Volume 12, Issue 4, Pages 267-273 (December 2005) Back extensor muscle oxygenation and fatigability in healthy subjects and low back pain patients during dynamic back extension exertion  Markku Kankaanpää, Willy N. Colier, Simo Taimela, Christoph Anders, Olavi Airaksinen, Satu-Mari Kokko-Aro, Osmo Hänninen  Pathophysiology  Volume 12, Issue 4, Pages 267-273 (December 2005) DOI: 10.1016/j.pathophys.2005.09.013 Copyright © 2005 Elsevier Ireland Ltd Terms and Conditions

Fig. 1 (a) The DBC110 back extension exercise unit where the 90s repetitive back extensions were performed up to 90s with the load that was calculated on the basis of upper body mass. (b) The bipolar EMG electrodes and NIRS optodes were placed on the L4–L5 spinal level. The optode locations are indicated with ×. The EMG electrodes were placed bilaterally and NIRS optodes on the right side over the paraspinal muscles. Pathophysiology 2005 12, 267-273DOI: (10.1016/j.pathophys.2005.09.013) Copyright © 2005 Elsevier Ireland Ltd Terms and Conditions

Fig. 2 The relationship between the paraspinal muscle oxygenation during the endurance test and subcutaneous tissue thickness are better described by quadratic (R2=0.542) than linear (R2=0.360) fitting. The detection depth of the NIRS seems to be limited to about 9mm in this experimental set up. Pathophysiology 2005 12, 267-273DOI: (10.1016/j.pathophys.2005.09.013) Copyright © 2005 Elsevier Ireland Ltd Terms and Conditions