Sense of effort is distorted in people with chronic low back pain

Michel W Coppieters,Jesper Andersen,Håvard Selbæk,Kjell Herland,Rahma Ajja,Harald Markussen,Paul W Hodges

doi:10.1016/j.msksp.2021.102376

Abstract

Background: Proprioceptive deficits in people with low back pain (LBP) have traditionally been attributed to altered paraspinal muscle spindle afference and its central processing. Studies conducted in the upper limb demonstrated that sense of effort is also an important source of kinaesthetic information. Objectives: To better understand proprioceptive deficits in people with chronic LBP (cLBP), this study aimed to test whether sense of effort is affected in people with cLBP. Design: Cross-sectional study. Method: Fourteen participants with cLBP and fourteen healthy participants performed a 120 s force matching task with their trunk extensor muscles at a low intensity. Results: When visual feedback of the generated force was provided, both groups performed the task accurately. Removal of visual feedback resulted in an increase in error for both groups (p < 0.0001), but the increase in error was significantly larger for the cLBP group (p = 0.023). This larger error could be attributed to undershooting of the target force (p = 0.020). The control group did not consistently undershoot or overshoot the target force (p = 0.93). Furthermore, the amount of undershooting for the cLBP group increased as the task progressed (p = 0.016), which was not observed for the control group (p = 0.80). Conclusions: The results of this study revealed that sense of effort is affected in cLBP. People with cLBP overestimated the trunk extension force they generated, and the error increased as the trial progressed. With visual feedback however, people with cLBP were able to compensate and perform the task as accurately as people without cLBP.

Highlights

Proprioception encompasses different senses, such as detection of joint position and movement, sensation of force and heaviness accompanying muscle contractions, and sensations related to descending motor commands (Proske and Gandevia, 2012)
There were no significant differences between the participants with and without chronic LBP (cLBP) for age, height, body weight, body mass index and level of physical activity during work, sport or leisure (Table 1)
For the cLBP group, the mean level of pain was mild on the day of testing and moderate when at its worst (Jensen et al, 2003)

Summary

Introduction

Proprioception encompasses different senses, such as detection of joint position and movement (kinaesthesia), sensation of force and heaviness accompanying muscle contractions, and sensations (e.g., effort) related to descending motor commands (Proske and Gandevia, 2012). Proprioceptive deficits in people with low back pain (LBP) have traditionally been attributed to altered paraspinal muscle spindle afference and its central processing. Objectives: To better understand proprioceptive deficits in people with chronic LBP (cLBP), this study aimed to test whether sense of effort is affected in people with cLBP. Results: When visual feedback of the generated force was provided, both groups performed the task accurately. Removal of visual feedback resulted in an increase in error for both groups (p < 0.0001), but the increase in error was significantly larger for the cLBP group (p = 0.023) This larger error could be attributed to undershooting of the target force (p = 0.020). People with cLBP were able to compensate and perform the task as accurately as people without cLBP

Objectives

Methods

Results

Conclusion