Intramuscular oxygenation of exercising trunk muscle in elderly persons

We evaluated the relative changes in tissue oxygenation during and after exercise in human lumbar muscle using near-infrared spectroscopy. Oxygenation changes in the trunk muscle were measured non-invasively using near-infrared spectroscopy (NIRS). The subjects analyzed were 111 volunteers over 60 year-old, comprised of two groups; the low back pain (LBP) group who complained of low back pain lasting more than 3 months and the non-LBP group who had no complaints of back pain. A near-infrared spectrophotometer was applied on the back, while maximally extending and bending the lumbar spine for 15 seconds, and isometric exercise in a standing position for 10 seconds. On lumbar extension, the amount of relative change in oxygenated hemoglobin (Oxy-Hb) and the tissue oxygen saturation index (SdO2) were significantly less in the LBP group than in the non-LBP group. No significant differences in deoxygenated hemoglobin (Deoxy-Hb) were found between the two groups on both extension and flexion. Relative changes of Deoxy-Hb and SdO2 were significantly higher in the LBP group than in the non-LBP group. The increase of Oxy-Hb during lumbar extension is conceived as the most available parameter in NIRS measurements, taking into account the performance of exercise even in patients with severe low back pain.