M. Griffioen, P. van Drunen, E. Maaswinkel, R. S. G. M. Perez, R. Happee, J. H. van Dieën


April 2020, pp 1 - 9 Original Article Read Full Article 10.1007/s00586-020-06385-9

First Online: 02 April 2020

Identification of intrinsic and reflexive contributions to trunk stabilization in patients with low back pain: a case-control study

Purpose

The goal of this study was to assess differences in low back stabilization and underlying mechanisms between patients with low back pain (LBP) and healthy controls. It has been hypothesized that inadequate trunk stabilization could contribute to LBP through high tissue strains and/or impingement. Evidence to support this is inconsistent, and not all methods that have been used to study trunk stabilization are equally suitable. We have recently developed a method to assess intrinsic and reflexive contributions to trunk stabilization, which aims to circumvent the limitations of previous studies.

Methods

Forty-nine participants suffering from chronic LBP and a control group of fifty healthy subjects participated in this study. Trunk stabilization was measured using force-controlled perturbations directly applied to the trunk. The actuator displacement and contact force between the actuator and subject were measured as well as electromyography (EMG) of the M. Longissimus. Underlying mechanisms were characterized using system identification.

Results

LBP patients showed lower admittance, i.e., less displacement per unit of force applied, mainly due to higher position, velocity and acceleration feedback gains. Among patients, lower trunk admittance and higher reflex gains were associated with more negative pain-related cognitions.

Conclusion

Trunk stabilization differs between LBP patients and controls, with the same perturbations causing less trunk movement in patients, due to stronger reflexes. We interpret these changes as reflecting protective behavior.

Graphic abstract

These slides can be retrieved under Electronic Supplementary Material.[graphic not available: see fulltext]


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