TABLE I.

Summary of TUG variations in chronological order.

Article	TUG Variant	Description
O’Brien et al. (1997) [100]	Extra chair	Added an additional chair at the 3 meter mark.
Lundin-Olsson et al. (1998) [101]	TUG-manual	Subjects carry a glass of water while walking and place it back on the table when returning to the chair.
Wall et al. (2000) [46]	Expanded TUG	Increased length to 10 meters and times each of the subtasks of the TUG separately.
Shumway-Cook et al. (2000) [31]	TUG-dual task w/cognitive	Subjects count backwards by 3’s from a randomly chosen number in the range 20 to 100.
Medley and Thompson (2005) [102]	TUG-environment	Subjects walk over varying carpet thickness. Simulated by 2 foam mats, 1 meter wide and ½ and ¾ inch thick respectively.
Silsupadol et al. (2006) [103]	TUG-dual task w/cognitive	Subjects were asked simple arithmetic questions such as “What is 3 plus 2?”
Vaillant et al. (2006) [104]	Extra turning	Subjects walk around the chair before sitting down.
Demura and Uchiyama (2007) [105]	TUG-obstacle	Subjects step over a box, turn 180°, step back over the box and return to the chair. Increased length to 5 meters.
Nordin et al. (2008) [106]	GUG-modified	Additional descriptions to each of the items on the original fall-risk 5-point ordinal scale.
Maranhão-Filho et al. (2011) [107]	TUG-dual task w/cognitive	Subjects to recite alternating letters of the alphabet while they performed the TUG.
Cuesta-Vargas et al. (2013) [108]	Water-TUG	TUG inside a 1 meter-deep swimming pool.
Sprint et al. (2014) [109]	Ecological TUG	TUG in an ecological environment including a vehicle transfer at the 180° turnaround point.