Table 1: Subject characteristics.

People with LBP
( )
People without LBP
( )

GenderM = 7, F = 8M = 10, F = 10
Age (years)28.1 (7.2)26.5 (5.9)
Weight (kg)74.1 (10.1)72.6 (7.6)
Height (cm)173.5 (10.9)171.4 (9.4)
Body mass index (kg/m2)24.8 (3.0)24.9 (2.8)
Spine length (cm)48.1 (3.6)46.8 (2.8)
Shank length (cm)38.7 (3.1)38.1 (3.1)
Passive hip lateral rotation* (degrees)45.4 (10.0)49.1 (7.2)
Femoral anteversion (degrees)11.3 (5.5)11.4 (5.5)
Generalized joint hypermobility (0–9)2.2 (3.2)2.1 (2.5)
Relative motion index , active condition4.7 (3.6)6.7 (4.0)
Relative motion index, active-instructed condition11.4 (8.5)18.2 (12.3)
Relative motion index, passive condition3.7 (7.1)4.8 (4.6)
Current pain score (0–10)2.0 (1.2)NA
Duration of LBP (years)6.8 (3.3)NA
Modified Oswestry Disability Index (0–100%)13.5 (9.5)NA
Number of acute flare-ups in previous 12 months#5.8 (4.3)NA

Values expressed as mean (standard deviation).
for all comparisons.
Passive hip lateral rotation with pelvis stabilized, measured in prone with an inclinometer.
Femoral anteversion measured with a goniometer using methods described by Ruwe et al. [37].
Generalized joint hypermobility measured with Beighton Hypermobility Scale [38].
Relative motion index calculated as the amount of hip lateral rotation completed prior to the start of lumbopelvic rotation.
Pain measured using a verbal numeric pain rating scale [32].
Disability measured using modified Oswestry Disability Index [31].
A flare-up is defined as a period (usually a week or less) when back pain is markedly more severe than usual [30].