Table 1.

Summary of experimental sequence and conditions

Posture	Purpose	Block	Perturbation	Stimulation	No. of trials	Duration (s)
Standing	Measure bEMG		No	No	1	30
Standing	Familiarization		Yes	No	10	80
Standing	Estimate reaction time		Yes	No	20	160
Sitting	Familiarization		Yes	No	10	80
Sitting	Estimate reaction time		Yes	No	20	160
Standing	Recruitment curve		No	Yes	2 per step	300
Standing	Control trials	1a	No	Yes	20	120
Standing	Experimental trials	1b	Yes	Yes	40	320
Any	Rest		No	No	0	120
Standing	Experimental trials	2a	Yes	Yes	40	320
Standing	Control trials	2b	No	Yes	20	160
Any	Rest		No	No	0	120
Sitting	Control trials	3a	No	Yes	20	120
Sitting	Experimental trials	3b	Yes	Yes	40	320
Any	Rest		No	No	0	120
Sitting	Experimental trials	4a	Yes	Yes	40	320
Sitting	Control trials	4b	No	Yes	20	120

‘Experimental trials refer to trials done with a self-perturbing arm swing

‘Control trials refer to trials done without a self-perturbing arm swing