Table 3.

Results of functional tests and correlation with quadriceps strength.

	N	Min	Max	Mean (SD)	r	P-value
IBMFRS	80	12	37	26.3 ± 5.7	0.375	0.001
mTUG (s)	63	5.6	35.2	12.2 ± 6.1	−0.419	0.001
Stairs-up (s)	58	2.0	21.5	6.3 ± 3.7	−0.307	0.019
Stairs-down (s)	58	1.6	22.9	6.1 ± 4.2	−0.380	0.003
Step height (inches)	50	2	8	4.4 ± 3.3	0.506	≤0.001
2MWT distance (meters)	84	25	219	104.0 ± 38.2	0.603	≤0.001
6MWT distance (meters)	85	61	620	304.2 ± 116.5	0.578	0.001

N, number of subjects capable of performing task. All items significant at P ≤ 0.05. Min and Max indicate performance range for each item; Stairs-up = ascending 4 stairs; Stairs-down = descending 4 stairs; Step height = stepping up a series of four curbs of increasing height (2, 4, 6, 8 inches). IBMFRS, Inclusion-Body Myositis Functional Rating Scale; mTUG, modified timed up and go; 2MWT, 2-minute walk test; 6MWT, 6-minute walk test.