Pending Publication

Authors: Sherrilyn Walters(1,2), Ben Hoffman(1), Celeste E. Coltman (3), Lester Walters (2), Muneeb Iqbal (1), Dean E. Mills (1)
(1) University of Southern Queensland
(2) Martial Arts Research and Testing Laboratory
(3) University of Canberra

Abstract
Back pain and injury are leading causes of premature retirement, particularly in physically demanding occupations. Direct and practical methods of assessing the spine are required to determine the effects of rehabilitative or preventative interventions to address this. Ultrasonography has been reliably used to estimate spinal loading via measurement of distances between vertebral processes. However, no previous research has assessed the inter-rater and between-visit reliability of ultrasonography to assess changes in intervertebral disc distance while a load is carried on the trunk. We assessed the inter-rater and within- and between-visit reliability of ultrasonography to quantify spinal compression via measurement of distances between the transverse processes of the lumbar vertebrae in healthy adults during load carriage. Eleven healthy adults had ultrasound images taken of the transverse processes of each lumbar vertebra (L1-L5) immediately on standing while unloaded, after 15 min of standing, and after 15 and 30 minutes of standing while loaded with a 25 kg weighted vest. These procedures were repeated on a separate day. Distances between the transverse processes of the lumbar vertebra were measured offline. Inter-rater, within- and between- day reliability were assessed using coefficients of variation (CV) and intraclass correlation coefficients (ICCs). Agreement between raters and days was assessed using Bland-Altman plots. A one-way analysis of variance was used to determine the effects of each loading condition on inter-transverse process distances. Inter-rater, within- and between- day reliability was good to excellent with ICCs between 0.81 and 0.99 for all measurements. Inter-rater, Within- and between-visit CVs were between 5.24 and 13.0 for all measurements. Inter-transverse process distances reduced at L2/L3 and L3/L4 following 15 and 30 minutes of loaded standing. These results indicate that ultrasonography may be a practical and affordable method of reliably assessing changes in the lumbar spine during standing heavy load carriage.