Table 3.

Test–retest reliability and construct validity

	Concordance of items between test and retest (n = 133)		Standardized factor loadings
	Weighted kappa (95% CI)	Interpretationa	Model 1	Model 2b
				Factor 1	Factor 2
1.1 Reduction strength arms	0.794 (0.658–0.840)	Substantial	0.695	0.725
1.2 Reduction strength legs	0.735 (0.637–0.834)	Substantial	0.897	0.930
1.3 Reduction muscle mass	0.682 (0.590–0.773)	Substantial	0.806	0.827
1.4 Reduction physical capacity	0.613 (0.495–0.732)	Substantial	0.917	0.951
1.5 Reduction length of walks	0.750 (0.673–0.828)	Substantial	0.867	0.873
2.1 Difficulty moderate effort	0.691 (0.541–0.842)	Substantial	0.901		0.915
2.2 Tired moderate effort	0.646 (0.485–0.808)	Substantial	0.856		0.864
3.1 Get up from floor	0.683 (0.512–0.854)	Substantial	0.786		0.802
3.2 Carrying heavy objects	0.546 (0.335–0.756)	Moderate	0.821		0.833
4 Tired when walking	0.798 (0.732–0.865)	Substantial	0.874		0.866
5 Feel weak	0.791 (0.709–0.873)	Substantial	0.877		0.900
6 Balance problems	0.867 (0.812–0.921)	Almost perfect	0.673		0.689
7 Limit movements	0.728 (0.637–0.819)	Substantial	0.850		0.868
8 Leisure activities	0.406 (0.185–0.627)	Moderate	0.594		0.605

^aKappas interpreted according to Landis and Koch, where ≥ 0.8 is almost-perfect agreement, ≥ 0.6 and < 0.8 is substantial agreement, ≥ 0.4 and < 0.6 is moderate agreement, ≥ 0.2 and < 0.4 is fair agreement, and < 0.2 is slight agreement

^bModel 2 is a 2-factor model with correlated residual variance between items 1.5 and 4