Isometric Force Parameters and Trunk Muscle Recruitment Strategies in a Population With Low Back Pain
Received 8 June 2006; received in revised form 26 July 2006; accepted 22 September 2006.
Abstract
Objective
This study correlates changes in trunk isometric force parameters and trunk muscle recruitment strategies in subjects with low back pain (LBP) and healthy participants.
Methods
A control group study with repeated measures was performed. Study participants included 15 control subjects and 14 patients with LBP. Participants were required to exert 50% and 75% of their maximal trunk flexion and extension. In a learning phase, feedback was provided, after which study participants were asked to perform 10 trials without any feedback. Spatiotemporal parameters of muscular activity and force production were recorded. Dependent variables included time to peak force, peak force variability, absolute error in peak force, electromyogram (EMG) burst duration for agonist muscles, and normalized integrated EMG.
Results
Average time to peak force was significantly longer for subjects with LBP than for healthy subjects. Subjects with LBP showed longer burst duration for all 4 muscles recorded. No group difference was noted in normalized integrated EMG.
Conclusions
We suggest that the observed changes in trunk motor control and trunk muscle recruitment strategies are not only mediated by a neurophysiologic adaptation to chronic pain but also by cognitive adaptations modulated by fear of movement and fear of reinjury.
aProfessor and Research Chair holder, Department of Chiropractic, University of Quebec at Trois-Rivières, Trois-Rivières, Quebec, Canada
bStudent, Department of Chiropractic, University of Quebec at Trois-Rivières, Trois-Rivières, Quebec, Canada
cDirector, Department of Chiropractic, University of Quebec at Trois-Rivières, Trois-Rivières, Quebec, Canada
Submit requests reprints to: Martin Descarreaux, DC, PhD, Département de chiropratique, bureau 3613, Université du Québec à Trois-Rivières, 3351 boul. des Forges, CP 500, Trois-Rivières, QC, Canada G9A 5H7
ABSTRACT