Table 1.

Step placement and metabolic cost values across visual perturbation conditions. Data are reported as mean ± standard deviation, with lengths given in units of leg length, L. Asterisk (*) denotes statistical significance (P < 0.05) relative to the control condition. Perturbation conditions refer to fore-aft (F-A) and medio-lateral (M-L) directions, translational (T) and rotational (R) motions, and maximum amplitudes of 0.20 and 0.35 L.

Perturbation	Step length mean (L)	Step width mean (L)	Step length RMS (L)	Step width RMS (L)	Net metabolic rate (Mg1.5L0.5)
Control	0.686 ± 0.047	0.125 ± 0.023	0.018 ± 0.004	0.028 ± 0.007	0.109 ± 0.017
F-A T 0.20	0.681 ± 0.047	0.120 ± 0.033	0.019 ± 0.005	0.032 ± 0.008	0.102 ± 0.012
F-A T 0.35	0.686 ± 0.045	0.123 ± 0.026	0.020 ± 0.008	0.031 ± 0.008	0.108 ± 0.017
F-A T 0.20	0.682 ± 0.048	0.116 ± 0.028	0.017 ± 0.004	0.032 ± 0.008	0.105 ± 0.012
F-A R 0.35	0.690 ± 0.043	0.125 ± 0.027	0.020 ± 0.007	0.033 ± 0.006	0.108 ± 0.018
M-L T 0.20	0.686 ± 0.041	0.132 ± 0.036	0.022 ± 0.011	0.042 ± 0.011*	0.109 ± 0.019
M-L T 0.35	0.682 ± 0.049	0.129 ± 0.032	0.019 ± 0.004	0.044 ± 0.012*	0.109 ± 0.018
M-L R 0.20	0.684 ± 0.045	0.135 ± 0.039	0.021 ± 0.006	0.043 ± 0.012*	0.111 ± 0.024
M-L R 0.35	0.679 ± 0.040	0.149 ± 0.040*	0.023 ± 0.012	0.046 ± 0.019*	0.115 ± 0.022*