ± 0.02a	0.011	0.520	0.921