H-22F FREE COMMUNICATION/SLIDE STRENGTH TRAINING

Abstract

There is growing documentation of a link between low back pain (LBP) and morphological alterations in paraspinal musculature (PM). A causal relationship between LBP and the occurrence of various alterations in PM has not been established, but alterations correspond with changes seen following inactivity and disuse. To date, only a few studies have evaluated whether changes in PM in LBP patients are reversible. PURPOSES 1) To evaluate the effects of training on back muscle strength, cross sectional area (CSA) and density in subjects with LBP, 2) to study the correlation between muscle CSA and strength. METHODS Twenty-four inactive persons sick-listed for sub-acute LBP were randomised to an exercise (EG; n = 11) or control (CG; n = 13) group. EG followed a 15 week biweekly training program meeting ACSM's recommendations for developing and maintaining cardiorespiratory and muscular fitness in healthy adults. CG received usual care. Muscle CSA and density at level L3/4 and L4/5 were measured by computer tomography before and after intervention. Back muscle strength was tested isokinetically. RESULTS There was a non-significant increase in all measures of muscle CSA and density in EG, a significant decrease in muscle CSA at level L4/5 in CG and a significant difference in change between groups in muscle CSA at level L4/5 (p= 0.03). EG increased muscle strength significantly. There was a significant correlation between muscle strength and CSA at baseline and at follow up, but no correlation between changes in strength and changes in CSA. CONCLUSION The results show a trend for reversal of muscle atrophy in PM after systematical training in inactive persons sick-listed for LBP. An association between muscle strength and CSA was found at baseline and at follow up, but no association was found for changes from before to after intervention. Further studies are needed to estimate which factors have significant impact on improved back muscle strength in subjects with LBP. Supported by The Norwegian Foundation for Health and Rehabilitation and from The Norwegian Fund for Postgraduate Education in Physiotherapy.