Table 3.

Internal consistency (CA) and test-retest reliability (ICC_{3, 1}) of the FFI-Th

Item	CA	ICC3, 1	95% CI	p-value
Total	0.974	0.942	0.897–0.967	< 0.001
Pain	0.946	0.904	0.830–0.946	< 0.001
1. Worst foot pain		0.891	0.808–0.939	< 0.001
2. Morning foot pain		0.899	0.821–0.943	< 0.001
3. Pain walking barefoot		0.896	0.815–0.941	< 0.001
4. Pain standing barefoot		0.829	0.696–0.903	< 0.001
5. Pain walking with shoes		0.796	0.638–0.885	< 0.001
6. Pain standing with shoes		0.692	0.451–0.827	< 0.001
7. Pain walking with orthotics		0.918	0.807–0.965	< 0.001
8. Pain standing with orthotics		0.902	0.765–0.959	< 0.001
9. Foot pain at end of day		0.900	0.819–0.945	< 0.001
Disability	0.975	0.938	0.890–0.965	< 0.001
10. Walking in house		0.921	0.860–0.955	< 0.001
11. Walking outside		0.957	0.923–0.976	< 0.001
12. Walking four blocks		0.830	0.693–0.906	< 0.001
13. Climbing stairs		0.861	0.751–0.922	< 0.001
14. Descending stairs		0.912	0.844–0.951	< 0.001
15. Standing on tiptoe		0.876	0.773–0.932	< 0.001
16. Getting up from chair		0.904	0.830–0.946	< 0.001
17. Climbing curbs		0.908	0.833–0.949	< 0.001
18. Running or walking fast		0.882	0.786–0.935	< 0.001
Activity limitation	0.714	0.866	0.763–0.925	< 0.001
19. Using device indoors		0.890	0.801–0.939	< 0.001
20. Using device outdoors		0.795	0.621–0.889	< 0.001
21. Staying inside all day		0.838	0.705–0.911	< 0.001
22. Staying in bed all day		0.691	0.351–0.853	0.001
23. Limiting activities		0.534	0.008–0.781	0.024

The data treated by the cold deck technique

CA Cronbach’s alpha, ICC_{3, 1} Intraclass Correlation Coefficient of the two-way mixed model (Consistency), CI Confidence interval