Variability in Strength, Pain, and Disability Changes in Response to an Isolated Lumbar Extension Resistance Training Intervention in Participants with Chronic Low Back Pain

James Steele; James Fisher; Stewart Bruce-Low; Dave Smith; Neil Osborne; Dave Newell

doi:10.3390/healthcare5040075

Variability in Strength, Pain, and Disability Changes in Response to an Isolated Lumbar Extension Resistance Training Intervention in Participants with Chronic Low Back Pain

Healthcare (Basel). 2017 Oct 16;5(4):75. doi: 10.3390/healthcare5040075.

Authors

James Steele¹, James Fisher², Stewart Bruce-Low³, Dave Smith⁴, Neil Osborne⁵, Dave Newell⁶

Affiliations

¹ School of Sport, Health and Social Science, Southampton Solent University, Southampton, Hampshire SO14 0YN, UK. james.steele@solent.ac.uk.
² School of Sport, Health and Social Science, Southampton Solent University, Southampton, Hampshire SO14 0YN, UK. james.fisher@solent.ac.uk.
³ School of Sport, Health and Social Science, Southampton Solent University, Southampton, Hampshire SO14 0YN, UK. stewart.bruce-low@outlook.com.
⁴ Department of Exercise and Sport Science, Manchester Metropolitan University, Manchester CW1 5DU, UK. D.d.smith@mmu.ac.uk.
⁵ Anglo European Chiropractic College, Bournemouth BH5 2DF, UK. NOsborne@aecc.ac.uk.
⁶ Anglo European Chiropractic College, Bournemouth BH5 2DF, UK. dnewell@aecc.ac.uk.

Abstract

Strengthening the lumbar extensor musculature is a common recommendation for chronic low back pain (CLBP). Although reported as effective, variability in response in CLBP populations is not well investigated. This study investigated variability in responsiveness to isolated lumbar extension (ILEX) resistance training in CLBP participants by retrospective analysis of three previous randomized controlled trials. Data from 77 participants were available for the intervention arms (males = 43, females = 34) 37 participants data (males = 20, females = 17) from the control arms. Intervention participants had all undergone 12 weeks of ILEX resistance training and changes in ILEX strength, pain (visual analogue scale; VAS), and disability (Oswestry disability index; ODI) measured. True inter-individual (i.e., between participants) variability in response was examined through calculation of difference in the standard deviation of change scores for both control and intervention arms. Intervention participants were classified into responder status using k-means cluster analysis for ILEX strength changes and using minimal clinically important change cut-offs for VAS and ODI. Change in average ILEX strength ranged 7.6 Nm (1.9%) to 192.1 Nm (335.7%). Change in peak ILEX strength ranged -12.2 Nm (-17.5%) to 276.6 Nm (169.6%). Participants were classified for strength changes as low (n = 31), medium (n = 36), and high responders (n = 10). Change in VAS ranged 12.0 mm to -84.0 mm. Participants were classified for VAS changes as negative (n = 3), non-responders (n = 34), responders (n = 15), and high responders (n = 19). Change in ODI ranged 18 pts to -45 pts. Participants were classified for ODI changes as negative (n = 2), non-responders (n = 21), responders (n = 29), and high responders (n = 25). Considerable variation exists in response to ILEX resistance training in CLBP. Clinicians should be aware of this and future work should identify factors prognostic of successful outcomes.

Keywords: deconditioning; heterogeneity; individual response; rehabilitation.