Reference change limits of the paraspinal spectral EMG in evaluation of low back pain rehabilitation.

Year: 1998  Country: Finland   Study Population: 15 chronic back pain patients/14 healthy females

Kankaanpää M, Taimela S, Airaksinen O. Reference change limits of the paraspinal spectral EMG in evaluation of low back pain rehabilitation. Pathophysiology 1998;5(3):217-224.

Objective

To investigate the reference change limits (RCL) of isoinertial back endurance test with EMG spectral mean power frequency compression (MPFslope) as a measure of paraspinal muscle fatigability, and to evaluate how the back extensor muscle endurance changes during the active back rehabilitation. 

Methods

Healthy subjects performed the back endurance test twice on the same day. 

Back pain patients participated in a 10-week active rehabilitation aiming to restore the endurance of lumbar muscles. Endurance test was performed before and after the rehabilitation program (L5-S1 level paraspinal MPFslope). 

Other outcomes: Pain, functional disability and Isometric test with spectral EMG
(MPFtest). 

Outcome

The correlation between the repeated measurements of MPFslope on the left and right side of the spine, and for their pooled data was 0.89–0.94 (P<0.001). The positive RCL with 90% confidence interval for pooled MPFslope (left and right side combined) was found to be 4.5% decrease min−1. 

Pooled paraspinal MPFslope improved during rehabilitation (P<0.05) indicating improved lumbar paraspinal muscle endurance. More specifically, MPFslope improved in ten CLBP patients (P<0.05), and in eight patients the change was significant (exceeded the positive RCL). Pain and functional disability decreased during the rehabilitation (p<0.05).

MPFtest and MPFslope were closely associated (r=0.84-0.91, p<0.001) indicating that spectral EMG calculation is valid during the isoinertial back endurance test.