Table 2.

Structure matrix for the MIL after removing 4 items that presented cross loadings (n = 170)

	EFA components
MIL items	ILBP	MLBP
1. Intermitent pain during day	.61	.26
2. Morning pain on waking and initial getting up	.76	.20
3. Stiffness after resting	.61	.01
4. Pain on repetive bending	.71	.20
5. Pain on trunk flexion	.33	.76
6. Pain on lateral bending	.36	.75
7. Palpatory pain of vertebrae	-.06	.72

Note: Extraction Method = Maximum Likelihood; Rotation Method: Oblimin with Kaiser Normalization.

Items were originally in Spanish and have been translated into English for this manuscript.

ILBP: inflammatory LBP; MLBP: mechanical LBP.