Altered proprioceptive weighting and trunk muscle activation in individuals with recurrent low back pain: a cross-sectional study.

BACKGROUND

Individuals with low back pain (LBP) rely more on ankle proprioception and have a reduced capacity for upweight proprioceptive feedback from the paraspinal muscles. However, whether this impairment persists during low-symptom phases in patients with recurrent LBP remains unclear. Individuals with recurrent LBP show different patterns of trunk muscle activation when performing lifting tasks. However, little is known about the association between trunk muscle activation patterns during lifting tasks and proprioceptive weight changes during postural control tasks. We aimed to compare proprioceptive weighting between individuals with recurrent LBP and healthy controls and examine the relationship between proprioceptive weighting and trunk muscle activation patterns during a lifting task.

METHODS

Twenty-five patients with recurrent LBP and 20 healthy controls were recruited. Electromyography (EMG) was employed to assess the onset time, EMG amplitude, and overall activity of trunk muscles during the lifting task. Proprioceptive postural control was evaluated by applying vibrations to the triceps surae or lumbar multifidus muscles while participants stood on an unstable force plate, and the relative proprioceptive weighting (RPW) was determined. Differences in muscle activation patterns during the lifting task and RPW in the proprioceptive postural control test were compared between both groups. The relationship between RPW during the proprioceptive postural control test and the pattern of trunk muscle activation during a lifting task was assessed.

RESULTS

RPW values were significantly higher in the recurrent LBP group than in the healthy control group (p = 0.03). During the lifting task, the onset of muscle activation in the multifidus, erector spinae, and transversus abdominis/internal oblique muscles was significantly delayed in the LBP group (p < 0.001), whereas the overall trunk muscle activity was higher (p = 0.04). RPW in the proprioceptive postural control test was significantly and positively correlated with the onset of multifidus activity during the lifting task in individuals with recurrent LBP (r = 0.41, p = 0.04).

CONCLUSIONS

Individuals with recurrent LBP demonstrate a reduced ability to upweight proprioceptive feedback from the paraspinal muscles and tend to rely more on ankle proprioception. The reduced ability to utilise proprioceptive feedback from the paraspinal muscles is associated with delayed activation of the multifidus muscle during lifting tasks.