Temporal patterns of the trunk muscles remain altered in a low back-injured population despite subjective reports of recovery

Janice M Moreside; D Adam Quirk; Cheryl L Hubley-Kozey

doi:10.1016/j.apmr.2013.10.003

Temporal patterns of the trunk muscles remain altered in a low back-injured population despite subjective reports of recovery

Arch Phys Med Rehabil. 2014 Apr;95(4):686-98. doi: 10.1016/j.apmr.2013.10.003. Epub 2013 Oct 15.

Authors

Janice M Moreside¹, D Adam Quirk², Cheryl L Hubley-Kozey³

Affiliations

¹ School of Health and Human Performance, Faculty of Health Professions, Dalhousie University, Halifax, Nova Scotia, Canada; School of Physiotherapy, Faculty of Health Professions, Dalhousie University, Halifax, Nova Scotia, Canada.
² School of Biomedical Engineering, Faculty of Health Professions, Dalhousie University, Halifax, Nova Scotia, Canada.
³ School of Health and Human Performance, Faculty of Health Professions, Dalhousie University, Halifax, Nova Scotia, Canada; School of Physiotherapy, Faculty of Health Professions, Dalhousie University, Halifax, Nova Scotia, Canada; School of Biomedical Engineering, Faculty of Health Professions, Dalhousie University, Halifax, Nova Scotia, Canada. Electronic address: cheryl.kozey@dal.ca.

PMID: 24139985
DOI: 10.1016/j.apmr.2013.10.003

Abstract

Objective: To compare temporal activation patterns from 24 abdominal and lumbar muscles between healthy subjects and those who reported recovery from recent low back injury (LBI).

Design: Cross-sectional comparative study.

Setting: University neuromuscular function laboratory.

Participants: Healthy adult volunteers (N=81; 30 LBI, 51 asymptomatic subjects).

Interventions: Trunk muscle electromyographic activity was collected during 2 difficulty levels of a supine trunk stability test aimed at challenging lumbopelvic control.

Main outcome measures: Principal component (PC) analysis was applied to determine differences in temporal and/or amplitude electromyographic patterns between groups. Mixed-model analyses of variance were performed on PC scores that explained more than 89% of the variance (α=.05).

Results: Four PCs explained 89% and 96% of the variance for the abdominal and back muscles, respectively, with both muscle groups having similar shapes in the first 3 PCs. Significant interactions or group main effects were found for all PC scores except PC4 for the back extensors. Overall activation amplitudes for both the abdominal and back muscles (PC1 scores) were significantly (P<.05) higher for the LBI group, with both abdominal and back muscles of the LBI group demonstrating an increased response to the leg-loading phase (PC2 scores) compared with the asymptomatic group. Differences were also found between groups in their preparatory activity (PC3 scores), with the LBI group having a higher early relative amplitude of abdominal and back extensor activity.

Conclusions: Despite perceived readiness to return to work and low pain scores, muscle activation patterns remained altered in this LBI group, including reduced synergistic coactivation and increased overall amplitudes as well as greater relative amplitude differences during specific phases of the movement. Electromyographic measures provide objective information to help guide therapy and may assist with determining the level of healing and return-to-work readiness after an LBI.

Keywords: Abdominal muscles; Back pain; Electromyography; Exercise movement techniques; Principal component analysis; Rehabilitation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Abdominal Muscles / physiopathology*
Adult
Analysis of Variance
Case-Control Studies
Cross-Sectional Studies
Electromyography*
Female
Humans
Low Back Pain / physiopathology*
Low Back Pain / rehabilitation
Lumbosacral Region
Male
Muscle, Skeletal / injuries
Muscle, Skeletal / physiopathology*
Principal Component Analysis
Return to Work