Table 1.

Study design

Phase	Location	Na	Balance Aid	Objective	Measures
I	4 BCUs, 1 high- fidelity BCU mockup	38	Chair (n = 10)	To observe HCW behavior in four existing BCUs and a high-fidelity mockup unit and identify key built environment requirements for the doffing area [14]	Performance (Behavioral coding for number and occurrence of risky behaviors) Physical Load (REBA/RULAbscore) Cognitive Load (NASA TLXc score)
			L-shaped step stool (n = 17)
			Vertical grab bar (n = 8)
			No aid (n = 3)
II A	1 High-fidelity BCU mockup	31	Stool	To compare different balance aids, levels of doffing area demarcation and define the optimized layout
			L-shaped step stool
			Vertical grab bar
			Horizontal grab bar
II B	1 High-fidelity BCU mockup	9	Vertical grab bar	To compare two optimized layouts and select one to test with HCWs
			Horizontal grab bar
III	1 High-fidelity BCU mockup	9	Horizontal grab bar	To observe HCW behavior in the optimized layout and make comparisons with existing BCUs (phase I)

^aN represents the number of participants who used a balance aid. In Phase I each HCW used the balance aid used in their unit; in Phase II students did multiple rounds of simulations, using each of the aids provided; in Phase III there was only one balance aid option.

^bRapid Entire Body Assessment (REBA) and Rapid Upper Limb Assessment (RULA).

^cNASA Task Load Index (TLX).